OSTEOPOROSIS
Definitions
- Osteoporosis
is a generalized decrease in bone tissue mass even though the ratio of
mineral (calcium and phosphorus) to organic elements (protein and
collagen) is unchanged in the remaining morphologically normal bone.
- It
is defined by the World Health Organization (1991) as a systemic disease
characterized by low bone mass and micro-architectural bone tissue
deterioration, leading to enhanced bone fragility and increased fracture
risk.
- From
a practical standpoint, osteoporosis is defined as a t score on a DEXA
scan of less than -2.5. Osteopenia
is defined as a t score between -1 and -2.5. This term was
coined by the World Health Organization in 1992. The t score is a
statistical measure which compares the bone density of the individual
with the average bone density of a 20-29 year old female. The
number actually refers to the number of standard deviations from the
mean; it is not an absolute number. A t score of -1 signifies
a 10% to 12% loss of bone mass.
- The
reason this number (the t score) is important is because it allows us to
predict the risk of fracture. Bone density measurement predicts
fracture risk as well as blood pressure measurement predicts stroke risk,
and better than cholesterol level predicts heart attack risk - fracture
risk is approximately doubled for each standard deviation decrement in
bone density.
- Primary
osteoporosis (no identifiable cause) must be differentiated from
secondary osteoporosis due to glandular problems such as
hyperparathyroidism, Cushing's syndrome, hypogonadism,
and hyperthyroidism; cancer such as multiple myeloma; and
gastrointestinal problems such as celiac disease, and malabsorption.
Blood tests (PTH, TSH, dexamethasone
suppression, testosterone, SPEP), stool tests (fecal fat), and urine
tests (24 hour calcium) can all be helpful in distinguishing primary from
secondary osteoporosis. Suspect secondary osteoporosis if the Z
score, which compares the bone density of the individual to the bone
density of a healthy age and sex matched control,
is less than -2.
- Osteomalacia, a much rarer disease caused by defective
calcification of bone, also causes decreased bone density. Osteomalacia causes soft bone; osteoporosis causes
brittle bone. These two conditions can be definitively differentiated only
by a bone biopsy, but abnormal blood tests (i.e. calcium, phosphorous,
alkaline phosphatase, 25 hydroxy vitamin D) can
point toward a diagnosis of osteomalacia.
Even though the interpretation of a DEXA scan refers to osteoporosis when
the bone density is low, the DEXA scan cannot actually
differentiate between osteomalacia and
osteoporosis.
- Bone
is morphologically divided into trabecular (cancellous) bone and cortical (compact) bone. Trabecular bone is more metabolically active and
therefore estrogen deficiency leads to more rapid loss. 80-85% of the
skeleton is cortical bone. The spine is 65-75% trabecular
bone, the heel is >75% trabecular bone, but
the hip is only 25-50% trabecular bone, and the
wrist is only 25% trabecular bone.
The staggering statistics (in the U.S.)
- Based
on NHANES III (1988 - 1994) DEXA data and the most recent census data,
there are 4 - 6 million women and 1 - 2 million men with osteoporosis, and
13 - 17 million women and 4 - 9 million men with osteopenia.
In women over age 50, these numbers translate into prevalence statistics
of 13% to 18% of women over age 50 with osteoporosis and up to 50% with osteopenia (J
Bone Miner Res. 1997. 12. 1761-1768 as cited in Arch Intern Med. 2004. 164. 1047-1048)
- Primary
osteoporosis affects 1 in 4 women over age 65.
- 1,200,000
fractures/year are attributed to osteoporosis.
- 25% of
women over age 50 will sustain a vertebral compression fracture. 80% are
associated with acute pain.
- 1/3 of
women and 1/6 of men over age 65 will sustain a hip fracture. 24% 1 year
mortality (Mayo Clin
Proc. 2001. 76. 295-298). Annual death toll is 50,000.
- At age
50, a white woman has a 40% lifetime chance of experiencing a fracture
related to decreased bone mass (J
Bone Miner Res. 1992. 7. 1005-1010); the lifetime risk of hip fracture
is 17% (Osteoporos Int. 1992. 2. 285-289).
- Each
year in the United States,
there are approximately 250,000 hip fractures, 240,000 wrist fractures,
and 500,000 vertebral compression fractures – the cost of treating
osteoporotic fractures in the U.S. in 2005 estimated at
$16.9 billion/year.
- One in
five patients with a hip fracture dies within a year of the fracture, and
50% fail to regain prefracture mobility and
independence.
- For
women, the lifetime risk of dying of hip fracture is the same as the
lifetime risk of dying of breast cancer.
- Men
over age 50 are at greater risk for osteoporosis-related fracture than
they are for prostate cancer.
- Osteoporosis-related
disability in one study in Switzerland
was associated with more inactive days in bed than stroke, myocardial
infarction, breast cancer, or COPD.
Other pertinent statistics (Cleve Clinic J Med. 2002. 69. 964-976)
- Aging
has a marked effect on the risk of falls; the yearly risk increases from 1
in 5 in the 60-64 age bracket to 1 in 3 in the 80-84 age bracket.
- NHANES
III found that "only" 42% of women age 80-84 have a t score
lower than -2.5 in the femoral neck - osteoporosis is thus not ubiquitous
in this age group.
- Celiac
disease is present in as many as 10% of premenopausal women with
idiopathic osteoporosis, based on a report in which 10.1% of 89
premenopausal women tested positive for celiac disease by antiendomesial antibody testing (Clin Rheumatol. 2005. 24. 239-243).
- The
contribution of low bone mass to hip fracture risk declines with age as
the contribution of falls increases
- Data
from the Rotterdam
study indicate that the risk of hip fracture in a 58 year old with a
femoral neck bone density of 0.5 g/cm2
has a one year risk for hip fracture of 0.5% whereas a 90 year old with
the same bone density has a one year risk of hip fracture of 5%.
- In
patients younger than age 65 in the lowest quartile of Singh grade (i.e.
the most osteoporotic), the risk of hip fracture is 33 times the risk in
the least osteoporotic patients; over age 85 the most osteoporotic are at
only 5 times the risk of the least osteoporotic.
- Only
about half of all hip fractures occur in patients with t scores lower
than -2.5.
- Bisphosphonate
medications are most effective at preventing hip fractures in the subset
of women with osteoporosis and previous vertebral compression fractures.
Other pertinent information
- Data
(i.e. autopsy data) would indicate that osteoporosis is a 20th
Century phenomenon.
- Bone
is dynamic, living tissue, composed of an organic component as well as an
inorganic component.
- Mineral crystals known as hydroxyappetites make up about 1/2 – 2/3 of
bone mass.
- The
remaining 1/3 – 1/2 of bone mass consists of living cells and type
1 collagen fibers (derived from
protein) that form a matrix referred to as ‘ground
substance.’
- Bone
is constantly remodeling and repairing microscopic damage. 25% of trabecular bone and 3% of cortical bone is remodeled
annually.
- Osteoblasts
make new bone and osteoclasts cause bone resorption.
- Osteoblasts
make new bone and osteoclasts cause bone resorption.
- Osteoporosis occurs when bone resorption exceeds bone formation (most of the time,
we don't understand why this happens).
- Bone
loss averages 1% per year after age 35; increased to 2% per year for 5-10
years after menopause.
- Vitamin and mineral intake from our food
is likely much less than it was a century ago in well nourished
individuals
- Refined
grains have far less vitamins and minerals than whole grains.
- Current
farming techniques deplete the soil of many key minerals.
- Food preservatives such as EDTA may
interfere with absorption of vitamins and minerals.
- Industrial chemicals such as hydrazines and hydrazides
can interfere with metabolism of vitamins and minerals.
Unanswered questions
- Ann Intern Med. 2004. 140. 153-156
o
While bone density clearly predicts fracture
risk in untreated patients, it is unclear whether it predicts fracture risk in
treated patients. Bone density is a surrogate marker for bone strength,
and available data suggests that current pharmacologic treatments have similar
effects on vertebral fracture reduction independent of their effects on bone
density.
o
Unclear for how long to continue treatment and
whether long-term pharmacologic treatment may in fact have risks which exceed
benefits.
o
Unclear
for how long reductions in fracture risk persist after discontinuation of
pharmacologic treatment.
- Am J Med. 2008. 121. 744-747
- Mechanism
of action of bisphosphonates is incompletely
understood
§
Mathematical modeling indicates that only 16-28%
of preventative action of alendronate and risendronate against fractures is attributable to the
increase in bone mineral density (Stat
Med. 2001. 20. 3175-3188).
§
This means that weekly or monthly administration
of bisphosphonates may not be as effective at
reducing fractures as daily administration, because the available data on
weekly or monthly administration uses BMD as a surrogate endpoint.
- As
of 2008, there are no comparative studies of the effectiveness of the various
bisphosphonates.
- If
a fracture occurs after 6 months on a given pharmacologic treatment, no
data on whether the pharmacologic agent should be changed.
- There
is no data on whether combination treatments are more effective than
monotherapy.
- The
effect of treatment with strontium ranelate or bisphosphonates on subsequent treatment is unknown.
- Still
unclear for how long reductions in fracture risk persist after
discontinuation of pharmacologic treatment (i.e. therapeutic window).
- There
is no data on safety and efficacy after more than 10 years of
pharmacologic treatment.
Risk factors for osteoporosis
- Aging
- Being
thin
- Genetic
influences: Asian, Caucasian, female, family history, osteogenesis
imperfecta, homocystinuria,
Marfan’s syndrome
- Endocrine
influences: decreased levels of estrogen or testosterone (i.e. hypogonadism), hyperthyroidism, Cushing’s
syndrome, hyperparathyroidism
- Nutrition:
low calcium intake, low protein intake, excessive alcohol intake,
excessive caffeine intake, excess (synthetic) vitamin A intake, possibly
excessive soda intake (phosphoric acid), malabsorption, vitamin D
deficiency
- Lifestyle:
immobility, cigarette smoking
- Medications:
aluminum containing antacids, anticonvulsants, aromatase inhibitors, cytotoxic drugs, estrogen-blockers (i.e. medroxyprogesterone acetate injection for
endometriosis, tamoxifen), furosemide
(Lasix),
glucocorticoids, GnRH
agonists, heparin, immunosuppressants, lithium, proton pump inhibitors,
SSRI and SNRI medications, thiazolidinediones
(TZs), and thyroid replacement (supra-physiologic doses)
- Associated
diseases: AIDS, amyloidosis, ankylosing
spondylitis, anorexia nervosa, celiac disease,
cirrhosis, COPD, depression (Arch
Intern Med. 2007. 167. 2329-2236), hemochromatosis,
hepatitis (chronic), inflammatory bowel disease, mastocytosis,
multiple myeloma, multiple sclerosis, rheumatoid arthritis, SLE, and
stroke.
- High
homocysteine
- The
hypothesis that homocysteine may be a risk factor was suggested by data
showing that individuals with homozygous homocystinuria
have a high incidence of osteoporosis and premature fractures (Am J Hum Genet. 1985. 37. 1-31).
- From
a mechanistic standpoint, homocysteine inhibits collagen cross linking (Biochim Boiphys Acta. 1996. 1315. 159-162) and impairs bone
mineralization (Bone. 2001. 28.
387-398).
- Large
epidemiologic studies in elderly men and women show a correlation between
elevated homocysteine and osteoporotic fractures, independent of bone
mineral density (N
Engl J Med. 2004. 350. 2033-2041; N Engl J Med. 2004. 350. 2042-2049).
- Common
variant in the MTHFR gene (which leads to increased homocysteine levels)
is associated with lower bone mineral density and increased fracture risk
in postmenopausal women (Calcif
Tissue Int. 2000. 66. 190-194; J Bone Miner Res. 2003. 18.
723-9).
- Reduction
in hip fracture risk following stroke in the group treated with vitamin
B12 1.5 mg daily and folate 5 mg daily suggests that elevated
homocysteine is causally related to osteoporosis. This study was
conducted in 628 elderly Japanese with residual hemiplegia,
and the number of hip fractures per 1000 patient years was reduced from
43 in the control group to 10 in the treatment group. This represents a
7.1% absolute decrease in risk of hip fracture, for a number needed to
treat of 14 to prevent one hip fracture (JAMA. 2005. 293. 1082-1088).
- In
the Hordaland Homocysteine Study in which bone
mineral density was measured in 2268 men and 3070 women, plasma
homocysteine was inversely related to bone mineral density in middle-aged
and elderly women (p<0.001) but there was no relationship in men (Arch Intern Med. 2006. 166.
88-94).
- Systemic
inflammation
- Diseases
such as rheumatoid arthritis and Crohn’s disease and multiple
sclerosis appear to be independent risk factors for osteoporosis.
- Decreased
estrogen leads to increased inflammatory cytokines and decreased bone
density (J Endocrinol
Invest. 2002. 25. 684-690).
- In
women more than 10 years post menopause, IL-6 levels predicted femoral
bone loss (J Clin
Endocrinol Metab.
2001. 86. 2032-2042).
- Trends
toward greater spinal bone loss were observed in women with high cytokine
production (Calcified Tissue Int.
1998. 63).
- Low
antioxidant status
- Mechanism
- free radicals are used by osteoclasts to “chisel away at older
bone” and excess free radicals can thus lead to excess bone resorption (Clin Chim Acta. 2002. 318.
145-148).
- Low
levels of plasma antioxidants correlated with increased osteoporotic risk
in a cross sectional study (J Clin Endocrinol Metab. 2003. 88. 1523-1527).
- Dietary
lycopene with vitamin C > 500 mg/day reduces
oxidative stress based on serum markers and decreases bone turnover
(Presentation at 2005 Meeting of the American Society for Bone and
Mineral Research).
- Probably
exposure to certain heavy metals, including aluminum, cadmium, lead, and
tin.
- Aluminum
is present in many antacids, cookware, beverage cans, and some tap water
supplies. Aluminum soda cans are probably a worse culprit than aluminum
beer cans because the acidity of the soda is likely to cause more
aluminum from the can to dissolve in the beverage.
- Cadmium
is present in cigarette smoke, motor oil, tires, galvanized parts of
motor vehicles, and is used in the manufacturing of batteries,
fertilizers, paints, plastics, and textiles.
- Even
with the elimination of leaded gasoline and reduced use of lead paint,
lead is still ubiquitous in our environment.
- Tin
is present in tin cans for food and beverages, some fungicides and
insecticides, some chemical preservatives (stannous chloride) and some
toothpastes (stannous fluoride).
- Probably
food sensitivities – celiac disease is a risk factor for
osteoporosis; a gluten free diet is associated with reversal of
osteoporosis.
- Probably
acid rain exposure
- Acid
rain increases the acidity of our drinking water. Calcium is leached from the bone to
buffer acidity in the bloodstream.
- More
toxic metals (aluminum, cadmium, lead) are released from rocks,
eventually entering the soil or drinking water supply.
- More
lead from plumbing may be released into drinking water supply by acidic
water in pipes.
- Possibly
a meat and grain based diet which increases acidity as these foods are
metabolized – calcium may be pulled from the bone to neutralize the
pH in the bloodstream. In a RCT in 161 women with osteopenia,
oral potassium citrate, 30 mEq/day, which
produced systemic alkalinization, led to
significant improvements in bone mineral density (J Am Soc Nephrol. 2006. 17.
3212-3222).
- Possibly
hypochlorhydria – Dr. Jonathan Wright has observed that
hypochlorhydria is common in osteoporosis, using Heidelberg testing to establish a
diagnosis of hypochlorhydria. A small clinical trial in 42 young adults
with “alveolar bone resorption” and
37 controls found decreased acidity by gastric analysis in those with bone
resorption (Proc
Soc Exp Biol Med. 1941. 48. 98).
- Possibly
excess fluoridation of the water supply – a study of 3777
individuals living in 75 different parishes in southwestern France showed
that the risk of hip fracture was 86% higher when water fluoride level was
above the median (0.11 mg/liter), as compared to the group in which the
water fluoride level was below the median (JAMA. 1995. 273. 775-776).
Diagnosis of
low bone density
- X
ray: 20-30% bone loss is necessary before X rays show osteopenia,
so X rays are not very sensitive.
- Dental
X rays: Mandibular inferior cortical shape on
dental panoramic X rays may be an indicator of bone turnover, with
sensitivity and specificity not currently known (J Bone Mineral Res. 2003. 210. 1689).
- Bone
mineral density measurement is definitive (bone densitometry was invented
by dentists in 1897)
- Single
photon absorptiometry - measures bone density
at the wrist. This is not very useful because this does not correlate
well with hip fracture or vertebral compression fracture risk.
- Dual
photon absorptiometry - measures bone density
at the hip. This is a 20 minute test which costs $150-$250. The radiation
exposure is less than that associated with a chest X ray, about 1/10 of
the average yearly total environmental exposure.
- Quantitative CT
- good measure, but 50-75 times the radiation exposure of dual photon absorptiometry.
- Dual
energy X ray absorptiometry (DEXA) - less
expensive than dual photon absorptiometry
($100-$150), and scan time is only 5-10 minutes. This is the diagnostic
test of choice. This came into
widespread use in the 1980s.
- Note
this is a stronger predictor of fracture risk in white women than
African American women, based on a prospective cohort study in 7334
white women and 636 African American women with 6.1 years of follow up (JAMA. 2005. 293. 2102-2108).
- Note
that African American women have a 30-40% lower fracture risk than white
women at every level of bone mineral density, based on a prospective
cohort study in 7334 white women and 636 African American women with 6.1
years of follow up (JAMA.
2005. 293. 2102-2108).
- Ultrasound
of the calcaneus.
- Do
the test only if it will change treatment.
- OST
index: 0.2 x (weight in kilograms - age in years). If value is 2 or
higher, no need to do DEXA scan.
- USPSTF
guidelines - screen women at age 65 in the absence of risk factors, at
the age of 60 with risk factors.
- Medicare
does cover the cost of a screening DEXA in women as of 2002.
Relationship between low bone mineral density and
fractures
- Bone density is a strong predictor of
fracture risk, just as HTN is a predictor of stroke risk and just as high
cholesterol is a predictor of MI risk.
- However, the majority of fractures occur
in individuals without osteoporosis by bone mineral density measurement
(i.e. T score < -2.5).
- In a longitudinal observational study
in which bone mineral density tests were conducted at peripheral sites in
postmenopausal women, at 12 months of follow up, 82% of women who
reported a fracture of the wrist, forearm, hip, rib, or spine had a T
score < -2.5, and 67% has a T score < -2.0 (Arch Intern Med. 2004.
164, 1108-1112).
- A study examining the 10 year risk of a
fracture of the hip, spine, forearm, or proximal humerus
in a 50 year old woman concluded that at 10 years, 96% of all fractures
in these locations will occur in women with a T score < -2.5 (Bone. 2002. 30. 251-258).
- The North American Menopause Society
(NAMS) in a 2006 position statement concluded that “fracture risk
depends largely on factors other than BMD” (Menopause. 2006. 13. 340-367).
- The WHO provides a free online tool for
estimating fracture risk named FRAX – this takes into account the
bone mineral density (BMD) as well as numerous of the risk factors listed
just above in this outline. www.shef.ac.uk./FRAX/index.
Osteoporosis treatment
- Calcitonin (subcutaneous injections or nasal spray), SERMs (Evista), oral bisphosphanates (Fosomax, Actonel, Boniva), PTH, +
fluoride
- Neither
calcium nor estrogen significantly reverses established osteoporosis.
Osteoporosis prevention
- Lifestyle
measures
- Alcohol
in moderation – 1-2 alcoholic beverages per day
- Caffeine
in moderation – 2-6 caffeinated beverages per day
- NOTE
adequate calcium intake may protect against caffeine-induced bone loss (Am J Clin Nutr. 1994. 60. 573-578).
- NOTE
black/green/oolong tea may be protective against osteoporosis, based on
epidemiological data.
- Limit
exposure to aluminum, cadmium, lead, and
tin
- Sources
of aluminum include pots and pans, aluminum foil, toothpaste tubes,
antacids, beverage cans, food additives, and tap water.
- Sources
of cadmium include emissions from factories as cadmium is used in the
manufacturing of many products, cigarettes and car exhaust fumes.
- Sources
of lead include industrial lead aerosols, leaded paint, and in the past
car exhaust fumes.
- Sources
of tin include as a chemical preservative (stannous chloride),
toothpaste (stannous fluoride), industrial emissions, and beverage cans.
- Limit
salt intake – sodium induces increased urine excretion of calcium
- Limit
sugar intake – sugar ingestion may deplete our bodies of calcium
and raise cortisol levels
- Lycopene intake – dietary lycopene
intake may work synergistally with vitamin C to
reduce bone turnover (Presentation at 2005 Meeting of the American
Society for Bone and Mineral Research).
- Moderate
dietary protein intake – despite conventional wisdom that high dietary protein intake can
increase urinary calcium losses and theoretically increase the risk of
osteoporosis (calcium balance is detrimentally affected by an increased
intake of purified proteins),
published data would suggest that it is actually low protein intake,
which is associated with inadequate intake of phosphorous, which can
increase the risk of osteoporosis.
- A
4 year study examining changes in bone density in 391 women and 224 men
from the population-based Framingham Osteoporosis Study. Even after
controlling for known confounders including weight loss, women and men
with relatively lower protein intake had increased bone loss, suggesting
that protein intake is important in maintaining bone or minimizing bone
loss in elderly persons. Further, higher intake of animal protein does
not appear to affect the skeleton adversely in this elderly population.
In this study, usual dietary protein intake was determined using a semiquantitative food frequency questionnaire (FFQ)
and expressed as percent of energy from protein intake (J Bone Miner Res. 2000. 15.
2504-2512).
- A
study in thirty-two subjects with usual protein intakes of less than
0.85 g/kg.d who were randomly assigned to
daily high (0.75 g/kg) or low (0.04 g/kg) protein supplement groups
found that changes in urinary calcium excretion in the two groups did
not differ significantly over the course of the study. Furthermore, the
high protein group had significantly higher levels of serum IGF-I (a
bone growth factor) and lower levels of urinary N-telopeptide
(a marker of bone resorption). In this study, Isocaloric diets were maintained by advising
subjects to reduce their intake of carbohydrates (J Clin Endodrinol
Metab. 2004. 89. 1169-1173).
- In
a study in 15 healthy postmenopausal women who consumed diets with
similar calcium content (approximately 600 mg), but either low or high
in meat (12 vs. 20% of energy as protein) for 8 wk each, in a randomized
crossover design, a high meat compared with a low meat diet for 8 wk did
not affect calcium retention or biomarkers of bone metabolism (J Nutr.
2003. 133. 1020-1026).
- The
type of protein consumed may be very important - women with a higher
animal protein intake have a greater 7-y rate of bone loss at the
femoral neck (p=0.02) and an adjusted RR of 3.7 for fracture (p=0.04) v.
women with high vegetable protein intake (Sellmeyer
DE et al. Am J Clin
Nutr. 2001. 73. 118).
- Smoking
cessation
- Tai
chi
- Reduces
the risk of falling
- Reduces
the risk of falling in the elderly by 47.5%, based on a RCT in 200
subjects over age 70, in which treatment subjects met with an
instructor twice a week for 20 minutes, and were encouraged to practice
on their own for 15 minutes twice a day (J Am Geriatr Soc. 1996. 44. 489).
This study in 2003 was named by the American Geriatric Society as the
best research paper from the 1990’s, and was republished (J Am Geriatr
Soc. 2003. 51. 1794-1803).
- Reduces
the risk of falling in the elderly, based on a RCT in 256 physically inactive
subjects over age 70. The treatment group attended one hour classes 3
times a week for 6 months, and those in the tai chi group had 55% fewer
falls (p=0.007). Repeat assessment 6 months after completion of the
study showed that group differences with regard to falls persisted
(p<0.001) [J Gerontol A Biol Sci Med Sci. 2005. 60. 187-194].
- Reduces
the number of falls among healthy elderly, based on aggregate data from
5 RCTs (Altern Ther
Health Med. 2011. 17[1]. 40-48).
- Improves
balance in older adults, based upon data from 13 RCTs (Altern Ther
Health Med. 2011. 17[1]. 40-48).
- Tai
Chi and prevention of osteoporosis
- A
systematic review article of 5
RCTs and 2 controlled clinical trials concludes that clinical trial
data is not convincing with regard to showing benefit (Osteoporosis Int. 2008. 19.
139-146).
- Reduced
rate of bone loss was seen in one study - a 12 month RCT in 132
postmenopausal Chinese women who practiced tai chi an average of 4.2
times per week. There were also fewer fractures in the tai chi group,
possibly due to fewer falls from improved balance (Arch Phys Med Rehab. 2004. 85. 717-722).
- For
more information on tai chi, return to Home Page and go to the
Complementary Modalities and/or Exercise outline and scroll to near the
bottom.
- Weight
bearing exercise
- Walking
one mile/day reduces rate of bone loss; it is unclear how much extra
benefit is derived from strenuous exercise.
- In
a RCT in 246 women age > 65, those assigned to the 18 month exercise
program showed significantly improved bone mineral density and a reduced
fall risk (Arch Intern Med.
2010. 170. 179-185).
- Extended
follow up, mean of 7.1 years, in 160 women, aged 70-73 at baseline,
enrolled in a RCT of a home exercise program showed that showed that
“home-based exercises followed by voluntary home training seem to
have a long-term (beneficial) effect on balance and gait, and may even
protect high-risk elderly women from hip fractures” (Arch Intern Med. 2010. 170.
1548-1556).
- Too
much exercise (i.e. enough to cause amenorrhea, which is the loss of
menstrual periods) is bad in pre-menopausal females
- Weight
training (also increase muscle mass, so a fracture is less likely with a
fall, and improves balance so that falling is less likely to occur).
- Whole
body vibration (Self Healing.
8/09. Pg. 4)
- These
machines in 2009 are in some health clubs and available for home
purchase (cost ranging from a few hundred dollars to a few thousand
dollars) look similar to a treadmill, but in place of a moving belt is a
platform that oscillates at a calibrated frequency between 5 and 45 Hz.
- Mechanism
of action uncertain in 2009; some published data showing use is
associated with increased bone density, increased muscle strength and
improved balance.
- May
be a good alternative to aerobic exercise and weight training for older
individuals or those with functional limitations interfering with
ability to exercise or weight train.
- Supplements
– see details below
- Boron
- Calcium
- Copper
- Folate
- Genistein
- Ipriflavone
- Magnesium
- Manganese
- Phosphorous
- Potassium
- Silicon
- Soy
protein
- Strontium
- Vitamin
B6
- Vitamin
B12
- Vitamin
C
- Vitamin
D
- Vitamin
K
- Zinc
- Medications
- Thiazide diuretics (prescription) based on several
epidemiologic studies and a prospective cohort study (Ann Intern Med. 2003. 139.
476-482).
- Beta-blockers
based on animal data and a case control study (JAMA. 2004. 292.
1326-1332).
- Hormones
- Estrogen
- effectiveness of estrogen well documented in controlled clinical
trials, but due to new data on harms, risk generally outweighs benefit
for the indication of osteoporosis prevention.
- Low
dose estrogen may be an option for which the risk/benefit ratio is
acceptable – in one 3 year trial, 0.25 mg/day of 17-beta-estradiol
(1/4 of the standard dose) was associated with increased bone density of
the hip, spine, and total body (JAMA.
2003. 290. 1042-1048).
- For
full details on risks and benefits of estrogen, return to Home Page and
click on Menopause.
- Progesterone
- Most
trials of progesterone have used estrogen plus progesterone together.
- Dr.
John Lee has published data on improvement in BMD in 100 women using a
3% progesterone cream 12 consecutive nights per month for 3 years (Int Clin Nutr Rev. 1990. 10. 384-391; Med Hypotheses. 1991. 35.
316-318). His positive results have not been replicated.
- NEGATIVE
study – a RCT of 102 women within 5 years of menopause, using 20
mg of topical progesterone daily. After 1 year, bone mineral density
(BMD) of the lumbar spine and hip were equal in the placebo group and
the topical progesterone group (Obstet Gynecol.
1999. 94. 225-228).
- Testosterone
- May
be beneficial in men on prescription corticosteroids, based on a trial
in 15 asthmatics (Arch Intern Med.
1996. 156. 1173-1177).
- May
be beneficial in men with low free testosterone serum levels, based one
trial in 36 men ((J Clin Endocrinol Metab. 1996. 81. 4358-4365) and another trial in
48 men (J Clin
Endocrinol Metab.
2004. 89. 503-510).
- Risks
of treatment with testosterone are not well defined.
- DHEA
– well tolerated in various clinical trials, but risks are not well
defined, especially with regard to men and women with hormone dependent
conditions (BPH, prostate cancer, endometriosis, fibroids, breast cancer,
ovarian cancer) [Alt Med Alert.
2007. 10. 13-17].
- In
a 2 year RCT in 58 women (aged 65-75), 50 mg/day (in conjunction with
640 IU/day vitamin D and 700 mg/day calcium), mean lumbar BMD increased
1.9% at one year and 3.6% at 2 years in the treatment group; hip BMD did
not change. No benefit though in the 55 men aged 65-75, analyzed
separately (Am J Clin Nutr. 2009. 89.
1459-1467).
- In
a 2 year RCT in 87 elderly men and 57 elderly women with low DHEA-S, the
29 men on DHEA showed statistically significant, but very little
improvement in BMD of the femoral neck, with no significant change in
BMD of the lumbar spine or radius; the 27 women showed statistically
significant, but very little improvement in BMD of the radius, with no
significant change in BMD of the lumbar spine or hip (New Engl J
Med. 2006. 355. 1647-1659).
- A
12 month RCT in 70 men and 70 women, aged 60-88, randomized to DHEA 50 mg/day
or placebo found BMD increases of 1% in the hip for men and women, BMD
increase of 2.2% in the lumbar spine in women, with no change in lumbar
spine BMD in men (J Clin Endocrinol Metab. 2006. 91. 2986-2993).
- Several
trials of DHEA in men failed to show an effect on BMD (J Clin Endocrinol Metab.
2002. 87. 1544-1549; Proc Natl Acad Sci U S A. 2000. 97. 4279-4284).
- Several
small trials of DHEA in women have shown a beneficial effect on BMD,
without an adverse effect on the endometrium (J Clin Endocrinol Metab.
1997. 82. 3498-3505; J Endocrinol. 1996. 150. S43-S50).
Boron
- In
one study, 3 mg per day of boron was associated with a 44% reduction in
calcium loss in the urine (Nutrition
Today. Jan/Feb 1988. 4-7).
- Multiple
possible mechanisms of action.
- Reduces
urinary losses of calcium and magnesium.
- Increases
estradiol and testosterone levels.
- May
enhance conversion of vitamin D to biologically active form.
- Food
sources of boron include fruits (especially apples, pears, grapes,
raisins, dates, and peaches), legumes, and nuts.
- Consider
a supplemental dose of 1-3 mg a day.
Calcium
- Total
intake (from diet and supplements) of calcium should be1000-1500 mg
calcium/day.
- The
adequacy of intake can be determined by measuring 24 hour urine calcium.
It should be greater than 100 mg.
- Good
dietary sources include green leafy vegetables, canned sardines and
salmon.
- Milk
products are advocated, but the protein content may offset any benefit of
the calcium in milk. 6 mg of calcium are required to offset the
urinary loss of calcium that occurs with 1 gram of protein intake. For more information on milk product
intake and osteoporotic fracture risk, go back to Home Page and click on
“Nutrition” and scroll down to “Milk.”
- Calcium
supplements
- Calcium
carbonate (40% calcium by weight) is the cheapest. Absorption is
approximately 30% higher if taken with meals. Not absorbed well in
those with achlorhydria. This form has
been shown in studies to prevent bone loss.
- Calcium
hydroxyapatite (25% calcium by weight) may be
more effective than calcium carbonate in slowing postmenopausal bone
loss.
- In
a 20 month RCT in 40 osteoporotic patients, there was statistically less
loss of trabecular bone by quantitative CT in
the group which received 1400 mg per day of calcium in the form of
calcium hydroxyapatite, compared to the group
which received 1400 mg per day of calcium carbonate (Osteoporosis Int. 1995. 5.
30-34).
- In
a 14 month RCT in 64 postmenopausal women with primary biliary cirrhosis, calcium hydroxyapatite
promoted positive cortical bone balance, based on pre- and
post-treatment hand radiographs, using the technique of caliper radiogrammetry to assess changes in metacarpal
cortical thickness (Am J Clin Nutr. 1982. 36.
426-430).
- Calcium
citrate (22% calcium by weight) may be absorbed more easily; this may be
a significant benefit in people over age 60. Absorption is the same
whether taken with food or on an empty stomach. Advisable in place
of calcium carbonate in patients with pernicious anemia, those taking
prescription H2 blockers (Tagamet, Zantac, Pepcid, Axid) or proton
pump inhibitors (Prilosec, Protonix,
Aciphex, Prevacid, Nexium), and those with constipation or bloating
secondary to calcium carbonate. No study data on this form of
calcium and prevention of postmenopausal bone loss.
- Calcium
lactate (13% calcium by weight) may be best absorbed.
- Calcium
triphosphate (38% calcium by weight) may be a
better choice for other forms for postmenopausal women (Mayo Clinic Proc. 2004. 79. 91-97).
- Bone
meal and dolomite (30% calcium by weight) may contain unsafe levels of
lead and other contaminants.
- Contrary
to folk wisdom, calcium supplementation does not increase the recurrence
of calcium oxalate kidney stones. Calcium citrate can actually
reduce the risk for stone formation by reducing urinary saturation of
calcium oxalate and calcium phosphate.
- Although
not proven, some experts believe that calcium supplements are more
effective if taken at bedtime.
- FDA
does not monitor bioavailability of calcium supplements. However,
bioavailability should be good if the label says "Meets USP
Dissolution Standards."
- Home
measure of bioavailability - place tablet in 30 ml white vinegar at room
temperature, stir every 2-3 minutes, expect at least 75% dissolution at
30 minutes.
- If
you take more than 600 mg of supplemental calcium a day, it will be best
absorbed if split into at least two doses.
- There
is good epidemiologic data showing that vegetarians have increased bone
density. The potential explanations for the observed association between
vegetarianism and increased bone density include:
- High
concentration of fat in meat interferes with calcium absorption.
- High
concentration of protein in meat causes increased calcium loss in the
urine.
- High
phosphorus/calcium ratio in meat causes a temporary drop in blood calcium
levels which triggers the parathyroid gland to release PTH (a hormone),
which in turn causes release of calcium from the bone in order to maintain
blood calcium levels. PTH also decreases calcium excretion in the urine -
the calcium from the bone ends up deposited in joint spaces and the walls
of arteries.
- Phytic acid in grains in fact does not inhibit
calcium absorption because the human intestinal tract can adapt and
produce phytase.
- Fiber,
and in particular, bran, can inhibit calcium absorption. With time, the
body seems able to overcome this inhibition.
- Iron
supplements can interfere with the absorption of calcium.
- NOTE
calcium supplementation decreases the absorption of phosphorous, and this may
be an issue in those eating a low protein diet (J Am Coll Nutr.
2002. 21. 239-244). This issue can be addressed by using calcium phosphate
as a supplemental source of both calcium and phosphorus.
- Clinical
studies
- In
a RCT in 36,282 postmenopausal women already enrolled in the WHI, at a
mean follow up of 7 years, those randomized to calcium carbonate 1000
mg/day with vitamin D 400 IU/day had a small but statistically
significant improvement in hip bone density, but no significant reduction
in hip fracture. Note however that women in this study were not
necessarily osteoporotic upon enrollment, greater than 50% of these women
were on HRT, personal use of calcium and vitamin D was permitted, and
when data were excluded for women with less than 80% adherence to
therapy, risk of hip fracture was 0.71 (0.52 – 0.97). Risk of renal
calculi was increased by 17% (New Engl J Med. 2006. 354. 669-683 and 750-752).
- There
were 12% fewer hip fractures in the treatment group, using an
intent-to-treat analysis, but this was not statistically significant.
- In
the subgroup of women compliant with taking the calcium and vitamin D,
there were 29% fewer fractures.
- The
mean intake of calcium from diet and supplements at baseline was 1150 mg
per day! In the subgroup of subjects with low or moderate calcium intake
at baseline, there was a 22% reduction in hip fracture, using an
intent-to-treat analysis.
- A
meta-analysis of 15 RCTs including 1806 patients followed for at least a
year showed that calcium supplementation alone has a small positive
effect on bone density. There was a trend toward reduction in vertebral
fractures, but no data regarding an effect on the incidence of nonvertebral fractures (Endocrin Rev. 2002. 23. 552-559).
- In
a two year trial in 59 postmenopausal women divided into 4 groups, those
who received placebo had a decrease in bone density of the lumbar spine
(-3.53%), those who received calcium citrate-malate
1000 mg a day also had a decrease in bone density (-1.25%), those who
received trace minerals daily (copper 2.5 mg, manganese 5 mg, and zinc 15
mg) had a decrease in bone density (-1.89%), BUT those who received
calcium and trace minerals had an increase in bone density (+1.48%) [J Nutr.
1994. 124. 1060-1064].
- Benefit
seen in a trial using tricalcium phosphate (New Engl J
Med. 1992. 327. 1637-1642).
- In
a 2 year RCT in 301 healthy postmenopausal women, (1) in the subgroup
with less than 400 mg of dietary calcium intake/day at baseline, calcium
citrate malate 500 mg daily prevented bone loss
at the hip, spine, and radius, and calcium carbonate 500 mg daily
prevented bone loss at the hip and radius, but not the spine, whereas (2)
in the subgroup of women with calcium intake of 400-650 mg/day, there
were no differences between the placebo group, calcium carbonate group,
and calcium citrate malate group, with all 3
groups maintaining bone density at the hip and radius, but losing bone
density at the spine (N Engl J Med. 1990. 323. 878-883).
- Consider
a supplemental dose of 500 mg once – twice a day.
Copper
- Copper is essential for the formation of
the collagen component in bone.
- Benefit of small doses is based on test
tube studies, animal studies, and a two year clinical trial in 73 women
who received either 3 mg/day of copper amino acid chelate
or placebo (Proc Nutr
Soc. 1995. 54. 191A).
- Foods rich in copper include eggs, green
leafy vegetables, legumes, nuts, organ meats, poultry, and whole grains.
- Consider a supplemental dose of 2-3 mg a
day; BEWARE that excess ingestion of copper is associated with health risks.
Folate
- Postmenopausal women have a reduced capacity
to metabolize homocysteine, as demonstrated by a study using a methionine load test in premenopausal and
postmenopausal women.
- High
homocysteine levels are correlated with an increased risk of osteoporosis.
- Supplemental folate lowers homocysteine
levels.
- Grains in the U.S. are now fortified with
folate, so folate deficiency is much less common than in the early
1990’s.
- In a study in which the trabecular heads were examined in 94 men and women who
underwent elective hip arthroplasty, histomorphometric analysis showed significantly lower trabecular thickness and trabecular
area in those patients with serum folate below the median, as compared
with those with serum folate above the median, even though BMD was similar
in both groups (Am J Clin Nutr. 2009. 90.
1440-1445).
- The 0.4 mg of folate in a multivitamin
should provide adequate supplementation for most women.
- Folate 5 mg/day along with Vitamin B12
1500 mcg/day markedly reduced the risk of hip fractures in a two year
trial in 628 Japanese patients, mean age 71 years, with residual hemiplegia from a stroke. The number of falls per
person did not differ between the groups. In this study, treatment of 15
people with this regimen of vitamin B12 and folate would prevent one hip
fracture! (JAMA. 2005. 293.
1082-1088).
- Consider a supplemental dose of 1-5 mg a
day if homocysteine is high, and if homocysteine does not decrease,
consider 5-MTHF 400 mcg a day.
Genistein
- This is an isoflavone
phytoestrogens which is abundant in soybean
products, and which structurally resembles 17 beta estradiol (Endocrinology. 1998. 139.
4252-4263).
- Genistein has greater affinity for the estrogen
beta receptor in bone than the estrogen alpha receptor in reproductive
tissue, and thus is a natural SERM.
- Genistein 54 mg/day increased BMD at the lumbar
spine and femoral neck in a short RCT in 90 patients (J Bone Miner Res. 2002. 17. 1904-1912).
- A 24 month RCT in 389 postmenopausal
women with osteoporosis showed that genistein 54
mg/day had positive effects on BMD. Note though that 19% in the genistein group versus 8% in the placebo group
discontinued treatment due to side effects, most often GI side effects
with genistein (Ann Intern Med. 2007. 146. 839-847).
Ipriflavone
- This
is a derivative of a naturally occurring class of isoflavones found mainly
in soy.
- Approved
for treatment of osteoporosis in some European and Asian countries.
- Metabolites
may have direct estrogenic effects, and ipriflavone
thus may potentiate the effect of estrogen.
- Clinical
trial data to date is conflicting:
- Benefit
seen in a 1 year RCT in 105 postmenopausal women who received 600 mg/day
(Gynecol Endocrinol.
1997. 11. 289-293).
- Benefit
seen in a 2 year RCT in 255 postmenopausal women who received 200 mg
three times a day (Osteoporosis Int.
1997. 7. 119-125).
- Benefit
seen in a study with 57 women (mean age 51 years) with osteopenia or osteoporosis randomized to receive ipriflavone 600 mg/day or calcium lactate 800 mg/day
for one year. Lumbar bone mineral density fell 0.8% in the ipriflavone group versus 3.1% in the calcium group (Horm Res. 1999. 51. 178-183).
- However,
in multicenter 4 year study of 474 postmenopausal white women in which
234 received ipriflavone 200 mg 3 times a day
and 240 received placebo (all women received 500 mg/day of calcium), ipriflavone did not prevent bone loss or affect
biochemical markers of bone metabolism (JAMA. 2001. 285. 1482-1488).
- Ipriflavone Multicentre European Fracture Study is an
ongoing 3 year RCT of 460 non-obese postmenopausal women with low bone
density, with vertebral non-traumatic fractures as the primary endpoint,
and changes in bone density as the secondary endpoint.
- May
produce a slowly progressive lymphocytopenia
(in 13% of participants in one study).
- Interactions
with theophylline and coumadin
have been noted.
- Dose
in most in published studies is 200 mg three times a day.
Magnesium
- The
typical American diet contains only 250 mg of magnesium per day, less than
the RDA of 350 mg, and far less than the optimal intake of approximately
600 mg.
- Stress
(physical, chemical, emotional) depletes magnesium.
- Magnesium
deficiency is associated with abnormal calcification of bone, based on
data from a magnesium load test in combination with infrared spectroscopy.
- Clinical
trial data is limited – a two year trial in 31 postmenopausal women
showed an increase in BMD at the end of one year in 22 of the 31 women;
only 10 women completed the entire two year trial (Nutr Rev. 1995. 53. 71-74).
- Beware
that too much supplemental magnesium can cause a fast transit time which
can manifest as diarrhea and also cause malabsorption of other nutrients.
- BEWARE
of excess magnesium intake in chronic kidney disease.
- Consider
a supplemental dose of 300-600 mg a day.
Manganese
- Stimulates
production of mucopolysaccharides, which provide
a structure upon which calcification can take place.
- EDTA,
a common preservative in food, may interfere with absorption of manganese.
- Food
sources of manganese include beans, cereals, oatmeal, nuts, pineapple,
spinach, tea, and whole wheat.
- Consider
a supplemental dose of 5-20 mg a day.
Phosphorous
- Principle anion in bone mineral; the
inorganic hydroxyapatite in bone is composed
primarily of calcium and phosphorous.
- Most
of the population obtains adequate phosphorous from the diet (phosphorous
is plentiful in protein), BUT it is estimated that 10% of women over age
60 and 15% of women over age 80 have a phosphorous intake less than 2/3 of
the RDA.
- Calcium
carbonate and calcium citrate supplements will bind dietary phosphorous
and thus inhibit absorption. A
calcium triphosphate or calcium hydroxyapatite supplement avoids this potential
problem.
Potassium
- Potassium helps regulate calcium absorption.
- High dietary potassium intake is
correlated with higher bone density.
- BEWARE of high potassium intake if
chronic kidney disease is present.
Silicon
- Important in small amounts for bone
health via regulation of bone mineralization and stimulation of type I
collagen synthesis (Bone. 2003.
32. 127-135).
- Recently recognized as an essential
nutrient; unknown whether typical diet includes an adequate amount.
- The most common substance on earth after
oxygen.
- Food sources include rice bran and brown
rice.
- Consider supplemental dose of 1-10 mg a
day; consider supplementing in the form of orthosilicic
acid as silicon must be solubilized into orthosilicic acid in the stomach as a prerequisite to
absorption.
Soy protein (see
also ‘genistein’ and ‘ipriflavone’ above)
- In
one study, a diet containing 40 grams/day of isolated soy protein
significantly increased bone mineral density in the spine when compared to
a control group ingesting a non soy protein diet (J Clin Endocrinol
Metab. 1998. 83. 2223-2235). No benefit
on hip bone mineral density was observed.
- A 24
week study in 48 postmenopausal women showed that the group randomized to
receive 40 gm/day of isoflavone-rich soy protein
isolate showed an increase in BMD, whereas the whey protein control group
showed a loss of BMD (Am J Clin Nutr. 2000. 72.
844-852).
- A
two year study in 89 postmenopausal women randomized to 1 of 4 treatments
showed that those who received 500 ml/day of soymilk, containing 76 mg/day
of isoflavones an increase in spinal BMD, whereas the placebo group had a
loss of BMD (Eur J Nutr.
2004. 43. 246-257).
- A
negative study was a RCT with 202 healthy postmenopausal women aged 60-75
who received either 25.6 grams of soy protein containing 99 mg
isoflavones or total milk protein as placebo. At 1 year, even though
the serum genistein levels were much higher in
the treatment group (615 versus 17 nmol/L),
there was no difference in bone mineral density, cognitive function, or
plasma lipids (JAMA. 2004. 292.
65-74).
- A 4
½ year prospective cohort study looking at the relationship between usual soy food consumption and fracture
incidence in 74,942 women aged 40-70 found a statistically significant
inverse relationship between soy consumption and bone fractures; the
relationship also showed a dose-response relationship across quintiles of
soy intake (Arch Intern Med.
2005. 165. 1890-1895).
- A 9
month RCT in 61 postmenopausal women receiving soy protein isolate showed
statistically significant decreases in biomarkers of bone turnover, but no
change in bone mineral density (Menopause.
2007. 14. 481-488).
- A meta-analysis of 10 RCTs (n=608)
found that soy isoflavone intake for 6 months
attenuates bone loss in the spine of postmenopausal women, with greatest
benefit seen in those consuming more than 90 mg per day of isoflavones (Clin Nutr.
2008. 27. 57-64).
- Two meta-analyses concluded that soy
isoflavones do not prevent bone loss (Bone.
2009. 44. 948-953; J Womens Health. 2010. 19. 1609-1617).
- The
SPARE study, a NIH-funded 2 year RCT of 248 women aged 45-60 and within 5
years of menopause found that 200 mg/day of soy isoflavones did NOT affect
bone loss in the lumbar spine, total hip, or femoral neck (Arch Intern Med. 2011. 171.
1363-1369 and Invited Commentary 1369-1370).
Strontium
- A
Mayo Clinic trial in which 32 patients received strontium lactate for up
to 3 years reported probable improvement in bone density, less bone pain,
and no significant side effects (Proc
Staff Meetings Mayo Clinic. 1959. 34. 329-334).
- A 2
year RCT in 353 osteoporotic women (STRATOS Study) in which strontium was
administered in doses of 170 mg, 340 mg, and 680 mg showed increases bone
density in a dose dependent manner. Those receiving 680 mg per day showed
positive changes in markers of bone metabolism and fewer new vertebral
fractures (J Clin
Endocrinol Metab.
2002. 87. 2060-2066).
- A 3
year RCT in 1649 postmenopausal women with at least one previous vertebral
compression fracture who received either 2 grams of strontium ranelate powder (providing 680 mg/day of strontium) or
placebo showed an increase in bone density and a reduction in symptomatic
vertebral fractures in the treatment group. Adverse effects were
uncommon. Treatment of 17 postmenopausal women who with a history of
vertebral compression fractures for 3 years will prevent one new
symptomatic vertebral compression fracture (Osteoporosis Int. 2002. 13. 521; New Engl J Med. 2004. 350. 459-468).
- A 3
year trial in over 7000 postmenopausal women with osteoporosis showed that
strontium ranelate 2 grams/day decreased
fracture risk and increased bone density (Bone. 2006. 38. 19-22).
- A 5
year trial in 5091 postmenopausal women, using strontium ranelate 2 grams/day (TROPOS study) showed that the
incidence of nonvertebral fractures in the
treatment group was 15% lower than in the placebo group (p=0.032) and the
incidence of vertebral fractures in the treatment group was 24% lower than
in the placebo group (p<0.001). In this study, the magnitude of
reduction in fracture incidence relative to placebo diminished with time (Arthritis Rheum. 2008. 58.
1687-1695). In a commentary, Dr Alan Gaby indicates that the effects of
pharmacological doses of strontium are thought to be mediated by
adsorption of strontium onto the crystal surface (as opposed to
incorporation into the crystal lattice). There is some concern that long
term high dose strontium in humans might cause mineralization defects, and
thus in clinical practice it may be wisest to consider a dosage reduction
after one year (Townsend Letter.
11/09. Pg 28).
- Strontium
is thought to both increase the formation of new bone and decrease bone resorption.
- Note
that because strontium accumulates in bone and attenuates X-rays more than
calcium (strontium has a higher atomic mass), DEXA studies will
overestimate BMD when patients are taking high dose strontium. Alert the radiologist reading the DEXA
scan.
- Consider
a daily supplemental dose of at least 1-10 mg/day for prevention, and as
much as 680 mg/day of elemental strontium for treatment of osteoporosis.
Vitamin B6 (pyridoxine)
- Supplementation reduces homocysteine
levels and increases progesterone levels.
- Widespread
industrial use of vitamin B6 antagonists (hydrazines
and hydrazides) may mean that consumption of RDA
of this vitamin is inadequate for many individuals.
- A
small study showed low P5’P (active form of vitamin B6) levels in 10
of 20 patients admitted for nontraumatic hip
fracture but only 3 of 21 patients admitted for elective arthroplasty (Acta Orthop Scand. 1992. 63. 635-638).
- In a study in which the trabecular heads were examined in 94 men and women who
underwent elective hip arthroplasty, histomorphometric analysis showed significantly lower trabecular number (defined as the number of trabeculae per unit of length) in those patients with
serum B6 below the median, as compared with those with serum B6 above the
median, even though BMD was similar in both groups (Am J Clin Nutr.
2009. 90. 1440-1445).
- Consider
a supplemental dose of 10-50 mg a day.
Vitamin B12
- Supplementation may reduce homocysteine
levels.
- Many seniors do not absorb this vitamin
well from food sources; B12 deficiency or insufficiency is common in
seniors.
- Recent population-based studies suggest
that correlation of B12 status and bone mineral density (J Nutr.
2003. 133. 801-807; J Bone Miner Res.
2005. 20. 152-158).
- Vitamin B12 affects osteoblast
activity and bone formation. It increases osteocalcin
concentration (osteocalcin is a major protein in
bone, and it binds with calcium) and promotes collagen cross linking (N Engl J Med.
1988. 319. 70-75; Metabolism.
1996. 45. 1443-1446; JAMA. 2005.
293. 1082-1088).
- Vitamin B12 1500 mcg/day along with
folate 5 mg/day markedly reduced the risk of hip fractures in a two year
trial in 628 Japanese patients, mean age 71 years, with residual hemiplegia from a stroke. The number of falls per
person did not differ between the groups. In this study, treatment of 15
people with this regimen of vitamin B12 and folate would prevent one hip
fracture! (JAMA. 2005. 293.
1082-1088).
- Consider a supplemental dose of 500
– 1500 mcg a day.
Vitamin C
- Important in small amounts for bone
health; promotes formation of collagen, which is the bone connective
tissue.
- In the Framingham Osteoporosis Study in
958 men and women, at 15-17 years of follow up, those in the highest third
of vitamin C intake (median 305 mg/day) had a 44% lower risk of hip
fracture than those in the lowest third of vitamin C intake (median 97
mg/day). When hip fracture was looked at as a function of dietary vitamin
C intake versus supplemental vitamin C intake, supplements accounted for
28% of vitamin C intake in the cohort, and it was specifically
supplemental vitamin C intake which was correlated with a lower risk of
hip fracture, with no effect of dietary vitamin C intake on hip fracture
risk. This epidemiologic data does not necessarily mean cause and effect;
the benefit might be due to confounding effects, such that those taking
vitamin C supplements are healthier than those not taking supplements
(Data presented at 2008 annual meeting for Bone and Mineral Research).
- Consider a supplemental dose of 100-200
mg a day.
Vitamin D
- The
data on reduction in fracture risk with vitamin D is mixed:
- A
meta-analysis of 5 RCTs using hip fracture (9294 participants) as an
endpoint and 7 RCTs using nonvertebral
fractures as an endpoint (9820 participants) found that if studies were
pooled based on the administration of low dose (400 IU daily) or higher
dose (700-800 IU daily) of vitamin D, oral vitamin D 700-800 IU daily
appears to reduce the risk of hip fracture (by 26%) and any nonvertebral fractures (by 23%) in ambulatory or
institutionalized older individuals.
Vitamin D 400 IU daily is not sufficient for fracture prevention (JAMA. 2005. 293. 2257-2264). Many
of the patients in the studies in this meta-analysis were nursing home
residents, and this may explain in part the positive findings (ACP Journal Club. 2005. 143. 72).
- HOWEVER
a Cochrane analysis of 18,668 individuals in 7 trials failed to show a
significant reduction in fracture risk with vitamin D alone (Cochrane Database Syst
Rev. 2005. CD000227). This same Cochrane analysis did find a 19%
reduction in hip fracture with a combination of calcium and vitamin D,
but the benefit seemed to be restricted to persons living in institutionalized
settings (ACP Journal Club.
2006. 144. 14).
- A
study of 2686 adults 65 to 85 years of age showed that those who took
vitamin D3 as a 100,000 IU capsule every 4 months for 5 years had a
statistically reduced risk of fracture (8.8% versus 11.1%; number needed
to treat = 44). Subgroup analysis showed that the benefit was
restricted to women. The daily supplemental dose can be calculated
at 100,000 IU divided by 122 days = 820 IU/day (BMJ. 2003. 326. 469-472).
- HOWEVER,
a large methodologically rigorous 5 year study in 5292 patients with a
previous fracture (RECORD) found no difference in rates of repeat
fractures in those who took vitamin D 800 IU per day (Lancet. 2005. 365. 1621-1628).
Negative result may have been a function of poor compliance (54.5% at two
years) or an underpowered study (ACP
Journal Club. 2005. 143. 74). Mean 25 OH vitamin D levels increased
from 15.2 to 24.8; a level of >30 ng/mL is
required for antifracture efficacy (Alt Med Alert. 2009. 12. 37-43).
- Another
NEGATIVE trial included 3454 community-dwelling women over age 70 and
with one or more risk factors for hip fracture. At a median follow up of 25 months,
those who took calcium 500 mg twice a day with vitamin D 400 IU twice a
day did not have a reduced fracture risk (BMJ. 2005. 330. 1003-1006). This study may have been
underpowered to detect a reduction in fracture risk, and the poor
compliance, 56.6% may also have contributed to the negative result (ACP Journal Club. 2005. 143. 73).
- Despite
these negative trials, a meta-analysis of 12 RCTs for nonvertebral
fracture (42,297) and 8 RCTs for hip fracture (n= 40,886) comparing
vitamin D with or without calcium to calcium or placebo found that when
trials were pooled based on the dose of supplemental vitamin D, benefit
was seen in the trials using a supplemental dose of vitamin D > 400
IU/day. When a higher dose of vitamin D was administered, the RR of nonvertebral fracture was 0.80 (0.72-0.89; n+33,265
from 9 trials) and the RR of hip fracture was 0.82 (0.69-0.97; n=31,872
from 5 trials). When stratified by institutional status, the reduction in
nonvertebral fractures in community dwelling
individuals receiving higher dose vitamin D was ~29% and the reduction in
institutionalized older individuals receiving higher dose vitamin D was
~15%. The benefit was independent of whether or not supplemental calcium
was administered with the supplemental vitamin D (Arch Intern Med. 2009. 169. 551-561).
- NEGATIVE
TRIAL – a RCT in 2256 community dwelling women (median baseline 25
OH vitamin D 49 nmol/L – 20 ng/ml) surprisingly showed that those supplemented
once a year each fall for 3-5 years with 500,000 IU of cholecalciferol had an increased risk of fractures
(and falls), despite normalization of 25 OH vitamin D levels. The
explanation for this surprising result is uncertain (JAMA. 2010. 303. 1815-1822 and editorial).
- Vitamin
D may prevent falls
- A
meta-analysis of 5 randomized, controlled trials involving 1237
participants found that vitamin D supplementation (400-800 IU) in seniors
over age 60 reduces the risk of falling by 22%. The number needed
to treat to prevent one fall is only 15.
The presumed mechanism is through muscle strength benefits (JAMA. 2004. 291. 1999-2006).
- A
3 year RCT in 199 men and 246 women over age 65 and living at home found
that cholecalciferol 700 IU/day with calcium
citrate malate 500 mg/day reduced the risk of
falls by 46% in women and 65% in the subgroup of less active women, but
had no significant impact on falls in men (Arch Intern Med. 2006. 166. 424-430).
- A
meta-analysis of 8 RCTs of supplemental vitamin D showed that doses of
700-1000 IU/day prevented falls, but doses < 700 IU/day did not
(Bischoff-Ferrari HA. BMJ.
2009. 339. b3692).
- NEGATIVE
TRIAL – a RCT in 2256 community dwelling women (median baseline 25
OH vitamin D 49 nmol/L – 20 ng/ml) surprisingly showed that those supplemented
once a year each fall for 3-5 years with 500,000 IU or cholecalciferol had an increased risk of falls (and
fractures), despite normalization of 25 OH vitamin D levels. The
explanation for this surprising result is uncertain (JAMA. 2010. 303. 1815-1822 and editorial).
- Vitamin
D may increase strength
- 6
months of vitamin D supplementation led to significant improvements in
isometric knee extensor strength (Aging.
2000. 12. 455-460).
- In
a RCT of 56 elderly institutionalized Brazilians, mean age 78, those
randomized to receive 6 months of vitamin D3 of vitamin D supplementation
(150,000 IU once a month for 2 months, followed by 90,000 IU/month for 4
months) showed a 16.4% increase in strength of hip flexors (p=0.0001) and
a 24.6% increase in the strength of the knee extensors (p=0.0007). Muscle
strength did not improve in the placebo group. Median 25 hydroxy vitamin
D level at baseline was 18 ng/dl (Ann Nutr Metab. 2009. 54. 291-300).
- Low
25-OH-vitamin D levels are correlated with sarcopenia
(J Clin Endocrinol Metab. 2003.
88. 5766-5772).
- In
a 6 month, 2 x 2 RCT in 113 elderly institutionalized females (average
age 80), dynamic muscle strength (and hip BMD) increased in the group
receiving 1600 IU per day vitamin D3 as well as the group receiving 880
IU per day vitamin D3. Note that in this trial (1) 57% of participants
had a baseline 25 hydroxy vitamin D level less than 20 ng/ml, (2) even though the 25 hydroxy vitamin D level
increased to a significantly greater extent in the 1600 IU per day
supplement group, dynamic muscle strength and BMD increases in the low
dose and high dose vitamin D3 groups were similar, (3) isometric strength
and muscle mass did not change in any of the groups, and (4) whole body
vibration training had no effect on BMD, muscle strength or muscle mass (J Bone Miner Res. 2011. 26.
42-49).
- Vitamin
D is necessary for the active intestinal absorption of calcium and
phosphorus.
- BEWARE
Vitamin D is a fat soluble vitamin, and too much (more than 2000
IU/day in supplement form) can be harmful.
- For more information on vitamin D,
return to Home Page and click on “Vitamins and Minerals”
- Dosage: the best available data
indicates that a daily supplemental dose of 800 IU per day is optimal from
the standpoint of increasing BMD, preventing falls, and increasing
strength. Meta-analyses of trials
using 400 versus 800 IU per day suggest that 800 IU per day is more
effective than 400 IU per day (see specifics above); one trial comparing
880 IU per day with 1600 IU per day did not show any added bone or muscle
benefit from the higher dose (see specifics above).
Vitamin K
- Catalyzes
a structural change in osteocalcin, a protein in
bone, such that the osteocalcin attracts
calcium, enhancing mineralization of bone. Matrix gamma-carboxyglutamic acid protein and protein S are other
vitamin K-dependent proteins in bone.
- Protects
osteoblasts from apoptosis in cell culture (J Lab Clin Med. 2000. 136. 181-193),
and (in mice) causes mature osteoclasts to undergo apoptosis (J Nutr Sci Vitaminol. 1999. 45.
501-507).
- Vitamin
K2 inhibits formation of PGE2, an inflammatory eicosanoid,
in vitro (J Bone Miner Res.
1993. 8. 535-542) and in cell culture (Biochem Pharmacol. 1993. 46. 1355-1362).
Vitamin K1 does NOT have this effect (Bone.
1995. 16. 179-184).
- Protects
against corticosteroid induce bone loss (Endocr J. 2001. 48. 11-18; Am
J Kidney Dis. 2004. 48. 11-18).
- Low
circulating vitamin K is correlated with an osteoporosis (J Clin Endocrinol Metab. 1985.
60. 1268-1269).
- A
systematic review of 13 RCTs, all longer than 6 months in duration, 7 of
which reported data on fractures, found that supplementation with phytonadione (1 – 10 mg/day) and menaquinone-4
(15 – 45 mg/day) reduces bone loss, and that supplementation with
menaquinone-4 is protective against fractures. These 13 trials varied in
size from 20 participants to 241 participants, and some included
co-supplementation with other vitamins and minerals (Cockayne S et
al. Vitamin K and the Prevention of Fractures: Systematic Review and
Meta-analysis of Randomized Controlled Trials. Arch Intern Med. 2006. 166. 1256-1261).
- A 3 year RCT among 325
postmenopausal women receiving either placebo or 45 mg/day of vitamin K2
(MK-4, menatetrenone) showed benefit with regard
to bone mineral content (BMC) and femoral neck width (FMW), but not BMD.
These results presumably translate into an improvement in strength [Osteoporosis Int. 2007. 18.
963-972].
- Consider
a minimum supplemental dose of 100-500 mcg a day, ideally a mixture of
vitamins K1 and K2 (BEWARE if on coumadin).
- Dietary
sources of vitamin K1 are green leafy vegetables and dietary sources of
vitamin K2 are organ meats, egg yolks, fermented dairy products, and natto (a fermented soy product).
Zinc
- Enhances the biochemical actions of
vitamin D.
- Important
in the formation of osteoblasts and osteoclasts and various proteins found
in bone tissue.
- Food
sources include poultry, meat, whole grains.
- Consider
a supplemental dose of 10-30 mg a day.
References:
- Gaby,
Alan. Preventing and Reversing
Osteoporosis. Prima Publishing. 1994.
- Gaby AR
and Wright JV. Nutrients and Osteoporosis. J Nutr Med. 1990. 1. 63-70.
- Weil,
Andrew. The Best Nutrients for Stronger Bones. Self Healing. March, 2005. 4-5.
Resource:
Determine the approximate risk of hip fracture using a calculator posted at http://hipcalculator.fhcrc.org. Data
derived from Women’s Health Initiative.
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Updated November 6, 2011] [Return to List of Topics]