title: BMI and all-cause mortality among middle-aged and older adults in Taiwan: a population-based cohort study.
abstract: OBJECTIVE
  The present study investigates the relationship between BMI and all-cause mortality among middle-aged and older adults with or without pre-existing diseases.
  
  
  METHODS
  A population-based cohort study.
  
  
  METHODS
  The Taiwan Longitudinal Study on Aging is a nationwide prospective cohort study comprising a representative random sample of middle-aged and older adults. The study period was 1996-2007.
  
  
  METHODS
  We followed 4145 middle-aged and older adults, totalling 42,353 person-years.
  
  
  RESULTS
  Overweight and mildly obese participants showed a 16% and 30% decrease in the risk of death, respectively, compared with those of normal weight after adjusting for potential covariates (e.g. demographic characteristics, health behaviour, co-morbidities and physical function). Underweight adults showed a 1.36-fold increased adjusted hazard ratio of death compared with normal-weight adults. Adults with a BMI of 27.0-28.0 kg/m(2) showed a significantly lower adjusted hazard ratio of all-cause mortality rate compared with adults who had normal BMI values when they had coexisting hypertension or diabetes (adjusted hazard ratio = 0.50; 95% CI 0.30, 0.81 for hypertension and adjusted hazard ratio=0.41; 95% CI 0.18, 0.89 for diabetes).
  
  
  CONCLUSIONS
  The study demonstrates that underweight people have a higher risk of death, and overweight and mildly obese people have a lower risk of death, compared with people of normal weight among middle-aged and older adults. An optimal BMI may be based on the individual, who exhibits pre-existing diseases or not.
authors.affiliation: 1Department of Internal Medicine,Taichung Hospital,Ministry of Health and Welfare,No. 199,Sec. 1,San-Min Road,Taichung City 40343,Taichung,Taiwan.
authors.forename: Wei-Sheng
authors.initials: WS
authors.lastname: Chung
authors.affiliation: 3Department of Internal Medicine,Taoyuan Hospital,Ministry of Health and Welfare,Taoyuan,Taiwan.
authors.forename: Feng-Ming
authors.initials: FM
authors.lastname: Ho
authors.affiliation: 1Department of Internal Medicine,Taichung Hospital,Ministry of Health and Welfare,No. 199,Sec. 1,San-Min Road,Taichung City 40343,Taichung,Taiwan.
authors.forename: Nan-Cheng
authors.initials: NC
authors.lastname: Cheng
authors.affiliation: 4Department of Family Medicine,Taichung Hospital,Ministry of Health and Welfare,Taichung,Taiwan.
authors.forename: Meng-Chih
authors.initials: MC
authors.lastname: Lee
authors.affiliation: 5School of Public Health,Chung-Shan Medical University,Room 1237,No. 110,Sec. 1,Jianguo N. Road,Taichung City 40201,Taiwan.
authors.forename: Chih-Jung
authors.initials: CJ
authors.lastname: Yeh
mesh_terms: D000368:Aged; D015992:Body Mass Index; D002423:Cause of Death; D003920:Diabetes Mellitus; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000401:mortality*; D050177:Overweight / Q000401:mortality; D011446:Prospective Studies; D012016:Reference Values; D012307:Risk Factors; D013624:Taiwan / Q000453:epidemiology; D013851:Thinness / Q000401:mortality*
keywords: BMI; Middle-aged and older adults; Mortality; Prospective cohort study