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Genetic and environmental influence on the association between testosterone, sex hormone‐binding globulin and body composition in K orean men
Author(s) -
Lee Kayoung,
Sung Joohon,
Song YunMi
Publication year - 2015
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/cen.12722
Subject(s) - sex hormone binding globulin , medicine , endocrinology , testosterone (patch) , lean body mass , body mass index , globulin , twin study , hormone , biology , androgen , heritability , genetics , body weight
Summary Objectives This study aimed to evaluate an association between testosterone, sex hormone‐binding globulin and body composition as well as the influence of genetic and environmental factors on the association. Design A cross‐sectional study. Setting Community‐based study. Participants One thousand and eighty‐three K orean men including 144 pairs of monozygotic twins. Main Outcome Measure Levels of serum total testosterone ( TT ) and sex hormone‐binding globulin ( SHBG ) were measured by chemiluminescence immunoassay, and free testosterone (c FT ) was calculated using V ermeulen's method. Detailed body composition was measured using dual‐energy X ‐ray absorptiometry. We performed linear mixed regression analysis with consideration of familial correlations and covariates. Results Each 1‐ SD increase in age‐adjusted levels of TT , c FT and SHBG was associated with lower levels of adiposity measures and absolute measures of lean body mass. On the other hand, percentage total lean mass increased with increasing levels of TT , c FT and SHBG ( P < 0·05). Bivariate variance‐component analyses revealed that most body composition measures had a significant inverse unique environmental correlation with both TT and SHBG , and a significant genetic correlation with TT . A co‐twin control study in monozygotic twins showed that within‐pair differences in adiposity measures were inversely associated with within‐pair differences in the levels of TT and SHBG , while within‐pair differences in lean mass were inversely associated with within‐pair differences in the levels of TT . Conclusions The significant associations of body composition with testosterone and SHBG were influenced by both genetic and environmental factors. Further efforts to elucidate related genes and modifiable environmental factors are needed.