Dose-dependent effect of cotinine-verified tobacco smoking on serum immunoglobulin E levels in Korean adult males.

Background: Smoking is one of the risk factors to exacerbate allergic diseases, and it may affect serum immunoglobulin E (IgE) levels. However, few studies have relied on an objective biomarker to examine the effect of tobacco smoking on serum IgE levels.

Method: A nationwide cross-sectional study was conducted to examine the relationship between urinary cotinine (Ucot) concentrations and IgE levels in 973 males using data from the 2010 Korean National Health and Nutrition Examination Survey (KNHANES). Ucot was classified into four groups based on concentration (ng/mL) as follows: nonsmoker group (Ucot <50 ng/mL) and three tertile groups in smokers (T1 [Ucot: 50.00-921.28 ng/mL]; T2 [Ucot: 921.29-1,869.36 ng/mL]; and T3 [Ucot ≥1,869.37 ng/mL]). The dose-response relationships between Ucot concentrations and total serum IgE level were estimated using analysis of covariance (ANCOVA) and multiple linear regression analysis after adjusting for confounding variables.

Results: We found a significant and positive dose-related effect of cigarette smoking as measured by Ucot concentrations on total serum IgE level. The multivariate adjusted means of total serum IgE levels (SE) were 321.0 (36.3), 404.4 (102.7), 499.2 (79.2), and 534.7 (82.7) IU/mL, after adjusting for age, body mass index, alcohol ingestion, physical exercise, job, and household income. The regression coefficient β for total serum IgE was β = 68.6 with increasing level of Ucot group after adjusting for the same co-variables (P = 0.009).

Conclusion: These findings suggest that the amount of smoking may have a dose-dependent effect on total serum IgE levels.

Implication: Smoking is one of the risk factors to exacerbate allergic diseases, and it may affect serum immunoglobulin E (IgE) levels, which is closely related to type 1 mediated allergic diseases. However, few studies have relied on an objective biomarker to examine the effect of tobacco smoking on serum IgE levels. We found that tobacco exposure, as measured by Ucot concentrations, increased the serum IgE levels in a dose-response manner in a representative sample of Korean adult males.