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Serum Total and Bioavailable Testosterone Levels, Central Obesity, and Muscle Strength Changes with Aging in Healthy Chinese Men
Author(s) -
Chu LeungWing,
Tam Sidney,
Kung Annie W. C.,
Lo Sue,
Fan Susan,
Wong Rachel L. C.,
Morley John E.,
Lam Karen S. L.
Publication year - 2008
Publication title -
journal of the american geriatrics society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.992
H-Index - 232
eISSN - 1532-5415
pISSN - 0002-8614
DOI - 10.1111/j.1532-5415.2008.01746.x
Subject(s) - medicine , waist , endocrinology , body mass index , testosterone (patch) , morning , analysis of variance , obesity , waist–hip ratio
OBJECTIVES: To investigate the effects of the changes in serum bioavailable and total testosterone (TT) levels with aging on visceral body fat distribution and muscle strength in Chinese men. DESIGN: Cross‐sectional study. SETTING: Ambulatory care. PARTICIPANTS: Four hundred seventy‐five healthy ambulatory Chinese men (aged 18–89, body mass index (BMI) 16.4–40.0 kg/m 2 ). MEASUREMENTS: Morning serum total and bioavailable testosterone levels, waist circumference (WC), waist‐hip ratio (WHR), and right handgrip strength. RESULTS: Mean serum TT levels fell mildly but significantly with aging ( P =.02, linear trend; one‐way analysis of variance (ANOVA)), whereas mean serum bioavailable testosterone (BT) levels fell greatly with aging ( P <.001, linear trend, one‐way ANOVA). The rates of decline in serum TT and BT levels were 0.2% and 1.14% per year, respectively. [Correction added after online publication 14‐May‐2008: BT levels have been corrected from 1.44% to 1.14%.] After adjustment for adiposity according to BMI, multiple linear regression analyses showed that age remained significantly related to serum TT and BT levels. Handgrip strength decreased with age (correlation coefficient ( r )=−0.394, P <.001) and was greater with higher serum BT levels ( r =0.239, P <.001) but not with higher TT levels. WHR, before and after adjustment for BMI, was inversely related to serum TT ( r =−0.34 and −0.197 respectively, P <.001) and BT levels ( r =−0.104, P <.05 and −0.161, P <.001, respectively). CONCLUSION: In Chinese men, serum BT levels decreased with aging and may contribute to central obesity and poorer muscle strength in aging men.