Low levels of testosterone may increase the long-term risk of death in men over 50 years old, according to researchers with the Department of Family and Preventive Medicine at the University of California, San Diego School of Medicine.
"The new study is only the second report linking deficiency of this sex hormone with increased death from all causes, over time, and the first to do so in relatively healthy men who are living in the community," said Gail Laughlin, Ph.D., assistant professor and study author.
Laughlin will present the findings to The Endocrine Society Tuesday June 5th, 2007. The findings will be among selected articles published in the distinguished The Endocrine Society's ENDO 07 Research Summaries Book .
"We have followed these men for an average of 18 years and our study strongly suggests that the association between testosterone levels and death is not simply due to some acute illness," said Laughlin.
In the study, Laughlin and co-workers looked at death, no matter the cause, in nearly 800 men, ages 50 to 91 years, who were living in Rancho Bernardo, California. The participants have been members of the Rancho Bernardo Heart and Chronic Disease Study since the 1970s. At the beginning of the 1980s, almost one-third of these men had suboptimal blood testosterone levels for men their age.
The group with low testosterone levels had a 33 percent greater risk of death during the next 18 years than the men with higher testosterone. This difference was not explained by smoking, drinking, physical activity level or pre-existing diseases (such as diabetes or heart disease).
In this study, "low testosterone" levels were set at the lower limit of the normal range for young adult men. Testosterone declines slowly with aging in men and levels vary widely, with many older men still having testosterone levels in the range of young men. Twenty-nine percent of Rancho Bernardo men had low
Contact: Kim Edwards
University of California - San Diego