Prevalence and determinants of Vitamin D deficiency in 1825 Cape Town primary schoolchildren: A cross-sectional study

Keren Middelkoop (Lead Author), Neil Walker, Justine Stewart, Carmen Delport, David A. Jolliffe, James Nuttall, Anna K. Coussens, Celeste E. Naude, Jonathan C. Y. Tang, William D. Fraser, Robert J. Wilkinson, Linda-Gail Bekker, Adrian R. Martineau

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Vitamin D deficiency (25-hydroxyvitamin D[25(OH)D] <50 nmol/L) is common among adults in Cape Town, South Africa, but studies investigating vitamin D status of children in this setting are lacking. We conducted a cross-sectional study to determine the prevalence and determinants of vitamin D deficiency in 1825 Cape Town schoolchildren aged 6–11 years. Prevalence of vitamin D deficiency was 7.6% (95% Confidence Interval [CI] 6.5% to 8.9%). Determinants of vitamin D de-ficiency included month of sampling (adjusted odds ratio [aOR] for July–September vs. January–March 10.69, 95% CI 5.02 to 22.77; aOR for October–December vs. January–March 6.73, 95% CI 2.82 to 16.08), older age (aOR 1.25 per increasing year, 95% CI: 1.01–1.53) and higher body mass index (BMI; aOR 1.24 per unit increase in BMI-for-age Z-score, 95% CI: 1.03–1.49). In a subset of 370 par-ticipants in whom parathyroid hormone (PTH) concentrations were measured; these were in-versely related to serum 25(OH)D concentrations (p < 0.001). However, no association between participants with hyperparathyroidism (PTH >6.9 pmol/L) and vitamin D deficiency was seen (p = 0.42). In conclusion, we report that season is the major determinant of vitamin D status among Cape Town primary schoolchildren, with prevalence of vitamin D deficiency ranging from 1.4% in January–March to 22.8% in July–September.
Original languageEnglish
Article number1263
Issue number6
Publication statusPublished - 16 Mar 2022


  • Children
  • Cross-sectional
  • Prevalence
  • South Africa
  • Vitamin D

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