Padrões de atividade física e associação da atividade física e do índice de massa corporal com sintomas depressivos nas mães da Coorte de Nascimentos de Pelotas de 2015: do pré-natal aos quatro anos pós-parto

Abstract

This thesis aimed to verify the prevalence and pattern of maternal physical activity (PA) practice before, during, and up to 48 months after pregnancy and to verify the relationships between PA and body mass index (BMI) and depressive symptoms. The Thesis consists of two articles, based on data from the mothers of the 2015 Birth Cohort in Pelotas (RS). Article 1 used self-reported data on leisure-time PA during preconception, pregnancy, 3, 12, 24, and 48 months postpartum. The prevalence of active mothers was calculated according to the recommendations (≥ 150 min/week) and changes in PA between follow-ups were described. The probability of mothers being active according to previous PA was estimated using Poisson Regression with robust variance. Group-based trajectory analysis was used to identify PA patterns across follow-ups. The prevalence of active mothers decreased during pregnancy and postpartum in relation to the pre-pregnancy period. That previous PA practice was an important determinant of PA maintenance. Trajectory analysis identified four PA patterns and ~80% of mothers were allocated to the predominantly inactive group. Article 2 evaluated the moderating role of moderate and vigorous PA (MVPA) in the association of BMI with maternal depressive symptoms. Depressive symptoms were assessed at antenatal, 3-, 24-, and 48-months postpartum follow-ups using the Edinburgh Depression Scale. MVPA was measured by accelerometry antenatal and at 24 months. BMI was calculated from postpartum weight and height measurements and self-reported prepregnancy weight. Moderation analysis was performed using the macro-PROCESS tool for SPSS, testing the following relationships: association of BMI with depressive symptoms; association of MVPA with depressive symptoms; and the interaction between BMI and MVPA. MVPA moderation was assessed both cross-sectionally and longitudinally. The outcome was always evaluated temporally after the BMI. A significant interaction was observed between antenatal MVPA (5 and 10-minute bouts) and preconception BMI, indicating that MVPA was a moderator of the relationship between antenatal depressive symptoms and BMI. When MVPA levels were low or intermediate (16th and 50th percentiles), the relationship between BMI and depressive symptoms was not significant. For higher levels of MVPA (84th percentile), the relationship becomes significant and inverse, in which mothers with higher BMI and high MVPA have lower scores of depressive symptoms. Three months postpartum, a similar relationship is demonstrated, with a significant interaction between MVPA (10-minute bout) and pre-pregnancy BMI. At 24 and 48 months no association was found. In conclusion, MVPA during pregnancy helps reduce antenatal depressive symptoms and three months postpartum among mothers with higher BMI.