Manganese levels in newborns' hair by maternal sociodemographic, dietary and environmental factors.

Exposure to manganese (Mn) has been associated with neurodevelopmental problems in children. Mn exposure begins in utero, and maternal sociodemographic, dietary and environmental factors may affect Mn levels in newborns' hair. This study aimed to characterize in utero Mn exposure using Mn levels in newborns' hair as a biomarker of prenatal exposure, and to analyze its relationship with sociodemographic, dietary and environmental factors in the Spanish INMA-Gipuzkoa cohort. Overall, 638 pregnant women were recruited in the first trimester of pregnancy and a hair sample was obtained from 473 newborns. Sociodemographic, dietary and environmental data were recorded through two questionnaires administered in the first and third trimesters of pregnancy. The median Mn concentration in newborns´ hair was 0.31 µg/g (P5 = 0.02; P95 = 1.23). Mn levels in newborns´ hair were associated with smoking during pregnancy (ß = 0.222; 95% CI = 0.065-0.379) and with maternal PM2.5 exposure (ß = 0.025; 95% CI = 0.004; 0.047), as well as with cereal and pasta intake in the first trimester of pregnancy (ß = 0.002; 95% CI = 0.0004; 0.003). In conclusion, fetal exposure to Mn was associated with smoking and exposure to atmospheric pollution during pregnancy.

Compositional analysis of dietary patterns.

Instead of looking at individual nutrients or foods, dietary pattern analysis has emerged as a promising approach to examine the relationship between diet and health outcomes. Despite dietary patterns being compositional (i.e. usually a higher intake of some foods implies that less of other foods are being consumed), compositional data analysis has not yet been applied in this setting. We describe three compositional data analysis approaches (compositional principal component analysis, balances and principal balances) that enable the extraction of dietary patterns by using control subjects from the Spanish multicase-control (MCC-Spain) study. In particular, principal balances overcome the limitations of purely data-driven or investigator-driven methods and present dietary patterns as trade-offs between eating more of some foods and less of others.