Cardiovascular Mortality, All-Cause Mortality, and Diabetes Incidence After Lifestyle Intervention for People With Impaired Glucose Tolerance in the Da Qing Diabetes Prevention Study: A 23-Year Follow-Up Study

Study Questions:

Does a long-term lifestyle intervention reduce long-term outcomes among adults with impaired glucose tolerance?

Methods:

The Da Qing Diabetes Prevention Study was a cluster randomized trial, which included 33 clinics in Da Qing, China. Patients with impaired glucose tolerance were randomized to lifestyle intervention groups (diet or exercise or the combination) and a control group. The intervention arms consisted of 25 clinics (439 subjects), of which nine clinics (138 subjects) were assigned to diet only intervention, nine clinics (155 participants) to exercise only intervention, and seven clinics (136 participants) to the combination of a diet and exercise intervention. The diet intervention was designed to produce weight loss in those who were overweight or obese, and to reduce simple carbohydrate and alcohol intake in people of normal weight. The exercise intervention was designed to increase the leisure time spent doing physical activity. Enrollment started in 1986; the intervention lasted for 6 years. All participants (including those at clinics in the control group) received examinations at baseline, 2 years, 4 years, and 6 years after randomization and at 20-year and 23-year follow-up. The primary outcomes included cardiovascular mortality, all-cause mortality, and incident diabetes.

Results:

A total of 577 subjects were enrolled, of which 439 were assigned to the intervention(s) and 138 to the control group. Ninety-four percent of the participants (n = 542) had complete data on mortality. During the 23 years of follow-up, 174 subjects died (121 in the intervention group and 53 in the control group). The cumulative incidence of all-cause death was 28.1% (95% confidence interval [CI], 23.9-32.4) in the intervention group and 38.4% (95% CI, 30.3-46.5) in the control group, with a hazard ratio [HR] (adjusted for cluster randomization) of 0.71 (95% CI, 0.51-0.99; p = 0.049). Cumulative incidence of cardiovascular disease mortality was 11.9% (95% CI, 8.8-15.0) in the intervention group versus 19.6% (12.9-26.3) in the control group (HR, 0.59; 95% CI, 0.36-0.96; p = 0.033). Incidence of diabetes was 72.6% (68.4-76.8) versus 89.9% (84.9-94.9; HR, 0.55; 95% CI, 0.40-0.76; p = 0.001).

Conclusions:

The investigators concluded that a 6-year lifestyle intervention program for Chinese people with impaired glucose tolerance can reduce incidence of cardiovascular and all-cause mortality and diabetes. These findings emphasize the long-term clinical benefits of lifestyle intervention for patients with impaired glucose tolerance, and provide further justification for adoption of lifestyle interventions as public health measures to control the consequences of diabetes.

Perspective:

These data suggest that lifestyle interventions among patients with impaired glucose tolerance cannot only reduce incident diabetes, but can also reduce cardiovascular disease and all-cause mortality. Key areas for further investigation are lifestyle interventions on a larger scale and with more diverse populations.

Clinical Topics: Prevention, Diet

Keywords: Glucose Intolerance, Life Style, China, Follow-Up Studies, Overweight, Weight Loss, Leisure Activities, Cardiovascular Diseases, Motor Activity, Obesity, Diet


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