Objective: In post-transitional countries, obesity disproportionally affects women. Longitudinal studies can detect high-risk groups in whom to target actions. We investigated the magnitude and velocity of BMI changes in Chilean women of reproductive age and evaluated whether these trends vary in specific groups.
Design: Longitudinal study. We measured weight and height in 2007 (baseline) and again in 2010 (follow-up); we estimated change in BMI (weight/height2) within the 3-year period and assessed its relationship with age, years of education and parity, collected at baseline and follow-up using a questionnaire.
Setting: Population-based cohort of low- to middle-income Chilean women.
Subjects: Seven hundred and sixty-one women of reproductive age (mean 32·0 (sd 7·0) years), mothers of children who participate in the Growth and Obesity Cohort Study (GOCS).
Results: At baseline, 61 % of women had BMI ≥ 25·0 kg/m2. After 3 years, women gained on average 2·6 kg and obesity (BMI ≥ 30·0 kg/m2) increased by 23 % (12 % new obesity cases). Women with normal nutritional status gained more BMI than obese women (1·4 v. 0·6 kg/m2, P < 0·001). An increase in parity was positively associated with BMI change, independently of age, nutritional status and education (P < 0·05). Age and education were not associated with BMI change after controlling for other factors (P > 0·05).
Conclusions: In Chile, a post-transitional country, we observed an alarming increase in obesity among women of reproductive age. Our results indicate that in this population actions need to be targeted at all women irrespective of their nutritional status. A key component of these policies should be avoiding excessive weight gain during pregnancy.