Dietary inflammatory index and anthropometric measures of obesity in a population sample at high cardiovascular risk from the PREDIMED trial

Abstract

The dietary inflammatory index (DII) is a new tool to assess the inflammatory potential of diet. We aimed to determine the association between the DII and body mass index (BMI), waist circumference and waist to height ratio (WHtR). We conducted a cross-sectional study of 7,236 participants recruited into the PREDIMED trial (PREvención con DIeta MEDiterránea). Information from a validated 137-item food frequency questionnaire was used to calculate energy, foods and nutrients. A 14-item dietary screener was used to assess adherence to the Mediterranean diet (MeDiet). Sex-specific multivariable linear regression models were fitted to estimate differences (and 95% confidence intervals) in BMI, waist circumference and WHtR across quintiles of the DII. All nutrient intakes, healthy foods and adherence to the MeDiet were higher in the quintile with lowest DII score (more anti-inflammatory values) except for animal protein, saturated and monounsaturated fat. Though an inverse association between DII and total energy was apparent, the DII was associated with higher average BMI, waist circumference and WHtR after adjusting for known risk factors. The adjusted difference in WHtR for women and men between the highest and lowest quintile of DII was 1.60% (95% CI 0.87-2.33) and 1.04% (95% CI 0.35-1.74), respectively. Pro-inflammatory scores remained associated with obesity after controlling for the effect that adherence to a MeDiet had on inflammation. In conclusion, this study shows a direct association between the DII and indices of obesity and supports the hypothesis that diet may have a role in the development of obesity through inflammatory modulation mechanisms.