Background:- Coronary heart disease (CHD) and non-insulin-dependent diabetes (NIDDM), appear to be common in the Arabian Peninsula, although reliable causespecific mortality and prevalence data are not available. This study aimed to determine the prevalence of diabetes and CHD in Bahraini natives and associations with risk factors. The specific hypothesis to be tested was that diabetes and other metabolic complications of obesity would account for high CHD rates in this population.
Objective:- To determine the prevalence of cardiographic abnormalities and diabetes, and to evaluate the association between these abnormalities and the level of diabetes and CHD among Bahraini native population.
Design:- Total community cross-sectional survey with questionnaire, physical examination, and electrocardiography.
Main outcome measures:- Prevalence of diabetes and ischaemic abnormalities on electrocardiogram.
Methods and Results:- A systematic random sample of 1245 men aged 40-59 years and 883 women aged 50-69 years. was studied. Subjects were invited to the clinic for interview, physical and laboratory examinations. Venous blood samples were taken fasting and 2 hours after a 75 g oral glucose load. Mean body mass index was 27.3 kg/m2 in men and 28 kg/m2 in women. Only 13% of men and I % of women walked at least 4 km/day. BMI was positively related to Sunni Arab ethnic origin, educational status and number of hours spent watching television, and inversely related to physical activity at work. Most obese participants did not rate themselves as overweight.
The overall prevalence rate of diabetes was 30%. In the age group 50-59 years prevalence was 29% in men and 35% in women. Prevalence of diabetes was lower in Shi'ite Arabs and Iranians than in Sunni Arabs: the odds ratio for diabetes in Shi'ite versus Sunni Arabs was 0.48 in men and 0.22 in women. Plasma cholesterol was 0.4 mmol/l higher in diabetic than in non-diabetic individuals, even after adjusting for obesity. In a multivariate logistic regression analysis adjusting for age, diabetes was associated with Sunni Arab origin, positive family history, obesity and raised plasma cholesterol in both men and women. In women post-menopausal status was an independent risk factor.
Prevalence of major Q waves (Minnesota codes 1-1 or 1-2) on ECG was 2.8% in men aged 40-59 years. Major Q waves were associated with smoking, hypertension and positive family history of CHD but not with diabetes or with plasma lipids. Positive
family history of CHD was however associated with higher plasma cholesterol and triglyceride, and with lower HDL cholesterol. Associations of CHD with ethnic origin were accounted for by adjusting for smoking and plasma cholesterol.
Conclusion:- Prevalence of NIDDM in Bahraini natives is among the highest in the world. Obesity and physical inactivity do not fully account for the high rates in Bahrainis compared with Europeans, or for the ethnic difference. The association of NIDDM with raised cholesterol is an unusual finding which suggests that disturbance of both carbohydrate and lipid metabolism may be present in this population. The high prevalence of NIDDM is likely to result from an interaction of genetic susceptibility with
environmental factors.
Prevalence of CHD is higher than in similar surveys in the UK. The lack of association of CHD with raised plasma lipids and diagnosed diabetes in this study may be because of the limitations of a cross-sectional study. The association of positive family history of CHD with raised triglyceride and cholesterol suggests that these risk factors would predict CHD in a prospective study.
On the basis of these findings, recommendations are made for measures to prevent and control NIDDM and CHD in Bahrain. Obesity is the most important target variable to control to prevent NIDDM. Measures to increase physical activity and to communicate awareness of the health consequences of obesity might help to achieve this. To reduce the risk of CHD, measures to discourage smoking, lower plasma cholesterol and improve control of hypertension are needed, especially for people with diabetes.