We studied total and specific serum IgE levels cross-sectionally, potential predictors of obstructive lung disease, in a stratified random sample of 18-73-year-old adults (n = 1512). The attendance rate was 84%. The total IgE level and prevalences of specific IgE antibodies against house dust mite and cat were higher for men than for women. Specific IgE levels decreased by increasing age, while total IgE decreased in women only. Smokers had a higher IgE level than non-smokers, while non-smokers had more often specific IgE antibodies against timothy and birch than smokers. Subjects with occupational dust or gas exposure had a higher total IgE level than unexposed. The general population prevalences were for specific IgE antibodies against timothy 4.5%, house dust mite 3.2%, birch 2.6%, cat dander 1.6% mould 0.2% and against any of these 7.6%. In a multivariate analysis age, occupational dust or gas exposure as well as the interaction terms between sex and age and between smoking and pack-years were independent predictors for total IgE levels. Male sex, young age, never having smoked and the season of the year were independent predictors for having one or more of the five specific IgE antibodies. Subjects with total serum IgE in the highest quintile (> or = 66 kU/l) had an adjusted odds ratio of 37 (95% confidence interval: 11-120) for having one or more of the specific IgE antibodies examined, compared with those in the lowest quintile (< 5 kU/l). Demographic and environmental factors were thus predictors of total and specific IgE levels in this adult community.(ABSTRACT TRUNCATED AT 250 WORDS)