Association of heavy metal exposure, C-reactive protein, and stroke risk in US adults: A cross-sectional analysis (NHANES 2005-2008).

Stroke occupies an important position in the global disease burden, but the combined effect of heavy metal exposure and the inflammatory marker C-reactive protein (CRP) on stroke remains unclear. Based on the National Health and Nutrition Examination Survey, this study explores the association between blood lead, blood cadmium, blood mercury, CRP, and the risk of stroke. A total of 8297 American adults aged 20 years and older were included in the National Health and Nutrition Examination Survey. Standardized questionnaires were used to collect stroke history and covariates such as age, gender, race, education, income poverty ratio, body mass index, smoking, drinking, hypertension, and diabetes; whole blood cadmium, lead, mercury, and serum CRP were measured. Weighted multivariate logistic regression was used to evaluate the relationship between heavy metal exposure and CRP outcomes; receiver operating characteristic curves were constructed to compare model performance; and a 3D interaction graph was used to evaluate the synergistic effect of plumbum and CRP. Baseline characteristics: the stroke group's median age (69 years) was significantly higher than the non-stroke group's (33 years). Stroke patients had higher blood lead, CRP, hypertension/diabetes rates, and body mass index, but lower blood mercury, education, income levels (P < .05). After adjustment, each unit increase in blood lead and CRP increased the risk of stroke by 7% (odds ratio [OR] = 1.07, 95% confidence interval: 1.00-1.14) and 19% (OR = 1.19, 95% confidence interval: 1.07-1.32), respectively; blood cadmium and mercury had no significant association. The Receiver Operating Characteristic curves showed model 2 (area under the curve = 0.80) outperformed model 1 (area under the curve = 0.64). In age subgroups, cadmium affected the 40- to 60-year age group (OR = 1.39); lead was positively and mercury negatively correlated with the ≥60 group; CRP rose in both groups. The 3D graph indicated that stroke risk increased when both blood lead and CRP levels were high. Blood lead and CRP are independent stroke risk factors. Each unit rise in blood lead raises stroke risk by 7%, and each unit increase in CRP raises it by 19%. When both are high, stroke risk may further rise, especially in the elderly. Clinically, regular monitoring of these factors aids in stroke risk assessment. For high-risk groups, including these in routine screening enables early risk identification.