title: Age-related decline in skeletal muscle mass and function among elderly men and women in Shanghai, China: a cross sectional study.
abstract: OBJECTIVE
  To investigate the relationship of muscle mass and muscle function with age.
  
  
  METHODS
  The study including 415 participants (aged 60-99 years). Upper (UMM) and lower (LMM) limbs muscle mass and whole body fat free mass (FFM) were measured by bioelectrical impedance analysis. The appendicular skeletal muscle mass (ASM) index (ASM/height2) was calculated. Muscle function was assessed by measuring hand grip strength (HGS) and gait speed.
  
  
  RESULTS
  Using ASM index cutoff values we found that higher prevalence of sarcopenia in women than in men (33.5% vs 23.6%, p=0.025). In the upper limb, HGS (β=-0.809) declined more rapidly with age than did UMM (β=-0.592) in men, but not in women (β=-0.389 and β=-0.486 respectively). In the lower limb, gait speed declined more rapidly than LMM in both men (β=-0.683 vs β=-0.442) and women (β=-1.00 vs β=-0.461). The variance of UMM explained 28-29% of the variance of HGS, and LMM explained 7-8% of the variance of gait speed in women and men respectively. In addition to the common predictors (BMI and age), the specific predictors were smoking, exercise and education for FFM and ASM, and smoking, drinking and exercise for HGS (p<0.05).
  
  
  CONCLUSIONS
  Loss of muscle function is greater than the decline of muscle mass particularly in the upper limbs in men. However, women are more prone to have low muscle mass than the men. Exercise programs need to be designed gender specifically.
authors.affiliation: Clinical Nutrition Center, Fudan University Affiliated Hua Dong Hospital, Shanghai, China.
authors.forename: Hui-Jing
authors.initials: HJ
authors.lastname: Bai
authors.affiliation: Clinical Nutrition Center, Fudan University Affiliated Hua Dong Hospital, Shanghai, China. Email: Jianqins@gmail.com.|Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China.|Research Center on Aging and Medicine, Fudan University, Shanghai, China.
authors.forename: Jian-Qin
authors.initials: JQ
authors.lastname: Sun
authors.affiliation: Clinical Nutrition Center, Fudan University Affiliated Hua Dong Hospital, Shanghai, China.
authors.forename: Min
authors.initials: M
authors.lastname: Chen
authors.affiliation: Clinical Nutrition Center, Fudan University Affiliated Hua Dong Hospital, Shanghai, China.
authors.forename: Dan-Feng
authors.initials: DF
authors.lastname: Xu
authors.affiliation: Clinical Nutrition Center, Fudan University Affiliated Hua Dong Hospital, Shanghai, China.
authors.forename: Hua
authors.initials: H
authors.lastname: Xie
authors.affiliation: Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China.|Research Center on Aging and Medicine, Fudan University, Shanghai, China.
authors.forename: Zhuo-Wei
authors.initials: ZW
authors.lastname: Yu
authors.affiliation: Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China.|Research Center on Aging and Medicine, Fudan University, Shanghai, China.
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Bao
authors.affiliation: Shanghai Key Laboratory of Clinical Geriatric Medicine, Shanghai, China.|Research Center on Aging and Medicine, Fudan University, Shanghai, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Chen
authors.affiliation: Clinical laboratory, Fudan University Affiliated Hua Dong Hospital, Shanghai, China.
authors.forename: Yi-Ru
authors.initials: YR
authors.lastname: Pan
authors.affiliation: School of Kinesiology, Shanghai University of Sport, Shanghai, China.
authors.forename: Da-Jiang
authors.initials: DJ
authors.lastname: Lu
authors.affiliation: Department of Sport and Physical Education, Shanghai Jiao Tong University, Shanghai, China.
authors.forename: Sulin
authors.initials: S
authors.lastname: Cheng
mesh_terms: D000367:Age Factors; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D002681:China / Q000453:epidemiology; D003430:Cross-Sectional Studies; D017097:Electric Impedance; D005260:Female; D005684:Gait / Q000502:physiology; D018737:Hand Strength / Q000502:physiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D055948:Sarcopenia / Q000453:epidemiology* / Q000503:physiopathology*; D012737:Sex Factors