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Taken from WWW.pubmed.gov (testosterone studies)
Arch Intern Med. 2006 Aug 14-28;166(15):1660-5.
Low serum testosterone and mortality in male veterans.
Shores MM, Matsumoto AM, Sloan KL, Kivlahan DR.
Geriatric Research, Education, and Clinical Center, VA Puget Sound Health Care System, 1660 S.
Columbian Way, Seattle, WA 98108, USA. mxs@u.washington.edu
BACKGROUND: Low serum testosterone is a common condition in aging associated with decreased muscle
mass and insulin resistance. This study evaluated whether low testosterone levels are a risk factor for
mortality in male veterans.
METHODS: We used a clinical database to identify men older than 40 years with repeated testosterone
levels obtained from October 1, 1994, to December 31, 1999, and without diagnosed prostate cancer. A
low testosterone level was a total testosterone level of less than 250 ng/dL (<8.7 nmol/L) or a free
testosterone level of less than 0.75 ng/dL (<0.03 nmol/L). Men were classified as having a low
testosterone level (166 [19.3%]), an equivocal testosterone level (equal number of low and normal
levels) (240 [28.0%]), or a normal testosterone level (452 [52.7%]). The risk for all-cause mortality
was estimated using Cox proportional hazards regression models, adjusting for demographic and
clinical covariates over a follow-up of up to 8 years.
RESULTS: Mortality in men with normal testosterone levels was 20.1% (95% confidence interval
[CI], 16.2%-24.1%) vs 24.6% (95% CI, 19.2%-30.0%) in men with equivocal testosterone levels and
34.9% (95% CI, 28.5%-41.4%) in men with low testosterone levels. After adjusting for age, medical
morbidity, and other clinical covariates, low testosterone levels continued to be associated with
increased mortality (hazard ratio, 1.88; 95% CI, 1.34-2.63; P<.001) while equivocal testosterone
levels were not significantly different from normal testosterone levels (hazard ratio, 1.38; 95% CI,
0.99%-1.92%; P=.06). In a sensitivity analysis, men who died within the first year (50 [5.8%]) were
excluded to minimize the effect of acute illness, and low testosterone levels continued to be
associated with elevated mortality.
CONCLUSIONS: Low testosterone levels were associated with increased mortality in male veterans.
Further prospective studies are needed to examine the association between low testosterone levels
and mortality.
PMID: 16908801 [PubMed - indexed for MEDLINE]
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