Reduction in incidence of Type 2 diabetes by lifestyle modification in a Middle Eastern urban population: Tehran Lipid and Glucose Study

Hadi Harati; Farzad Hadaegh; Laleh Ghanei; Fereidoun Azizi

Aims: Lifestyle modification has been shown to prevent development of Type 2 diabetes in high risk American, European and Asian populations. We wanted to test whether such intervention could have similar results in a white Middle Eastern population.

Methods: A total of 8212 non-diabetic subjects≥20 years were selected by cluster random sampling method in the cross-sectional phase of the Tehran Lipid and Glucose Study (TLGS) from 1999 to 2001. A subsample of 3098 subjects was then selected as the lifestyle modification and the remaining 5114 subjects as the control group in the interventional phase of the TLGS from 2002 to 2005. Interventions were aimed at lifestyle modification through improving nutrition and dietary pattern, increasing physical activity levels, and smoking cessation. Fasting and 2-hours plasma glucose as well as other major diabetes risk factors were measured at baseline and follow-up examinations.

Results: After median follow-up of 3.5 years, 4747 subjects (2993 and 1754 respectively from the control and intervention group) completed the follow-up examination. Mean age and BMI of the participants were 41±12 years and 26.5 kg/m² respectively and 58% were females. The intervention group had significantly lower rate of increase in major diabetes risk factors (Table 1). The incidence rate of Type 2 diabetes was significantly lower in the intervention versus control group (8.2 and 12.2 per 1000 person-years respectively, P<0.001). The hazard ratio of developing Type 2 diabetes in the intervention group after adjustment for all the major risk factors was 0.34 (95% CI: 0.25–0.47, P<0.001). To prevent one case of diabetes, 25.0 individuals in the whole population, 5.7 in those with impaired glucose tolerance and 6.7 in those with BMI≥25 kg/m² had to participate in the intervention program.

Conclusion: Lifestyle modification could result in a significant decrease in the incidence of Type 2 diabetes in an Iranian urban population. This effect was independent of the level of major diabetes risk factors.

Table 1. Comparison of risk factor changes overtime between treatment groups.
Risk factors	Percent of change after 3.5 years
	Control	Intervention
Body weight	3.2 (0.1)	2.5 (0.1)*
BMI	2.6 (0.2)	2.4 (0.3)
Waist circumference	5.7 (0.1)	4.5 (0.2)**
Systolic blood pressure	−1.0 (0.1)	−0.5 (0.3)
Diastolic blood pressure	−2.8 (0.2)	−2.1 (0.3)
Fasting plasma glucose	3.3 (0.2)	0.6 (0.4)**
Two-hours plasma glucose	10.6 (0.3)	5.4 (0.3)**
Triglyceride	6.2 (0.4)	1.2 (0.4)**
HDL-cholesterol	−7.6 (0.2)	−6.1 (0.2)
Data are mean (S.D.) of percent of change over time. , *: represent P<0.01 and P<0.001 respectively in comparison to the control group.

Endocrine Abstracts

HTC1