Decrease in the urine cotinine concentrations of Korean non-smokers between 2009 and 2011 following implementation of stricter smoking regulations

This study aimed to determine if there was an association between the implementation of smoking regulation policies and the urine cotinine concentrations of Korean non-smokers. The subjects of this study were 4612 non-smoking Korean citizens (aged 19 or older) selected from the first stage of the Korean National Environmental Health Survey conducted by the National Institute of Environmental Research from 2009 to 2011. Cotinine concentrations in urine were measured by GC-MS (limit of detection: 0.05 ng/mL). Changes in the urine cotinine concentration were analyzed using a weighted general linear model and linear regression and values were shown as geometric mean (GM). The GM urine cotinine concentration decreased over time (2.92 ng/mL in 2009, 1.93 ng/mL in 2010, and 1.25 ng/mL in 2011). The total decrease in the subjects' urine cotinine concentration between 2009 and 2011 was 2.79 ng/mL, representing a relative decrease of 54.7%. The decrease in GM urine cotinine concentration in each subgroup ranged from 2.17 ng/mL to 3.29 ng/mL (relative decreases of 46.4% and 62.8%, respectively), with the largest absolute reductions in subjects in the following groups: females, aged 40-49 years, detached residence type, no alcohol consumption, employed, secondhand smoke exposure. All groups had negative regression coefficients, all of which were significant (p < 0.001). Our results provide indirect indicators of the effectiveness of smoking regulation policies including the revision of the National Health Promotion Act in Korea.