Grandmaternal pre-pregnancy body mass index and infant birthweight: a mediation analysis of maternal pre-pregnancy body mass index.

The objectives of this study were to examine the total effect of grandmaternal [G0] pre-pregnancy body mass index (BMI) on infant [G2] birthweight z-score and to quantify the mediation role of maternal [G1] pre-pregnancy BMI. Data were extracted from the Nova Scotia 3G Multigenerational Cohort. The association between G0 pre-pregnancy BMI and G2 birthweight z-score and the mediated effect by G1 pre-pregnancy BMI were estimated using g-computation with adjustment for confounders identified using a directed acyclic graph and accounting for intermediate confounding. 20822 G1-G2 dyads from 18450 G0 were included. Relative to G0 normal weight, G0 underweight decreased mean G2 birthweight z-score (-0.11, 95% confidence interval (CI) -0.20, -0.030), while G0 overweight and obesity increased mean G2 birthweight z-score (0.091 [95% CI 0.034, 0.15] and 0.22 [95% CI 0.11, 0.33]). G1 pre-pregnancy BMI partly mediated the association, with the largest effect size observed for G0 obesity (0.11, 95% CI 0.080, 0.14). Estimates of the direct effect were close to the null. In conclusion, grandmaternal pre-pregnancy BMI was associated with infant birthweight z-score. Maternal pre-pregnancy BMI partly mediated the association, suggesting that factors related to BMI may play an important role in the transmission of weight across the maternal line.

Teachers reported that children with special health care needs displayed more attention problems.

AIM: Children with special health care needs (SHCN) perform more poorly at school compared to their classmates. Specific causal pathways have not yet been extensively studied. Therefore, we investigated teacher-rated global attention, an important prerequisite for educational attainment, in children with SHCN. METHODS: Data of a population-based prospective cohort study, which recruited preschool children from the Mainz-Bingen area, Germany, were analysed. Children with SHCN were identified by the Children with Special Health Care Needs screening tool. In 2016, global attention was reported by teachers at the end of first grade (mean age: 7.3 years) on a 5-point rating scale ranging from -2 through +2. Associations between SHCN consequences and teacher-rated attention were estimated by linear mixed models, adjusted for confounding variables. RESULTS: We included 1921 children (51% males); of these, 14% had SHCN. Compared to their classmates, children with SHCN had poorer teacher-rated attention scores (adjusted mean difference: -0.35, 95% CI: -0.52 to -0.17). The effect was strongest among children with treatment or counselling for mental health problems or functional limitations. The effect remained after excluding children with attention deficit hyperactivity disorder from the analysis. CONCLUSION: Children with SHCN showed more teacher-rated attention problems, which could explain their lower educational attainment.