Exposure to systemic corticosteroids is known to be associated with a risk of cataract. This study was undertaken to determine the risk of cataract associated with the use of inhaled corticosteroids and to assess whether there is a dose-response relation. It was designed as a population based case-control study based on the General Practice Research Database in the UK. 15 479 people with cataract (mean age 75 years) and 15 479 controls were matched for age, sex, practice, and observation period. The mean daily dose of inhaled corticosteroids (mostly beclomethasone, rarely budesonide or fluticasone) was categorised as low (up to 400 µg a day), moderate (401–800 µg/day), high (801–1600 µg/day), and very high (>1600 µg/day).

A dose-response relation was found, with the adjusted odds ratio rising from 0.99 (95% CI 0.87 to 1.13) at daily doses up to 400 µg to 1.69 (95% CI 1.17 to 2.43) for daily doses of >1600 µg. The association was also stronger with increasing duration of use.

The study concluded that higher doses and longer duration of exposure to inhaled corticosteroids are associated with an increased risk of cataract. The authors do not define either a minimum “safe” dose or a maximum “safe” period of steroid use, but do urge practitioners to use the “the lowest doses compatible with good control of airways disease”. Naturally, the risks of inadequate treatment of asthma or COPD need to be borne in mind, but the authors point out the need for wider appreciation of the risk of cataracts associated with high dose inhaled steroids.