title: Reference Ranges and Association of Age and Lifestyle Characteristics with Testosterone, Sex Hormone Binding Globulin, and Luteinizing Hormone among 1166 Western Chinese Men.
abstract: Decreased total testosterone (TT) is the recommended metric to identify age-related hypogonadism. However, average TT and the extent to which it varies by age, can vary substantially among different populations. Population-specific reference ranges are needed to understand normal versus abnormal TT levels. Therefore, the goal for this study was to describe androgen concentrations and their correlates among Western Chinese men. We completed a population-based, cross-sectional study including 227 young adults (YA) (20-39 years) and 939 older adults (OA) (40-89 years). We measured TT, sex-hormone binding globulin (SHBG), luteinizing hormone (LH), testosterone secreting index (TSI), and calculated free testosterone (cFT). Reference ranges for this population were determined using average YA concentrations. Multivariable regression models were used to predict hormone concentrations adjusting for age, waist-to-height ratio (WHR), marital status, education, occupation, smoking, alcohol, blood glucose, and blood pressure. Among OA, 3.8% had low TT, 15.2% had low cFT, 26.3% had low TSI, 21.6% had high SHBG, and 6.1% had high LH. Average cFT was significantly lower in OA (0.30 nmol/L; standard deviation (SD): 0.09) versus YA (0.37; SD: 0.11) but TT was not different in OA (16.82 nmol/L; SD: 4.80) versus YA (16.88; SD: 5.29). In adjusted models increasing age was significantly associated with increased SHBG or LH, and decreased cFT or TSI; however, TT was not significantly associated with age (β = 0.02 nmol/L; 95% confidence interval (CI): -0.01, 0.04). Higher WHR was associated with significantly decreased TT, SHBG, TSI, and LH. The only variable significantly related to cFT was age (β = -0.0033; 95% CI:-0.0037, -0.0028); suggesting that cFT measurements would not be confounded by other lifestyle factors. In conclusion, cFT, but not TT, varies with age in this population, suggesting cFT may be a better potential marker for age-related androgen deficiency than TT among Western Chinese men.
authors.affiliation: School of Public Health, Zunyi Medical University, Zunyi, China.
authors.forename: Xubo
authors.initials: X
authors.lastname: Shen
authors.affiliation: Huichuan District Center for Disease Control and Prevention, Zunyi, China.
authors.forename: Ruifeng
authors.initials: R
authors.lastname: Wang
authors.affiliation: School of Public Health, Zunyi Medical University, Zunyi, China.
authors.forename: Na
authors.initials: N
authors.lastname: Yu
authors.affiliation: School of Public Health, Zunyi Medical University, Zunyi, China.
authors.forename: Yongjun
authors.initials: Y
authors.lastname: Shi
authors.affiliation: Institute of Family Planning, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Honggang
authors.initials: H
authors.lastname: Li
authors.affiliation: Institute of Family Planning, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
authors.forename: Chengliang
authors.initials: C
authors.lastname: Xiong
authors.affiliation: School of Public Health, Zunyi Medical University, Zunyi, China.
authors.forename: Yan
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Health Sciences, Purdue University, West Lafayette, Indiana, United States of America.
authors.forename: Ellen M
authors.identifier: http://orcid.org/0000-0002-7293-1395
authors.initials: EM
authors.lastname: Wells
authors.affiliation: School of Public Health, Zunyi Medical University, Zunyi, China.
authors.forename: Yuanzhong
authors.initials: Y
authors.lastname: Zhou
mesh_terms: D000328:Adult; D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D001774:Blood Chemical Analysis / Q000592:standards*; D002681:China; D006801:Humans; D008019:Life Style; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012738:Sex Hormone-Binding Globulin / Q000032:analysis*; D013739:Testosterone / Q000097:blood*; D055815:Young Adult
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D007986:Luteinizing Hormone