Predictors of vitamin D status in undernourished and well-nourished children 6–59 months old, in the JB Marks Municipality of South Africa.

Abstract

Objective: to investigate the predictors of vitamin D (vitD) status of undernourished and well-nourished children aged under five years in the North West Province of South Africa. Design: this cross-sectional study assessed sociodemographic data, nutritional supplement intake, vitD-rich food consumption, and sunlight exposure via a structured questionnaire. Venous blood samples were collected to evaluate vitD, iron, and inflammatory markers. Setting: the maternal and child wellness departments of six community clinics in the JB Marks Municipality. Participants: 121 undernourished and 51 well-nourished children, 6–59 months old. Results: The prevalence of serum 25 (OH) D< 30 ng/ml was 20.3%, 19.9%, and 21.6% in the total, undernourished, and wellnourished groups, respectively. The total mean 25 (OH) D concentration was 38.41±9.64 ng/ml. Age showed a negative association trend with 25 (OH) D in the well-nourished group (β:− 0.172, 95% CI− 0.353, 0.010, p= 0.063), while household income was inversely associated with 25 (OH) D (β=− 1.86, 95% CI=− 2.99,− 0.733, p= 0.001) in the total group. Among the undernourished children, iron-deficiency anaemia (IDA) was associated with almost five times greater odds for 25 (OH) D< 30 ng/ml (OR: 4.646, 95% CI 1.339, 16.123, p= 0.016). Intake of vitD supplements, therapeutic foods, multivitamins, and formula milk was associated with significantly higher 25 (OH) D concentrations and was adjusted for in subsequent analyses. Additionally, consumption of eggs more than once a month was associated with higher 25 (OH) D levels in the wellnourished children aged 24–59 months. Nutritional status, inflammation, and sunlight exposure were not associated with 25 (OH) D concentrations. Conclusion: vitD insufficiency exists in both the undernourished and the well-nourished. Age, egg consumption, and IDA should be considered in the correction of vitD insufficiency in children.