Vitamin D Deficiency in Young African Children

Background: Vitamin D deficiency is linked to infections, rickets, and poor child development. However, data on the vitamin D status of African children are limited. We examined the prevalence and predictors of low vitamin D status in young African children. Methods: We measured 25-hydroxyvitamin D (25OHD), C-reactive protein (CRP), malaria parasitaemia, and anthropometry among 3880 children aged 0-8 years living in Kenya, Uganda, Burkina Faso, and South Africa. We evaluated associations between vitamin D status and country, age, sex, anthropometric indices, inflammation and malaria parasitaemia in regression analyses and structural equation models. Findings: The overall prevalence of vitamin D deficiency using 25OHD cut-offs of <30 nmol/L and <50 nmol/L was 0·7% (95% CI 0·5, 1·0) and 7·4% (95% CI 6·6, 8·3) respectively, while 35·4% (95% CI 33·9, 36·9) of children had levels between 50–75 nmol/L. Overall geometric mean 25OHD level was 78·1 nmol/L (95% CI 77·3, 78·9) and median age was 22·1 months (interquartile range 12·1, 25·2). Vitamin D deficiency was more prevalent in South African and in older children. 25OHD levels were lower in children with malaria parasitaemia and higher in those with inflammation, but were not associated with sex, stunting, underweight or wasting. Interpretation: Only 1% and 7% of children were vitamin D deficient as defined by 25OHD levels <30 nmol/L and <50 nmol/L, respectively. Latitude, age and prevalence of inflammation and malaria should be considered in strategies to assess and manage vitamin D deficiency in young children living in Africa. Funding Statement: This work was funded by Wellcome [grant numbers SHA 110255, TNW 202800, AJM 106289 and AME 064693, 079110, 095778], and with core awards to the KEMRI-Wellcome Trust Research Programme [203077]. AA is supported by the Intramural Research Program of the National Institutes of Health in the Center for Research on Genomics and Global Health (CRGGH). The CRGGH (1ZIAHG200362) is supported by the National Human Genome Research Institute, the National Institute of Diabetes and Digestive and Kidney Diseases, the Center for Information Technology, and the Office of the Director at the National Institutes of Health. RMM and JMM are supported through the Developing Excellence in Leadership, Training and Science (DELTAS) Africa Initiative [DEL-15-003]. The DELTAS Africa Initiative is an independent funding scheme of the African Academy of Sciences (AAS)’s Alliance for Accelerating Excellence in Science in Africa (AESA) and supported by the New Partnership for Africa’s Development Planning and Coordinating Agency (NEPAD Agency) with funding from Wellcome [107769] and the UK government. Declaration of Interests: We declare no competing interests. Ethics Approval Statement: Informed written consent was obtained from all children’s parents or guardians before inclusion in the study. Ethical approvals were granted by the Scientific Ethics Review Unit of the Kenya Medical Research Institute (KEMRI/SERU/CGMR-C/046/3257) in Kenya, the Uganda Virus Research Institute (GC/127/12/07/32) and Uganda National Council for Science and Technology (MV625) in Uganda, by Ministere de la Recherche Scientifique et de l’Innovation (reference 2014-12-151) in Burkina Faso, the University of Witwatersrand Human Research (M130714) in South Africa and in the UK by the London School of Hygiene and Tropical Medicine (A340) and the Oxford Tropical Research Ethics Committees (39-12, 41-12, 42-14, and 1042-13).