RELATIONSHIP BETWEEN CORONARY ARTERY DISEASE an‎d SERUM VITAMIN D LEVEL IN A GROUP OF POSTMENOPAUSAL WOMEN IN IRAN

INTRODUCTION: Female carpet-weavers are vulnerable to vitamin D deficiency due to cultural, occupational and economic reasons. This case-control study was conducted to compare the frequency coronary artery disease (CAD) and its risk factors in relation with the serum vitamin D level in 260 female carpet-wearers and non-carpet-weavers in the villages across Isfahan Province in the centre of Iran. METHODS: All postmenopausal women aged over 50 were matched for cultural and socioeconomic status. The participants underwent clinical examinations. Blood samples were obtained and electrocardiography was performed. When necessary, echocardiography and exercise test were also administered to diagnose heart disease. Dietary intake of vitamin D was determined by completing a semi-quantitative food frequency questionnaire. A questionnaire obtaining personal data and length of daily exposure to sunlight was also completed. The existence of CAD was determined using standardized WHO Rose questionnaire and/or the Minnesota electrocardiography coding system. Blood lipids and vitamin D levels were measured using an ELAN- 2000 auto analyzer and radioimmunoassay, respectively. RESULTS: The results showed that only the frequency percentage of myocardial infarction (MI) in non-carpet-weavers was significantly higher than in female carpet weavers (P=0.001). The differences of age, serum vitamin D level, blood lipids, blood pressure and other variables were not significant (P>0.05). Neither was there any statistical association between serum vitamin D level and CAD risk factors, however, after adjustment for confounders (age, etc.), a direct relationship was observed between abdominal obesity as measured by waist-to-hip ratio (WHR) (WHR>1) and serum vitamin D level (OR=0.99, P>0.05). Carpet weaving had no effect on CAD risk factors (P>0.05). CONCLUSION: The findings of this study reveal no association between vitamin D and CAD. Further research is recommended into the possible relationship between CAD and vitamin D, as well as vitamin D receptor (VDR) gene polymorphisms responsible for genetic differences in vitamin D uptake by the bone.