Gaining too much weight can accelerate the decline
in testosterone levels that accompanies aging, a new
study shows.
"Although hormone declines appear to be an integral
aspect of the aging process, rapid declines need not
be dismissed as inevitable," the researchers conclude.
Men's testosterone levels fall as they get older,
which may contribute to health problems such as diabetes,
loss of bone and muscle mass, and sexual dysfunction,
Dr. Thomas G. Travison of New England Research Institutes
in Watertown, Massachusetts and colleagues note in a
report in The Journal of Clinical Endocrinology and
Metabolism.
To better understand how much of the decline in testosterone
over time is due to aging and how much might be related
to health and lifestyle changes, the researchers looked
at data for 1,667 men 40 to 70 years old followed from
1987-1989 to 2002-2004. They were able to gather data
for the entire time period on 35 percent, or 584, of
the men.
Sharper declines in testosterone occurred among men
who developed a chronic illness during the course of
the study, those who lost a spouse, those who began
taking six or more medications, and those who quit smoking,
the researchers found.
And adding 4 to 5 points to one's body mass index
(BMI) -- a tool used to determine how fat or thin a
person is -- resulted in a drop in testosterone levels
similar to that seen over 10 years of aging.
On average, the men experienced a 14.5 percent drop
in total testosterone levels for every decade of life
and a 27 percent reduction in free testosterone, but
when the researchers looked at a subset of men who were
completely healthy throughout the course of the study,
declines in total and free testosterone were 10.5 percent
and 22.8 percent, respectively. This suggests, the researchers
say, that a "substantial proportion" of testosterone
decline is due to changes in health.
"These results suggest the possibility that age-related
hormone decline may be decelerated through the management
of health and lifestyle factors," they conclude.
SOURCE: The Journal of Clinical Endocrinology and Metabolism,
February 2007.
