Legislation reduces exposure to second-hand tobacco smoke in New Zealand bars by about 90%.

AIM: To measure exposure to second-hand smoke (SHS) in New Zealand bars before and after comprehensive smoke-free legislation enacted on 10 December 2004. METHODS: Cotinine is the main specific metabolite of nicotine and a well-established biomarker for SHS exposure. We measured cotinine levels in saliva of non-smoking volunteers before and after a 3 h visit to 30 randomly selected bars in 3 cities across the country. Two measures of cotinine before the smoke-free law change during winter and spring 2004, and two follow-up measurements in the same volunteers and venues during winter and spring 2005, were included. RESULTS: Before the smoke-free law change, in all bars and in all volunteers, exposure to SHS was evident with an average increase in saliva cotinine of 0.66 ng/ml (SE 0.03 ng/ml). Increases in cotinine correlated strongly with the volunteers' subjective observation of ventilation, air quality and counts of lit cigarettes. However, even venues that were judged to be "seemingly smoke free" with "good ventilation" produced discernable levels of SHS exposure. After the law change, there remained some exposure to SHS, but at much lower levels (mean saliva cotinine increase of 0.08 ng/ml, SE 0.01 ng/ml). Smoking indoors in bars was almost totally eliminated: in 2005 only one lit cigarette was observed in 30 visits. CONCLUSIONS: Comprehensive smoke-free legislation in New Zealand seems to have reduced exposure of bar patrons to SHS by about 90%. Residual exposures to SHS in bars do not result from illicit smoking indoors.

Secondhand tobacco smoke exposure in New Zealand bars: results prior to implementation of the bar smoking ban.

AIMS: To measure secondhand smoke (SHS) levels in New Zealand bars prior to smokefree legislation enacted on 10 December 2004. METHODS: Thirty bars were randomly selected from urban, surburban, and surrounding rural areas of Auckland, Wellington, and Invercargill. Bars were visited (on a Friday or Saturday night for a 3-hour stay between 1800 and 2400 hours) in July/August/September 2004 (winter) and again in October/November 2004 (spring). Each bar was visited by a group of 4 or 5 non-smokers participating in the study. All groups of participants spent a 3-hour block of continuous time in the bar. Saliva samples (approximately 0.5-2 mL) were provided immediately prior to entering the bar as well as 5-15 minutes after leaving the bar. Each group recorded the initial impression of air quality and ventilation, the number of observed lit cigarettes over three 10-minute intervals throughout the evening, and the number of patrons at each interval. In addition, any general comments about the venue (relevant to bar attendance or air quality on the evening) was recorded. Cotinine, the main metabolite of nicotine, was measured in saliva samples using Liquid Chromatography with tandem Mass Spectrometry (LC-MS-MS). RESULTS: In all bars, and in all volunteers, exposure to SHS was evident. Saliva cotinine increased after 3 hours in the bar (mean increase=0.66 ng/mL, SE=0.03 ng/mL, p value of <0.0001). The 30 bars randomly selected provided a good spectrum of SHS exposures, with mean cotinine increasing by approximately 8-fold. Smaller population centres showed greater exposures to SHS. A north-south gradient of exposure was also seen (highest exposures were in Southland). Higher exposures were seen in the winter than in the spring. The objective measures of SHS exposure correlated strongly with the volunteers' subjective observation of ventilation, air quality, and counts of lit cigarettes. One exception was where objective salivary markers indicated that even "seemingly smokefree" venues with "good ventilation" produced discernable levels of SHS exposure. CONCLUSIONS: We have utilised an objective, non-invasive scientific approach to assess SHS smoke exposure in patrons of New Zealand bars. Our results clearly indicate exposure to SHS, with regional and seasonal variation, prior to the introduction of smokefree legislation.

Increase in saliva cotinine after three hours' exposure to second-hand smoke in bars.

OBJECTIVE: To determine whether measurement of cotinine in saliva is a sensitive measure of exposure to second-hand smoke (SHS) among customers in bars. DESIGN: Before/after comparison of saliva cotinine and subjective assessments of SHS. SETTING: Three bars in Wellington, New Zealand, June 2003. PARTICIPANTS: Eleven non-smoking medical students spent three hours in each location. They provided saliva samples before and after the visit, counted numbers of lit cigarettes in each bar, and assessed the smokiness of the venue. Samples were tested for cotinine using liquid chromatography coupled with mass spectrometry. RESULTS: Cotinine levels post-visit were consistently higher than baseline. The mean difference was 1.03 ng/mL with a 95% confidence interval of 0.76-1.30 ng/ mL. Adjustments to post-visit levels for metabolism and clearance of cotinine made very little difference to these results. Males tended to have higher baseline levels than females, and to show smaller increases. The bar with the greatest increase in cotinine was judged to be the smokiest on the basis of averaged cigarette counts and scores for presence of smoke and odour. CONCLUSION: The cotinine in saliva, when tested with the analytic methods described here, provides a means of assessing relatively short-term exposures to SHS.