Abstract
OBJECTIVE Recent public health recommendations emphasize adopting a healthful dietary pattern, but evidence is scarce on whether incremental diet quality changes have an impact on long-term diabetes prevention. We aim to evaluate diet quality changes during a 4-year period and subsequent 4-year type 2 diabetes incidence.
RESEARCH DESIGN AND METHODS Participants of prospective cohorts, the Nurses’ Health Study (NHS), NHS II, and the Health Professionals Follow-up Study, who were free of diabetes at baseline (n = 124,607), were observed for ≥20 years. Diet quality, reflected by the Alternate Healthy Eating Index (AHEI) score, was assessed every 4 years to calculate changes.
RESULTS We documented 9,361 cases of type 2 diabetes during 2,093,416 person-years of follow-up. A >10% decrease in AHEI score over 4 years was associated with a higher subsequent diabetes risk (pooled hazard ratio 1.34 [95% CI 1.23–1.46]) with multiple adjustment, whereas a >10% increase in AHEI score was associated with a lower risk (0.84 [0.78–0.90]). Greater improvement in diet quality was associated with lower diabetes risk across baseline diet quality status (P for trend ≤ 0.001 for low, medium, or high initial diet quality) and baseline BMI (P for trend ≤ 0.01 for BMI <25, 25–29, or 30 kg/m2). Changes in body weight explained 32% (95% CI 24–41) of the association between AHEI changes (per 10% increase) and diabetes risk.
CONCLUSIONS Improvement in overall diet quality is associated with a lower risk of type 2 diabetes, whereas deterioration in diet quality is associated with a higher risk. The association between diet quality changes and diabetes risk is only partly explained by body weight changes.
- Received March 15, 2016.
- Accepted August 24, 2016.
- © 2016 by the American Diabetes Association.
Readers may use this article as long as the work is properly cited, the use is educational and not for profit, and the work is not altered. More information is available at http://www.diabetesjournals.org/content/license.