Background: A number of cross-sectional studies have demonstrated that higher levels of IgE are found in subjects who currently smoke cigarettes and/or who are atopic and that IgE levels decline with age.
Objective: This report examines the interactions among atopic status, smoking, and IgE with longitudinal data and methods.
Methods: Subjects were participants in the Tucson Epidemiological Study of Airways Obstructive Disease and were 6 years of age and older. Total serum IgE measures and allergen skin test results were obtained during three surveys spanning a period of up to 20 years.
Results: The results showed no significant gender differences between nonatopic nonsmoking subjects, who were considered the reference group. Nonatopic current smokers had IgE levels similar to those of the reference subjects initially, but IgE levels did not decline with age at the same rate as in the reference subjects, causing significant differences at older ages. There was a significant relationship between number of cigarettes smoked and IgE level.
Conclusions: Atopy and smoking are both associated with elevated total serum IgE levels. Although the exact mechanism for elevated IgE levels in smokers is not known, the significant dose relationship is suggestive of a causal association.