title: Identifying the energy gap: magnitude and determinants of 5-year weight gain in midage women.
abstract: OBJECTIVE
  The aims of this study were to estimate average yearly weight gain in midage women and to identify the determinants of weight gain and gaining weight at double the average rate.
  
  
  METHODS
  The study sample comprised 8071 participants (45 to 55 years old) in the Australian Longitudinal Study on Women's Health who completed mailed surveys in 1996, 1998, and 2001.
  
  
  RESULTS
  On average, the women gained almost 0.5 kg per year [average 2.42 kg (95% confidence interval, 2.29 to 2.54) over 5 years]. In multivariate analyses, variables associated with energy balance (physical activity, sitting time, and energy intake), as well as quitting smoking, menopause/hysterectomy, and baseline BMI category were significantly associated with weight gain, but other behavioral and demographic characteristics were not. After adjustment for all of the other biological and behavioral variables, the odds of gaining weight at about twice the average rate (>5 kg over 5 years) were highest for women who quit smoking (odds ratio = 2.94; 95% confidence interval, 2.17, 3.96). There were also independent relationships between the odds of gaining >5 kg and lower levels of habitual physical activity, more time spent sitting, energy intake (but only in women with BMI > 25 at baseline), menopause transition, and hysterectomy.
  
  
  CONCLUSIONS
  The average weight gain equates with an energy imbalance of only about 10 kcal or 40 kJ per day, which suggests that small sustained changes in the modifiable behavioral variables could prevent further weight gain.
authors.affiliation: School of Human Movement Studies, University of Queensland, St. Lucia, Queensland 4072, Australia. wbrown@hms.uq.edu.au
authors.forename: Wendy J
authors.initials: WJ
authors.lastname: Brown
authors.forename: Lauren
authors.initials: L
authors.lastname: Williams
authors.forename: Jessica H
authors.initials: JH
authors.lastname: Ford
authors.forename: Kylie
authors.initials: K
authors.lastname: Ball
authors.forename: Annette J
authors.initials: AJ
authors.lastname: Dobson
mesh_terms: D000367:Age Factors; D001315:Australia; D002149:Energy Intake; D004734:Energy Metabolism; D015444:Exercise; D005260:Female; D006801:Humans; D008137:Longitudinal Studies; D008875:Middle Aged; D009765:Obesity / Q000517:prevention & control; D012307:Risk Factors; D013997:Time Factors; D015430:Weight Gain / Q000502:physiology