Prevalence of Vitamin D deficiency in a multiracial female population in KwaZulu-Natal province, South Africa

Abstract

Objective: Vitamin D deficiency is a global health issue affecting many countries, especially those in temperate climates. The aim of this study was to determine the prevalence of Vitamin D deficiency and level of 25-hydroxyvitamin D [25(OH)D] in females categorised by age and race.
Methods: The study was performed between January 2015 and January 2016. This study consisted of 1 976 females stratified by age into < 18, reproductive age (18–45) and > 45 years. Demographic variables were recorded and serum 25(OH)D levels measured by chemiluminescent emission.
Results: The predictors of lower 25(OH)D levels included age and race, (p < 0.0001 for each predictor). Approximately 46% of females had < 20 ng/ml 25(OH)D level, the majority of whom were Indian (35%). The 25(OH)D level varied by race (White 27.33 ng/ml; Black 23.43 ng/ml and Indian 15.05 ng/ml; p < 0.0001). In the <18-year age category, White and Black women had significantly higher 25(OH)D levels when compared with Indian women (38.25 ng/ml vs. 37.51 ng/ml vs. 13.68 ng/ml respectively; p < 0.0001). Similarly, in the reproductive age category (18–45 years); White (27.63 ng/ml) and Black (20.93 ng/ml) women had a significantly higher 25(OH)D level compared with Indian (13.15 ng/ml) women (p < 0.0001). Moreover, similar data were observed within the > 45-year age category, where the White and Black women had higher 25(OH)D levels compared with Indian women (25.46 ng/ml vs. 22.73 ng/ml vs. 17.04 ng/ml; p < 0.0001) respectively. Irrespective of age category, severe vitamin D deficiency was highest amongst Indian females.
Conclusion: This study demonstrates a significant difference in 25(OH)D concentration in healthy females living in Durban, with Indians presenting with the highest vitamin D deficiency. These findings clearly highlight the need for a policy on vitamin D supplementation and/or fortification of food. Further studies are under way to assess the genetic predisposition of women to vitamin D deficiency.