Occupational asthma in the city of São Paulo, 1995-2000, with special reference to gender analysis.

Background: Occupational asthma (OA) is the leading occupational respiratory disease in the area of São Paulo Municipality. Understanding its characteristics can provide useful information for better interventions.

Methods: From a joint registry of OA from five outpatient public clinics for occupational respiratory diseases, data on occupation, with job titles corrected by an expert evaluation, agents, exposure and symptom duration, and spirometry were analyzed by gender. Data on employment for São Paulo Municipality were used to calculate expected ratios for men/women in broad economical sectors.

Results: Three hundred and ninety four OA cases were reported with a ratio of men/women of 1.5. Women had significantly shorter exposure duration (5.6 +/- 5.2 vs. 8.9 +/- 9.0 years, P = 0.0005), shorter symptoms duration (2.6 +/- 3.7 vs. 3.2 +/- 3.5 years, P = 0.1270), and higher prevalence of previous atopy (27.0 vs. 18.4%, P = 0.0485). The main occupations related to OA cases were cleaning activities, working in plastics manufacture and in chemical and pharmaceutical plants. Women reported significantly more exposures to cleaning products, biologic agents, and textile fibers, whereas men reported more exposures to isocyanates, metal dusts and fumes, oil mists, wood dusts and anhydrides. Women presented an increased risk of OA in the service sector (odds ratio (OR) = 1.77, confidence interval (CI) = 1.61-1.96).

Conclusions: Cleaning services was the main reported occupation and cleaning products the main reported agents. Women had significantly shorter exposure duration possibly due to difference in exposures, previous atopy, and behavior. There was an excess of cases of women in the service sector.