To determine the prevalence of baker's asthma due to flour dust in an industrial bakery in Korea.

Of the 596 active workers, 380 were allocated to a category of either direct exposure (DE) or indirect exposure (IE) to flour dust and completed a modified ISAAC questionnaire. Of the 380 participants, 233 were screened by an occupational physician interview, a skin prick test, and an ELISA for serum-specific IgE antibodies to wheat flour extracts. Selected workers received serial monitoring of peak expiratory flow rate (PEFR), and positive PEFR respondents received a methacholine challenge test. The diagnosis of baker's asthma was confirmed by a specific inhalation challenge with wheat flour extracts.

The prevalence of sensitization to wheat flour and baker's asthma was 21.0% (25.9% DE, 13.3% IE) and 3.2% (5.1% DE, 1.8% IE), respectively. DE had an increased risk of sensitization to wheat flour (OR 2.15, 95% CI = 1.03~4.51). Sensitization to wheat flour and the prevalence of baker's asthma correlated significantly (PR 38.63, 95% CI = 6.14~243.22).

These findings indicate a considerable prevalence of baker's asthma among flourexposed workers in Korea. Future studies will be required to survey the situation in flour mill companies and seek ways to protect the health and socioeconomic position of flour industry workers.