Effect of second-hand smoke exposure on lung function among non-smoking Korean women

Background: Previous literature has implicated that there might be an individual susceptibility difference in terms of race/ethnicity and gender in response to second hand smoke (SHS) exposure. This study was done to examine the effect of SHS exposure on lung function in non-smoking Korean women. Methods: This cross-sectional study was conducted using the Korea National Health and Nutrition Examination Survey (KNHANES) from 2008-2011. A total of 2, 513 female participants, age 40 yr and older, with no respiratory symptoms or prior lung diseases, were included in this study. Participants' smoking status was examined using both self-reported history and measurement of urinary cotinine level. Lung function was assessed using spirometry data, including FVC and FEV1. T-test and Chi-square tests were performed to compare diverse variables between groups. Analysis of covariance (ANCOVA) adjusted for age, height, alcohol consumption, and level of exercise was used to see any statistical differences in lung function parameters between non-SHS exposed and SHS-exposed groups. Results: Among 2, 513 non-smoking females, 767 (30.5%) were SHS-exposed. The urinary cotinine levels clearly distinguished SHS exposure, and the mean urinary cotinine levels were 7.1±0.4 and 11±0.7 in non-SHS exposed group vs. SHS-exposed group, respectively (P < 0.001). Urinary cotinine levels were correlated with duration of SHS exposure. However, both groups had normal lung function and there was no significant difference between the two groups in lung function. Conclusions: Urinary cotinine is a valuable marker of SHS exposure. Korean women may have higher tolerance for SHS exposure-induced lung function decline.