Reduction in incidence of type 2 diabetes by lifestyle intervention in a middle eastern community

Very few studies have used community-based interventions for primary prevention of Type 2 diabetes, and the direct effect of such interventions on diabetes incidence is relatively unknown.

This study aims to assess the effect of lifestyle modification on risk factors for noncommunicable diseases (NCDs) and the development of Type 2 diabetes at the community level.

A cluster-controlled trial was conducted.

In all, 3098 and 5114 individuals in intervention and control groups, respectively (mean age=43 years), recruited from District 13 of Tehran, Iran, participated in the baseline examination in 1999-2001. Among these individuals, a total of 1754 and 2993 individuals in the intervention and control groups, respectively (58%), completed a follow-up examination in 2002-2005.

The study intervention involved improvement in diet, increase in the level of physical activity, and reduction in cigarette smoking through educational interviews, lectures, and publications.

Incident Type 2 diabetes was measured by fasting plasma glucose (FPG) and 2-hour plasma glucose (2hPG) and change in NCD risk factors.

The mean follow-up time was 3.6 years. The incidence of diabetes in the control and intervention groups was 12.2 and 8.2 per 1000 person-years, respectively, with a relative risk reduction of 65% (95% CI=30%, 83%, p<0.003). The adjusted difference in mean change of risk factors between the intervention and control groups was significant for weight (-0.5 kg in men); BMI (-0.18 kg/m(2) in men); waist circumference (-1.0 cm in women); systolic and diastolic blood pressure (-1.1 and -0.6 mmHg, respectively, in women); FPG (-2.1 and -2.3 mg/dL in men and women); 2hPG (-4.6 mg/dL in women); total cholesterol (-2.8 mg/dL in women); triglycerides (-7.6 and -5.2 mg/dL in men and women); and high-density lipoprotein cholesterol (1.1 mg/dL in women; all p<0.05).

Lifestyle intervention resulted in a significant decrease in the incidence of Type 2 diabetes and better control of NCD risk factors in a population-based setting. ISRCTN TRIAL REGISTRATION #: ISRCTN52588395.