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Background: The association of physical activity through early childhood on children's chronic stress still is unclear. Therefore, the aim of the present study is to test the association of physical activity through early childhood (1–4 y) with chronic stress, measured by hair cortisol at age 4. Methods: Longitudinal study including children from the 2015 Pelotas (Brazil) Birth Cohort. Cortisol at age 4 was measured using a hair sample, which provided cortisol concentration from the past months. Physical activity was measured using accelerometers at 1, 2, and 4 years. Linear regression models were used to assess the association between physical activity and chronic stress. Trajectory models were also applied to examine chronic stress in relation to physical activity patterns throughout early childhood. Results: Children with valid physical activity and hair cortisol data were included in the analyses (N = 1475). Three groups of physical activity trajectories between 1 and 4 years were identified: low, medium, and high. No association between physical activity at 1, 2, and 4 years and chronic stress at age 4 was observed. However, children in the "high" physical activity trajectory presented low cortisol concentration; the magnitude of the regression coefficient was slightly larger in girls (β = −0.125; 95% confidence interval, −0.326 to 0.074) than boys (β = −0.051; 95% confidence interval, −0.196 to 0.09). Conclusion: There was no clear association between physical activity and chronic stress in early childhood. Trajectories models suggest that higher activity throughout early childhood may positively impact chronic stress; however, more studies are needed to confirm that hypothesis. [ABSTRACT FROM AUTHOR]

Background: Motherhood has been associated with reduced leisure-time physical activity (LTPA) levels. We aim to assess maternal LTPA patterns from preconception to 4 years postpartum. Methods: The study was developed with mothers from the Pelotas 2015 Birth Cohort, Southern Brazil (n = 4273). LTPA data were self-reported for preconception, antenatal, and 3, 12, 24, and 48 months postpartum. Information on LTPA referring to preconception (3 mo before pregnancy) and each gestational trimester was retrospectively collected in perinatal. The prevalence of active mothers was calculated according to recommendations (≥150 min/wk). We described changes in LTPA between follow-ups and estimated the probability of mothers being active according to previous LTPA. We used group-based trajectory analysis to identify patterns of LTPA throughout the follow-ups. Results: The prevalence of active mothers during leisure time decreased in pregnancy and postpartum compared with preconception. At 12 months postpartum, LTPA levels rose again, but at 48 months, the rates of active mothers still had not returned to preconception levels. Prior LTPA engagement was an important determinant of the maintenance of LTPA. Trajectory analysis identified 4 patterns of maternal LTPA, and ∼80% of mothers were allocated to the "always inactive" group. Higher education and income, working outside the home, multiple births, and participating in the PAMELA study intervention were associated with a higher probability of mothers not being included in this predominantly inactive group. Conclusions: Motherhood is associated with declining rates of women meeting physical activity recommendations during pregnancy and early postpartum. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to investigate the effect of exercise during pregnancy on early childhood neurodevelopment (cognitive, motor, and language domains). Methods: A randomized controlled trial nested into the 2015 Pelotas (Brazil) Birth Cohort was conducted. Healthy pregnant women were enrolled between 16 and 20 weeks of gestation; 424 women and their children (intervention [n = 141]; control [n = 283]) were analyzed. An exercise-based intervention 3 times per week was delivered over 16 weeks. Child neurodevelopment and its domains were assessed at 1, 2, and 4 years. Standardized mean differences and 95% confidence intervals are presented. Results: No effects of exercise during pregnancy on child neurodevelopment and its domains at age 1 year were observed. Compared with the control group, children from women in the exercise group had higher language score at age 2 years (standardized mean differences = 0.23; 95% confidence intervals, 0.02 to 0.44) and higher cognitive score (standardized mean differences = 0.22; 95% confidence intervals, 0.03 to 0.41) at age 4 years. No effects of exercise during pregnancy were observed in the motor domain at 1, 2, and 4 years. Conclusions: No detrimental effects of exercise during pregnancy on child neurodevelopment were observed. In addition, these findings suggest that exercise during pregnancy can result in small benefits for language and cognitive development. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to investigate longitudinal associations between physical activity and early childhood neurodevelopment. Methods: Data from 1673 children from the 2015 Pelotas (Brazil) birth cohort study were analyzed. Physical activity was measured using accelerometers on the wrist at ages 1, 2, and 4 years. Neurodevelopment was measured using the Battelle Development Inventory at age 4 years. Linear regression models were used to test trajectories and cumulative associations of physical activity with child neurodevelopment. Results: Of the 3 physical activity trajectories observed, children in the medium (β = 1.17; 95% confidence interval, 0.25 to 2.10) and high (β = 2.22; 95% confidence interval, 0.61 to 3.82) trajectories showed higher neurodevelopment scores than children in the lower activity trajectory. Cumulative analyses showed that children in the highest tertile of physical activity in all follow-ups presented a mean neurodevelopment score 4.57 (95% confidence interval, 2.63 to 6.51) higher than children in the lowest tertile in all follow-ups. All analyses showed a dose–response characteristic of association, with higher physical activity indicating higher neurodevelopment scores. Conclusions: Physical activity may be an important predictor of neurodevelopment through early childhood. [ABSTRACT FROM AUTHOR]

Background: The aim of this study was to investigate the associations between screen time from ages 2 to 4 years and child neurodevelopment at age 4. Methods: The participants were from the 2004 (N = 3787) and 2015 (N = 3604) Pelotas (Brazil) birth cohort studies. Childhood neurodevelopment was assessed at age 4 using the Battelle Development Inventory. The time children spent on screen devices was reported by their guardians at ages 2 and 4 years. Linear regression models were used to investigate the association of: (i) time spent on television at ages 2 and 4 years; (ii) time spent on other screens at age 4; and (iii) total screen time at age 4 (television + other screens) with childhood neurodevelopment at age 4. Results: Average daily screen time among children born in 2004 and those born in 2005 aged 4 years were 3.4 (SD: 2.4) and 4.4 h (SD: 2.9), respectively. Overall, few associations of very small magnitude between screen time and child neurodevelopment were observed. Television time at 2 years of age was statistically associated with lower neurodevelopment at 4 years of age in the 2015 cohort (β = −0.30, 95%CI = −0.55; −0.05). Conversely, television time (β = 0.17, 95%CI = 0.07, 0.26) and total screen time (β = 0.22, 95%CI = 0.13, 0.31) at age 4 were associated with higher neurodevelopment at age 4 in the 2004 cohort. Conclusions: The findings of this study suggest that the amount of time spent on screen devices might not be associated with neurodevelopment of children under 5 years of age. The small magnitude and inconsistencies in the direction of associations did not find evidence to support the current guidelines for screen time at this age. Therefore, more studies, especially those with longitudinal data, are important to comprehend the true effect of screen time on neurodevelopment and other health outcomes. [ABSTRACT FROM AUTHOR]

Background: Physical activity levels decrease during pregnancy, and the time course of return to prepregnancy levels is unclear. This study aimed to describe changes in leisure-time physical activity (LTPA) and sitting time from 16 to 24 weeks of pregnancy to 12, 24, and 48 months postpartum in women with different education levels in Brazil. Methods: Data from 4000 mothers of children enrolled in the 2015 Pelotas (Brazil) Birth Cohort were analyzed. The women were interviewed between 16 and 24 weeks of pregnancy and when their children were aged 12, 24, and 48 months. The LTPA and sitting time were self-reported. Results: Only 15.7% of the women reported any LTPA during pregnancy; this declined to 7.9% at 12 months postpartum; it was 16.8% at 24 months and 23.2% at 48 months. On average, participants spent a mean (SD) of 6.4 (3.9), 4.2 (3.2), 4.3 (3.3), and 4.4 (3.3) hours per day sitting during pregnancy, and at 12, 24, and 48 months after the birth, respectively. Both any LTPA and high sitting (8+ h/d) were consistently higher among women with higher education. Conclusion: After 24 months postpartum, LTPA levels had returned to or exceeded pregnancy levels, but sitting time remained lower than during pregnancy. [ABSTRACT FROM AUTHOR]

Background: Physical activity (PA) during pregnancy is associated with several benefits in maternal and child outcomes, and its relationship with preterm birth is still conflicting. This study aims to examine the associations between PA during pregnancy and occurrence of preterm birth. Methods: PA was assessed by questionnaire (for each trimester) and accelerometry (second trimester) in women enrolled in a birth cohort study that started during pregnancy and included births that occurred between January 1 and December 31, 2015. Gestational age was based on the last menstrual period and ultrasonography. All deliveries before 37 weeks of gestation were considered preterm births. A Poisson regression model was used to measure associations controlling for potential confounders. Results: PA information was available for 4163 women and 13.8% of births were preterm. A total of 15.8% of women were engaged in PA during pregnancy. Multivariate analysis showed that only PA performed in the third trimester of pregnancy (prevalence ratio = 0.58; 95% confidence interval, 0.36–0.96) was associated with the outcome. Conclusions: PA performed in the third trimester of pregnancy was associated with a protection to preterm birth. Pregnant women should be counseled to engage in PA to lower the risk of premature delivery. [ABSTRACT FROM AUTHOR]

O objetivo deste estudo foi avaliar a percepção e o conhecimento sobre o exercício físico em uma população adulta urbana e estudar a associação entre o nível de conhecimento e características sócio-econômicas, demográficas e comportamentais. O delineamento utilizado foi do tipo transversal, de base populacional, e incluiu 3.182 indivíduos com idade igual ou superior a 20 anos. O questionário desenvolvido para pesquisa gerou um escore de conhecimento (0 a 25 pontos). O escore médio na população foi de 17,1 (DP = 4,0). Após ajuste, o sexo feminino, a faixa etária entre 30 e 40 anos, elevados níveis social e de escolaridade, mostraram-se fortemente associadas ao desfecho (p < 0,001). Também estiveram associados (p < 0,01) maiores níveis de atividade física, cor da pele branca e maiores Índices de Massa Corporal (IMC). Os resultados indicam que benefícios específicos do exercício são desconhecidos por parcelas da população. O aconselhamento sobre as vantagens de uma vida ativa não é uma prática comum entre professores.