title: Independent association between serum C-peptide levels and fat mass-to-lean mass ratio in the aging process.
abstract: OBJECTIVE
  The changes in body composition and biomarker levels that occur during the aging process are complex and remain poorly understood. The present study aimed to evaluate changes in serum C-peptide levels and fat mass-to-lean mass ratio (FM/LM ratio) with increasing age, and to explore the associations between serum C-peptide levels and FM/LM ratio.
  
  
  METHODS
  This was a population-based cross-sectional study that included 3912 participants aged 30-85 years. Body composition was measured using dual-energy X-ray absorptiometry. Analysis of covariance was used to evaluate how the serum C-peptide level and FM/LM ratio change with increasing age, as well as how the FM/LM ratio changes in line with increasing serum C-peptide level. A multiple linear regression analysis was carried out to determine the association between serum C-peptide level and FM/LM ratio.
  
  
  RESULTS
  Analysis of covariance showed that serum C-peptide levels, and most regional FM/LM ratios tended to increase in line with increasing age. Total fat mass, total lean mass, percentage total fat mass and total FM/LM ratio were significantly elevated, and percentage total lean mass decreased significantly with increasing serum C-peptide levels in both men and women. Multiple linear regression analysis showed that serum C-peptide level was strongly associated with the total FM/LM ratio.
  
  
  CONCLUSIONS
  The findings showed that both serum C-peptide level and FM/LM ratio increased with increasing age, and the serum C-peptide level was closely associated with changes in the total FM/LM ratio.
authors.affiliation: Department of Social Medicine, School of Public Health, Zhejiang University, Hangzhou, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Basic Medical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Lian Shun
authors.initials: LS
authors.lastname: Zheng
authors.affiliation: School of Basic Medical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Yue
authors.initials: Y
authors.lastname: Li
authors.affiliation: School of Basic Medical Sciences, Zhejiang University, Hangzhou, China.
authors.forename: Duo Duo
authors.initials: DD
authors.lastname: Zhao
authors.affiliation: Department of Social Medicine, School of Public Health, Zhejiang University, Hangzhou, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Meng
mesh_terms: D015502:Absorptiometry, Photon; D000328:Adult; D000368:Aged; D000375:Aging; D015992:Body Mass Index; D015519:Bone Density; D002096:C-Peptide / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood*
chemical_list: D002096:C-Peptide
keywords: aging; dual-energy X-ray absorptiometry; fat mass to lean mass ratio; public health; serum C-peptide