Respiratory symptoms and lung function in aborigines from tropical Western Australia.

To estimate the prevalence of respiratory symptoms, bronchial hyperresponsiveness, smoking, and atopy in a population of Australians of Aboriginal descent (AAD), to determine the association of these and other factors with lung function, and to compare levels of lung function of AAD with Australians of European descent (AED) according to age and height, and to explore reasons for their differences, we conducted a study of 96 male (41 of whom were under 18 yr of age) and 111 female (48 of whom were under 18 yr of age) AAD living in a single remote tropical community in 1993. This population provided data on age, height, and lung function. A modified British Medical Research Council (MRC) questionnaire on respiratory symptoms and smoking was administered. FEV1, FVC, height, age, and bronchial responsiveness to inhaled methacholine were measured. Atopic status was assessed by skin prick tests for eight common allergens. Age- and sex-adjusted lung function was similar to that of other AAD groups and lower than in AED. For children, lung function increased less with increasing height in AAD than in AED. Lung function was reduced in adult AAD as compared with adult AED, although it was not possible to determine statistically whether lung function started to decline at an earlier age or declined faster with increasing age in AAD. A history of asthma, smoking, dyspnea, cough, or sputum production; atopic status; and increased bronchial responsiveness were all associated with lower levels of lung function. Differences in lung function between AAD and AED appear to be determined by characteristics that may be inherited, as well as by adverse external influences.

Fc epsilon R1-beta polymorphism and total serum IgE levels in endemically parasitized Australian aborigines.

Endemic helminthic infection is a major public-health problem and affects a large proportion of the world's population. In Australia, helminthic infection is endemic in Aboriginal communities living in tropical northern regions of the continent. Such infection is associated with nonspecific (polyclonal) stimulation of IgE synthesis and highly elevated total serum IgE levels. There is evidence that worm-infection variance (i.e., human capacity of resistance) and total serum IgE levels may be related to the presence of a major codominant gene. The beta chain of the high-affinity IgE receptor, Fc epsilon R1-beta, has been previously identified as a candidate for the close genetic linkage of the 11q13 region to IgE responses in several populations. We show a biallelic RsaI polymorphism in Fc epsilon R1-beta to be associated with total serum IgE levels (P = .0001) in a tropical population of endemically parasitized Australian Aborigines (n = 234 subjects). The polymorphism explained 12.4% of the total residual variation in serum total IgE and showed a significant (P = .0000) additive relationship with total serum IgE levels, across the three genotypes. These associations were independent of familial correlations, age, gender, racial admixture, or smoking status. Alleles of a microsatellite repeat in intron 5 of the same gene showed similar associations. The results suggest that variation in Fc epsilon R1-beta may regulate IgE-mediated immune responses in this population.