A high lean body mass - calculated using
an equation to determine body mass minus the fat -- may
lower the risk of prostate cancer, a new study indicates.
Prostate cancer is a hormone-related disease affected
by a variety of other factors including genetics, age,
ethnicity and family history. In the last few years, researchers
started to suspect that body size might also affect the
risk of prostate cancer, but research has provided conflicting
results.
Most studies investigated body mass index, but this index
includes lean and fat tissue, which may have different
influences on the risk of cancer.
In an attempt to settle things, Dr. John S. Witte from
the University of California, San Francisco, and his colleagues
conducted a study of 439 men with prostate cancer and
479 of their siblings without prostate cancer.
They examined the effects of weight, height, body mass
index, and lean body mass, which they thought might be
more relevant than body mass index to the risk of prostate
cancer and aggressiveness of the disease.
The researchers found that the higher the lean body mass,
the lower the risk of prostate cancer, especially in men
with more aggressive disease or who were older when their
cancer was diagnosed. They also observed a similar, though
weaker, inverse pattern for weight, but found no associations
between risk of prostate cancer and body mass index or
height.
The investigators suspect that the inverse associations
between higher lean body mass and prostate cancer risk
may reflect the potentially protective effect of high
levels of the male hormone androgen in patients with high
lean body mass on the development and progression of prostate
cancer.
SOURCE: Journal of Urology, December 2005.
