A prospective study of the association between home gas appliance use during infancy and subsequent dust mite sensitization and lung function in childhood

Background Home gas appliance use has been associated with child respirator y illness but prospective data on the relationship between infant exposure and the development of child allergic disease has not been readily availabl e. Objectives (a) To determine if home gas appliance use is associated with increased risk of house dust mite (HDM), sensitization. (b) To examine whe ther any association between current home gas use and airway obstruction is influenced by HDM sensitization. Methods Design: an 8-year follow-up birth cohort study of children born dur ing 1988 and 1989. Participants: a population-based sample (n = 498) of chi ldren who participated in the Tasmanian Infant Health Survey (TINS) and res ided in Northern Tasmania in 1997 (84% of eligible children). Main outcome measures: (a) Skin prick test reaction to nine allergens, including Dermato phagoides pteronyssinus (Der p 1) and Dermatophagoides farinae (Der f 1). ( b) Spirometric lung function indices, including forced expiratory volume in one.second (FEV1) and forced vital capacity (FVC). Results The relative risk for home gas appliance use at 1 month of age and HDM sensitization was 1.98 (1.04, 3.79) in a cohort analysis with confounde r matching. Current home gas use was also associated with HDM sensitization (ARR 1.73 (1.43, 2.76)). Current home gas use was. related to a stronger ( P = 0.006) reduction in the FEV1 : FVC ratio among HDM-sensitive children ( adjusted difference - 6.2% (- 10.0 to - 2.4)) titan non-HDM-sensitive child ren (adjusted difference - 0.3% (- 2.5 to 1.8)). Conclusion Indoor pollutants. from gas combustion may increase the likeliho od of initial sensitization to HDM and play a role in the development of at opic asthma. HDM-sensitized children may be more vulnerable to indoor pollu tant-induced airway obstruction. The ability of this study to, detect such effects may partly reflect unflued gas appliance use among this sample.