View Article PDF

A systematic review has reported that smoking in cars leads to extremely high exposure to secondhand smoke (SHS), “even in the presence of air-conditioning or increased airflow from open windows”.1 Many jurisdictions have responded to this hazard by legislating against smoking in cars (particularly in Canada, Australia and the US). However, the latest Cochrane systematic review on the impact of smoke-free legislation does not specifically consider the impact of such laws on youth exposure to SHS in cars.2 We therefore aimed to examine the relevant literature to determine the impact of such legislation and to help policymakers decide if further evaluation is worthwhile around the planned smoke-free cars legislation for New Zealand.

Methods for the literature review

Searches of the peer-reviewed literature were conducted using PubMed and Google Scholar on 9 February 2020 using a range of search terms (eg, smoke AND cars/vehicles AND ban/law). In these searches we aimed to identify studies where the impact of a smoke-free car law was estimated from survey data on smoking in cars containing children/youth. The bibliographies of these identified studies were also searched for additional relevant studies.

Results of the literature review

From publications identified by the searches (n=136 in PubMed; the first n=100 items in Google Scholar), we identified five relevant peer-reviewed studies. These studies covered nine different jurisdictions with smoke-free car laws (England, California and seven Canadian provinces) (Table 1). In all these jurisdictions there was evidence of declines in youth exposure to SHS after implementing the law, and in jurisdictions where it was assessed these declines persisted in all the subsequent survey waves.

Table 1: Studies identified in the peer-reviewed journal literature on the impact of smoke-free cars legislation on smoking in cars containing children/youth.

Putting the evidence in context

The findings of this review indicate that smoke-free car legislation was consistently associated with reduced SHS exposure in cars with children/youth in all nine jurisdictions studied. This finding is consistent with other types of evidence, eg, a study in Quebec where smoking in cars with children was lower among smokers who mistakenly believed Quebec had such a law.9 Similarly, it is consistent with spill-over benefits of reduced smoking/SHS exposure in cars from other smoke-free legislation for public places (eg, in England,10 in the three other UK jurisdictions,11 Canada12 and the US for adopting smoke-free car rules13). It is also consistent with international evidence from a Cochrane systematic review on smoke-free legislation being effective in many other settings,2 and with what is known about the effectiveness of public health laws in general from a major systematic review.14

What evaluation of the upcoming law should New Zealand do?

From a health protection perspective, there appears to be enough real-world evidence for policy-makers to introduce smoke-free car legislation. However, there are still major knowledge gaps. For example, there is a need to evaluate the equity impacts of such laws (eg, the relative size of Māori vs non-Māori benefits in the New Zealand context) and to evaluate the impact of any laws that prohibit vaping in cars. It also seems desirable to determine the value of co-interventions to enhance the law, such as mass media campaigns around the SHS hazard. Finally, evaluation of the impact by level of enforcement, would also provide useful information, as has been argued by others.15

New Zealand, with its upcoming law to prohibit smoking in cars with youth (<18 years), is well positioned to do this work. This is because past New Zealand research has refined methods for on-street observing smoking in cars (in these studies:16–18) and has an ongoing national annual survey of around 30,000 14–15-year-old school students (Year 10 survey) which collects relevant data (eg, as in a study19 which considered inequalities by ethnicity and school-based socioeconomic position). Indeed, this survey of school students has been running annually since 1999 and so it could provide enough time points for a time-series analysis. There are also data from a cohort of adults about self-reported smoking in cars with children from the New Zealand arm of the International Tobacco Control (ITC) Survey, which will allow for repeat cross-sectional, and possibly within-cohort analyses. It is conceivable that a time-series analysis of smoking prevalence among adults in their 20s and 30s (ie, those who are most likely to have young children) from the New Zealand Health Survey might show a differential impact relative to other age-groups. But this is probably unlikely given the law is more likely to result in a change of where smoking occurs (ie, not in vehicles) as opposed to quitting.

Evaluation work using biomarkers (cotinine and nicotine levels) would be more expensive but is also probably justified to verify changes in self-reported exposures and to assess whether total exposure to SHS for children from all sources has decreased (ie, a reduction in SHS exposure from inside vehicles has not been replaced by more smoking in the home, albeit a remote possibility given available international data from other smoke-free laws). The “Growing up in New Zealand” longitudinal study20 could potentially adopt biomarker assessment of SHS exposure in children in conjunction with other routine assessments.

Such research should ideally be commissioned by the government agency which developed the law: the Ministry of Health. It could be tendered for by relevant university based researchers, consultancies doing research or non-governmental agencies (eg, the organisation ASH runs the Year 10 Survey). Such an approach was taken by the Ministry when it commissioned evaluation work21 of the new smoke-free environments law implemented in 2004 (covering smoke-free bars and restaurants), including an additional evaluation of the impacts on Māori health.22 The Ministry has also recently commissioned evaluation work on tobacco taxes.23 Unfortunately however, the Ministry has failed to evaluate other recent major national tobacco control policy interventions, including: the initial introduction of pictorial health warnings, the point-of-sale display ban for tobacco and (most recently) standardised packs with enhanced pictorial health warnings.

The results from evaluating the new smoke-free cars law would be potentially be very useful for New Zealand in refining the design of the law or adjusting the level of media promotion or enforcement. It would also make a valuable contribution to advancing the knowledge base for international tobacco control.

Summary

Abstract

In this viewpoint we briefly review the evidence for smoke-free car legislation. We find that this legislation has been consistently associated with reduced secondhand exposure in cars with children/youth in all nine jurisdictions studied. Despite this, there are various aspects of this intervention that warrant further study—especially determining its impact on reducing tobacco-related ethnic inequalities. So we argue that the New Zealand Ministry of Health should invest in a thorough evaluation of this important upcoming public health intervention. This could both help the country in further refining the design of the law (if necessary) and would also be a valuable contribution to advancing the knowledge base for international tobacco control.

Aim

Method

Results

Conclusion

Author Information

Nick Wilson, Department of Public Health, University of Otago, Wellington; George Thomson, Department of Public Health, University of Otago, Wellington; Richard Edwards, Department of Public Health, University of Otago, Wellington.

Acknowledgements

Correspondence

Professor Nick Wilson, Department of Public Health, University of Otago, Wellington.

Correspondence Email

nick.wilson@otago.ac.nz

Competing Interests

Nil.

1. Raoof SA, Agaku IT, Vardavas CI. A systematic review of secondhand smoke exposure in a car: Attributable changes in atmospheric and biological markers. Chron Respir Dis 2015; 12:120–31.

2. Frazer K, Callinan JE, McHugh J, van Baarsel S, Clarke A, Doherty K, Kelleher C. Legislative smoking bans for reducing harms from secondhand smoke exposure, smoking prevalence and tobacco consumption. Cochrane Database Syst Rev (Online) 2016; 2:CD005992.

3. Nguyen HV. Do smoke-free car laws work? Evidence from a quasi-experiment. J Health Econ 2013; 32:138–48.

4. Elton-Marshall T, Leatherdale ST, Driezen P, Azagba S, Burkhalter R. Do provincial policies banning smoking in cars when children are present impact youth exposure to secondhand smoke in cars? Prev Med 2015; 78:59–64.

5. Patel M, Thai CL, Meng YY, Kuo T, Zheng H, Dietsch B, McCarthy WJ. Smoke-Free Car Legislation and Student Exposure to Smoking. Pediatrics 2018; 141:S40–S50.

6. Faber T, Mizani MA, Sheikh A, Mackenbach JP, Reiss IK, Been JV. Investigating the effect of England’s smoke-free private vehicle regulation on changes in tobacco smoke exposure and respiratory disease in children: a quasi-experimental study. Lancet Public Health 2019; 4:e607–e17.

7. Amrhein V, Greenland S, McShane B. Scientists rise up against statistical significance. Nature 2019; 567:305–07.

8. Laverty AA, Hone T, Vamos EP, Anyanwu PE, Taylor-Robinson D, de Vocht F, Millett C, Hopkinson NS. Impact of banning smoking in cars with children on exposure to second-hand smoke: a natural experiment in England and Scotland. Thorax 2020.

9. Montreuil A, Tremblay M, Cantinotti M, Leclerc BS, Lasnier B, Cohen J, McGrath J, O’Loughlin J. Frequency and risk factors related to smoking in cars with children present. Can J Public Health 2015; 106:e369–74.

10. Lee JT, Glantz SA, Millett C. Effect of smoke-free legislation on adult smoking behaviour in England in the 18 months following implementation. PLoS One 2011; 6:e20933.

11. Moore GF, Currie D, Gilmore G, Holliday JC, Moore L. Socioeconomic inequalities in childhood exposure to secondhand smoke before and after smoke-free legislation in three UK countries. J Public Health (Oxf) 2012; 34:599–608.

12. Naiman AB, Glazier RH, Moineddin R. Is there an impact of public smoking bans on self-reported smoking status and exposure to secondhand smoke? BMC Public Health 2011; 11:146.

13. Cheng KW, Okechukwu CA, McMillen R, Glantz SA. Association between clean indoor air laws and voluntary smokefree rules in homes and cars. Tob Control 2015; 24:168–74.

14. Moulton AD, Mercer SL, Popovic T, Briss PA, Goodman RA, Thombley ML, Hahn RA, Fox DM. The scientific basis for law as a public health tool. Am J Public Health 2009; 99:17–24.

15. Houghton F, O’Doherty D, Houghton B. Teeth or no teeth: exploring punitive measures for adults smoking in cars containing children in Aotearoa/New Zealand. N Z Med J 2020; 133:118–22.

16. Martin J, George R, Andrews K, Barr P, Bicknell D, Insull E, Knox C, Liu J, Naqshband M, Romeril K, Wong D, Thomson G, Wilson N. Observed smoking in cars: a method and differences by socioeconomic area. Tob Control 2006; 15:409–11.

17. Patel V, Thomson G, Wilson N. Objective measurement of area differences in ‘private’ smoking behaviour: observing smoking in vehicles. Tob Control 2013; 22:130–5.

18. Thomson G, Oliver J, Wilson N. Trends in smoking in vehicles at a local community-level in New Zealand: Wainuiomata 2005–2013. N Z Med J 2014; 127:47–56.

19. Healey B, Hoek J, Wilson N, Thomson G, Taylor S, Edwards R. Youth exposure to in-vehicle second-hand smoke and their smoking behaviours: trends and associations in repeated national surveys (2006–2012). Tob Control 2015; 24:146–52.

20. Morton SM, Atatoa Carr PE, Grant CC, Robinson EM, Bandara DK, Bird A, Ivory VC, Kingi TK, Liang R, Marks EJ, Perese LM, Peterson ER, Pryor JE, Reese E, Schmidt JM, Waldie KE, Wall C. Cohort profile: growing up in New Zealand. Int J Epidemiol 2013; 42:65–75.

21. Edwards R, Thomson G, Wilson N, Waa A, Bullen C, O’Dea D, Gifford H, Glover M, Laugesen M, Woodward A. After the smoke has cleared: evaluation of the impact of a new national smoke-free law in New Zealand. Tob Control 2008; 17:e2.

22. Edwards R, Gifford H, Waa A, Glover M, Thomson G, Wilson N. Beneficial impacts of a national smokefree environments law on an indigenous population: a multifaceted evaluation. Int J Equity Health 2009; 8:12.

23. Ernst and Young. Evaluation of the tobacco excise increases – Final Report – 27 November 2018. Wellington: Ministry of Health 2018.

Contact diana@nzma.org.nz
for the PDF of this article

View Article PDF

A systematic review has reported that smoking in cars leads to extremely high exposure to secondhand smoke (SHS), “even in the presence of air-conditioning or increased airflow from open windows”.1 Many jurisdictions have responded to this hazard by legislating against smoking in cars (particularly in Canada, Australia and the US). However, the latest Cochrane systematic review on the impact of smoke-free legislation does not specifically consider the impact of such laws on youth exposure to SHS in cars.2 We therefore aimed to examine the relevant literature to determine the impact of such legislation and to help policymakers decide if further evaluation is worthwhile around the planned smoke-free cars legislation for New Zealand.

Methods for the literature review

Searches of the peer-reviewed literature were conducted using PubMed and Google Scholar on 9 February 2020 using a range of search terms (eg, smoke AND cars/vehicles AND ban/law). In these searches we aimed to identify studies where the impact of a smoke-free car law was estimated from survey data on smoking in cars containing children/youth. The bibliographies of these identified studies were also searched for additional relevant studies.

Results of the literature review

From publications identified by the searches (n=136 in PubMed; the first n=100 items in Google Scholar), we identified five relevant peer-reviewed studies. These studies covered nine different jurisdictions with smoke-free car laws (England, California and seven Canadian provinces) (Table 1). In all these jurisdictions there was evidence of declines in youth exposure to SHS after implementing the law, and in jurisdictions where it was assessed these declines persisted in all the subsequent survey waves.

Table 1: Studies identified in the peer-reviewed journal literature on the impact of smoke-free cars legislation on smoking in cars containing children/youth.

Putting the evidence in context

The findings of this review indicate that smoke-free car legislation was consistently associated with reduced SHS exposure in cars with children/youth in all nine jurisdictions studied. This finding is consistent with other types of evidence, eg, a study in Quebec where smoking in cars with children was lower among smokers who mistakenly believed Quebec had such a law.9 Similarly, it is consistent with spill-over benefits of reduced smoking/SHS exposure in cars from other smoke-free legislation for public places (eg, in England,10 in the three other UK jurisdictions,11 Canada12 and the US for adopting smoke-free car rules13). It is also consistent with international evidence from a Cochrane systematic review on smoke-free legislation being effective in many other settings,2 and with what is known about the effectiveness of public health laws in general from a major systematic review.14

What evaluation of the upcoming law should New Zealand do?

From a health protection perspective, there appears to be enough real-world evidence for policy-makers to introduce smoke-free car legislation. However, there are still major knowledge gaps. For example, there is a need to evaluate the equity impacts of such laws (eg, the relative size of Māori vs non-Māori benefits in the New Zealand context) and to evaluate the impact of any laws that prohibit vaping in cars. It also seems desirable to determine the value of co-interventions to enhance the law, such as mass media campaigns around the SHS hazard. Finally, evaluation of the impact by level of enforcement, would also provide useful information, as has been argued by others.15

New Zealand, with its upcoming law to prohibit smoking in cars with youth (<18 years), is well positioned to do this work. This is because past New Zealand research has refined methods for on-street observing smoking in cars (in these studies:16–18) and has an ongoing national annual survey of around 30,000 14–15-year-old school students (Year 10 survey) which collects relevant data (eg, as in a study19 which considered inequalities by ethnicity and school-based socioeconomic position). Indeed, this survey of school students has been running annually since 1999 and so it could provide enough time points for a time-series analysis. There are also data from a cohort of adults about self-reported smoking in cars with children from the New Zealand arm of the International Tobacco Control (ITC) Survey, which will allow for repeat cross-sectional, and possibly within-cohort analyses. It is conceivable that a time-series analysis of smoking prevalence among adults in their 20s and 30s (ie, those who are most likely to have young children) from the New Zealand Health Survey might show a differential impact relative to other age-groups. But this is probably unlikely given the law is more likely to result in a change of where smoking occurs (ie, not in vehicles) as opposed to quitting.

Evaluation work using biomarkers (cotinine and nicotine levels) would be more expensive but is also probably justified to verify changes in self-reported exposures and to assess whether total exposure to SHS for children from all sources has decreased (ie, a reduction in SHS exposure from inside vehicles has not been replaced by more smoking in the home, albeit a remote possibility given available international data from other smoke-free laws). The “Growing up in New Zealand” longitudinal study20 could potentially adopt biomarker assessment of SHS exposure in children in conjunction with other routine assessments.

Such research should ideally be commissioned by the government agency which developed the law: the Ministry of Health. It could be tendered for by relevant university based researchers, consultancies doing research or non-governmental agencies (eg, the organisation ASH runs the Year 10 Survey). Such an approach was taken by the Ministry when it commissioned evaluation work21 of the new smoke-free environments law implemented in 2004 (covering smoke-free bars and restaurants), including an additional evaluation of the impacts on Māori health.22 The Ministry has also recently commissioned evaluation work on tobacco taxes.23 Unfortunately however, the Ministry has failed to evaluate other recent major national tobacco control policy interventions, including: the initial introduction of pictorial health warnings, the point-of-sale display ban for tobacco and (most recently) standardised packs with enhanced pictorial health warnings.

The results from evaluating the new smoke-free cars law would be potentially be very useful for New Zealand in refining the design of the law or adjusting the level of media promotion or enforcement. It would also make a valuable contribution to advancing the knowledge base for international tobacco control.

Summary

Abstract

In this viewpoint we briefly review the evidence for smoke-free car legislation. We find that this legislation has been consistently associated with reduced secondhand exposure in cars with children/youth in all nine jurisdictions studied. Despite this, there are various aspects of this intervention that warrant further study—especially determining its impact on reducing tobacco-related ethnic inequalities. So we argue that the New Zealand Ministry of Health should invest in a thorough evaluation of this important upcoming public health intervention. This could both help the country in further refining the design of the law (if necessary) and would also be a valuable contribution to advancing the knowledge base for international tobacco control.

Aim

Method

Results

Conclusion

Author Information

Nick Wilson, Department of Public Health, University of Otago, Wellington; George Thomson, Department of Public Health, University of Otago, Wellington; Richard Edwards, Department of Public Health, University of Otago, Wellington.

Acknowledgements

Correspondence

Professor Nick Wilson, Department of Public Health, University of Otago, Wellington.

Correspondence Email

nick.wilson@otago.ac.nz

Competing Interests

Nil.

1. Raoof SA, Agaku IT, Vardavas CI. A systematic review of secondhand smoke exposure in a car: Attributable changes in atmospheric and biological markers. Chron Respir Dis 2015; 12:120–31.

2. Frazer K, Callinan JE, McHugh J, van Baarsel S, Clarke A, Doherty K, Kelleher C. Legislative smoking bans for reducing harms from secondhand smoke exposure, smoking prevalence and tobacco consumption. Cochrane Database Syst Rev (Online) 2016; 2:CD005992.

3. Nguyen HV. Do smoke-free car laws work? Evidence from a quasi-experiment. J Health Econ 2013; 32:138–48.

4. Elton-Marshall T, Leatherdale ST, Driezen P, Azagba S, Burkhalter R. Do provincial policies banning smoking in cars when children are present impact youth exposure to secondhand smoke in cars? Prev Med 2015; 78:59–64.

5. Patel M, Thai CL, Meng YY, Kuo T, Zheng H, Dietsch B, McCarthy WJ. Smoke-Free Car Legislation and Student Exposure to Smoking. Pediatrics 2018; 141:S40–S50.

6. Faber T, Mizani MA, Sheikh A, Mackenbach JP, Reiss IK, Been JV. Investigating the effect of England’s smoke-free private vehicle regulation on changes in tobacco smoke exposure and respiratory disease in children: a quasi-experimental study. Lancet Public Health 2019; 4:e607–e17.

7. Amrhein V, Greenland S, McShane B. Scientists rise up against statistical significance. Nature 2019; 567:305–07.

8. Laverty AA, Hone T, Vamos EP, Anyanwu PE, Taylor-Robinson D, de Vocht F, Millett C, Hopkinson NS. Impact of banning smoking in cars with children on exposure to second-hand smoke: a natural experiment in England and Scotland. Thorax 2020.

9. Montreuil A, Tremblay M, Cantinotti M, Leclerc BS, Lasnier B, Cohen J, McGrath J, O’Loughlin J. Frequency and risk factors related to smoking in cars with children present. Can J Public Health 2015; 106:e369–74.

10. Lee JT, Glantz SA, Millett C. Effect of smoke-free legislation on adult smoking behaviour in England in the 18 months following implementation. PLoS One 2011; 6:e20933.

11. Moore GF, Currie D, Gilmore G, Holliday JC, Moore L. Socioeconomic inequalities in childhood exposure to secondhand smoke before and after smoke-free legislation in three UK countries. J Public Health (Oxf) 2012; 34:599–608.

12. Naiman AB, Glazier RH, Moineddin R. Is there an impact of public smoking bans on self-reported smoking status and exposure to secondhand smoke? BMC Public Health 2011; 11:146.

13. Cheng KW, Okechukwu CA, McMillen R, Glantz SA. Association between clean indoor air laws and voluntary smokefree rules in homes and cars. Tob Control 2015; 24:168–74.

14. Moulton AD, Mercer SL, Popovic T, Briss PA, Goodman RA, Thombley ML, Hahn RA, Fox DM. The scientific basis for law as a public health tool. Am J Public Health 2009; 99:17–24.

15. Houghton F, O’Doherty D, Houghton B. Teeth or no teeth: exploring punitive measures for adults smoking in cars containing children in Aotearoa/New Zealand. N Z Med J 2020; 133:118–22.

16. Martin J, George R, Andrews K, Barr P, Bicknell D, Insull E, Knox C, Liu J, Naqshband M, Romeril K, Wong D, Thomson G, Wilson N. Observed smoking in cars: a method and differences by socioeconomic area. Tob Control 2006; 15:409–11.

17. Patel V, Thomson G, Wilson N. Objective measurement of area differences in ‘private’ smoking behaviour: observing smoking in vehicles. Tob Control 2013; 22:130–5.

18. Thomson G, Oliver J, Wilson N. Trends in smoking in vehicles at a local community-level in New Zealand: Wainuiomata 2005–2013. N Z Med J 2014; 127:47–56.

19. Healey B, Hoek J, Wilson N, Thomson G, Taylor S, Edwards R. Youth exposure to in-vehicle second-hand smoke and their smoking behaviours: trends and associations in repeated national surveys (2006–2012). Tob Control 2015; 24:146–52.

20. Morton SM, Atatoa Carr PE, Grant CC, Robinson EM, Bandara DK, Bird A, Ivory VC, Kingi TK, Liang R, Marks EJ, Perese LM, Peterson ER, Pryor JE, Reese E, Schmidt JM, Waldie KE, Wall C. Cohort profile: growing up in New Zealand. Int J Epidemiol 2013; 42:65–75.

21. Edwards R, Thomson G, Wilson N, Waa A, Bullen C, O’Dea D, Gifford H, Glover M, Laugesen M, Woodward A. After the smoke has cleared: evaluation of the impact of a new national smoke-free law in New Zealand. Tob Control 2008; 17:e2.

22. Edwards R, Gifford H, Waa A, Glover M, Thomson G, Wilson N. Beneficial impacts of a national smokefree environments law on an indigenous population: a multifaceted evaluation. Int J Equity Health 2009; 8:12.

23. Ernst and Young. Evaluation of the tobacco excise increases – Final Report – 27 November 2018. Wellington: Ministry of Health 2018.

Contact diana@nzma.org.nz
for the PDF of this article

View Article PDF

A systematic review has reported that smoking in cars leads to extremely high exposure to secondhand smoke (SHS), “even in the presence of air-conditioning or increased airflow from open windows”.1 Many jurisdictions have responded to this hazard by legislating against smoking in cars (particularly in Canada, Australia and the US). However, the latest Cochrane systematic review on the impact of smoke-free legislation does not specifically consider the impact of such laws on youth exposure to SHS in cars.2 We therefore aimed to examine the relevant literature to determine the impact of such legislation and to help policymakers decide if further evaluation is worthwhile around the planned smoke-free cars legislation for New Zealand.

Methods for the literature review

Searches of the peer-reviewed literature were conducted using PubMed and Google Scholar on 9 February 2020 using a range of search terms (eg, smoke AND cars/vehicles AND ban/law). In these searches we aimed to identify studies where the impact of a smoke-free car law was estimated from survey data on smoking in cars containing children/youth. The bibliographies of these identified studies were also searched for additional relevant studies.

Results of the literature review

From publications identified by the searches (n=136 in PubMed; the first n=100 items in Google Scholar), we identified five relevant peer-reviewed studies. These studies covered nine different jurisdictions with smoke-free car laws (England, California and seven Canadian provinces) (Table 1). In all these jurisdictions there was evidence of declines in youth exposure to SHS after implementing the law, and in jurisdictions where it was assessed these declines persisted in all the subsequent survey waves.

Table 1: Studies identified in the peer-reviewed journal literature on the impact of smoke-free cars legislation on smoking in cars containing children/youth.

Putting the evidence in context

The findings of this review indicate that smoke-free car legislation was consistently associated with reduced SHS exposure in cars with children/youth in all nine jurisdictions studied. This finding is consistent with other types of evidence, eg, a study in Quebec where smoking in cars with children was lower among smokers who mistakenly believed Quebec had such a law.9 Similarly, it is consistent with spill-over benefits of reduced smoking/SHS exposure in cars from other smoke-free legislation for public places (eg, in England,10 in the three other UK jurisdictions,11 Canada12 and the US for adopting smoke-free car rules13). It is also consistent with international evidence from a Cochrane systematic review on smoke-free legislation being effective in many other settings,2 and with what is known about the effectiveness of public health laws in general from a major systematic review.14

What evaluation of the upcoming law should New Zealand do?

From a health protection perspective, there appears to be enough real-world evidence for policy-makers to introduce smoke-free car legislation. However, there are still major knowledge gaps. For example, there is a need to evaluate the equity impacts of such laws (eg, the relative size of Māori vs non-Māori benefits in the New Zealand context) and to evaluate the impact of any laws that prohibit vaping in cars. It also seems desirable to determine the value of co-interventions to enhance the law, such as mass media campaigns around the SHS hazard. Finally, evaluation of the impact by level of enforcement, would also provide useful information, as has been argued by others.15

New Zealand, with its upcoming law to prohibit smoking in cars with youth (<18 years), is well positioned to do this work. This is because past New Zealand research has refined methods for on-street observing smoking in cars (in these studies:16–18) and has an ongoing national annual survey of around 30,000 14–15-year-old school students (Year 10 survey) which collects relevant data (eg, as in a study19 which considered inequalities by ethnicity and school-based socioeconomic position). Indeed, this survey of school students has been running annually since 1999 and so it could provide enough time points for a time-series analysis. There are also data from a cohort of adults about self-reported smoking in cars with children from the New Zealand arm of the International Tobacco Control (ITC) Survey, which will allow for repeat cross-sectional, and possibly within-cohort analyses. It is conceivable that a time-series analysis of smoking prevalence among adults in their 20s and 30s (ie, those who are most likely to have young children) from the New Zealand Health Survey might show a differential impact relative to other age-groups. But this is probably unlikely given the law is more likely to result in a change of where smoking occurs (ie, not in vehicles) as opposed to quitting.

Evaluation work using biomarkers (cotinine and nicotine levels) would be more expensive but is also probably justified to verify changes in self-reported exposures and to assess whether total exposure to SHS for children from all sources has decreased (ie, a reduction in SHS exposure from inside vehicles has not been replaced by more smoking in the home, albeit a remote possibility given available international data from other smoke-free laws). The “Growing up in New Zealand” longitudinal study20 could potentially adopt biomarker assessment of SHS exposure in children in conjunction with other routine assessments.

Such research should ideally be commissioned by the government agency which developed the law: the Ministry of Health. It could be tendered for by relevant university based researchers, consultancies doing research or non-governmental agencies (eg, the organisation ASH runs the Year 10 Survey). Such an approach was taken by the Ministry when it commissioned evaluation work21 of the new smoke-free environments law implemented in 2004 (covering smoke-free bars and restaurants), including an additional evaluation of the impacts on Māori health.22 The Ministry has also recently commissioned evaluation work on tobacco taxes.23 Unfortunately however, the Ministry has failed to evaluate other recent major national tobacco control policy interventions, including: the initial introduction of pictorial health warnings, the point-of-sale display ban for tobacco and (most recently) standardised packs with enhanced pictorial health warnings.

The results from evaluating the new smoke-free cars law would be potentially be very useful for New Zealand in refining the design of the law or adjusting the level of media promotion or enforcement. It would also make a valuable contribution to advancing the knowledge base for international tobacco control.

Summary

Abstract

In this viewpoint we briefly review the evidence for smoke-free car legislation. We find that this legislation has been consistently associated with reduced secondhand exposure in cars with children/youth in all nine jurisdictions studied. Despite this, there are various aspects of this intervention that warrant further study—especially determining its impact on reducing tobacco-related ethnic inequalities. So we argue that the New Zealand Ministry of Health should invest in a thorough evaluation of this important upcoming public health intervention. This could both help the country in further refining the design of the law (if necessary) and would also be a valuable contribution to advancing the knowledge base for international tobacco control.

Aim

Method

Results

Conclusion

Author Information

Nick Wilson, Department of Public Health, University of Otago, Wellington; George Thomson, Department of Public Health, University of Otago, Wellington; Richard Edwards, Department of Public Health, University of Otago, Wellington.

Acknowledgements

Correspondence

Professor Nick Wilson, Department of Public Health, University of Otago, Wellington.

Correspondence Email

nick.wilson@otago.ac.nz

Competing Interests

Nil.

1. Raoof SA, Agaku IT, Vardavas CI. A systematic review of secondhand smoke exposure in a car: Attributable changes in atmospheric and biological markers. Chron Respir Dis 2015; 12:120–31.

2. Frazer K, Callinan JE, McHugh J, van Baarsel S, Clarke A, Doherty K, Kelleher C. Legislative smoking bans for reducing harms from secondhand smoke exposure, smoking prevalence and tobacco consumption. Cochrane Database Syst Rev (Online) 2016; 2:CD005992.

3. Nguyen HV. Do smoke-free car laws work? Evidence from a quasi-experiment. J Health Econ 2013; 32:138–48.

4. Elton-Marshall T, Leatherdale ST, Driezen P, Azagba S, Burkhalter R. Do provincial policies banning smoking in cars when children are present impact youth exposure to secondhand smoke in cars? Prev Med 2015; 78:59–64.

5. Patel M, Thai CL, Meng YY, Kuo T, Zheng H, Dietsch B, McCarthy WJ. Smoke-Free Car Legislation and Student Exposure to Smoking. Pediatrics 2018; 141:S40–S50.

6. Faber T, Mizani MA, Sheikh A, Mackenbach JP, Reiss IK, Been JV. Investigating the effect of England’s smoke-free private vehicle regulation on changes in tobacco smoke exposure and respiratory disease in children: a quasi-experimental study. Lancet Public Health 2019; 4:e607–e17.

7. Amrhein V, Greenland S, McShane B. Scientists rise up against statistical significance. Nature 2019; 567:305–07.

8. Laverty AA, Hone T, Vamos EP, Anyanwu PE, Taylor-Robinson D, de Vocht F, Millett C, Hopkinson NS. Impact of banning smoking in cars with children on exposure to second-hand smoke: a natural experiment in England and Scotland. Thorax 2020.

9. Montreuil A, Tremblay M, Cantinotti M, Leclerc BS, Lasnier B, Cohen J, McGrath J, O’Loughlin J. Frequency and risk factors related to smoking in cars with children present. Can J Public Health 2015; 106:e369–74.

10. Lee JT, Glantz SA, Millett C. Effect of smoke-free legislation on adult smoking behaviour in England in the 18 months following implementation. PLoS One 2011; 6:e20933.

11. Moore GF, Currie D, Gilmore G, Holliday JC, Moore L. Socioeconomic inequalities in childhood exposure to secondhand smoke before and after smoke-free legislation in three UK countries. J Public Health (Oxf) 2012; 34:599–608.

12. Naiman AB, Glazier RH, Moineddin R. Is there an impact of public smoking bans on self-reported smoking status and exposure to secondhand smoke? BMC Public Health 2011; 11:146.

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