Systematic Review of Exposure to Polycyclic Aromatic Hydrocarbons and Obstructive Lung Disease

Background. There is fast-growing epidemiologic evidence of the effects of environmental chemicals on respiratory health. Polycyclic aromatic hydrocarbons (PAHs) have been linked with airway obstruction common in asthma and/or asthma exacerbation, and chronic bronchitis and emphysema. Objectives. A systematic review of the association between exposure to PAHs and obstructive lung diseases is not yet available. The present systematic review aims to evaluate the evidence available in epidemiological studies that have associated PAHs with obstructive lung diseases such as asthma, chronic bronchitis, emphysema. Methods. We performed a systematic literature search on PubMed, Google Scholar, and Scopus databases using relevant keywords and guided by predesigned eligibility criteria. Results. From the total of 30 articles reviewed, 16 articles examined the link between PAHs and lung function in both adults and children. Twelve articles investigated the association between PAHs and asthma, asthma biomarkers, and/or asthma symptoms in children. Two articles studied the relationship between PAHs and fractional exhaled nitric oxide (FeNO), a biomarker of airway inflammation and the relationship between PAHs and obstructive lung diseases and infections, respectively. One study assessed exposure to daily ambient PAHs and cough occurrence. Discussion. Twenty-seven studies found an association between PAHs and asthma and reduced lung function. In children it is reinforced by studies on prenatal and postnatal exposure, whereas in adults, reductions in lung function tests marked by low forced expiratory volume in 1 second, (FEV1), forced vital capacity (FVC), and forced expiratory flow (FEF25–75%) were the major health outcomes. Some studies recorded contrasting results: insignificant and/or no association between the two variables of interest. The studies reviewed had limitations ranging from small sample size, to the use of cross-sectional rather than longitudinal study design. Conclusions. The literature reviewed in the present study largely suggest positive correlations between PAHs and obstructive lung diseases marked mainly by asthma and reduced respiratory function. This review was registered with PROSPERO (Registration no: CRD42020212894) Competing Interests. The authors declare no competing financial interests