EPIDEMIOLOGIC-STUDY OF TRACE-ELEMENTS AND MAGNESIUM ON RISK OF CORONARY-ARTERY DISEASE IN RURAL AND URBAN INDIAN POPULATIONS

Objective: To determine the association of trace elements and magnesiu m with risk of coronary artery disease (CAD) in rural and urban popula tions of India. Design and Setting: Cross-sectional surveys in the ran domly selected municipal streets in Moradabad city and one village in Moradabad tahsil in North India.Subjects and Methods: There were 162 r ural (86 men and 96 women) and 152 urban (80 men and 72 women) subject s between 26 to 65 years of age. Evaluations were obtained by physicia n- and dietitian-administered, validated questionnaires, physical exam ination, electrocardiogram and blood examination. Results: The prevale nce of CAD and coronary risk factors was 2.5 times higher in the urban population compared to rural subjects (8.6 vs. 3.0%). In rural subjec ts, dietary intakes and plasma levels of vitamins and minerals were co mparable with those of urban subjects except for higher dietary intake of magnesium in rural subjects and higher plasma vitamin A level in u rban subjects. In both rural and urban subjects, low serum zinc (80 +/ - 82 vs. 110 +/- 11.0 mu g/dl, p < 0.05) and magnesium levels (1.60 +/ - 0.36 vs. 1.71 +/- 0.41 mEQ/L, p < 0.05) and lower zinc/copper ratio (0.58 +/- 0.08 vs. 1.11 +/- 0.25 p < 0.50) were inversely associated w ith CAD. Serum levels of copper and iron were significantly higher and plasma levels of antioxidant vitamins A, E and C and beta-carotene we re significantly lower in patients with CAD compared to the rest of th e subjects. In both rural (7.1 +/- 1.2 mg/day) and urban subjects (8.6 +/- 1.6 mg/day), zinc consumption was half of the recommended dietary allowances. Higher prevalence of CAD in urban compared to rural subje cts was attributed to higher dietary fat intake and higher prevalence of risk factors in urban subjects. Conclusions: The findings suggest t hat lower serum levels of zinc and magnesium and lower zinc copper rat io were inversely associated with CAD. It is possible that urban popul ations with higher risk of CAD may benefit by decreasing dietary fat i ntake and by increasing their intake of foods rich in zinc and magnesi um.