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Background: American women tend to reduce physical activity (PA) during the transition to motherhood. Their main barrier to participation in PA is lack of time due to new/increased parenting and housework responsibilities. Because there are known racial/ethnic variations in time spent on housework among American women, their PA changes during the transition to motherhood might also differ by racial/ ethnic background. This study aimed to compare PA between American mothers of young child(ren) under age 5 years (YC) and American women without children by their racial/ethnic background., Methods: Secondary data analyses were conducted using 2011-2018 US National Health and Nutrition Survey data. The study sample included 4,892 women aged 20-45 years (Asian n = 760; Black n = 1,162; Hispanic n = 1,324; White n = 1,646). Participants completed a Physical Activity Questionnaire that asked about participation in transportation and leisure-time moderate- and vigorous-intensity PA (MVPA; minutes/week). Multivariable regression analyses were conducted to compare MVPA among women living without children and with YC (no older children) in each of the racial/ethnic groups., Results: Overall, the prevalence of physical inactivity, defined as zero minutes of MVPA in a typical week, was 43% (95% CI = 38-49%) vs. 32% (95% CI = 29-35%) among women living with YC vs. without children. The adjusted odds of physical inactivity for women living with YC, compared to women living without children, was significantly higher among Asian (OR = 2.08 [95% CI = 1.37-3.17]) and White women (OR = 1.63 [95% CI = 1.11-2.38]), while it was statistically insignificant among Hispanic and Black women. Among women who reported participating in MVPA, Asian women living with YC had 35 fewer minutes/week of MVPA than their counterparts living without children (p = 0.06), while other racial and ethnic groups showed no significant differences., Conclusions: American mothers of YC were less likely to engage in transportation or leisure-time MVPA, compared to those living without children. This association was particularly strong among Asian women. The study results suggest that a PA reduction in the transition to motherhood may be particularly large among Asian American women, calling for targeted efforts for PA promotion among Asian American mothers of YC; e.g., culturally-tailored community-based physical activity programs for Asian American mothers., (© 2023. BioMed Central Ltd., part of Springer Nature.)

Background: In utero exposure to diabetes has been shown to contribute to preterm birth, though the underlying biological mechanisms are yet to be fully elucidated. Fetal epigenetic variations established in utero may be a possible pathway. This study aimed to investigate whether in utero exposure to diabetes was associated with a change in newborn DNA methylation, and whether the identified CpG sites mediate the association between diabetes and preterm birth in a racially diverse birth cohort population., Methods: This study included 954 mother-newborn pairs. Methylation levels in the cord blood were determined using the Illumina Infinium MethylationEPIC BeadChip 850 K array platform. In utero exposure to diabetes was defined by the presence of maternal pregestational or gestational diabetes. Preterm birth was defined as gestational age at birth less than 37 weeks. Linear regression analysis was employed to identify differentially methylated CpG sites. Differentially methylated regions were identified using the DMRcate Package., Results: 126 (13%) newborns were born to mothers with diabetes in pregnancy and 173 (18%) newborns were born preterm, while 41 newborns were born both preterm and to mothers with diabetes in pregnancy. Genomic-wide CpG analysis found that eighteen CpG sites in cord blood were differentially methylated by maternal diabetes status at an FDR threshold of 5%. These significant CpG sites were mapped to 12 known genes, one of which was annotated to gene Major Histocompatibility Complex, Class II, DM Beta (HLA-DMB). Consistently, one of the two identified significant methylated regions overlapped with HLA-DMB. The identified differentially methylated CpG sites mediated the association between diabetes in pregnancy and preterm birth by 61%., Conclusions: In this US birth cohort, we found that maternal diabetes was associated with altered fetal DNA methylation patterns, which substantially explained the link between diabetes and preterm birth., (© 2023. The Author(s).)

Background: Low-dose mercury (Hg) exposure has been associated with cardiovascular diseases, diabetes, and obesity in adults, but it is unknown the metabolic consequence of in utero Hg exposure. This study aimed to investigate the association between in utero Hg exposure and child overweight or obesity (OWO) and to explore if adequate maternal folate can mitigate Hg toxicity., Methods: This prospective study included 1442 mother-child pairs recruited at birth and followed up to age 15 years. Maternal Hg in red blood cells and plasma folate levels were measured in samples collected 1-3 days after delivery (a proxy for third trimester exposure). Adequate folate was defined as plasma folate ≥ 20.4 nmol/L. Childhood OWO was defined as body mass index ≥ 85% percentile for age and sex., Results: The median (interquartile range) of maternal Hg levels were 2.11 (1.04-3.70) μg/L. Geometric mean (95% CI) of maternal folate levels were 31.1 (30.1-32.1) nmol/L. Maternal Hg levels were positively associated with child OWO from age 2-15 years, independent of maternal pre-pregnancy OWO, diabetes, and other covariates. The relative risk (RR = 1.24, 95% CI 1.05-1.47) of child OWO associated with the highest quartile of Hg exposure was 24% higher than those with the lowest quartile. Maternal pre-pregnancy OWO and/or diabetes additively enhanced Hg toxicity. The highest risk of child OWO was found among children of OWO and diabetic mothers in the top Hg quartile (RR = 2.06; 95% CI 1.56-2.71) compared to their counterparts. Furthermore, adequate maternal folate status mitigated Hg toxicity. Given top quartile Hg exposure, adequate maternal folate was associated with a 34% reduction in child OWO risk (RR = 0.66, 95% CI 0.51-0.85) as compared with insufficient maternal folate. There was a suggestive interaction between maternal Hg and folate levels on child OWO risk (p for interaction = 0.086)., Conclusions: In this US urban, multi-ethnic population, elevated in utero Hg exposure was associated with a higher risk of OWO in childhood, and such risk was enhanced by maternal OWO and/or diabetes and reduced by adequate maternal folate. These findings underscore the need to screen for Hg and to optimize maternal folate status, especially among mothers with OWO and/or diabetes.