Chlorinated persistent organic pollutants in plasma and risk of cardiovascular disease: a prospective nested case-control study in two Swedish cohorts

Abstract

BACKGROUND AND AIM: Cardiovascular toxic effects derived from high exposures to persistent organic pollutants (POPs) are well documented. Evidence in general population with low-dose and long-term exposures is limited. To analyze the association of chlorinated POP plasma levels, which include polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs), with risk of composite cardiovascular disease (CVD) and separate ischemic stroke and myocardial infarction (MI) in a general Swedish population. METHODS: Within the Swedish Mammography Cohort-Clinical (SMC-C) and the Cohort of 60-Year-Old (60YO), we conducted a population-based nested case-control study with first incident stroke (n=708) and MI (n=820) ascertained via linkage. Controls were matched by age, sex, and sampling date. Baseline blood sampling occurred during 2003-2009 and 1997-1999 with follow-up through 2017 and 2014 for the SMC-C and the 60YO, respectively. POP levels were evaluated as cohort-specific tertiles based on controls. Multivariable adjusted logistic regressions were conducted to estimate odds ratios (OR) and 95% confidence intervals (CI). RESULTS:Mean age was 72 (±7) years in SMC-C and 61 (±0.1) years in 60YO. The individual chlorinated POPs found in highest concentrations (ng/ml) were by far PCB-153 [1016 (721–1365) in controls and 1072 (816–1366) in cases] and pp-DDE [1889 (1057–3240) in controls and 2348 (1296–3724) in cases]. Sum of standardized chlorinated POP levels associated with composite CVD, OR (95% CI) 1.40 (1.03-1.92), and with stroke 1.62 (1.01-2.59) but not with MI, 1.24 (0.77-1.98), comparing extreme tertiles. These associations were mainly driven by OCPs, which associated with composite CVD 1.45 (1.07-1.99), and with MI 1.91 (1.16-1.37), but less clear with stroke 1.52 (0.92-2.50). CONCLUSIONS:These findings indicate that high levels of OCPs in human blood might increase the risk of both stroke and MI, while the cardiovascular risk associated with PCBs was less clear. More evidence from studies using biological samples is needed. KEYWORDS: Chlorinated persistent organic pollutants, endocrine disrupting chemicals, prospective nested case-control study, Swedish cohorts, cardiovascular disease