Polycyclic aromatic hydrocarbons, brachial artery distensibility and blood pressure among children residing near an oil refinery

Background: Polycyclic aromatic hydrocarbons (PAH) are produced by the burning and processing of fuel oils, and have been associated with oxidant stress, insulin resistance and hypertension in adults. Few studies have examined whether adolescents are susceptible to cardiovascular effects of PAHs. Objective: To study associations of PAH exposure with blood pressure (BP) and brachial artery distensibility (BAD), an early marker of arterial wall stiffness, in young boys attending three schools in Jeddah, Saudi Arabia in varying proximity to an oil refinery. Methods: Air samples collected from the three schools were analyzed for PAHs. PAH metabolites (total hydroxyphenanthrenes and 1-hydroxypyrene) were measured in urine samples from 184 adolescent males, in whom anthropometrics, heart rate, pulse pressure, brachial artery distensibility and blood pressure were measured. Descriptive, bivariate and multivariable analyses were performed to assess relationships of school location and urinary PAH metabolites with cardiovascular measures. Results: Total suspended matter was significantly higher (444±143μg/m3) at the school near the refinery compared to a school located near a ring road (395±65μg/m3) and a school located away from vehicle traffic (232±137μg/m3), as were PAHs. Systolic (0.47 SD units, p=0.006) and diastolic (0.53 SD units, p<0.001) BP Z-scores were highest at the school near the refinery, with a 4.36-fold increase in prehypertension (p=0.001), controlling for confounders. No differences in pulse pressure, BAD and heart rate were noted in relationship to school location. Urinary total hydroxyphenanthrenes and 1-hydroxypyrene were not associated with cardiovascular outcomes. Conclusions: Proximity to an oil refinery in Saudi Arabia is associated with prehypertension and increases in PAH and particulate matter exposures. Further study including insulin resistance measurements, better control for confounding, and longitudinal measurement is indicated.