Immune markers and oxidative stress among welders prolongedly exposed to heavy metals

Chronic occupational exposure to heavy metals is among the most significant health risks faced by workers in environmentally hazardous industries, particularly in welding. These elements are associated with cumulative toxic effects on the immune and renal systems, as well as redox balance, often leading to long-term chronic health disorders. A cross-sectional study was conducted in Ramadi, Iraq, from January 1 to February 1, 2024, including 40 welders exposed to metal fumes and a control group of 20 healthy, unexposed individuals. Participants were aged 25–60 years, with welding work ranging from 5 to 30 years, stratified into four groups with 5-year exposure intervals. Blood and urine samples were collected from all subjects to assess immunoglobulins (IgE) and cytokines (IL-5), neutrophil gelatinase-associated lipocalin (NGAL), oxidative stress biomarkers (GSH-PX), and blood metal levels (Pb, Cd, Cr). Significant increases in mean ± SD IgE levels were observed, rising from 86.2 ± 22.7 IU/mL (5 years exposure) to 139.8 ± 39.0 IU/mL (25–30 years), compared with 66.9 ± 21.7 IU/mL in controls (p < 0.001). The mean ± SD IL-5 increased numerically from 12.8 ± 3.1 to 17.2 ± 5.1 pg/mL, compared with 9.2 ± 2.7 pg/mL in controls, but did not reach statistical significance (p = 0.088). Urinary NGAL mean ± SD rose significantly from 120.8 ± 21.3 to 191.6 ± 39.2 ng/mL, compared with 104.5 ± 23.3 ng/mL in controls (p = 0.001), suggesting progressive tubular kidney damage. GSH-PX mean ± SD activity decreased markedly from 45.2 ± 9.2 to 26.7 ± 9.1 units/mL, against 47.6 ± 11.6 units/mL in controls (p = 0.002), indicating diminished antioxidant defense. Lead and cadmium blood levels showed linear increases, with mean ± SD Pb rising from 25.7 ± 9.1 to 66.1 ± 13.7 μg/dL and mean ± SD Cd rising from 3.2 ± 1.1 to 8.0 ± 2.4 μg/L, while chromium remained elevated but not statistically significant. The study reveals a clear cumulative impact of chronic heavy metal exposure in welding environments on workers’ immune, renal, and oxidative systems, with severity increasing alongside years of service, notably beyond 10 years. These findings support the urgent need for enhanced preventive measures and ongoing medical surveillance among long-term exposed workers to curb progressive health risks.