Genetic and environmental factors associated with vitamin B12 status in Amazonian children.

To evaluate the prevalence of vitamin B12 deficiency and factors associated with vitamin B12 status in Amazonian children. Genetic risk score (GRS), socio-economic and nutritional status, and morbidity data were the independent variables used in multiple linear regression models to evaluate factors associated with vitamin B12 status in a population-based cross-sectional study. GRS was created by summing a number of known risk alleles for low serum vitamin B12. Acrelândia, western Brazilian Amazon. Children (n 988) aged <10 years. Overall prevalence of vitamin B12 deficiency (<150 pmol/l) was 4·2 (95 % CI 3·0, 5·6) % and was highest in children aged <24 months: 13·6 (95 % CI % 8·8, 19·7) %. For children <24 months, wealth index (β=0·017, P=0·030) and animal protein intake (β=0·219, P=0·003) were positively associated with vitamin B12 status. GRS (β=-0·114, P<0·001) and serum homocysteine (β=-0·049, P<0·001) were negatively associated. Among children aged ≥24 months, vitamin B12 status was positively associated with wealth index (β=0·012, P<0·001), height-for-age Z-score (β=0·024, P=0·033) and serum vitamin A (β=0·089, P<0·001). Age≥60 months (β=-0·118, P<0·001), GRS (β=-0·048, P<0·001), maternal schooling <5 years (β=-0·083, P<0·001), low intake of animal-derived foods (β=-0·050, P=0·030), serum homocysteine (β=-0·053, P<0·001), serum folate ≥23·6 nmol/l (β=-0·055, P=0·012) and geohelminth infection (β=-0·141, P=0·017) were negatively associated with vitamin B12 status. GRS, poverty, low intake of animal-derived foods, geohelminth infection, vitamin A and folate status were important factors associated with vitamin B12 status of children in our study.