Genetics, obesity, and environmental risk factors associated with type 2 diabetes

To determine the association between consanguineous marriages, obesity, and environmental risk factors associated with type 2 diabetes, in the adult Qatari population.

The case-control study was carried out among diabetic patients and healthy subjects at the Primary Healthcare Clinics (PHCs) and the survey was conducted from February to November 2003. The study included 338 cases (with diabetes) and 338 controls (without diabetes). Face-to-face interviews were based on a questionnaire that included variables such as age, gender, socioeconomic status, parity, income level, cigarette smoking, physical activity, body mass index (BMI), obesity, and lifestyle. Their health status was assessed by medical conditions, family history, physical examination, blood pressure, blood glucose, blood count, lipid profile, cholesterol total, HDL, LDL, and triglycerides analysis.

The mean age (in years-/+standard deviation) of cases versus controls was 45.5-/+8.9 vs 42.4-/+8.0, P<0.001. The study revealed that there were statistically significant differences between diabetic and control subjects with respect to body mass index, low educational level, consanguineous marriage, and number of children (P<0.001). The obesity was considerably more frequent among diabetes subjects (P<0.001). Self reported family history (in first degree relatives) of diabetes (62.1% vs 44.4%, OR=2.06, 95% confidence interval (CI)=1.49-2.83) P<0.001) was prominent among diabetic subjects. The diabetes was significantly common among the consanguineous marriages of the first degree relatives compared with the control group (33.1% vs. 24.6%, OR=1.59, 95% CI=1.11-2.29), P=0.008). Systolic blood pressure (P=0.023) and glucose fasting (P<0.001) levels were significantly higher in diabetic patients than in control subjects. The logistic regression model showed that smoking (OR=2.42 95% CI=1.66-3.54, P<0.0001); degree of consanguinity (OR=1.38 95% CI=1.13-1.69, P=0.002), BMI (OR=1.41 95% CI=1.12-1.76), P=0.003), level of education (OR=1.23 95% CI=1.04-1.45, P=0.017), number of children (OR=1.34 95% CI=1.02-1.77, P=0.037), and systolic blood pressure (OR=1.01 95% CI=1.00-1.02, P=0.044) were considered as associated risk factors for diabetes.

The present study revealed that obesity, consanguinity, blood pressure, total cholesterol, HDL-cholesterol, and triglycerides were more prevalent in diabetic patients. The characterization of these factors will contribute to defining more effective and specific strategies to screen for and control diabetes and cardiovascular disease in a developing country.