Prevalence of vitamin D deficiency and association with metabolic syndrome in a Qatari population

OBJECTIVES: Despite long hours of sunlight in Qatar and other regions of the Middle East, vitamin D deficiency has been rising. In parallel, the prevalence of metabolic syndrome has also been increasing in Qatar. Vitamin D levels have been associated with metabolic syndrome but the data are inconsistent and no studies have addressed these inter-relationships in a Middle Eastern population where the prevalence of these conditions is high. The objective is to investigate the prevalence of vitamin D deficiency and its association with metabolic syndrome and its components in the Qatar Biobank population. METHODS: A cross-sectional study of 1205 participants (702 women and 503 men) from the Qatar Biobank, comprising Qataris and non-Qataris between the ages of 18 and 80 years, was used to perform multivariate linear regression analyses to examine the association between metabolic syndrome and prevalence of vitamin D deficiency (defined as < 20 ng ml(-1) serum vitamin D levels) adjusting for age, sex, ethnicity, season of blood collection, physical activity and education. Odds ratios and 95% confidence intervals were calculated for all analyses. RESULTS: Approximately 64% of participants were vitamin D deficient (< 20 ng ml(-1)) with more men being deficient (68.6%) than women (61.3%). Serum vitamin D was 8% lower in individuals with metabolic syndrome (RR: 0.92, 95% CI: 0.87-0.98, P-value: 0.01) compared to individuals without metabolic syndrome. Waist circumference and HDL as well as high triglyceride levels were also significantly positively associated with vitamin D deficiency. No association was found between the other components of metabolic syndrome or diabetes and the presence of vitamin D deficiency. CONCLUSIONS: Vitamin D deficiency is prevalent in this Qatari population. Presence of metabolic syndrome was associated with presence of vitamin D deficiency. Future prospective studies need to be conducted to investigate the potential for causality.