Association between lead exposure and increased risk of bronchial asthma in Korean adolescents

Abstract

Purpose: Several studies have reported an association between lead exposure and increased risk of allergic sensitization and asthma. According to the Centers for Disease Control and Prevention guidelines, An elevated blood lead level (BLL) is defined as a BLL of ≥ 5 µg/dL. However, no safe BLL has been identified, and it is controversial whether a BLL of < 5 µg/dL affects the risk of asthma. Methods: We examined asthma prevalences and BLLs using data from the 2010-2013 Korea National Health and Nutrition Examination Survey (KNHANES), which was a cross-sectional survey of 1,478 adolescence (aged 10-19 years) throughout the country. The adjusted odds ratios (ORs) (with 95% confidence intervals [CIs]) for the prevalence of asthma in adolescence with elevated BLLs were calculated by complex samples multivariate logistic regression analysis. The presence of asthma was based on self-reported, physician-diagnosed asthma in the Health Interview Surveys. Results: The mean of total BLLs was 1.33 μg/dL. Overall, 5.1% (n= 71) of the subjects were physician diagnosed asthma. In the model controlling for population characteristics, the adjusted odds ratio for asthma per 1 μg/dL increase in blood lead was 1.94, 95% CI (1.06, 3.57), and stronger associations were observed among boys (adjusted OR, 2.31; 95% CI, [1.18, 4.51]). The group of BLL≥ 2 μg/dL was associated with an OR of 2.84 (95% CI, 1.06, 7.63) for asthma, after adjusting for potential confounding factors in boys. Conclusion: Our results suggest an association between total BLLs and asthma in Korean adolescent boys, although confirmation is warranted in further prospective studies.