Vitamin D deficiency and its association with iron deficiency in African children

Abstract

Background Nutritional deficiencies, including vitamin D and iron deficiency, are prevalent among children living in sub-Saharan Africa. Vitamin D inhibits the transcription of the iron hormone hepcidin thus permitting efficient iron absorption, and iron deficiency alters vitamin D metabolism. Studies have reported associations between vitamin D and iron status, but little is known about their association in African populations. Objective We aimed to evaluate the association between vitamin D and iron status in African children. Methods In this cross-sectional study, we measured biomarkers of iron status, inflammation and 25-hydroxyvitamin D (25(OH)D) levels in 4509 children aged 0.3 months to 8 years from Kenya, Uganda, Burkina Faso, The Gambia and South Africa. We used regression analyses to evaluate the association between vitamin D and iron status. Results Stunting, underweight, inflammation and malaria were highly prevalent. Overall prevalence of iron deficiency was 35.1%, while the prevalence of vitamin D deficiency was 0.6% and 7.8% as defined by 25(OH)D levels of <30 nmol/L and <50 nmol/L respectively. Children with 25(OH)D levels <50 nmol/L had an 80% increased risk of iron deficiency (OR 1.80 [95% CI 1.40, 2.31]) and had lower hepcidin levels than those with 25(OH)D levels >75 nmol/L. 25(OH)D levels were positively associated with ferritin, hepcidin and soluble transferrin receptor levels and negatively associated with serum iron and transferrin saturation in multivariable regression analyses. Vitamin D status was not associated with hemoglobin levels or anemia. Conclusions These findings suggest that vitamin D deficiency may variably influence different iron compartments and measures of iron status in young African children. Additional research is required to confirm these findings and determine direction of causality. The interplay between vitamin D and iron status should be considered in strategies to manage these nutrient deficiencies in African populations.

Prevalence and associated risk factors of Vitamin D deficiency in children under five years of age, at the Diamniadio Childrens Hospital in Senegal

“…Lower prevalence of vitamin D levels below 50 nmol/L and below 30 nmol/L of 7.8 and 0.6% respectively, were found in another study conducted in Kenya, Uganda, Burkina Faso, Gambia, and South Africa (Mogire et al, 2021). In sub-Saharan Africa, although sunshine is permanent, children are not protected against vitamin D deficiency.…”

“…hepcidin, while low iron levels can indirectly influence vitamin D status by decreasing its activation enzymes(Mogire et al, 2021).In malnourished, the acute form is considered a risk factor associated with vitamin deficiency with OR = 3.36, 95% CI (1.28 to 8.80). However, further studies are needed for confirmation.…”