Vitamin D and Metabolic Syndrome in Immigrant East Asian Women Living in Sydney, Australia: A Pilot

Abstract

Background: As epidemiological studies have linked vitamin D deficiency to risk of metabolic syndrome, we investigated vitamin D deficiency with metabolic syndrome prevalence in immigrant Asian women. Materials and Methods: In a cross-sectional pilot survey of older East Asian women (n=85 aged 60-95) we examined the association between vitamin D status (measured by serum 25-hydroxyvitamin D) with metabolicsyndrome risk factors. Results: The population mean for 25-hydroxyvitamin D concentration in serum was 56 ± 22 nmol/L with forty percent being vitamin D deficient (< 50 nmol/L). Ninety-eight percent of the population had at least one metabolic syndrome risk factor, 85% had two, 55% had three and 8% had four. Having four metabolic syndrome risk factors was associated with a three fold risk of vitamin D deficiency. Vitamin D deficiency was associated with high non-fasting blood glucose levels ≥7.7 mmol/L (OR=5.2, 95%CI=1.8-18) and non-significantly, with being overweight (OR=1.8, 95%CI =0.7-5). In contrast, vitamin D deficiency was not associated with either hypertension or central obesity. Environmental factors associated with vitamin D deficiency in these data were no vitamin tablet intake (calcium or vitamin D) (OR=7.2, 95%CI=1.8-29; OR=6.3, 95%CI=1.2-32, respectively); not being acculturated to an Australian lifestyle, (OR=2.6, 95%CI=0.9-8) or less sun exposure on the weekends (OR=3.6, 95%CI=1.0-13). After adjustment for these predictors, if these Asian immigrants were vitamin D deficient they were at an eight fold risk of having high blood glucose measurements (OR=7.6, 95%CI=1-53). Conclusion: Further larger prospective studies should be conducted to examine the association between vitamin D deficiency and risk of metabolic syndrome in similar immigrant populations.