SEATLLE -- Low testosterone may be a signal that a man's body is running down-or maybe out.
SEATLLE, Aug. 14 -- Low testosterone may be a signal that a man's body is running down-or maybe out.
Scant levels of the hormone in men were linked to an 88% increase in mortality risk, found researchers at the University of Washington and the Veterans Affairs Puget Sound Health Care System here.
Testosterone levels can dip from both chronic and acute illness, but after adjusting for these and other factors low testosterone was still a significant predictor of mortality, reported Molly M. Shores, M.D., in the Aug.14-28 issue of Archives of Internal Medicine.
The study included about 850 veterans at least 40 years old (average age, about 62) without prostate or testicular cancer. These men had their testosterone levels checked at least twice between 1994 and 1999. They were followed for all-cause morality through 2002.
About 19% of the men had low testosterone levels (defined as less than 250 ng/dL total testosterone). More than half (53%) had normal levels. The remaining 28% had levels that fluctuated between normal and low during the study period.
Men with low testosterone tended to be older (P=.007), have a higher BMI (P
"However, a retrospective cohort study can not establish a causal relationship between testosterone status and mortality," they said, "and it is possible that the association is because of the mediation of some other factor that is linked to low testosterone level and mortality."
A chief limitation of the study was that the investigators did not know which men with low testosterone were being treated for the condition, a factor that is likely to be important in morbidity and mortality outcomes, they said.
Previous research suggests testosterone levels decline by about 1.5% per year in men after age 30. About 20% of men in their 50s have low testosterone, and that figure jumps to 50% by age 80, the investigators said.