0.05 was considered statistically significant.ResultsBasic characteristics of study subjects are shown

0.05 was considered statistically significant.ResultsBasic characteristics of study subjects are shown in Table 2 (unweighted values: S1 Table). The total weighted number, approximating total employee distribution in Japan, was 32,482,081 in 2002, 29,322,435 in 2007, and 36,018,201 in 2012, although the unweighted number wasPLOS ONE | DOI:10.1371/journal.pone.QuizartinibMedChemExpress AC220 0152096 April 6,3 /Secondhand Smoke Exposure among EmployeesTable 2. Basic characteristics of study subjects in percent (weighted results). Characteristics Weighted number Smoking status Nonsmoker at the workplace Smoker at the workplace Sex Men Women Age group less than 30 years 30?9 years 40?9 years 50?9 years 60 years or more Employment category Regular employee Others including part-time worker Worksite scale (employee number) 10?9 30?9 50?9 100?99 300?99 1000 or more Workplace smoking ban status Complete ban Partial ban No ban 2.1 64.9 33.0 9.9 69.9 20.2 35.6 49.8 14.6 16.8 60.8 22.4 36.0 14.3 15.7 19.4 9.9 4.8 36.6 13.6 16.8 17.6 10.5 5.0 33.7 11.6 14.4 21.2 11.0 8.1 35.3 13.1 15.6 19.5 10.5 6.1 83.0 17.0 77.0 23.0 74.0 26.0 77.9 22.1 22.9 25.0 25.5 22.6 4.1 21.1 26.9 23.9 22.6 5.5 18.8 28.3 25.4 19.4 8.1 20.9 26.8 25.0 21.4 6.0 61.9 38.1 59.3 40.7 55.5 44.5 58.8 41.2 60.7 39.3 65.6 34.4 73.1 26.9 66.7 33.3 2002 32,482,081 2007 29,322,435 2012 36,018,201 Total 97,822,The unweighted number of missing values was 239 for employment category in 2012 (see S1 Table). No other variables had missing values. doi:10.1371/journal.pone.0152096.t32,940 in total (11,707 in 2002, 11,340 in 2007 and 9893 in 2012). Smoking prevalence (at the workplace) decreased from 39.3 in 2002 to 26.9 in 2012. The proportion of employees in workplaces with complete smoking bans increased from 2.1 scan/nsw074 in 2002 to 35.6 in 2012, SART.S23506 while the proportion in workplaces with partial bans increased from 64.9 in 2002 to 69.9 in 2007, but then decreased to 49.8 in 2012. As for no bans, the proportion decreased from 33.0 in 2002 to 14.6 in 2012. To examine determinants of SHS exposure, prevalence of and covariates-adjusted RRs for workplace SHS exposure stratified by smoking status are shown in Table 3 (unweighted values: S2 Table). Everyday SHS exposure prevalence was 21.2 in workplace-nonsmokers and 60.3 in workplace-smokers, while everyday or sometimes SHS exposure prevalence was 57.1 and 83.6 , respectively. For all eight categories (2x2x2 = 8; i.e., [workplace-nonsmokers and workplace-smokers] x [everyday SHS and everyday or sometimes SHS] x [weighted result and unweighted result]), compared with complete workplace smoking bans, partial and no bans were significantly associated with high SHS exposure, although the degree of the association was larger among nonsmokers than smokers. Similarly for all eight categories, younger age was associated with higher SHS exposure. Further, we also observed disparities in SHS exposure byPLOS ONE | DOI:10.1371/journal.pone.0152096 April 6,4 /Secondhand Smoke Exposure among EmployeesTable 3. Trends in prevalence and rate ratio for workplace SHS exposure from other EnasidenibMedChemExpress AG-221 people among employees according to characteristic, stratified by smoking status. Combined all years of 2002, 2007 and 2012 (weighted results).Nonsmokers at the workplace Characteristics Everyday SHS exposure ( ) 21.2 33.2 19.2 11.4 Rate ratioa(95 CI) NA 1 (reference) 0.68 (0.65, 0.72) 0.54 (0.50, 0.58) 1 (reference) 0.79 (0.75, 0.83) 1 (reference) 0.87 (0.82, 0.94) 0.80 (0.75, 0.86) 0.89 (0.83, 0.95) 0.69 (0.61,.0.05 was considered statistically significant.ResultsBasic characteristics of study subjects are shown in Table 2 (unweighted values: S1 Table). The total weighted number, approximating total employee distribution in Japan, was 32,482,081 in 2002, 29,322,435 in 2007, and 36,018,201 in 2012, although the unweighted number wasPLOS ONE | DOI:10.1371/journal.pone.0152096 April 6,3 /Secondhand Smoke Exposure among EmployeesTable 2. Basic characteristics of study subjects in percent (weighted results). Characteristics Weighted number Smoking status Nonsmoker at the workplace Smoker at the workplace Sex Men Women Age group less than 30 years 30?9 years 40?9 years 50?9 years 60 years or more Employment category Regular employee Others including part-time worker Worksite scale (employee number) 10?9 30?9 50?9 100?99 300?99 1000 or more Workplace smoking ban status Complete ban Partial ban No ban 2.1 64.9 33.0 9.9 69.9 20.2 35.6 49.8 14.6 16.8 60.8 22.4 36.0 14.3 15.7 19.4 9.9 4.8 36.6 13.6 16.8 17.6 10.5 5.0 33.7 11.6 14.4 21.2 11.0 8.1 35.3 13.1 15.6 19.5 10.5 6.1 83.0 17.0 77.0 23.0 74.0 26.0 77.9 22.1 22.9 25.0 25.5 22.6 4.1 21.1 26.9 23.9 22.6 5.5 18.8 28.3 25.4 19.4 8.1 20.9 26.8 25.0 21.4 6.0 61.9 38.1 59.3 40.7 55.5 44.5 58.8 41.2 60.7 39.3 65.6 34.4 73.1 26.9 66.7 33.3 2002 32,482,081 2007 29,322,435 2012 36,018,201 Total 97,822,The unweighted number of missing values was 239 for employment category in 2012 (see S1 Table). No other variables had missing values. doi:10.1371/journal.pone.0152096.t32,940 in total (11,707 in 2002, 11,340 in 2007 and 9893 in 2012). Smoking prevalence (at the workplace) decreased from 39.3 in 2002 to 26.9 in 2012. The proportion of employees in workplaces with complete smoking bans increased from 2.1 scan/nsw074 in 2002 to 35.6 in 2012, SART.S23506 while the proportion in workplaces with partial bans increased from 64.9 in 2002 to 69.9 in 2007, but then decreased to 49.8 in 2012. As for no bans, the proportion decreased from 33.0 in 2002 to 14.6 in 2012. To examine determinants of SHS exposure, prevalence of and covariates-adjusted RRs for workplace SHS exposure stratified by smoking status are shown in Table 3 (unweighted values: S2 Table). Everyday SHS exposure prevalence was 21.2 in workplace-nonsmokers and 60.3 in workplace-smokers, while everyday or sometimes SHS exposure prevalence was 57.1 and 83.6 , respectively. For all eight categories (2x2x2 = 8; i.e., [workplace-nonsmokers and workplace-smokers] x [everyday SHS and everyday or sometimes SHS] x [weighted result and unweighted result]), compared with complete workplace smoking bans, partial and no bans were significantly associated with high SHS exposure, although the degree of the association was larger among nonsmokers than smokers. Similarly for all eight categories, younger age was associated with higher SHS exposure. Further, we also observed disparities in SHS exposure byPLOS ONE | DOI:10.1371/journal.pone.0152096 April 6,4 /Secondhand Smoke Exposure among EmployeesTable 3. Trends in prevalence and rate ratio for workplace SHS exposure from other people among employees according to characteristic, stratified by smoking status. Combined all years of 2002, 2007 and 2012 (weighted results).Nonsmokers at the workplace Characteristics Everyday SHS exposure ( ) 21.2 33.2 19.2 11.4 Rate ratioa(95 CI) NA 1 (reference) 0.68 (0.65, 0.72) 0.54 (0.50, 0.58) 1 (reference) 0.79 (0.75, 0.83) 1 (reference) 0.87 (0.82, 0.94) 0.80 (0.75, 0.86) 0.89 (0.83, 0.95) 0.69 (0.61,.