Association of serum zinc concentration with multiple surrogates of insulin resistance in a population-based study

The global prevalence of insulin resistance is increasing and it plays a significant role in the pathophysiology of chronic non-communicable diseases. Lipid metabolism disorder is a key mediator of insulin resistance. This cross-sectional study investigated the possible association between serum zinc (SZn) concentration and distinct surrogates of insulin resistance (IR). SZn were measured using flame atomic absorption spectrometry (FAAS) in 3078 adults (mean age of 48.8 ± 14.5, and 39.8% were male) participated in the Tehran Lipid and Glucose Study (2009-2011). The associations between SZn concentrations and surrogates of IR including homeostasis model assessment of insulin resistance (HOMA-IR), the triglyceride-glucose (TyG) index, the TyG-body mass index (TyG-BMI index), the metabolic score for insulin resistance (METS-IR), and the triglyceride-to-high-density lipoprotein cholesterol ratio (TG-to-HDL-C ratio), were assessed using multivariable logistic regression analysis. The mean serum zinc concentration was 112 ± 37.1 µg/dL. Serum zinc concentrations exceeding 119 µg/dL were significantly associated with a 32% increased probability of IR, identified by elevated TyG index (OR = 1.32; 95% CI = 1.08-1.59). Similarly, SZn concentrations greater than 91.3 µg/dL and 119 µg/dL were associated with a 30% and 34% increased probability of IR, as identified by the TG-HDL-C ratio, respectively. Our study revealed that elevated SZn concentrations, probably due to exposure to environmental pollutants, may be associated with increased probability of IR, identified by the high TyG index and TG-to-HDL-C ratio.