Associations between Insulin Index and dietary insulin load with cardiometabolic phenotype in the AZAR cohort population in north-western Iran: a cross-sectionalstudy

OBJECTIVES: Hyperinsulinaemia and insulin resistance are proposed as contributors to the incidence of cardiometabolic phenotypes (CMPs) with unhealthy metabolic status. This study analysed the association between dietary insulin load (DIL) and Dietary Insulin Index (DII) with CMPs in the AZAR cohort population. DESIGN: This study was a cross-sectional analysis of the AZAR Cohort Study, beginning in 2014 and continuing to this date. SETTING: The AZAR cohort is a part of an Iranian screening programme named the Persian cohort and involves participants living in the Shabestar region, Iran for at least 9 months. PARTICIPANTS: A total of 15 006 participants agreed to partake in the study. We excluded participants with missing data (n=15), daily energy intake lower than 800 kcal (n=7) or higher than 8000 kcal (n=17), and cancer (n=85). Finally, 14 882 individuals remained. PRIMARY AND SECONDARY OUTCOME MEASURES: The gathered information included the participants' demographic, dietary, anthropometric and physical activity data. RESULTS: The frequency of DIL and DII significantly decreased from the first to fourth quartiles in metabolically unhealthy participants (p≤0.001). The mean values of DIL and DII were greater in metabolically healthy participants than in unhealthy ones (p<0.001). The results of the unadjusted model showed that the risks of unhealthy phenotypes in the fourth DIL quartile decreased by 0.21 (0.14–0.32) and 0.37 (0.33–0.43), respectively, compared with the first quartile. The same model showed the same risks for DII decreased by 0.18 (0.11–0.28) and 0.39 (0.34–0.45), respectively. The results in both genders were the same as all participants combined. CONCLUSIONS: DII and DIL were correlated with a decreased OR of unhealthy phenotypes. We suggest the reason may be either a lifestyle change in metabolically unhealthy participants or elevated insulin secretion not being as detrimental as previously thought. Further studies can confirm these speculations.