Vitamin D Deficiency is Widespread in Tunisian Pregnant Women and Inversely Associated with the Level of Education

Background: Vitamin D deficiency seems to be common in pregnant women and would be associated with an increased risk of maternal and fetal poor outcomes. This study aimed to determine the prevalence and the main risk factors for vitamin D deficiency in pregnant women living in a sun -rich environment. Methods: A total of 255 pregnant women living in Tunis City (latitude, 36 degrees N) were randomly selected at 12 - 18 weeks of gestation. Plasma 25-hydroxyvitamin D (25-OHD) was assessed by chemiluminescence immunoassay method. A logistic regression model adjusting for confounding variables was used to identify the independent risk factors for vitamin D deficiency. Results: Plasma 25-OHD concentrations ranged from 4.02 to 78.3 nmol/L [median (IQR), 18.0 (13.6)]. More than 96% of the study population had 25-OHD levels below 50 nmol/L with 82.3% of women having vitamin D deficiency (25-OHD < 30 nmol/L) and 31.4% of women having severe vitamin D deficiency (25-OHD < 15 nmol/L). Daily dietary vitamin D intake [median (IQR), 3.49 (2.92) lig] was clearly lower than the recommended dose. Vitamin D deficiency was more frequent during the low -sunshine season, and in veiled women and those with an average level of education. In multivariate analysis, the independent predictors of vitamin D deficiency were low sunshine season [multi - adjusted OR (95% CI), 2.29 (1.24 - 4.22); p < 0.01], covering clothing [OR (95% CI), 2.54 (1.23 - 5.24); p < 0.05], and average level of education [OR (95% CI), 2.11 (1.09 - 5.91); p < 0.05]. Conclusions: Tunisian pregnant women, especially those with average/high level of education, are exposed to a high risk of vitamin D deficiency. The main causes of hypovitaminosis D are low sunshine exposure and little dietary vitamin D intake. Public health policies should target the awareness for optimal and safe sun exposure and adequate vitamin D dietary intake. Otherwise, tolerable vitamin D supplementation should be prescribed.