Discussion
toxicity, inflammation, PTB, weight gain
INFLAMMATION, IUGR, DISEASE, OSTEOCHONDROPATHY, MISCARRIAGE, OXIDATIVE STRESS, INFLAMMATORY RESPONSE
In this study of mother–infant dyads, we found measures of Se status in maternal delivery and VC blood serum, whole blood and plasma SEPP1 to be modestly associated with infant growth outcomes at birth, 12 months and 24 months of age, with variability in the strength and magnitude of associations across biomarkers and age points. Effect sizes in path analyses were negligible and do not suggest any mediation of the association between WBSe and WAZ at birth or 12 months, by VC SEPP1, likely because WBSe and SEPP1 have differing functions and therefore different impacts on weight and act as part of different metabolic pools that do not interact or share common pathways, as described in online Supplementary Fig. Several studies have examined the effects of Se in a variety of biological specimen types and their associations with infant growth outcomes
Epidemiological studies examining associations between SGA, small-for-gestational age; LBW, low birth weight; IUGR, intra-uterine growth restriction; IQR; inter-quartile range; GPx, glutathione peroxidase.During pregnancy, In a recent review of studies conducted across a variety of different geographies, results of the association between Se and birth and growth outcomes have been mixed, although overall associations suggested a positive and protective effect of this micronutrient (pooled correlation coefficient between VC blood The negative association between WBThe protective antioxidant effects of Se bound to selenoproteins including SEPP1 may work to increase birth weight during gestation. This may explain the positive associations with birth weight as observed in our study, given the known antioxidant properties of selenoproteins, which can protect the fetus from free radicals in utero, modulate inflammation and protect biological membranes and DNA during early stages of embryo developmentMixed findings about the effects of varied biomarkers of The primary mechanisms whereby Se has been associated with adverse growth outcomes include its essential role in antioxidant defence and its role in mediating oxidative stress, which could impact peri-natal morbidity and mortalityLow Se status, particularly in women, can impact the risk of PTBMechanistically, Se and PTB are linked because of the role this micronutrient plays in the body’s inflammatory response which can in turn cause ruptures to the fetal membraneWomen at increased risk of miscarriage may also have lower serum Similar to other birth-related outcomes, an increased risk for SGA has also been observed in relation to Se, likely driven by mechanisms associated with oxidative stressIn our study, we found very small negative associations between WBSe in VC blood and LAZ across age time points, in unadjusted and adjusted linear models, although other Se biomarkers were not associated with LAZ. We observed small effect sizes that were not significant for associations between serum Se at delivery and LAZ. This was in line with the literature for maternal serum SeLinear growth has been implicated as a potential outcome of interest in relation to the role of Se in bone growth. Kashin–Beck disease is a chronic osteochondropathy known to result from inherited genetic polymorphisms in Se-related genes which impair collagen synthesisIt is important to note that effect estimates for other growth outcomes in our study were negligible in magnitude and therefore do not suggest that Se biomarkers measured in our study play a major role in birth and growth outcomes in this cohort of mother–infant pairs. We did however find meaningful and substantial effect sizes for the associations between birth weight and biomarkers of Se status. These associations should be investigated further given that different Se biomarkers may act differently on mechanisms of weight gain at birth and in early infancy.Biomonitoring equivalents for toxic concentrations of Evidence exists to suggest that Se has a U-shaped dose–response toxicity curve, with negative health impacts experienced due to deficiency and excess as is evidenced in our dose–response analyses as well