ABSTRACT
Background Exercise during pregnancy is closely related to maternal and infant health. Previous studies in developed countries have linked maternal exercise during pregnancy with newborn body weight as well as subcutaneous fat thickness. However, the relevant studies in China are limited, and the conclusions remain inconsistent. Objective To investigate the effects of maternal exercise during pregnancy on neonatal weight and subcutaneous fat thickness. Methods Based on the Shanghai Birth Cohort, 959 maternal-infant pairs were included in this study. The International Physical Activity Questionnaire was used to collect average weekly frequency and daily minutes of walking in the first and second trimesters, and entropy weight method was used to calculate the cumulative exercise index in the two trimesters. Birth weight was measured using a calibrated weigh scale. Subcutaneous fat thickness was measured at abdomen, scapula, and triceps with a Harpenden skinfold caliper for all newborns and the sum of the thickness for the three sites was then calculated. A multiple linear regression model was employed to estimate the relationships of cumulative exercise index during pregnancy with neonatal body weight and subcutaneous fat thickness. Subgroup analyses stratified by pre-pregnancy body mass index (BMI) and sex of newborns were also performed. Results The mean age of pregnant women was (28.5±3.8) years, and the pre-pregnancy BMI was (21.4±3.0) kg·m−2. Newborn boys were slightly more than newborn girls (54.3% vs 45.7%), and the neonatal weight was (3374.0±427.5) g. The means of newborns' abdominal, scapular, and triceps subcutaneous fat thickness were (4.4±1.3), (5.4±1.4), and (6.0±1.5) mm, respectively, and the sum of subcutaneous fat thickness was (15.8±3.9) mm. In the first and second trimesters, 77.3% and 88.7% of pregnant women walked 4 d per week and more, respectively; the daily minutes of walking was (36.9±27.2) min and (43.3±26.3) min, respectively; the cumulative exercise index was 25.6±17.7 and 35.9±21.1, respectively. The results of multiple linear regression analysis showed that the cumulative exercise index in the second trimester was negatively associated with newborns' abdominal (b=−0.006, 95%CI: −0.010-−0.003), scapular (b=−0.005, 95%CI: −0.009-−0.002), triceps (b=−0.006, 95%CI: −0.010-−0.002), and their sum of (b=−0.018, 95%CI: −0.028-−0.007) subcutaneous fat thickness (P<0.05); in the first and second trimesters, however, the relationship between maternal cumulative exercise and newborns' body weight was not significant. The results of stratified analyses showed that the negative associations between maternal cumulative exercise index and newborns' subcutaneous fat thickness for the second trimester remained significant in the subgroups of boys and neonates whose mothers had normal pre-pregnancy BMI (P<0.05). Conclusion Cumulative exercise index in the second trimester is negatively correlated with the neonatal thickness of subcutaneous fat, and the association may be altered by neonatal sexes and maternal pre-pregnancy BMI levels.
ABSTRACT
Per-and polyfluoroalkylated substances (PFASs) are a group of persistent organic pollutants that are widespread in the environment and organisms. Given their unique hydrophobicity, oil-repellence, and chemical stability, PFASs are widely used in various industrial and commercial products. PFASs can accumulate and be biomagnified through the food chain, and its toxic effects have posed a certain threat to human health. The response of the immune system to PFASs exposure is one of the most sensitive human health effects, and has attracted remarkable attention from related scientists and organizations. We summarized international and domestic epidemiological studies on the associations between exposure to PFASs and immune system, including immunosuppression and immunoenhancement. We also reviewed experimental evidence of PFASs on immune system from perspectives of immune organs, immune cells, and cytokines. Furthermore, the possible mechanisms of peroxisome proliferator-activated receptor-α (PPAR-α)-dependent, nuclear factor-κB (NF-κB)-activated, and mitochondrial apoptosis pathways were summarized. While the relationships between PFASs and immune-related diseases in human are not yet conclusive, accumulative epidemiological studies provide evidence for associations between PFASs and reduced immune response to vaccination in children. In addition, previous studies mainly focus on the immunotoxicity of traditional PFASs, and our understanding of the molecular mechanism of the effects of PFASs on immune system is still in its infancy. Therefore, it is necessary to further explore the immunotoxicity of new PFASs and associated mechanism.