Dietary and lifestyle indices for insulin resistance and nonalcoholic fatty liver disease

Purpose The aim of the present study was to investigate the association of the empirical dietary index for insulin resistance (EDIR) and empirical lifestyle index for insulin resistance (ELIR) with the risk of nonalcoholic fatty liver disease (NAFLD) in Iranian adults. Design/methodology/approach In this case-control study, 120 cases of NAFLD and 240 controls aged ≥20 years were included. NAFLD was detected by a gastroenterologist using an ultrasonography test. The food frequency questionnaire was used to collect nutritional data and determine the score of EDIR in participants. ELIR was determined based on body mass index, physical activity and dietary pattern. The odds ratios (ORs) of NAFLD were reported across tertiles of EDIR and ELIR using a logistic regression test. Findings The mean±SD age and BMI of subjects were 41.8 ± 7.5 years and 27.4 ± 2.2 kg/m 2 , respectively. In the age and sex-adjusted model, the odds of NAFLD were increased across tertiles of ELIR (OR = 3.00; 95% CI: 1.63–5.55, P trend = 0.001). Also, based on the fully adjusted model, the odds of NAFLD were increased according to tertiles of ELIR (OR = 2.66; 95% CI: 1.38–5.10, P trend = 0.006). However, no significant association was found between the higher score of EDIR and odds of NAFLD based on the age and sex-adjusted model (OR = 1.18; 95% CI: 0.68–2.05, P trend = 0.52) and the multivariable-adjusted model (OR = 0.91; 95% CI: 0.48–1.70, P trend = 0.87). Originality/value To the best of the authors’ knowledge, this was the first study to examine the role of the insulinemic potential of diet and lifestyle in predicting NAFLD risk. Our findings suggested that a lifestyle with a higher score of ELIR was positively associated with NAFLD risk. However, a diet with a higher score of EDIR was not related to the odds of NAFLD.