No association for estradiol, but high testosterone, SHBG linked to less loss of lean mass
TUESDAY, Nov. 1 (HealthDay News) -- Higher levels of testosterone are associated with reduced loss of appendicular lean mass in older men, especially those who are losing weight, according to a study published online Oct. 5 in the Journal of Clinical Endocrinology & Metabolism.
Erin S. LeBlanc, M.D., M.P.H., from Kaiser Permanente Northwest in Portland, Ore., and colleagues investigated the associations of testosterone, estradiol, and sex hormone binding globulin (SHBG) with changes in body composition and physical function in 1,183 men aged 65 years or older from the Osteoporotic Fractures in Men study. Serum levels of sex steroids at baseline were measured using mass spectrometry. Dual energy X-ray absorptiometry and physical performance tests (grip strength, leg power, timed chair stands, narrow walk, and six-meter walk) were carried out at baseline and 4.5 years later to measure body composition.
The investigators found that, between study visits, the men lost an average of 1.3 kg weight overall. Higher baseline testosterone levels were significantly associated with a reduced decline in lean mass, especially appendicular lean mass. This was most evident in the 40 percent of men who lost more than 2.0 kg during follow-up. Higher testosterone was associated with less reduction in timed chair stands among weight losers. Elevated SHBG was associated with reduced decline in appendicular lean mass and also with grip strength. Estradiol was independent of body composition or physical function changes.
"Higher endogenous testosterone is associated with reduced loss of lean mass and lower extremity function in older men losing weight," the authors write.
Two authors disclosed financial relationship with the pharmaceutical industry.
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