A pooled effect (percentage change) was observed, with a 1 μg/m3 increase in NO2 associated with a significant 1.25% change (95% CI: 0.67, 1.84; I2 = 0.00%, p = 0.07) in the Homeostasis Model Assessment of Insulin Resistance (HOMA-IR) and a 0.60% change (95% CI: 0.17, 1.03; I2 = 30.94%, p = 0.27) in insulin. Here, INS is linked to Insulin resistance.