title: Decline in non-smoking workers' urine cotinine levels after increased smoking regulation in Korea.
abstract: OBJECTIVE
  To identify any association between implementing smoking regulation policies and workers' urine cotinine concentration levels in Korea.
  
  
  METHODS
  From the first stage of the Korean National Environmental Health Survey conducted by the National Institute of Environmental Research from 2009 to 2011, 2,475 non-smoking workers selected. We analyzed the trend in the changes of cotinine concentration in urine using the general linear model and linear regression, in various jobs as categorized by the National Center for Health Statistics (NCHS) and Korea Standard Classification of Occupations (KSCO).
  
  
  RESULTS
  The urine cotinine concentration tended to decrease every year (2.91 ng/ml in 2009, 2.12 ng/ml in 2010, and 1.31 ng/ml in 2011), showing a decreasing trend (P < 0.001). The total subjects' decreased cotinine concentration in urine between 2009 and 2011 was 2.72 ng/ml (54.1 % relative decrease). The changes in each subgroup's urine cotinine concentration ranged from 1.59 to 6.03 ng/ml (33.2 to 77.5 %). All groups except for the managerial group (n = 49), which had a small sample size, had statistically significant negative regression coefficients (p < 0.05). The ranges of the decrease in urine cotinine were 2.75 ng/ml (53.6 %) for males and 2.72 ng/ml (54.9 %) for females. The negative slope in urine cotinine level was statistically significantly greater in men than women. The changes in urine cotinine by occupation as classified by the NCHS occupational categories ranged from 2.43 to 3.36 ng/ml (46.6 to 61.5 % relative decrease). The negative slopes in urine cotinine levels of the white-collar and farm workers were statistically significantly greater than those of the service workers and blue-collar workers. The change by occupation as classified by the KSCO ranged from 1.59 to 6.03 ng/ml (a 33.2 to 77.5 % relative decrease). The negative slopes in urine cotinine levels of the professionals and related workers and clerks were statistically significantly greater than those of the service workers and plant and machine operators and assemblers.
  
  
  CONCLUSIONS
  The cotinine concentration in urine among non-smoking worker groups tended to decline from 2009 to 2011. Such a result may be an indirect indicator of the effectiveness of smoking regulation policies including the revision of the National Health Promotion Act.
authors.affiliation: Department of Occupational and Environmental Medicine & Institute of Environmental and Occupational Medicine, Pusan Paik Hospital, Inje University, 75, Bokji-ro, Busanjin-gu, Busan 633-165 Republic of Korea.
authors.forename: Ju-Hyoung
authors.initials: JH
authors.lastname: Park
authors.affiliation: Department of Occupational and Environmental Medicine & Institute of Environmental and Occupational Medicine, Pusan Paik Hospital, Inje University, 75, Bokji-ro, Busanjin-gu, Busan 633-165 Republic of Korea.
authors.forename: Chae-Kwan
authors.initials: CK
authors.lastname: Lee
authors.affiliation: Department of Occupational and Environmental Medicine & Institute of Environmental and Occupational Medicine, Pusan Paik Hospital, Inje University, 75, Bokji-ro, Busanjin-gu, Busan 633-165 Republic of Korea.
authors.forename: Se-Yeong
authors.initials: SY
authors.lastname: Kim
authors.affiliation: Department of Occupational and Environmental Medicine & Institute of Environmental and Occupational Medicine, Pusan Paik Hospital, Inje University, 75, Bokji-ro, Busanjin-gu, Busan 633-165 Republic of Korea.
authors.forename: Chunhui
authors.initials: C
authors.lastname: Suh
authors.affiliation: Department of Occupational and Environmental Medicine & Institute of Environmental and Occupational Medicine, Pusan Paik Hospital, Inje University, 75, Bokji-ro, Busanjin-gu, Busan 633-165 Republic of Korea.
authors.forename: Kun-Hyung
authors.initials: KH
authors.lastname: Kim
authors.affiliation: Department of Occupational and Environmental Medicine & Institute of Environmental and Occupational Medicine, Pusan Paik Hospital, Inje University, 75, Bokji-ro, Busanjin-gu, Busan 633-165 Republic of Korea.
authors.forename: Jeong-Ho
authors.initials: JH
authors.lastname: Kim
authors.affiliation: Department of Occupational and Environmental Medicine & Institute of Environmental and Occupational Medicine, Pusan Paik Hospital, Inje University, 75, Bokji-ro, Busanjin-gu, Busan 633-165 Republic of Korea.
authors.forename: Byung-Chul
authors.initials: BC
authors.lastname: Son
authors.affiliation: Department of Occupational and Environmental Medicine & Institute of Environmental and Occupational Medicine, Pusan Paik Hospital, Inje University, 75, Bokji-ro, Busanjin-gu, Busan 633-165 Republic of Korea.
authors.forename: Jong-Tae
authors.initials: JT
authors.lastname: Lee
authors.affiliation: Environmental Health Research Department, National Institute of Environmental Research, Incheon, Republic of Korea, Hwangyong-ro 42, Seogu, Incheon 404-708 Republic of Korea.
authors.forename: Seung-Do
authors.initials: SD
authors.lastname: Yu
authors.affiliation: Environmental Health Research Department, National Institute of Environmental Research, Incheon, Republic of Korea, Hwangyong-ro 42, Seogu, Incheon 404-708 Republic of Korea.
authors.forename: Wookhee
authors.initials: W
authors.lastname: Choi
authors.affiliation: Center for life & environmental science, Seegene medical foundation, Seoul, Republic of Korea, 320, Cheonho-daero, Seongdong-gu, Seoul 133-847 Republic of Korea.
authors.forename: Hosub
authors.initials: H
authors.lastname: Im
keywords: Non-smoker; Occupation; Secondhand smoke; Urine cotinine