Research paper smoking room on site. Of these seven plants, two worksites (one with a smoke-free policy, one with a restrictive smoking policy) had implemented their policies for 3 years, and the other ﬁve sites (two with smoke-free policies and three with restrictive smoking policies) had implemented their policies for about 10 years. Before the survey, the purpose of the study was explained to the plant management and commitment obtained to support the study. To encourage worker participation, employees in all worksites were sent brochures and/or emails and exposed to posters promoting the survey. Each plant designated one survey coordinator who received a half-day training session. During March and May 2008, a self-administered questionnaire was distributed via the coordinators to all employees. Completion of the questionnaires was anonymous. Questions covered: < Occupation: professionals and managers, laboratory workers and technicians, sales and marketing, production operators. < Smoking status: ever smokers were deﬁned as those who had smoked at least 100 lifetime cigarettes and current smokers were those who reporting smoking at the time of survey. Current smokers were further stratiﬁed as light (<10 cigarettes per day), moderate (10e19 cigarettes per day), heavy (20e29 cigarettes per day) and very heavy smokers ($30 cigarettes per day). < Intention to quit was categorised as no quitting intention in the next 6 months; intention to quit within 6 months; and intention to quit within 1 month. A quit attempt was deﬁned as at least one period of 24 h of non-smoking in the past 12 months. Other questions covered perceptions of smoking’s impact on health, cessation beneﬁts and attitudes to the smoking policies in their workplace. The c2 test was used to examine associations between smoking control policies and several dependent smoking behavioural variables. The ManneWhitney test was used for subgroups with sample sizes less than 5. To adjust for possible confounding factors, we performed multivariate analyses using multiple linear and multiple logistic regression models. The control variables included in the analyses were age, education, occupation, night shift work, intention to quit, number of quit attempts in the past year and the period of time smoking poli- cies had been imposed in a worker ’s workplace. The dependent variables were daily cigarette consumption and quit intention. We categorised daily cigarette consumption as <10 cigarettes per day and $10 cigarettes per day; and quitting intention as no quitting intention in the next 6 months or having an intention to quit in the next 6 months. These analyses were performed with SPSS V.11.0 (SPSS, Chicago, Illinois, USA). RESULTS In total, 1132 questionnaires were distributed and 1070 responses were collected (response rate 94.5%). Non-responses were employees on extended sick leave or those who had been relocated to other workplaces in the company. After deleting records with missing values, 1043 (92%) records were available for analysis. The age of respondents ranged from 19e72 years, with the average age being 37 years old. Half the employees had 10e12 years of education, while 20% had an education of less than 10 years and 30% had at least college education. Two-thirds were production operators, professional/management and tech- nical staff made up around 15% each and 7% were sales and marketing personnel. Since the number of female employees in these production plants was less than 10% and their smoking rate was quite low (<5%), they were excluded from the analysis in this study. 132 Table 1 shows current smoking prevalence and intention to quit by age, education, occupation and night shift workers with two types of smoking control policies in their workplaces. In workplaces that had implemented smoking policies for 3 years, employees from completely smoke-free workplaces had a smoking prevalence 24.3% lower than those with only restrictive smoking workplaces (55.5% vs 73.3%). However, there was no difference between employees working at sites that have had smoking policies in place for 10 years. Among occupational groups, production operators consistently had the highest smoking prevalence, regardless of the type of smoking policy at their workplaces and the period the policy had been imposed for (p<0.05). For workplaces where smoking policies had been imposed for 10 years, professionals and laboratory technicians had the lowest smoking prevalence, while sales/ marketing workers had a higher smoking prevalence (75.9%) than the production workers (68.6%). Trend analyses indicated that smoking prevalence decreased with higher education levels across all workplaces (p<0.01), regardless of type of smoking policy. No such trend was found between smoking prevalence and age (p>0.05). Night shift workers from plants with 3-year smoking control policies had a higher smoking prevalence (62.4% to 90.0%) than day shift workers (40.0% to 49.5%). Table 2 shows patterns of smoking behaviours of employees in workplaces with different smoking restriction policies. Work- places where a smoke-free policy had been imposed for 3 years had a greater proportion of light smokers, less heavy and very heavy smokers, a longer time until ﬁrst cigarette after waking, a higher proportion of smokers having made quit attempts, more workers with quit intentions and more workers who were likely to accept the company cessation programme compared to smokers from restrictive smoking policy workplaces. However, other than the proportion of very heavy smokers and the time to ﬁrst cigarette after waking, the patterns were not much different between the workplaces with different smoking policies in the Table 1 Current smoking prevalence among employees by type of workplace smoking policy imposed for 3 or 10 years Policy in place for Policy in place for 3 years 10 years Restricted, % (n) Smoke free, Restricted, Smoke free, % (n) % (n) % (n) Age <30 77.4 (24) 30 39 61.5 (13) 40 49 e 50+ 100 (1) Education #9 years e 10e12 years 87.5 (32) 13e14 years 55.6 (9) $15 years e Occupation Production operators 87.5 (32) Professionals 20.0 (5) Laboratory technicians 33.3 (6) Sales/marketing 100 (1) Night shift work Yes 90.0 (30) No 40.0 (15) Total 73.3 (45) *p<0.01. yUsing the ManneWhitney test. 45.8 (72)* 61.7 (133) 47.1 (17) 60.0 (5) e 61.5 (117)* 59.7 (62)y 35.4 (48) 59.9 (157)* 33.3 (18)y 48.9 (47)y 60.0 (5) 62.4 (157)* 40.0 (70) 55.5 (227)* 39.6 (144) 59.7 (139) 73.6 (208) 62.0 (100) 64.6 (130) 73.6 (277) 50.0 (80) 26.0 (104) 68.6 (369) 34.6 (78) 36.0 (86) 75.9 (58) 70.1 (321) 48.1 (270) 60.1 (591) 40.4 (47) 61.5 (65) 64.6 (48) 80.0 (20) 78.3 (23) 72.3 (83) 46.2 (39) 28.6 (35) 71.7 (106) 36.4 (33) 41.2 (34) 57.1 (7)y 72.0 (75) 49.5 (105) 58.9 (180) Tobacco Control 2011;20:131e136. doi:10.1136/tc.2010.036335