(Ivanhoe Newswire) -- Ill effects of vitamin D deficiency in men are
amplified by lower levels of estrogen, but not by testosterone.
Vitamin D is essential to good health, and can be obtained from fortified
foods such as milk and cereals, and by exposure to sunlight. Previous
studies showed that deficiencies in vitamin D and low levels of estrogen
were independent risk factors for hardened and narrowed arteries and
weakened bones.
Researchers conducted a national study of 1,010 men to investigate the
relationship between Vitamin D and heart and bone health. "Our results
confirm a long-suspected link and suggest that vitamin D supplements, which
are already prescribed to treat osteoporosis, may also be useful in
preventing heart disease," lead investigator and cardiologist Erin Michos,
M.D., M.H.S., Johns Hopkins University School of Medicine and its Heart and
Vascular Institute, was quoted as saying.
"All three steroid hormones – vitamin D, estrogen and testosterone – are
produced from cholesterol, whose blood levels are known to influence
arterial and bone health," said Michos. "Our study gives us a much better
understanding of how the three work in concert to affect cardiovascular and
bone health."
Michos says the overall biological relationship continues to puzzle
scientists because studies of the long-term effects of adding estrogen in
the form of hormone replacement therapy in women failed to show fewer deaths
from heart disease. Indeed, results showed that in some women, an actual
increase in heart disease and stroke rates occurred, although bone fractures
declined.
The men in the study had their hormone levels measured for both chemical
forms of testosterone and estrogen found in blood.
Initial results showed no link between vitamin D deficiency and depressed
blood levels of either hormone. And despite finding a harmful relationship
between depressed testosterone levels and rates of heart disease, stroke,
high blood pressure, and osteopenia in men, researchers found that it was
independent of deficiencies in vitamin D.
When researchers compared ratios of estrogen to sex hormone binding globulin
(SHBG) levels, however, they found that rates of both diseases, especially
osteopenia, were higher when both estrogen and vitamin D levels were
depressed.
Using the same measure of estrogen levels, men low in vitamin D were also at
heightened risk of cardiovascular diseases. Michos explained, "These results
reinforce the message of how important proper quantities of vitamin D are to
good bone health, and that a man's risk of developing osteoporosis and heart
disease is heavily weighted on the complex and combined interaction of how
any such vitamin deficits interact with both their sex hormones, in
particular, estrogen."
SOURCE: Presented at the American Heart Association Annual Scientific
Sessions, Orlando, FL, November 15, 2009
