Normal Triglyceride is Associated with Insulin Resistance in the Absence of Risk Factors

BACKGROUND: Traditionally, absence of insulin resistance risk factors (IRRFs) is considered low risk for insulin resistance (IR). However, even individuals without IRRFs still have IR. This study aimed to explore the predictors of IR among the population who are non-smokers, non-diabetic and non-obese with normal blood pressure and lipids. METHODS: The data was derived from the 2007-2014 National Health and Nutrition Survey (NHANES). Participants without regular insulin resistance risk factors (IRRF-Free, n =2 317) and a subgroup without optimal insulin resistance risk factors (IRRF-Optimal, n =1 325) were involved to explore predictors of IR, which was indexed by homeostatic model assessment (HOMA). The logistic regression model and the areas under receiver operating characteristic curve (AUROC) were used to evaluate IRRFs and the predictive capacity, and Jordan index was performed to determine the optimal cut-off value of triglyceride (TG) to predict IR in IRRF-Free and IRRF-Optimal. FINDINGS: The prevalences of IR were 6.9% and 5.8% in IRRF-Free and IRRFOptimal respectively. TG and waist circumference (WC) were independently associated with the prevalence of IR (P<0·05) in both the IRRF-Free and IRRF-Optimal, where TG was positively associated with IR. The AUROC of TG was 0·7013 (95% CI 0·7011-0·7016) and 0·7180 (95% CI 0·7176-0·7183) in IRRF-Free and IRRF-Optimal respectively, and the optimal cut-off value of TG to predict IR for the two groups were both 87·5 mg/dl. INTERPRETATION: TG, even at levels currently considered normal, was independently associated with IR in the absence of IRRFs. TG can be used as an important indicator to predict the prevalence of IR. FUNDING: The Natural Science Foundation of Science and Technology Department of Jilin Province, China; the Outstanding Youth Foundation of Science and Technology Department of Jilin Province, China; the National Natural Science Foundation of China; the National Key Research and Development Program of China. DECLARATIONS OF INTERESTS: No other potential conflicts of interest relevant to this article were reported. All subjects provided written informed consent, and the study was approved by the NCHS Research Ethics Review Board (ERB).