Associations among urinary 1-hydroxypyrene level, oxidative stress, and high blood pressure: A panel study among...

Polycyclic aromatic hydrocarbons (PAHs) are environmental carcinogens. However, there is limited evidence for the relations between PAHs exposure and blood pressure (BP) with the mediating role of oxidative stress. Therefore, in this study, we evaluated relations among PAHs exposure, oxidative stress, and BP in the elderly population. We measured the levels of 1-hydroxypyrene (1-OHP), an indicator of PAHs exposure, and malondialdehyde (MDA), an oxidative stress marker, in urine samples repeatedly collected from 560 elderly persons aged ≥60 years, and then evaluated the relations among 1-OHP level, MDA level, and systolic or diastolic BP (SBP or DBP) measured on the day of urine collection. Urinary 1-OHP level was significantly associated with both MDA level (β = 0.19 and p < 0.0001) and BP (β = 1.72 and p < 0.0001 for SBP; and β = 1.24 and p < 0.0001 for DBP). Furthermore, urinary MDA level was also significantly associated with BP (β = 4.35 and p < 0.0001 for SBP; and β = 2.51 and p < 0.0001 for DBP). The trend for the change of SBP and DBP by 1-OHP quartile was more apparent in the elderly female participants (p_trend<0.0001 for SBP; and p_trend<0.0001 for DBP) compared with the elderly male participants (p_trend = 0.8351 for SBP; and p_trend = 0.3736 for DBP). To explore the mediating role of oxidative stress in the relation between 1-OHP level and SBP or DBP, we repeated these analyses after adjustment for the MDA levels. The increase in BP by 1-OHP exposure was largely mediated by the production of MDA (96.3% for SBP and 94.7% for DBP). These results revealed that PAHs exposure may increase BP through the mediation of oxidative stress.