Association between Dietary Inflammatory Index (DII) and risk of prediabetes: a case-control study

The possible relationship between diet-related inflammation and the risk of prediabetes requires further investigation, especially in non-Western populations. We examined the ability of the dietary inflammatory index (DII) to predict the risk of prediabetes in a case-control study conducted at specialized centers in Esfahan, Iran. A total of 214 incident cases of prediabetes were selected with the nonrandom sampling procedure, and the 200 controls randomly selected from the same clinics were frequency-matched on age (±5 years) and sex. DII scores were computed based on dietary intake assessed using a validated and reproducible 168-item food-frequency questionnaire. Linear and logistic regression models were used to estimate multivariable beta estimates and odds ratios (ORs). Subjects in tertile 3 versus tertile 1 (T3VS1) of DII had significantly higher fasting plasma glucose (DII_T3VS1: b = 4.49; 95% CI 1.89, 7.09), oral glucose tolerance (DII_T3VS1: b = 8.76; 95% CI 1.78, 15.73), HbA1c (DII_T3VS1: b = 0.30; 95% CI 0.17, 0.42), low-density lipoprotein (DII_T3VS1: b = 16.37; 95% CI 11.04, 21.69), triglyceride (DII_T3VS1: b = 21.01; 95% CI 8.61, 33.42) and body fat (DII_T3VS1: b = 2.41; 95% CI 0.56, 4.26) and lower high-density lipoprotein (DII_T3VS1: b = -3.39; 95% CI -5.94, -0.84) and lean body mass (DII_T3VS1: b = -3.11; 95% CI -4.83, -1.39). After multivariate adjustment, subjects in the most pro-inflammatory DII group had 19 times higher odds of developing prediabetes compared with subjects in tertile 1 (DII_T3VS1: OR = 18.88; 95% CI 7.02, 50.82). Similar results were observed when DII was used as a continuous variable, (DII_continuous: OR = 3.62; 95% CI 2.50, 5.22). Subjects who consumed a more pro-inflammatory diet were at increased risk of prediabetes compared with those who consumed a more anti-inflammatory diet.