title: Influence of socioeconomic status on the association between body mass index and cause-specific mortality among older Japanese adults: The AGES Cohort Study.
abstract: OBJECTIVE
  Many studies have suggested a U-shaped curve for the association between body size and mortality risks, i.e., mortality risks increase in those who are both overweight and underweight. The strength of the associations may vary according to socioeconomic statuses (SES), as they determine levels of access to healthcare and psychosocial stresses. We investigated the modifying effects of SES on the relationship between body mass index (BMI) and mortality.
  
  
  METHODS
  We used prospective cohort data of participants in the Aichi Gerontological Evaluation Study in 2003 (n=14,931), who were 65years or older and physically and cognitively independent at baseline, and residing in eight municipalities in Japan. Data on all-causes mortality and mortality from cancer, cardiovascular disease, and respiratory disease was obtained from municipal government registries.
  
  
  RESULTS
  Proportional hazard regression analyses showed that, among men, the associations between overweight (BMI≥25kg/m(2)) and higher mortality risks by any cause were stronger among lower income groups. Even adjusting for multiple confounding factors, hazard ratios (95% confidence intervals) for mortality by all causes among low income group (household income<1.5 million yen) were 1.96 (1.02-3.73) for overweight compared with BMIs between 23.0 and 24.9, whereas they were 0.94 (0.57-1.38) among men in high income group (income>3 million yen). The modifying effects of income were not marked among women.
  
  
  CONCLUSIONS
  Household income, which may directly reflect accessibility to healthcare and psychosocial stress among older Japanese men, may be an important modifying factor in the health risks attributable to overweight.
authors.affiliation: Department of Health and Nutrition, Tokaigakuen University, 2-901 Nakahira, Tempaku-ku, Nagoya-shi, Aichi-ken 468-0014, Japan.
authors.forename: Miyo
authors.initials: M
authors.lastname: Nakade
authors.affiliation: Department of Health and Social Behavior, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan.
authors.forename: Daisuke
authors.initials: D
authors.lastname: Takagi
authors.affiliation: Department of Policy Studies, Aichi Gakuin University, 12 Araike, Iwasaki-cho, Nisshin-shi, Aichi-ken 470-0131, Japan.
authors.forename: Kayo
authors.initials: K
authors.lastname: Suzuki
authors.affiliation: Graduate School of Dentistry, Tohoku University, 4-1 Seiryo-cho, Aoba-ku, Sendai-shi, Miyagi-ken 980-8575, Japan.
authors.forename: Jun
authors.initials: J
authors.lastname: Aida
authors.affiliation: Department of Community Health and Preventive Medicine, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu-shi, Shizuoka-ken 431-3192, Japan.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Ojima
authors.affiliation: Center for Well-being and Society, Nihon Fukushi University, 5-22-35 Chiyoda, Naka-ku, Nagoya-shi, Aichi-ken 460-0012, Japan; Center for Preventive Medical Science, Chiba University, 1-8-1 Inohana, Chuo-ku, Chiba-shi, Chiba-ken 260-8670, Japan.
authors.forename: Katsunori
authors.initials: K
authors.lastname: Kondo
authors.affiliation: Department of Civil and Environmental Engineering, Iwate University, 4-3-5 Ueda, Morioka-shi, Iwate-ken 020-8551, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Hirai
authors.affiliation: Department of Health and Social Behavior, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan. Electronic address: naoki-kondo@umin.ac.jp.
authors.forename: Naoki
authors.initials: N
authors.lastname: Kondo
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015992:Body Mass Index; D002318:Cardiovascular Diseases / Q000401:mortality; D002423:Cause of Death; D005260:Female; D006801:Humans; D007564:Japan / Q000453:epidemiology; D008297:Male; D009369:Neoplasms / Q000401:mortality; D050177:Overweight / Q000401:mortality; D011446:Prospective Studies; D012140:Respiratory Tract Diseases / Q000401:mortality; D012923:Social Class; D013851:Thinness / Q000401:mortality
keywords: Aged; Japan; Mortality; Overweight; Socioeconomic status; Underweight