Impact of occupational asthma on health and employment status: a long-term follow-up study

The aim of this study was to assess the predictors of a favourable prognosis of occupational asthma (OA) and the employment status of patients with OA at least 2 years after diagnosis.

We collected data from 204 patients who had a diagnosis of OA confirmed by a positive specific inhalation challenge. We defined OA remission as meeting the following three criteria: no asthma symptoms, no antiasthma therapy for the last year and having normal lung function at the end of follow-up. A logistic regression analysis was performed to estimate the effects of the covariates.

At 10.6±7.8-year follow-up, 60 of 204 possible patients participated in the study, and among them 17 showed OA remission. When compared with the 43 patients with persistent OA, these patients exhibited at diagnosis younger age (p=0.0039), shorter duration of symptomatic exposure (p=0.0512), better lung function expressed by higher forced vital capacity (FVC%) predicted (p=0.0164), forced expiratory volume in 1 s (FEV₁) % predicted (p=0.0066) and FEV₁/FVC% (p=0.0132), and less bronchial hyper-responsiveness (p=0.0118). Nevertheless, in the multivariable model, no variables were significantly associated with OA remission. At follow-up, three individuals have retired; among the remaining 57 workers, 91.2% were still employed and 43.8% of them had continued working in the same factory after ceasing exposure to the causative agent.

This monocentric study did not identify a strong predictor of OA remission, but documented a high employment rate and a good job preservation over a long timeframe after diagnosis of OA mainly induced by low molecular weight agents.