Pre-pregnancy weight excess and body mass index: Analysis of three generations Brazilian birth cohort

To evaluate the relationship between the grandmother's maternal pre-pregnancy body mass index (BMI) (first generation-G1), the BMI of the female members of the birth cohort of Pelotas/RS, Brazil, 1993 (second generation-G2) and the children of the cohort members (third generation-G3). a longitudinal study using data from the 1993 Pelotas/RS cohort. The maternal pre-pregnancy BMI of the mothers of the members (first generation-G1) was self-reported, and of the participants in the cohort (second generation-G2) was collected using weight and height in follow-ups prior to 22 years of age. Children from the third generation (G3) were included in this last follow-up (22 years) and anthropometric measurements were collected. The outcome was BMI-for-age z-score obtained using weight and height measures collected in every follow-up. Linear regression was performed with adjustment for possible confounding factors. The cohort's original sample consists of 5249 participants and 855 children (their first children). At 12 and 48 months, the average increase in BMI-for-age z-score of children of women with pre-pregnancy weight excess was 0.11 and 0.47 kg/m(2), respectively, increasing to around 0.60 kg/m(2) in adolescence, reaching an average increase of 2.71 kg/m(2) in BMI at 22 years of age. The G2 pre-pregnancy weight excess was also associated with G3 BMI-for-age z-score [beta = 0.43 kg/m(2) (95% CI 0.21; 0.65)]. Maternal pre-pregnancy weight excess was associated with the child's BMI-for-age z-score, in both G2 and G3, suggesting a proximal relationship, with no association between G1 and G3.