The relationship between smoking and total immunoglobulin E levels.

Results of skin testing to common allergens, total serum IgE levels, and the responses to a respiratory questionnaire were obtained for 1768 individuals participating in a survey of a rural population. The geometric mean total IgE levels in a group of subjects without skin-test reactions and with no histories of asthma or hay fever was 14.8 U/ml for men and 11.9 U/ml for women. When individuals were classified according to skin reactivity and smoking history there was a significant difference in IgE levels among nonsmokers, exsmokers, and smokers, with smokers having the highest levels. The percentage of subjects with elevated total IgE levels was higher in smokers than in nonsmokers regardless of skin reactivity to common allergens. Among smokers there was no relationship between intensity and duration of smoking and IgE levels. Among exsmokers IgE levels tended to be lower in those who had stopped smoking earlier.