Research article
Reduction in Incidence of Type 2 Diabetes by Lifestyle Intervention in a Middle Eastern Community

https://doi.org/10.1016/j.amepre.2010.03.003Get rights and content

Background

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.

Purpose

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.

Design

A cluster-controlled trial was conducted.

Setting/participants

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.

Intervention

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.

Main outcome measures

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

Results

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/m2 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).

Conclusions

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.

Introduction

Type 2 diabetes has reached epidemic levels in most populations. The epidemiologic evidence1 suggests that unless effective preventive measures are implemented, the prevalence of this disease will continue to rise globally. It is estimated2 that developing countries in Asia, and in the Middle East in particular, will have the largest increases in the prevalence of diabetes by 2030. The prevalence of Type 2 diabetes is reported3 to be more than 14% in Tehran, Iran, with an estimated incidence4 of new cases in about 1% of the population per year.

Randomized interventional studies in high-risk populations5, 6, 7, 8 have demonstrated that weight-loss and exercise programs can reduce risk factors associated with diabetes. A meaningful decrease in the prevalence of diabetes can be achieved mainly by changing the underlying contributing factors (e.g., obesity and/or sedentary lifestyle) in the general population.9 As far as we know, there is limited evidence about application of community-based interventions for primary prevention of Type 2 diabetes and their direct effect on diabetes incidence is relatively unknown.10 The Tehran Lipid and Glucose Study (TLGS) has provided a unique opportunity to address this issue through a large-scale community-based prospective trial on a representative sample of residents of District 13 of Tehran. The purpose of the current study was to assess whether lifestyle interventions could prevent or delay the onset of Type 2 diabetes in the aforementioned participants.

Section snippets

Study Population

The rationale and design of the TLGS has been published elsewhere.11 The TLGS had two major components: Phase 1 was a cross-sectional prevalence study of noncommunicable diseases (NCDs) and their associated risk factors implemented from 1999 to 2001; Phase 2 was a prospective follow-up study in which NCD risk factors were measured approximately every 3 years.

The current study used data from the first follow-up visit, which took place from 2002 to 2005. A cluster-controlled trial, nested within

Results

Baseline characteristics of the individuals who participated or were lost to follow-up are presented in Table 1. The mean age and BMI of the studied population was 43±13 years and 26.8 kg/m2, respectively; 40% were men. The risk profiles of the intervention and control groups were comparable except for the prevalence of smoking and the level of physical activity, which were lower in the intervention group. Comparison of the retained and drop-out samples showed that respondents of both control

Discussion

This nonrandomized study demonstrated that a general lifestyle modification program was effective in reducing major modifiable diabetes risk factors, had a favorable effect on weight reduction in overweight and obese individuals, and resulted in a 65% reduction in the incidence of diabetes in men and women living in the city of Tehran. The findings are in accordance with those of other studies, suggesting that Type 2 diabetes can be postponed or prevented by lifestyle intervention. Moreover, to

Conclusion

The present study demonstrated that a community-based prevention program not only can slow down the trend toward greater prevalence of cardiovascular risk factors in the general population, and in some cases even reduce them, contributing to overall health, but also can substantially delay the onset of Type 2 diabetes. Taking logical steps toward changing the lifestyle of the population via community-based programs can efficiently decrease the burden of noncommunicable diseases in those

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