Exposure to road noise and asthma prevalence in adults.

Noise has been reported as one of the most important risk factors for asthma, but there are some disagreements. This study aimed to investigate the effect of road noise on asthma prevalence in adults. In the current study, 3172 adults were interviewed through the ECRHS standardized questionnaire in Tehran, the capital of Iran. Exposure to road noise was assessed considering distance of individual participants from the noise monitoring stations via the spatial analysis in GIS software. Logistic regression was used to assess the effect of noise on the symptoms of asthma. Findings showed a significant positive association between wheezing with dyspnea as the best marker for asthma and noise levels at daytime (OR 1.03; 0.98-1.05) and nighttime (OR 1.05; 0.84-1.09). Also, a significant positive association was obtained between daytime and nighttime noise levels and other asthma symptoms including wheezing, nocturnal chest tightness, nocturnal dyspnea, wheezing without cold, nocturnal cough, and asthma medication. Association between current asthma and noise level was not significant. There was a significant association between population age and current asthma prevalence (P = 0.001). Therefore, chronic exposure to road noise especially in the nighttime could increase asthma prevalence. So, control of noise sources can be suggested to diminish asthma in adults.