Associations between respiratory health, reported traffic, and occupational-related exposure

Rapid urbanisation over the past century has led to increased traffic density and higher levels of ambient air pollutants. We aimed to investigate whether the prevalence of respiratory symptoms, asthma, and chronic bronchitis increases with the level of self-reported exposure to traffic and occupational-related pollution.

The study population comprised 25,889 general population subjects ages 16-75 years participating in the Swedish part of the GA²LEN study. Data were collected in the cities of Umeå, Uppsala, Stockholm, and Gothenburg. Self-reported data on disturbance of fumes from traffic in the residential area or occupational exposure to gas, dust, or smoke, as well as on patient demographics, respiratory symptoms, asthma and chronic bronchitis, were obtained from questionnaires.

The prevalence of respiratory symptoms, asthma, and chronic bronchitis was higher both among participants reporting traffic-related exposure and those with a history of occupational exposure to fumes, smoke, and dust than among those unexposed; (wheeze 27 vs 13%), nocturnal cough (35 vs 22%), asthma (11 vs 6%) and chronic bronchitis (22 vs 8%); all p < 0.0001. When combining traffic and occupational exposure, the highest prevalence was found amongst those exposed to both. Associations with occupational exposure were generally stronger in women, and those with traffic exposure were stronger in men.

In this large population-based sample, self-reported residential traffic exposure and occupational exposure to dust, fumes, or smoke were associated with increased prevalence of respiratory symptoms, asthma, and chronic bronchitis. Although causality cannot be inferred, these findings underscore the importance of assessing environmental and occupational exposures in evaluating respiratory health.