Flour has been identified as the main cause of occupational asthma in France, closely followed by cleaning products.

A new study, which was presented at the European Respiratory Society's International Congress, analysed all cases of occupational asthma in France. The research, which is the largest of its kind to be undertaken in France, aimed to understand who was most affected by the condition and what the main causes were.

Data were collected over a 3-year period from a network of respiratory doctors specialised in occupational diseases. 330 cases were analysed.

Researchers estimated the incidence rate based on the figures they collected and the results of the analysis showed that;

• Flour was identified as the main cause (seen in 20% of cases), closely followed by ammonium compounds often found in cleaning products (seen in 15% of cases)
• Women were more likely to be diagnosed with occupational asthma (43 per million compared with 29 per million seen in men)
• Incidence rates were higher among skilled and unskilled workers (116 per million) when compared with farmers (97 per million)
• The highest incidence rate was seen in people working in the manufacture of food products and beverages (279 per million) compared with those working in agriculture (160 per million)

Professor Frederic De Blay, lead author from the University Hospital Strasborg, said: "This study has given us a detailed understanding of the occupational asthma cases in France. It helps to show us where people are being exposed to harmful agents and who is most likely to be affected. These findings are important as they can help with future prevention methods to make sure people who are at risk of occupational asthma are protected from it."