Pro-Oxidative and Pro-Inflammatory Effects After Traveling from Los Angeles to Beijing: A Biomarker-Based Natural Experiment

BACKGROUND:Air pollution exposure increases cardiovascular morbidity and mortality. Preventing chronic cardiovascular diseases caused by air pollution relies on detecting the early effects of pollutants on the risk of cardiovascular disease development, which is limited by the lack of sensitive biomarkers. We have identified promising biomarkers in experimental animals but comparable evidence in humans is lacking. METHODS:Air pollution is substantially worse in Beijing than in Los Angeles. We collected urine and blood samples from 26 non-smoking, healthy adult residents of Los Angeles (mean age, 23.8 years, 14 women) before, during, and after they spent 10 weeks in Beijing during the summers of 2014 and 2015. We assessed a panel of circulating biomarkers indicative of lipid peroxidation and inflammation. Personal exposure to polycyclic aromatic hydrocarbons (PAHs), a group of combustion-originated air pollutants, was assessed by urinary PAHs metabolites. RESULTS:Urinary concentrations of four PAHs metabolites were 176% (95% CI, 103% to 276%) to 800% (95% CI, 509% to 1780%) greater in Beijing than in Los Angeles. Concentrations of six lipid peroxidation biomarkers were also increased in Beijing, among which 5-, 12-, 15-hydroxyeicosatetraenoic (HETE), and 9-, 13-hydroxyoctadecadienoic (HODE) acids reached statistical significance (false discovery rate