Sociodemographic and lifestyle determinants of insulin resistance scores in 273,154 Spanish workers: A cross-sectional analysis using TyG, METS-IR, and SPISE-IR

Objective: Insulin resistance (IR) is a pivotal factor in the pathophysiology of metabolic syndrome, type 2 diabetes mellitus, and cardiovascular disease. Surrogate indices such as the triglyceride-glucose (TyG) index, the metabolic score for insulin resistance (METS-IR), and the single-point insulin sensitivity estimator (SPISE-IR) offer non-invasive, cost-effective tools to assess IR in large populations. Our aim was to investigate the sociodemographic and lifestyle determinants of insulin resistance in a large occupational cohort of Spanish workers using TyG, METS-IR, and SPISE-IR indices, and to identify high-risk subgroups for targeted preventive strategies. Materials and methods: A cross-sectional analysis was conducted on 273,154 Spanish workers (128,197 men and 144,957 women). Sociodemographic (sex, age, social class) and lifestyle variables (smoking, physical activity, Mediterranean diet adherence, alcohol consumption) were examined in relation to TyG, METS-IR, and SPISE-IR scores. Prevalence estimates, stratified mean comparisons, and multinomial logistic regression models were applied to assess independent associations. Results: Men exhibited higher TyG and METS-IR scores and lower SPISE-IR scores than women. Insulin resistance increased with age and was more prevalent among individuals from lower social classes. Physically inactive individuals and those not adhering to a Mediterranean diet had markedly higher IR scores across all indices. Alcohol consumption and smoking were also associated with increased odds of insulin resistance, although patterns varied by sex. Multivariate models confirmed that male sex, older age, lower social class, unhealthy diet, inactivity, smoking, and alcohol use were independently associated with elevated IR scores. Conclusion: This study highlights the utility of TyG, METS-IR, and SPISE-IR indices in detecting insulin resistance in working populations. Sociodemographic inequalities and modifiable lifestyle factors strongly influence IR profiles, supporting workplace health programs that promote physical activity, healthy eating, and behavioral change as strategies to reduce metabolic risk.