[Association between dietary diversity score and overweight and obesity among postpartum women]

To investigate the association between the dietary diversity score(DDS) at one month postpartum and the risk of overweight/obesity during the first year after childbirth.

Based on Taicang and Wuqiang mother-child cohort study(TAWS) in China, we recruited women aged 18 to 45 in their first trimester of pregnancy and tracked their weight changes until one year postpartum. Doctors measured women's heights(at the first prenatal care) and measured their weights during pregnancy at 42 days and 3 months postpartum. Women measured their weights at home and reported to doctors by phone at 6 months and 1 year postpartum. The body mass index(BMI) was calculated and BMI ≥ 24.0 kg/m~2 was defined as overweight/obesity. The food frequency questionnaire(FFQ) was used to collect their food intake information. Foods were classified into six major categories and 27 subcategories, and the DDS was calculated(range:-2 to 10). Subjects were divided into four groups based on their DDS quartiles(Q1-Q4). Multivariate Logistic regression analysis was used to analyze the association between DDS and the risk of overweight/obesity.

There were 257 women in this study, and the rates of overweight/obesity were 10.89% before pregnancy, 23.74%, 18.78% 17.90%, and 15.17% at 42 days, 3 months, 6 months and 1 year postpartum. The median(P25, P75) DDS was 6.71(5.43, 7.65). Compared with the Q1 group, the Q3 group had a significantly lower likelihood of overweight/obesity after childbirth within 1 year postpartum(42 days: OR=0.32, 95%CI 0.10-1.00; 3 months: OR=0.19, 95%CI 0.05-0.72; 6 months: OR=0.22, 95%CI 0.07-0.69; 1 year: OR=0.22, 95%CI 0.06-0.84); whereas the Q4 group had a lower likelihood of overweight/obesity at 3 months postpartum(OR=0.19, 95%CI 0.04-0.88). In the subgroup of 194 women with a daily energy intake between 1000 and 4000 kcal/d, after adjusting for energy intake, the Q3 group had a lower likelihood of overweight/obesity at 6 months(OR=0.19, 95%CI 0.05-0.76) and 1 year postpartum(OR=0.16, 95%CI 0.03-0.96) compared with Q1; while the likelihood of overweight/obesity in the Q4 group was not statistically different from that in the Q1 group at any time point.

When dietary energy intake is within a appropriate range, a higher DDS is beneficial for weight control in postpartum women.