The purpose of the present study was to analyse whether sex, age, skin test reactivity, cigarette smoking and occupational exposure were related to the total serum immunoglobulin (Ig)E concentrations (kU x L[-1]), in a general population sample. We studied 1,905 subjects (915 males, 990 females) of a general population sample (n=2,841, 8-73 yrs) participating in the second cross-sectional respiratory epidemiological survey in the rural Po Delta area (near Venice, North Italy). Distribution of total serum IgE concentrations was skewed, thus a log-transformation was performed to obtain a Gaussian shape. Significantly higher values of IgE were found in males compared to females. In general, a peak of IgE concentration was found at 8-14 yrs. IgE values tended to be lower in older than younger adults. Significantly higher serum IgE levels were shown in subjects with a positive skin-prick test index (ST+) than in those with a negative skin-prick test index (ST-). There was a significant relationship of total IgE levels with skin reactivity to pollens and house-dust mites. In both sexes higher values of IgE were found in current smokers than in ex-nonsmokers, regardless of skin-test reactivity. There was no significant difference in IgE values between ex- and nonsmokers. Passive smoking and occupational exposure were significantly related to increased IgE values. Our results confirm that in a general population sample immunoglobulin E concentrations are related not only to skin-prick test reactivity to common aeroallergens, but also to other risk factors for chronic obstructive lung diseases, such as sex, active/ passive smoking and occupational exposure.