Here's the New York Times version:

December 19, 2006
Vital Signs

Aging: Lifestyle May Influence Testosterone Level

By Eric Nagourney

As men age, they experience a natural decline in the male hormone
testosterone. But a new study finds that unhealthy habits may hasten that
process. Even a fairly small increase in body mass index, for example, is
associated with a drop in testosterone like that normally associated with 10
years of aging, the researchers said. And that can put men at increased risk
for diabetes, reduced bone and muscle mass and sexual problems.

The results suggest that changes in health and lifestyle might slow the drop
in testosterone, the authors wrote. The study appears in The Journal of
Clinical Endocrinology and Metabolism and was led by Thomas G. Travison of
the New England Research Institutes in Massachusetts.

The researchers followed the health of more than 1,600 men in the Boston
area over a period of about 17 years. Some things that were found to be
associated with a drop in testosterone were out of the men's control, like
the death of a spouse. But other factors that the study looked at, like
excessive alcohol use and being sedentary, were another matter.

"These results presented here suggest that while hormone declines appear to
be an integral aspect of the aging process, rapid declines need not be
dismissed as inevitable," the authors said.

Here's the journal summary of the article:

Journal of Clinical Endocrinology & Metabolism, doi:10.1210/jc.2006-1859

The relative contributions of aging, health, and lifestyle factors to serum
testosterone decline in men

Thomas G. Travison, Andre B. Araujo, Varant Kupelian, Amy B. O'Donnell, and
John B. McKinlay
New England Research Institutes, Watertown, MA, USA

Context. Though it is known that serum testosterone (T) concentrations
decline with age, the relative contributions of changes in health and
lifestyle to that decline have not been adequately assessed.

Objective. To establish the relative importance of aging, health and
lifestyle in contributing to male testosterone decline.

Design. A prospective cohort study of health and endocrine functioning in
randomly selected men, with a baseline (T1: 1987-89) and two follow-up (T2:
1995-97, T3: 2002-04) visits.

Setting. An observational study of men residing in greater Boston, MA, USA.

Participants. 1667 men aged 40-70 at baseline; follow-up on 947 (57%) and
584 (35%) at T2 and T3, respectively.

Main outcome measures. Total serum testosterone (TT), calculated free
testosterone (FT), sex hormone-binding globulin (SHBG).

Results. There were substantial declines in TT and FT levels associated with
aging alone. However, many health and lifestyle changes were associated with
accelerated decline. A 4-5 kg/m2 increase in BMI, or loss of spouse, was
associated with declines in TT comparable to that associated with
approximately 10 years of aging. Results were similar for FT, but fewer
factors were associated with SHBG after age was taken into account.