Iron Deficiency, Anemia, and Low Vitamin B-12 Serostatus in Middle Childhood Are Associated with Behavior Problems in Adolescent Boys: Results from the Bogotá School Children Cohort

Abstract

Iron deficiency (ID) in infancy is related to subsequent behavior problems. The effects of micronutrient status in middle childhood are uncertain. The aim of the study was to examine the associations of micronutrient status biomarkers in middle childhood with externalizing and internalizing behavior problems in adolescence. We assessed whether ID (ferritin <15 µg/L), anemia (hemoglobin <12.7 g/dL), or blood concentrations of zinc, vitamins A and B-12, and folate at ages 5-12 y were associated with externalizing or internalizing behavior problems in adolescence in 1042 schoolchildren from Bogotá, Colombia. Behavior problems were assessed with the Youth Self-Report questionnaire after a median 6.2 y of follow-up. Mean problem score differences with 95% CIs were estimated between categories of micronutrient status biomarkers with the use of multivariable linear regression. Mean±SD externalizing and internalizing problems scores were 52.6±9.6 and 53.8±9.9, respectively. Among boys, middle-childhood ID, anemia, and low plasma vitamin B-12 were associated with 5.9 (95% CI: 1.0, 10.7), 6.6 (95% CI: 1.9, 11.3), and 2.7 (95% CI: 0.4, 4.9) units higher mean externalizing problems scores in adolescence, respectively-after adjustment for baseline age, time spent watching television or playing video games, mother's height, and socioeconomic status. Also in boys, ID was related to an adjusted 6.4 (95% CI: 1.2, 11.6) units higher mean internalizing problems score. There were no associations among girls. Other micronutrient status biomarkers were not associated with behavior problems. ID, anemia, and low vitamin B-12 in middle childhood are related to behavior problems in adolescent boys.This study was registered at clinicaltrials.gov as NCT03297970.