Association between exposure to particulate matter from sand and gravel industries and respiratory diseases in residents of San Lorenzo, Puerto Rico: A cross sectional study

Studies have documented increased risks of respiratory diseases (RD) associated with long term exposure to particulate matter, PM. In Puerto Rico, residents from San Lorenzo's communities requested help to validate their concerns about pollution's effects on health. This cross-sectional study developed in response to this request and focuses on RD due to PM exposure from eleven sand and gravel industries. The objective is to evaluate the prevalence of RD among residents living in communities of lower and higher PM exposure. Two independent representative samples were selected from residents living in communities far and close to those industries based on three stage stratified cluster design. A questionnaire administered via personal interview collected data from 681 participants, which included socio-demographic variables, smoking habits, allergies, house characteristics, symptoms, respiratory illnesses diagnosis, and occupational exposures. Prevalence estimates were based on a weighted sample. Logistic regression model evaluated the association and estimated the adjusted prevalence for confounding variables. The response rate was 90.4%. Weighted prevalence for RD was statistically significant (p< 0.05) in higher exposed group: 25.9% rhinitis, 20.3% sinusitis, 3.2% pneumonia and 2.1 % COPD. Adjusting by confounding variables, the odds ratios for respiratory, allergic, and skin diseases was statistically significant (1.71, 2.78 and 2.40 respectively; all p< 0.05). Results suggest the prevalence of RD is significantly higher among residents living in communities of higher PM exposure compared to residents living in lower PM exposed communities (POR= 1.68, 95%CI: 1.57–1.79). The PM exposure from sand and gravel industries is associated to risk excess of suffering from respiratory, skin and allergic diseases. Recommendations on reducing the risk of developing RD include: modifying house environment, avoiding allergic materials, humidity, dusty rugs and cloth curtains, effective management of current RD and awareness of air quality reports.