title: Relationship between low free testosterone levels and loss of muscle mass.
abstract: We assessed longitudinal relationships between baseline testosterone and muscle mass changes in Japanese men. Data were collected from community-dwelling 957 adult men who participated in a longitudinal study of ageing biennially from 1997-2010. Appendicular muscle mass (AMM) was measured with dual-energy X-ray absorptiometry at baseline and follow-up examinations. The cut-off point of sarcopenia was defined as a skeletal muscle index (AMM/height(2)) < 6.87 kg/m(2). Total testosterone (TT) and free testosterone (FT) were measured with a radioimmunoassay. The calculated FT (cFT) was determined with a formula using albumin, TT, and sex hormone-binding globulin levels. We analyzed 4,187 or 2,010 cumulative data points using generalized estimating equations. Low TT was not associated with sarcopenia. Low cFT (odds ratio = 2.14, 95% confidence interval: 1.06-4.33) and FT (odds ratio = 1.83, 95% confidence interval: 1.04-3.22) were associated with sarcopenia. Low FT may be a predictor of risk for muscle loss in Japanese men.
authors: Department for Development of Preventive Medicine, National Center for Geriatrics and Gerontology, Japan.
authors: Atsumu
authors: A
authors: Yuki
authors: Rei
authors: R
authors: Otsuka
authors: Rumi
authors: R
authors: Kozakai
authors: Itsuko
authors: I
authors: Kitamura
authors: Tomohiro
authors: T
authors: Okura
authors: Fujiko
authors: F
authors: Ando
authors: Hiroshi
authors: H
authors: Shimokata
mesh_terms: D000375:Aging / Q000502:physiology; D015992:Body Mass Index; D016022:Case-Control Studies; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000033:anatomy & histology* / Q000473:pathology; D009929:Organ Size; D012307:Risk Factors; D055948:Sarcopenia / Q000097:blood / Q000473:pathology; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone
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