Interactions of arsenic exposure, arsenic metabolism with red blood cell folate on the risk of hypertension: NHANES 2007–2016

Arsenic exposure was associated with hypertension, and arsenic metabolism might be influenced by folate concentrations. Thus, this study aimed to explore the interaction between arsenic exposure and metabolism with folate concentrations on hypertension. We studied 6643 adults aged 20 years and older who participated in the National Health and Nutrition Examination Survey from 2007 through 2016. Urinary total arsenic (UTAs), the percentage of urinary dimethylarsinic acid (DMA%), serum and red blood cell (RBC) folate were collected. Logistic regression and restricted cubic spline (RCS) analyses were performed to determine the association and dose-response relationship. Interaction analyses were conducted on both additive and multiplicative scales. UTAs (median: 7.05 μg/L) was positively associated with hypertension risk, and the adjusted OR was 1.44 (95% CI: 1.06–1.95) when comparing the third with the lowest quartile. And participants with the highest quintile of RBC folate had increased hypertension risk than those with the lowest quintile (adjusted OR = 1.43, 95% CI: 1.06–1.94). Significant additive interaction was observed between excessive RBC folate with high UTAs (AP = 0.323, 95% CI: 0.083–0.564) and low DMA% (AP = 0.381, 95% CI: 0.119–0.643) on hypertension risk. Our results suggested significant interactions between high UTAs and low DMA% with excessive RBC folate on hypertension risk.