Vitamin D Deficiency and Its Association with Iron Deficiency in African Children
Reagan M. Mogire, John M. Muriuki, Alireza Morovat, Alexander J. Mentzer, Emily L. Webb, Wandia Kimita, Francis M. Ndungu, Alex Macharia, Clare Cutland, Sodiomon B. Sirima, Amidou Diarra, Alfred B. Tiono, Swaib A. Lule, Shabir A. Madhi, Andrew M. Prentice, Philip Bejon, John Μ. Pettifor, Alison M. Elliott, Adebowale Adeyemo, Thomas N. Williams, Sarah H. Atkinson
Abstract
Vitamin D regulates the master iron hormone hepcidin, and iron in turn alters vitamin D metabolism. Although vitamin D and iron deficiency are highly prevalent globally, little is known about their interactions in Africa. To evaluate associations between vitamin D and iron status we measured markers of iron status, inflammation, malaria parasitemia, and 25-hydroxyvitamin D (25(OH)D) concentrations in 4509 children aged 0.3 months to 8 years living in Kenya, Uganda, Burkina Faso, The Gambia, and South Africa. Prevalence of iron deficiency was 35.1%, and prevalence of vitamin D deficiency was 0.6% and 7.8% as defined by 25(OH)D concentrations of <30 nmol/L and <50 nmol/L, respectively. Children with 25(OH)D concentrations of <50 nmol/L had a 98% increased risk of iron deficiency (OR 1.98 [95% CI 1.52, 2.58]) compared to those with 25(OH)D concentrations >75 nmol/L. 25(OH)D concentrations variably influenced individual markers of iron status. Inflammation interacted with 25(OH)D concentrations to predict ferritin levels. The link between vitamin D and iron status should be considered in strategies to manage these nutrient deficiencies in African children.