Stressful life events and the onset of asthma.

The status of stressful life events as a risk factor for asthma is unclear and may be dependent on pre-existing allergic rhinitis. This study examined whether exposure to stressful life events predicted the onset of asthma in adults. This is a prospective, population-based cohort study of 16,881 males and females, aged 20-54 yrs and free of diagnosed asthma at the beginning of the follow-up (January 1, 2004). Data about stressful life events were gathered with a postal survey. The onset of asthma was ascertained through national registers until December 31, 2005. During the follow-up period, 192 incident cases of asthma were identified. High total exposure to stressful life events, as indicated by a cumulative severity score, predicted the onset of asthma (hazard ratio 1.96, 95% CI 1.22-3.13). This association was robust to adjustment for demographics, smoking and having a cat/dog at home and it was observed both among those with and without allergic rhinitis at baseline. Of the 10 most stressful life events, the illness of a family member, marital problems, divorce or separation and conflicts with a supervisor were associated with the onset of asthma. Our study suggests that stressful life events may increase the onset of asthma.