Association between exposure to polychlorinated biphenyls and risk of hypertension: A systematic review and meta-analysis

Experimental and epidemiological studies have suggested an association between exposure to polychlorinated biphenyls (PCBs), ubiquitous environmental toxic compounds, and the risk of hypertension. We conducted a systematic review and meta-analysis of epidemiological studies of the association between PCB exposure and the risk of hypertension. Studies were identified by searching PubMed, Embase and Web of Science and by reviewing reference lists. Study-specific risk estimates comparing the highest versus lowest quantile of PCB distribution were combined using random-effects models. We identified 10 cross-sectional studies, 6 cohort studies, and 1 nested case-control study. A pooled excess risk of hypertension was found for total PCBs (OR 1.70, 95% CI 1.28–2.26), dioxin-like (DL)-PCBs (OR 1.46, 1.19–1.79), but not for non-dioxin like (NDL)-PCBs (OR 1.19, 0.81–1.73) comparing the highest with the lowest quartile of the distribution. According to a dose-response meta-analysis, a linear dose-effect relationship was found for total PCBs [OR 2.23 (95% CI: 1.59–3.14) for 1000 ng PCB/g lipid increase]. This positive association remained when stratifying the analyses by study design (cohort vs cross-sectional studies) and population (general population vs high exposed workers/residents). Among single PCB congeners, DL-PCB 105 and 118, and non-DL-PCB138 and 153 were related to hypertension. In conclusion, this meta-analysis suggests that exposure to PCBs, particularly to DL-PCBs, may be a risk factor for hypertension, independently of other risk factors