Poor vitamin D status increases the risk of anemia in school children: National Food and Nutrition Surveillance.

OBJECTIVES

This study aimed to investigate the association between 25-hydroxyvitamin D (25[OH]D) concentrations and the risk of anemia in a large cohort of children with consideration for the effects of sex, body mass index (BMI), serum intact parathyroid hormone (iPTH) concentrations, and iron level status.

METHODS

A total of 937 children (493 boys, 444 girls) ages 9 to 12 y were enrolled in a cross-sectional study. The children underwent various examinations including anthropometric measurements and blood sampling.

RESULTS

Overall, 13.3% of the children were anemic and 64.2% and 28.1% of the subjects had a vitamin D deficiency (<25 nmol/L) and insufficiency (25-50 nmol/L), respectively. Approximately 13% of the children had concurrent low hemoglobin and hypovitaminosis D levels. The prevalence of hypovitaminosis D in the group of children with anemia was 96.8% compared with 91.6% in the non-anemic group (P = 0.046). Mean 25(OH)D concentrations were significantly lower in the anemic children compared with the non-anemic children (19.6 ± 13.3 vs. 24.0 ± 23.1 nmol/L; P = 0.003). After controlling for sex and BMI, children with a vitamin D deficiency were almost 3.45 times more likely to be anemic compared with children with a vitamin D sufficiency (95% confidence interval [CI], 1.21-9.81). The increased risk of anemia was found to start significantly at 25(OH)D < 44 nmol/L (17.6 ng/mL; odds ratio: 2.29; 95% CI, 1.07-4.91, P = 0.032).

CONCLUSIONS

These findings strongly suggest an association between low circulating concentrations of 25(OH)D and anemia in a large, representative sample of children, even after adjustment for sex, age, BMI, and iPTH.