title: Total testosterone may not decline with ageing in Korean men aged 40 years or older.
abstract: OBJECTIVE
  It is generally believed that gonadal function in men declines with ageing. However, observations on ageing-related decrease in total testosterone (TT) are not consistent. The aim of this study is to examine the ageing-related changes of testosterone and to investigate the influence of the ageing-related factors on TT.
  
  
  METHODS
  Changes of TT with ageing were observed in longitudinal design in a single health promotion centre.
  
  
  METHODS
  A total of 220 Korean men aged ≥40 years were included between 2002 and 2011. TT assay was repeated for all subjects, with an interval of ≥3 years.
  
  
  METHODS
  Information of medical history and lifestyle habits was collected. Anthropometry and blood pressure were measured. TT, glucose, creatinine, highly sensitive C-reactive protein, liver enzymes and lipid profiles were tested.
  
  
  RESULTS
  Mean TT level did not decline significantly with ageing during median 4·3 years follow-up (18·1 vs 17·8 nm, P = 0·439). Longitudinal change of TT was approximately + 0·8% per year. TT was negatively correlated with body mass index (BMI), waist circumference and glucose. With mixed effects model, diabetes (P = 0·038) and BMI (P = 0·007) affected TT level, but age and follow-up interval did not.
  
  
  CONCLUSIONS
  TT did not change significantly in 220 Korean men for a median 4·3 years follow-up. TT was not influenced by the age and follow-up interval. BMI and diabetes mellitus affected TT decline.
authors.affiliation: Department of Family Medicine, Cha University School of Medicine, Pochon, Korea.
authors.forename: Young-Sang
authors.initials: YS
authors.lastname: Kim
authors.forename: Doohee
authors.initials: D
authors.lastname: Hong
authors.forename: Duck-Joo
authors.initials: DJ
authors.lastname: Lee
authors.forename: Nam-Seok
authors.initials: NS
authors.lastname: Joo
authors.forename: Kwang-Min
authors.initials: KM
authors.lastname: Kim
mesh_terms: D000328:Adult; D000375:Aging / Q000097:blood*; D044466:Asian People; D015992:Body Mass Index; D003920:Diabetes Mellitus / Q000097:blood; D006801:Humans; D008297:Male; D008875:Middle Aged; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone