Chances of developing diabetes increases among those who use inhaled steroids, Montreal researchers have discovered.

Samy Suissa, director of the Centre for Clinical Epidemiology at the Lady Davis Institute for Medical Research of the Jewish General Hospital said, "Patients with lung disease should ask their physicians about treatment with the synthetic hormone medication because the higher the dose, the greater the risk."

Suissa, lead author of the study and a professor of epidemiology and biostatistics at McGill University said that the risk of diabetes is increased by oral corticosteroids like prednisone but the effect of inhaled form has been observed for the first time now.

The mainstay of medical treatment of asthma and chronic obstructive pulmonary disease (COPD) are inhaled steroids now.

Suissa said, "But they have been shown to increase the risk of cataracts and pneumonia and now we are finding the increase in diabetes."

Suissa's team studied 400,000 patients over 18 years dipping into the database kept by the Quebec health insurance board.

The rate of onset of diabetes increased by 34 per cent for every year of use of the inhaled steroids and 14 people per 1,000, to 19 per 1,000 is the rate of people who are at risk.