Epidemiology

PURPOSE

Physical activity and obesity contribute to premature mortality among persons with diabetes. The independent effects of physical activity on all-cause mortality among persons with diabetes requires further examination in well-characterized cohort studies. We test the hypothesis that regular habitual physical activity of 5 or more times a week among persons with diabetes, regardless of duration, intensity or mode, will be associated with lower all-cause mortality when compared to sedentary adults with diabetes.

METHODS

We used data from the Third National Health and Nutrition Examination Survey (NHANES III) conducted from 1988-1994. Participant records were linked to mortality data from the National Death Index to establish all-cause mortality. Detailed health information was obtained via a home interview and a medical examination. Self-reported participation in leisure time physical activity was used to classify participants as inactive (0 times/wk), infrequently active (1-4 times/wk) and habitually active (5 + times/wk). Measured weight and height were used to calculate body mass index (kg/m2) categories as follow: Underweight BMI < 18.5, Normal weight BMI = 18.5-24.9, Overweight BMI = 25-29.9, and Obesity BMI > =30. We used data from persons ages 40-74 years of age with a complete Oral Glucose Tolerance Test. Adults with A1C > =6.5%, fasting blood glucose > = 126 mg/dl or 2 hr. plasma glucose> = 200 mg/dl were classified as with diabetes. We used SAS version 9.4 for our statistical analysis. The outcome variable was all-cause mortality.

RESULTS

Our analytic sample consisted of 240 adults, 183 were assumed alive, 56 were assumed deceased, and 1 had missing value. Among persons with diabetes, those who exercised during leisure time habitually (5+ times/wk) had significantly lower odds ratios (OR = 0.42, 95% CI: 0.18,0.96) of all-cause mortality than persons with diabetes that were physically inactive, independent of obesity status. Further adjustment for education or smoking did not change the association.

CONCLUSIONS

For persons with diabetes, exposure to habitual physical activity 5+ times/wk is associated with lower all-cause mortality. The effect of physical activity was independent of obesity status.