title: BMI and BMI Changes to All-cause Mortality among the Elderly in Beijing: a 20-year Cohort Study.
abstract: OBJECTIVE
  To explore the association between body mass index (BMI) and all-cause mortality among the elderly in Beijing.
  
  
  METHODS
  This analysis was based on the Beijing multidimensional longitudinal study of aging (BLSA), which included 2,090 subjects over 55 years old and was followed-up from 1992 to 2012. BMI-mortality curves were drawn to find the optimal BMI range with the lowest mortality. Cox proportional hazard models were used to obtain the hazard ratios (HRs) for BMI and BMI changes in the overall population and in specific stratified populations.
  
  
  RESULTS
  During follow-up, 1,164 deaths were recorded; BMI-mortality curve was U-shaped, with the lowest mortality at a BMI of approximately 25 kg/m2. After adjusting for gender, age, smoking, drinking and some pre-existing diseases, HRs for underweight, overweight and obesity compared with normal weight were 1.372 (95% CI: 1.154-1.631), 0.767 (95% CI: 0.666-0.884) and 0.871 (95% CI: 0.830-1.246), respectively. HR for BMI drop was 3.245 (95% CI: 0.824-12.772) in the underweight group and 1.892 (95% CI: 0.830-1.246) in the normal weight group, HR for BMI rise was 1.795 (95% CI: 1.243-2.591) in normal weight group and 1.962 (95% CI: 1.202-3.203) in the overweight group.
  
  
  CONCLUSIONS
  Keeping BMI in an overweight status and stable is related to a reduced mortality.
authors.affiliation: School of Public Health, Capital Medical University, Beijing 100069, China; Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing 100069, China.
authors.forename: Yun Feng
authors.initials: YF
authors.lastname: Wang
authors.affiliation: Xuan Wu Hospital, Capital Medical University, Beijing 100053, China.
authors.forename: Zhe
authors.initials: Z
authors.lastname: Tang
authors.affiliation: School of Public Health, Capital Medical University, Beijing 100069, China; Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing 100069, China.
authors.forename: Jin
authors.initials: J
authors.lastname: Guo
authors.affiliation: School of Public Health, Capital Medical University, Beijing 100069, China; Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing 100069, China.
authors.forename: Li Xin
authors.initials: LX
authors.lastname: Tao
authors.affiliation: School of Public Health, Capital Medical University, Beijing 100069, China; Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing 100069, China.
authors.forename: Long
authors.initials: L
authors.lastname: Liu
authors.affiliation: School of Public Health, Capital Medical University, Beijing 100069, China; Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing 100069, China.
authors.forename: Hai Bin
authors.initials: HB
authors.lastname: Li
authors.affiliation: School of Basic Medical Sciences, Peking University Health Science Center, Beijing 100191, China.
authors.forename: Di Tian
authors.initials: DT
authors.lastname: Li
authors.affiliation: School of Public Health, Capital Medical University, Beijing 100069, China; Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing 100069, China.
authors.forename: Xiu Hua
authors.initials: XH
authors.lastname: Guo
authors.affiliation: School of Public Health, Capital Medical University, Beijing 100069, China; Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing 100069, China.
authors.forename: Xing Hua
authors.initials: XH
authors.lastname: Yang
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000068476:Beijing; D015992:Body Mass Index; D002908:Chronic Disease / Q000401:mortality*; D015331:Cohort Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016016:Proportional Hazards Models; D012307:Risk Factors
keywords: All-cause mortality; Beijing; Body mass index; The elderly