Higher dietary inflammatory or insulinemic potential may be associated with increased risk for type 2 diabetes in adults, according to study results published in Diabetes Care.
Previous studies suggest that inflammation may contribute to insulin resistance and development of type 2 diabetes. Dietary habits may also significantly affect inflammation and insulin resistance. Available data suggest that a healthy dietary pattern may be associated with reduced risk for type 2 diabetes.
The current study sought to investigate the association between proinflammatory and hyperinsulinemic diets and the risk for type 2 diabetes.
Using data from the Nurses’ Health Study (1984-2016), the Nurses’ Health Study II (1989-2017), and the Health Professionals Follow-up Study (1986-2016), investigators identified participants without diabetes, cardiovascular disease, or cancer. Based on repeated food-frequency questionnaires completed by the participants, empirical dietary inflammatory pattern (EDIP) and empirical dietary index for hyperinsulinemia (EDIH) scores were calculated, as food-based indices for dietary inflammatory or insulinemic potential, respectively.
Cox proportional hazards regression models were used to estimate the risk for type 2 diabetes associated with quintiles of EDIP and EDIH scores.
During follow-up of over 4.9 million person-years, a total of 19,666 incident type 2 diabetes cases were documented.
In the pooled multivariable-adjusted analyses, compared with individuals in the lowest EDIP quintile, those in the highest EDIP quintile had a 3.11 times higher risk for type 2 diabetes (95% CI, 2.96-3.27). Similarly, compared with individuals in the lowest EDIH quintile, those in the highest EDIH quintile had 3.40 times higher risk for type 2 diabetes (95% CI, 3.23-3.58).
Additional adjustment for body mass index (BMI) attenuated the magnitude of the associations, but the strong positive association remained statistically significant for both EDIP (hazard ratio [HR], 1.95; 95% CI, 1.85-2.05) and EDIH (HR, 1.87; 95% CI, 1.78-1.98), suggesting that the effect of diet can be mediated through adiposity.
The association between EDIP or EDIH and type 2 diabetes incidence was stronger among younger, leaner, or more active adults.
In the joint analysis of EDIP and EDIH, patients in both highest EDIP and EDIH quintiles had 4.62 times (95% CI 4.29-4.97) increased risk for type 2 diabetes, compared with
those in both lowest quintiles. The association remained statistically significant after further adjustment for BMI (HR, 2.34; 95% CI, 2.17-2.52).
This study had several limitations, including potential measurement errors as data was based on self-report questionnaires and potential residual confounding by unmeasured variables.
“Dietary guidelines and interventions highlighting the importance of reducing or avoiding inflammatory and insulinemic dietary patterns may have great potential for the primary prevention of type 2 diabetes,” the researchers concluded.
Lee DH, Li J, Li Y, et al. Dietary inflammatory and insulinemic potential and risk of type 2 diabetes: results from three prospective U.S. cohort studies. Published online September 1, 2020. Diabetes Care. doi: 10.2337/dc20-0815