title: Do socioeconomic factors shape weight and obesity trajectories over the transition from midlife to old age? Results from the French GAZEL cohort study.
abstract: BACKGROUND
  Obesity is a contemporary epidemic that does not affect all age groups and sections of society equally.
  
  
  OBJECTIVE
  The objective was to examine socioeconomic differences in trajectories of body mass index (BMI; in kg/m(2)) and obesity between the ages of 45 and 65 y.
  
  
  METHODS
  A total of 13,297 men and 4532 women from the French GAZEL (Gaz de France Electricité de France) cohort study reported their height in 1990 and their weight annually over the subsequent 18 y. Changes in BMI and obesity between ages 45 and 49 y, 50 and 54 y, 55 and 59 y, and 60 and 65 y as a function of education and occupational position (at age 35 y) were modeled by using linear mixed models and generalized estimating equations.
  
  
  RESULTS
  BMI and obesity rates increased between the ages of 45 and 65 y. In men, BMI was higher in unskilled workers than in managers at age 45 y; this difference in BMI increased from 0.82 (95% CI: 0.66, 0.99) at 45 y to 1.06 (95% CI: 0.85, 1.27) at 65 y. Men with a primary school education compared with those with a high school degree at age 45 y had a 0.75 (95% CI: 0.51, 1.00) higher BMI, and this difference increased to 1.32 (95% CI: 1.03,1.62) at age 65 y. Obesity rates were 3.35% and 7.68% at age 45 y and 9.52% and 18.10% at age 65 y in managers and unskilled workers, respectively; the difference in obesity increased by 4.25% (95% CI: 1.87, 6.52). A similar trend was observed in women.
  
  
  CONCLUSIONS
  Weight continues to increase in the transition between midlife and old age; this increase is greater in lower socioeconomic groups.
authors.affiliation: INSERM U1018 Centre for Research in Epidemiology and Population Health, Villejuif, France. aline.dugravot@inserm.fr
authors.forename: Aline
authors.initials: A
authors.lastname: Dugravot
authors.forename: Séverine
authors.initials: S
authors.lastname: Sabia
authors.forename: Silvia
authors.initials: S
authors.lastname: Stringhini
authors.forename: Mika
authors.initials: M
authors.lastname: Kivimaki
authors.forename: Hugo
authors.initials: H
authors.lastname: Westerlund
authors.forename: Jussi
authors.initials: J
authors.lastname: Vahtera
authors.forename: Alice
authors.initials: A
authors.lastname: Guéguen
authors.forename: Marie
authors.initials: M
authors.lastname: Zins
authors.forename: Marcel
authors.initials: M
authors.lastname: Goldberg
authors.forename: Hermann
authors.initials: H
authors.lastname: Nabi
authors.forename: Archana
authors.initials: A
authors.lastname: Singh-Manoux
mesh_terms: D000368:Aged; D015992:Body Mass Index; D015331:Cohort Studies; D004522:Educational Status; D005260:Female; D005602:France / Q000453:epidemiology; D014943:Global Health; D006801:Humans; D008017:Life Expectancy; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000453:epidemiology*; D009790:Occupations; D012307:Risk Factors; D012923:Social Class; D012959:Socioeconomic Factors; D015430:Weight Gain; D014944:World Health Organization