[The trend of change in insulin resistance among Chinese adults from 2010 to 2018]

Objective: To investigate the trends in insulin resistance, as represented by the triglyceride-glucose index (TyG index), among Chinese adult residents from 2010 to 2018 and to explore influencing factors. Methods: China Chronic Disease and Risk Factor Surveillance was conducted in 2010, 2013, and 2018, using a multi-stage stratified cluster random sampling method across all 31 provinces (autonomous regions and municipalities) in China. This study sampled 98 712 adults in 2010, 176 534 adults in 2013, and 184 876 adults in 2018, all aged ≥18 years, totaling 406 933 participants. Individuals with a TyG index >P₇₅ were classified as having insulin resistance. The mean TyG index and the prevalence of insulin resistance were calculated for different years, sexes, age groups, provinces (autonomous regions and municipalities), and subgroups for 2018. Linear and logistic regression models were used to test trends in means and rates over time, and multivariate logistic regression models were conducted to analyze potential factors associated with insulin resistance. All analyses were adjusted for complex sampling weights based on the study design. Results: From 2010 to 2018, the mean TyG index among Chinese adults increased from 8.44±0.63 to 8.70±0.64, with significant upward trends observed across different age groups, sexes, and urban-rural residencies (all P<0.001). The mean TyG index was higher among males, urban residents, and those aged 45-59. There were significant differences in the mean TyG indices and prevalence of insulin resistance across provinces (autonomous regions and municipalities) (all P<0.05). Higher insulin resistance prevalence was independently associated with being male, aged ≥45 years, living in urban areas, excessive alcohol consumption, and insufficient physical activity (all P<0.05). Conclusions: From 2010 to 2018, the level of insulin resistance, as indicated by the TyG index, showed an increasing trend among Chinese adults. Males, individuals aged ≥45 years, urban residents, and individuals with unhealthy lifestyles such as excessive alcohol consumption or insufficient physical activity should be the focus of efforts to prevent and control metabolic diseases related to insulin resistance.