London School of Hygiene & Tropical Medicine

Long term use of inhaled steroids to prevent asthma symptoms may increase the risk of cataracts, according to research carried out by the London School of Hygiene & Tropical Medicine and published today in the British Journal of Ophthalmology.

Previous research has indicated that systemic steroids increase the risk of cataract, but whether the inhaled variety also carries a risk has not been known.

Researchers from the School's Department of Epidemiology and Population Health studied almost 15, 500 people with cataract over the age of 40 and an equal number of people of the same age and gender who did not have cataract. Among those with cataract, just under 11.5% had been prescribed inhaled steroids compared with just under 7.5% of those without the eye condition. The researchers based their findings on information from the UK's General Practice Research Database, which contains complete prescribing and diagnostic information for almost 1.5 million patients from 177 general practices in England and Wales.

The risk seemed to increase according to the daily dose of inhaled steroid prescribed, with little or no apparent increased risk of for those taking the lowest daily dose (up to 400 ug), rising to an increased risk of around 70% for those taking doses greater than 1600 ug a day, after adjusting for other influential factors. Risk also rose according to how long patients had been taking their treatment.

Nearly one in 10 people over the age of 65 has asthma or chronic obstructive pulmonary disease, most of whom are prescribed an inhaled steroid at some point.

The authors caution that the large therapeutic benefits of inhaled steroids have to be weighed up against this potential side effect, but they urge doctors to prescribe the lowest possible dose to their older patients.

Contact: Dr Liam Smeeth, Department of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine. Tel: 020 7927 2296 liam.smeeth@lshtm.ac.uk

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