title: Changes in health behaviors and the trajectory of body mass index among older Japanese: A 19-year longitudinal study.
abstract: OBJECTIVE
  Although the modification of lifestyle factors might facilitate weight control, the effects of health behaviors on the trajectory of bodyweight among older adults have been understudied. We examined the effect of changes in smoking, alcohol use and physical activity on the long-term trajectory of body mass index (BMI) among older Japanese adults.
  
  
  METHODS
  Data came from a national sample of 4869 Japanese adults aged 60 years and older at baseline, with up to seven repeated observations over a period of 19 years (1987-2006). Hierarchical linear modeling was used to analyze the intrapersonal and interpersonal differences in BMI trajectory.
  
  
  RESULTS
  The average BMI among older Japanese adults was 22.3 at baseline, and decreased with an accelerating rate over time. Smoking was significantly associated with lower BMI over time, whereas smoking cessation was associated with higher BMI. Drinking and physical activity were not associated with BMI. We found significant interactions between age and smoking status, and between sex and physical activity, on BMI trajectory: the association between smoking and lower BMI was stronger in younger participants compared with older participants. The association between physical activity and higher BMI was more pronounced among men compared with women.
  
  
  CONCLUSIONS
  The present findings yield important new information regarding the complex dynamics underlying the linkage between lifestyles factors and BMI trajectory among older Japanese, and suggest that there might be cross-cultural differences in these linkages. Geriatr Gerontol Int 2017; 17: 2008-2016.
authors.affiliation: Institute of Gerontology, The University of Tokyo, Tokyo, Japan.|Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Murayama
authors.affiliation: Department of Health Management and Policy, University of Michigan School of Public Health, New York.
authors.forename: Jersey
authors.initials: J
authors.lastname: Liang
authors.affiliation: Department of Health Policy, Management and Behavior, School of Public Health, State University of New York at Albany, New York.
authors.forename: Benjamin A
authors.initials: BA
authors.lastname: Shaw
authors.affiliation: Department of Health and Human Services, University of Michigan, Michigan, USA.|Institute of Gerontology, University of Michigan, Michigan, USA.
authors.forename: Anda
authors.initials: A
authors.lastname: Botoseneanu
authors.affiliation: Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Erika
authors.initials: E
authors.lastname: Kobayashi
authors.affiliation: Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Fukaya
authors.affiliation: Tokyo Metropolitan Institute of Gerontology, Tokyo, Japan.
authors.forename: Shoji
authors.initials: S
authors.lastname: Shinkai
mesh_terms: D000368:Aged; D000428:Alcohol Drinking / Q000523:psychology; D015992:Body Mass Index; D000077962:Body-Weight Trajectory; D015444:Exercise / Q000523:psychology; D005260:Female; D015438:Health Behavior; D006801:Humans; D007564:Japan; D008019:Life Style; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D012907:Smoking / Q000523:psychology
keywords: Japan; body mass index; health behavior; hierarchical linear modeling; trajectory