London, Sep 8 (IANS): German researchers have identified flour as the main cause of occupational asthma, closely followed by cleaning products.

The research, 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.

A team from University Hospital Strasbourg collected data over a three year period from a network of respiratory doctors specialising in occupational diseases.

"Flour was identified as the main cause - seen in 20 percent of cases - closely followed by ammonium compounds often found in cleaning products - seen in 15 percent of cases," explained lead study author and professor Frederic De Blay from the University Hospital Strasbourg.

Women were more likely to be diagnosed with occupational asthma compared with men.

The highest incidence rate was seen in people working in the manufacture of food products and beverages compared with those working in agriculture.

"It helps to show us where people are being exposed to harmful agents and who is most likely to be affected. These findings can help with future prevention methods to make sure people who are at risk of occupational asthma are protected from it," Blay concluded.

The paper was presented Sunday at the European Respiratory Society's (ERS) International Congress in Munich, Germany.