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Effect of improved home ventilation on asthma control and house dust mite allergen levels
Author(s) -
Wright G. R.,
Howieson S.,
McSharry C.,
McMahon A. D.,
Chaudhuri R.,
Thompson J.,
Donnelly I.,
Brooks R. G.,
Lawson A.,
Jolly L.,
McAlpine L.,
King E. M.,
Chapman M. D.,
Wood S.,
Thomson N. C.
Publication year - 2009
Publication title -
allergy
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 3.363
H-Index - 173
eISSN - 1398-9995
pISSN - 0105-4538
DOI - 10.1111/j.1398-9995.2009.02098.x
Subject(s) - evening , medicine , house dust mite , asthma , morning , placebo , ventilation (architecture) , allergen , dust mites , population , allergy , anesthesia , toxicology , immunology , environmental health , meteorology , pathology , astronomy , physics , alternative medicine , biology
Background: The warm, humid environment in modern homes favours the dust mite population, but the effect of improved home ventilation on asthma control has not been established. We tested the hypothesis that a domestic mechanical heat recovery ventilation system (MHRV), in addition to allergen avoidance measures, can improve asthma control by attenuating re‐colonization rates. Methods: We conducted a randomized double‐blind placebo‐controlled parallel group trial of the installation of MHRV activated in half the homes of 120 adults with asthma, allergic to Dermatophagoides pteronyssinus . All homes had carpets steam cleaned and new bedding and mattress covers at baseline. The primary outcome was morning peak expiratory flow (PEF) at 12 months. Results: At 12 months, the primary end‐point; change in mean morning PEF as compared with baseline, did not differ between the MHRV group and the control group (mean difference 13.5 l/min, 95% CI: −2.6 to 29.8, P = 0.10). However, a secondary end‐point; evening mean PEF, was significantly improved in the MHRV group (mean difference 24.5 l/min, 95% CI: 8.9–40.1, P = 0.002). Indoor relative humidity was reduced in MHRV homes, but there was no difference between the groups in Der p 1 levels, compared with baseline. Conclusions: The addition of MHRV to house dust mite eradication strategies did not achieve a reduction in mite allergen levels, but did improve evening PEF.