Selenium status in pregnancy influences children's cognitive function at 1.5 years of age.

BACKGROUND & AIMS: Selenium deficiency has been shown to affect the neurological development in animals, but human research in this area is scarce. We aimed to assess the impact of selenium status during pregnancy on child development at 1.5 years of age. METHODS: This prospective cohort study was nested into a food and micronutrient supplementation trial (MINIMat) conducted in rural Bangladesh. Using inductively coupled plasma mass spectrometry, we measured selenium concentrations in erythrocyte fraction of blood collected from 750 mothers at gestational week 30, and calculated µg per g hemoglobin. A revised version of Bayley Scales of Infant Development was used to assess children's mental and psychomotor development. A Bangladeshi version of MacArthur's Communicative Development Inventory was used to assess language comprehension and expression. Linear regression analyses adjusted for multiple covariates were used to assess the associations. RESULTS: Maternal erythrocyte selenium concentrations varied considerably, from 0.19 to 0.87 µg/g hemoglobin (median 0.46 µg/g hemoglobin), and were associated with developmental measures. An increase in erythrocyte selenium by 0.50 µg/g hemoglobin was associated with an increase in children's language comprehension by 3.7 points (0.5 standard deviations; 95% confidence interval: 0.40, 7.1; p = 0.028). The same increase in erythrocyte selenium corresponded to an increase in the girls' psychomotor development by 12 points (0.9 standard deviation; 95% confidence interval: 4.3, 19; p = 0.002), but much less in boys. CONCLUSIONS: Low prenatal selenium status seems to be disadvantageous for children's psychomotor and language development. Further studies are needed to elucidate the underlying mechanisms of these effects.

Maternal and early life exposure to manganese in rural Bangladesh.

Manganese exposure and biomarker concentrations during early pregnancy and lactation were investigated in 408 women living in an area with elevated concentrations of both arsenic and manganese in drinking water derived from wells. About 40% of the water samples had manganese concentrations above the World Health Organization's guideline value and showed a strong inverse correlation with arsenic concentrations. Water manganese was found to correlate to urine concentrations, but not to blood or breast milk concentrations. No correlations were found among manganese concentrations in urine, blood, or breast milk. Compared to other populations, manganese concentrations in both urine and blood, but not breast milk, were elevated in the Bangladeshi women and more similar to those of occupationally exposed groups. The lack of associations with water manganese is likely due to variable exposure via water and food, and differences in bioavailability, as well as a complex and/or strict regulation of intestinal manganese absorption, in turn being influenced by nutritional as well as physiological and genetic factors. The results indicate that elevated maternal manganese exposure does not necessarily lead to exposure of breast-fed infants, stressing the importance of breast feeding in high manganese areas. However, the implications of fetal exposurefrom elevated maternal exposure need further investigation.