title: Is there an obesity paradox in the Japanese elderly population? A community-based cohort study of 13 280 men and women.
abstract: OBJECTIVE
  Despite increased interest in an obesity paradox (i.e. a survival advantage of being obese), evidence remains sparse in Japanese populations. We aimed to verify this phenomenon among community-dwelling older adults in Japan.
  
  
  METHODS
  Older adults aged 65-84 years randomly chosen from all 74 municipalities in Shizuoka Prefecture completed questionnaires including body mass index information. Participants were followed from 1999 to 2009. Following World Health Organization guidelines, participants were classified using an appropriate body mass index for Asian populations as follows: <18.5 kg/m2(underweight), 18.5-23.0 kg/m2(normal weight), 23.0-27.5 kg/m2(overweight) and ≥27.5 kg/m2(obesity). We estimated hazard ratios and their 95% confidence intervals for all-cause mortality, controlling for sex, age, smoking status, alcohol consumption, physical activity, hypertension and diabetes mellitus.
  
  
  RESULTS
  Compared with normal-weight participants, overweight/obese participants tended to have lower hazard ratios; the multivariate hazard ratios (95% confidence interval) were 0.86 (0.62-1.19) for obesity, 0.83 (0.73-0.94) for overweight and 1.60 (1.40-1.82) for underweight. In subgroup analyses by sex and age, the hazard ratios tended to be lower among obese men, albeit not significantly; hazard ratios (95% confidence interval) were 0.56 (0.25-1.27) in men aged 65-74 years, and 0.78 (0.41-1.45) in men aged 75-84 years.
  
  
  CONCLUSIONS
  The present study provides evidence of a conservative obesity paradox among older Japanese people, using the appropriate body mass index cut-off points for Asian populations. In particular, obese older men tend to have a lower risk of all-cause mortality. Geriatr Gerontol Int 2017; 17: 1257-1264.
authors.affiliation: Department of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Kenji
authors.initials: K
authors.lastname: Yamazaki
authors.affiliation: Department of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Etsuji
authors.initials: E
authors.lastname: Suzuki
authors.affiliation: Department of Human Ecology, Graduate School of Environmental and Life Science, Okayama University, Okayama, Japan.
authors.forename: Takashi
authors.initials: T
authors.lastname: Yorifuji
authors.affiliation: Department of Human Ecology, Graduate School of Environmental and Life Science, Okayama University, Okayama, Japan.
authors.forename: Toshihide
authors.initials: T
authors.lastname: Tsuda
authors.affiliation: National Hospital for Geriatric Medicine, National Center for Geriatrics and Gerontology, Aichi, Japan.|Nagoya Heart Center, Aichi, Japan.
authors.forename: Toshiki
authors.initials: T
authors.lastname: Ohta
authors.affiliation: Program of Health Promotion and Exercise, National Institute of Health and Nutrition, Tokyo, Japan.|Department of Nutritional Education, National Institutes of Biomedical Innovation, Health and Nutrition, Tokyo, Japan.
authors.forename: Kazuko
authors.initials: K
authors.lastname: Ishikawa-Takata
authors.affiliation: Department of Epidemiology, Graduate School of Medicine, Dentistry and Pharmaceutical Sciences, Okayama University, Okayama, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Doi
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D015331:Cohort Studies; D005260:Female; D015577:Geriatric Assessment; D006801:Humans; D057187:Independent Living; D007564:Japan / Q000453:epidemiology; D008297:Male; D009026:Mortality / Q000639:trends*; D009765:Obesity / Q000453:epidemiology*; D011795:Surveys and Questionnaires
keywords: Japanese; body mass index; elderly; mortality; obesity