The association of respiratory symptoms and lung function with the use of gas for cooking

The domestic combustion of fossil fuels, especially the use of unvented gas appliances such as gas stoves, produces high indoor concentrations of several agents potentially harmful to health [1, 2]. Some [3–8] but not all [9, 10] studies have reported increased respiratory symptoms suggestive of either increased respiratory infection or asthma in children living in homes with gas cookers compared to those in homes with electric cookers. Few of these studies have reported significant loss of lung function [11] in exposed children. A case-control study in the UK showed no association between the presence of a gas cooker in the house and severe asthma in adolescents [12]. Studies in adults have not been conclusive. COMSTOCK et al. [13] reported an increased risk of respiratory symptoms in nonsmoking males living in homes with gas cookers. In a subsample [14] of this group gas cooking was associated with an increased risk of airway obstruction. Other studies in the USA have shown no association bet-ween gas cooking and symptoms in adults [15]. In Sin-gapore nonsmoking females who frequently used gas for cooking had more respiratory symptoms and worse lung function than females who used gas infrequently or not at all [16]. The European Community Respiratory Health Survey (ECRHS) has collected information on respiratory symptoms, lung function and the use of domestic gas appliances from representative samples of adults living in more than 30 centres, predominantly in Europe. An analysis of the data collected from three of the UK centres in East Anglia has shown a strong and consistent association between the use of gas cookers and respiratory symptoms in females but not in males [17]. Further analysis suggested that females sensitized to common environmental allergens may be at a greater risk of symptoms than nonatopic women, although formal statistical tests for effect modification by atopy failed to reach conventional levels of significance. In this analysis we use data from all centres taking part in the ECRHS to examine whether there is an association between respiratory symptoms and lung function in adult females and if any such association is modified by atopy.