Diet, lifestyle, and the risk of type 2 diabetes mellitus in women.
Level 3 - non-randomized controlled study
Prospective non-randomized longitudinal cohort study.
PubMed 11556298 · doi:10.1056/NEJMoa010492
What was done
Researchers followed 84,941 female nurses from 1980 to 1996 who were free of diagnosed cardiovascular disease, diabetes, and cancer at baseline. Dietary and lifestyle habits were updated periodically via self-reported questionnaires. A low-risk group was defined by five factors: body-mass index under 25, a diet high in cereal fiber and polyunsaturated fat and low in trans fat and glycemic load, at least 30 minutes per day of moderate-to-vigorous physical activity, no current smoking, and consumption of at least half an alcoholic drink per day on average.
What was found
During 16 years of follow-up, 3,300 incident cases of type 2 diabetes occurred. Overweight or obesity was the single most important predictor of diabetes. Lack of exercise, poor diet, current smoking, and abstinence from alcohol were each associated with significantly increased diabetes risk after adjusting for body-mass index. Women in the low-risk category (3.4% of the cohort) had a relative risk of diabetes of 0.09 (95% CI, 0.05 to 0.17) compared with the rest of the cohort. Overall, 91% of diabetes cases (95% CI, 83 to 95) were attributable to habits not conforming to the low-risk pattern.
Why it matters
This study demonstrates that the vast majority of type 2 diabetes cases are potentially preventable through the combined adoption of a healthy diet, regular exercise, weight management, and smoking cessation.
Limits
The cohort consisted entirely of female registered nurses, limiting direct generalizability to men and populations with different socioeconomic or racial backgrounds. Diet and lifestyle factors were self-reported and subject to measurement error, and residual confounding cannot be ruled out in an observational study.
Cited by
- supports Approximately 80% of heart disease and diabetes cases are preventable with diet and lifestyle modifications.