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

Objective: To evaluate the prevalence of vitamin B-12 deficiency and factors associated with vitamin B-12 status in Amazonian children. Design: 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 B-12 status in a population-based cross-sectional study. GRS was created by summing a number of known risk alleles for low serum vitamin B-12. Setting: Acrelandia, western Brazilian Amazon. Subjects: Children (n 988) aged <10 years. Results: Overall prevalence of vitamin B-12 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 (beta = 0.017, P = 0.030) and animal protein intake (beta = 0.219, P = 0.003) were positively associated with vitamin B-12 status. GRS (beta = -0.114, P < 0.001) and serum homocysteine (beta = -0.049, P < 0.001) were negatively associated. Among children aged >= 24 months, vitamin B-12 status was positively associated with wealth index (beta = 0.012, P < 0.001), height-for-age Z-score (beta = 0.024, P = 0.033) and serum vitamin A (beta = 0.089, P < 0.001). Age >= 60 months (beta = -0.118, P < 0.001), GRS (beta = -0.048, P < 0.001), maternal schooling <5 years (beta = -0.083, P < 0.001), low intake of animal-derived foods (beta = -0.050, P = 0.030), serum homocysteine (beta = -0.053, P < 0.001), serum folate = 23.6 nmol/l (beta = -0.055, P = 0.012) and geohelminth infection (beta = -0.141, P = 0.017) were negatively associated with vitamin B-12 status. Conclusions: GRS, poverty, low intake of animal-derived foods, geohelminth infection, vitamin A and folate status were important factors associated with vitamin B-12 status of children in our study.