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.

Keywords:

• Vitamin D
• vitamin D deficiency
• race
• age

Acknowledgements

The authors would like to thank the National Research Funding Institute for providing support for the project, including Prof T. Naicker, Prof J. Moodley and Dr Madurai for their continued support.

Disclosure statement

No potential conflict of interest was reported by the authors.