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Evidence summaries

Ionisers for Chronic Asthma

The use of room air ionisers may not reduce symptoms in patients with chronic asthma. Level of evidence: "C"

A Cochrane review [Abstract] 1 included 6 studies with a total of 106 subjects. No results were combined as the studies were all of a crossover design. Effects of negative ion generators (5 studies): No study reported a significant difference in lung function between ionised and control air (morning PEF, 3 studies; FEV1, 1 study). There were no significant differences in symptoms or beta-2 agonist usage between ionised and control air in 3 studies. Effects of positive ion generators (1 study): This study demonstrated that although positively ionised air was associated with a larger fall in FEV1 with exercise, this did not reach statistical significance. Baseline FEV1 was not demonstrated to be significantly different between treatment groups.

Comment: The quality of evidence is downgraded by study quality (unclear allocation concealment) and by imprecise results (limited study size for each comparison).

    References

    • Blackhall K, Appleton S, Cates CJ. Ionisers for chronic asthma. Cochrane Database Syst Rev 2012;(9):CD002986. [PubMed]

Primary/Secondary Keywords