title: Dynamic alteration of serum testosterone with aging: a cross-sectional study from Shanghai, China.
abstract: BACKGROUND
  Level of the testosterone in a man's life span is very important. Studies on the serum testosterone concentrations in different age groups of healthy men were controversial. The aim of this study was to investigate dynamic changes of serum reproductive hormones with aging in healthy Chinese male and to compare its correlation with age.
  
  
  METHODS
  Total of 1,093 healthy Chinese men from Shanghai aged from 20 to 87  years old was enrolled in the study. Concentrations of serum total testosterone (T), luteinizing hormone (LH) and sex hormone binding globulin (SHBG) were quantified by EIA. Testosterone secretion index (TSI) and free testosterone index (FTI) were then calculated. Data were analyzed by SPSS program. Non-parametric tests and univariate linear regression analyses were used.
  
  
  RESULTS
  The 1,039 male participants were grouped into 12 groups by 5-year apart for each group. Significant differences in T, LH, SHBG, FTI and TSI were found between the 12 different age groups. Average of serum total T was 15.36 ± 4.86 nmol/L; LH was 4.76 ± 2.76 IU/L, SHBG was 32.61 ± 17.24 nmol/L. Compared to age 20 ~ 24 group, serum T level of age 35 ~ 39, 40 ~ 44, 45 ~ 49, 50 ~ 54, and 55 ~ 59 was significantly decreased (p < 0.05). Intriguingly, however, serum T level of age 60 or older did not significantly reduced compared to the age of 20 ~ 24 group. Serum LH and SHBG were positively correlated with aging (p <0.01), while TSI and FTI were negatively correlated with aging (p <0.01). In addition, BMI was negatively and significantly correlated with levels of T (r = -0.585, p < 0.001), LH (r = -0.090, p < 0.001), SHBG (r = - 1.817, p < 0.001), and TSI (r = - 0.104, p < 0.001), but positively and significantly correlated with FTI level (r = 0.011, p < 0.001).
  
  
  CONCLUSIONS
  Serum total testosterone fluctuated with aging in adult men, and FTI and TSI decreased gradually with aging. While age was not significantly correlated with T level, BMI was significantly and negatively correlated with T level, suggesting body weight may affect testosterone level.
authors.affiliation: Department of Reproductive Medicine Center, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, 200233, China. liuzhangshun@126.com.
authors.forename: Zhangshun
authors.initials: Z
authors.lastname: Liu
authors.affiliation: Department of Reproductive Medicine Center, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, 200233, China. liujie32jat@126.com.
authors.forename: Jie
authors.initials: J
authors.lastname: Liu
authors.affiliation: Department of Reproductive Medicine Center, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, 200233, China. shixiaohong@126.com.
authors.forename: Xiaohong
authors.initials: X
authors.lastname: Shi
authors.affiliation: Department of Reproductive Medicine Center, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, 200233, China. lihongwang1976@126.com.
authors.forename: Lihong
authors.initials: L
authors.lastname: Wang
authors.affiliation: Department of Reproductive Medicine Center, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, 200233, China. yangyan19850608@yahoo.cn.
authors.forename: Yan
authors.initials: Y
authors.lastname: Yang
authors.affiliation: Department of Reproductive Medicine Center, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, No. 600 Yishan Road, Shanghai, 200233, China. taomf@sjtu.edu.cn.
authors.forename: Minfang
authors.initials: M
authors.lastname: Tao
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000097:blood*; D015415:Biomarkers / Q000097:blood; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D006801:Humans; D008297:Male; D008875:Middle Aged; D013739:Testosterone / Q000097:blood*; D055815:Young Adult
chemical_list: D015415:Biomarkers; D013739:Testosterone