Whole blood selenium and growth outcomes
LBW
REGRESSION
We examined associations between WBSe and birth weight among infants in our sample. We found negative associations between delivery WBSe and birth weight in unadjusted models, where per scaled unit increased in WBSe, birth weight decreased by 10 g, although results were not statistically significant.Likewise, we found null associations (risk ratio: 1·03, 95 % CI: 0·96, 1·1) for LBW per unit (g) increase in maternal delivery WBSe in unadjusted models, with increased risk (12–15 %) after accounting for confounders.In line with our findings for maternal delivery WBSe, we found estimates for associations between VC WBSe and birth weight to be significant with effect estimates suggesting a decrease in birth weight of between 24 and 27 g per unit increase in Se, between unadjusted and adjusted models. Results for risk of LBW were in concordance with our findings for birth weight, with a 6–11 % increased risk of the outcome per unit increase in WBSe in cord blood as presented in 
Modified Poisson regression analyses (risk ratios) for associations between maternal delivery and venous cord Se biomarkers and adverse birth outcomes(95 % confidence intervals)WBSe, whole blood selenium; SEPP1, selenoprotein P.WBSe scaled to represent the change in anthropometric outcome for every 10 µg/l increase in WBSe. Serum Se scaled to represent the change in anthropometric outcome for every 10 µg/l increase in serum Models adjusted for infant sex, season of birth, maternal age, maternal education, maternal height, maternal BMI, gravidity, vitamin D treatment group, delivery CRP, asset index quintiles, daily protein intake (kg), smoking and tobacco use during pregnancy.Associations between LAZ and WBSe in maternal delivery samples were not significant, although we found small negative associations between WBSe in VC blood and LAZ at birth, 12 and 24 months of age. Although effect estimates for associations between WBSe in maternal delivery samples and LAZ were small and in the negative direction, we did not find statistical significance across analyses for WBSe and growth outcomes across age time points. For associations between WBSe in VC blood and LAZ, we found small negative effect estimates across unadjusted models at birth, 1 year and 2 years of age. Although mildly attenuated after adjustment, associations between WBSe in VC blood and LAZ were no longer significant, or in sensitivity analyses, after adjusting for cotinine (online Supplementary Tables Associations between WAZ and delivery WBSe, although similar in magnitude to those observed for LAZ, were not significant in unadjusted models; however, effect estimates increased marginally, and significance was achieved after adjustment and in sensitivity analyses with cotinine. We found small negative associations between WAZ and WBSe in VC at birth in unadjusted and adjusted models. Overall trends ran in the same direction across unadjusted and adjusted models for other growth outcomes including weight-for-length and head circumference for age z-scores.