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Still
dying from second-hand smoke at work: a brief review of the evidence for
smoke-free workplaces in New Zealand
Nick Wilson and George Thomson
There is strong evidence that second-hand smoke (SHS) is a
cause of lung cancer,1–3 with the United
States Surgeon General4 and the United States
National Research Council5 also reaching this
conclusion. Although this evidence is not specific to workplace SHS exposure, it
is biologically plausible that such a risk would apply in any settings in which
such exposure is significant.
A number of major reviews have reported that exposure to SHS
is associated with heart disease in adults6 or
is causal of heart disease in adults.7,8 A
review of workplace studies on SHS and cardiovascular disease risk found that
while five out of six studies were suggestive of increased risk, none were
statistically significant.9 Nevertheless, the
reviewers noted that there is no biologically plausible reason to believe that
the hazards of SHS exposure that have been demonstrated in the home should not
also apply to the workplace. A subsequent review has concurred with this
assessment regarding workplace SHS exposure.10
There is also recent direct experimental evidence that passive smoking may cause
endothelial dysfunction of the coronary circulation in healthy
nonsmokers.11
Major reviews have also reported that there is a causal
association between SHS exposure and the risk of respiratory
illness.7,8,12 A recent study has identified a
dose-response relationship for SHS exposure among workers, and the occurrence
for those workers of significant respiratory symptoms and physician consultation
rates for respiratory symptoms.13 A causal
association between SHS exposure and increased severity of asthma episodes and
symptoms has been reported by major
reviews.4,8,12
SHS in the workplace may also have an impact on child
health. One review considered that the risk of SHS exposure in pregnant women
for adverse pregnancy outcomes can be generalised to the work
environment.14
While many developed countries regulate against exposure to
SHS in workplace settings, substantial exposure can still occur. For example, in
spite of regulations, SHS remains “the most common occupational exposure
to chemical carcinogens in Finland”.15 In
New Zealand, there is currently draft legislation before the Parliament to
extend the scope of smoke-free workplaces. To encourage evidence-based policy
making, this article briefly reviews the relevant New Zealand data and puts them
into the international context.
MethodsMedline searches were conducted
for the period 1966 to July 2002, with search terms covering “second-hand
smoke”, “passive smoking”, “environmental tobacco
smoke” and “involuntary smoking”. The search term “New
Zealand” in relation to “smoking” or “tobacco” was
also used. Unpublished reports relating to New Zealand data were identified by
searches of New Zealand health databases (including medical library databases).
Major international reviews on SHS in the workplace were identified to help put
the New Zealand data into a broader context.
ResultsExposure
to SHS in New Zealand and its effects The Smoke-free Environment Act
(1990)16 effectively banned smoking in offices,
but not in many other interior workplaces. A study that used 1992/93 data from
workers in a nationwide multi-industry corporation, found that exposure of the
workers to SHS averaged 47 minutes per week
(for the total of work and home exposure).17
This group of workers reported more regular
exposure to SHS than those in the community cohort who were also part of
this study (52% versus 23%) – which indicated extra exposure at
work.
A national survey in 1996 found 36% of indoor workers were
exposed to SHS at lunch and tea breaks, and 19% were exposed to SHS during
working hours.18 Maori and blue-collar workers
were around 50% more likely to be exposed to SHS during working hours than
others (28% and 29% respectively were exposed). Another national survey, in
1999, reported that 84% of respondents working in indoor workplaces stated that
smoking restrictions were in place in these
settings.19
A survey in 1999–2000 by Jones et al indicated that
59% of Wellington hospitality workers were exposed to
SHS.20 More than half of the exposed workers
reported irritation to their throat or lungs from SHS.
Another study by Al-Delaimy et al reported on hair nicotine
levels amongst workers in the hospitality
industry.21 It found that the exposure level
was substantial, with hair nicotine levels among nonsmokers working in places
with no restriction on smoking being similar to the hair nicotine levels of
active smokers. The findings of this study highlight the importance of
workplace exposure, as the results were
unchanged when adjusted for other sources of SHS exposure.
The most recent study by Bates et al examined the
concentrations of salivary cotinine (a marker for tobacco smoke exposure) found
in hospitality workers.22 It reported that the
levels of cotinine found in non-smoking workers exposed to SHS “have been
associated with substantial involuntary risks for cancer and heart
disease”. Furthermore, workers in premises permitting customer smoking
reported a higher prevalence of respiratory and irritation symptoms than workers
in smoke-free workplaces.
SHS exposure in New Zealand workplace settings has been
estimated to cause 101 avoidable deaths per
year from lung cancer, coronary heart disease and stroke
collectively.23 This is 29% of the estimated
total of all deaths attributable to SHS in New Zealand (estimated to be in the
range of 174 to 490 deaths per year). However, these were conservative estimates
that did not include the exposure of workers to SHS at lunch and tea breaks, or
the effect of SHS on smokers. SHS exposure at work was also estimated to cause
190 hospital admissions for heart attacks annually, as well as contributing to
illness from strokes and other
causes.24
There is also evidence from a New Zealand study that total
SHS exposure (from work and home) contributes to the risk of
stroke.25
Impact of SHS control
measures and education In New Zealand, legislation for smoke-free
workplaces (Smoke-free Environments Act,
199016) appears to have been highly effective
in reducing exposure to tobacco smoke.26
Further survey data have also shown that the proportion of workers exposed to
tobacco smoke during working hours decreased from 31% in 1989, to 19% in
1996.18
The New Zealand study by Al-Delaimy et
al21 found that non-smoking workers working in
100% smoke free restaurants had much lower hair nicotine levels than staff
working in bars with no restrictions on smoking (with levels being intermediate
for staff working in places with a partial smoking ban) (p
<0.0001).
Similarly, the study by Bates et
al22 found that hospitality workers in premises
allowing smoking by customers had significantly greater increases in salivary
cotinine than workers in smoke-free premises. Workers in premises with no
restrictions on customer smoking were more highly exposed to SHS than were
workers in premises permitting smoking only in designated areas (p
<0.03).
Attitudes to SHS and
control measures Three quarters of the hospitality sector interviewees
surveyed by Jones et al wanted some sort of smoking restriction in
bars.20 Even so, knowledge of the hazard posed
by SHS was limited, with less than one third of these workers and owners being
aware that SHS increases the risk of stroke. In a 1996/97 national population
survey of adults, just under half of the nonsmokers reported that they were
“bothered a lot” by cigarette smoke and nearly a further third were
“bothered a little”.27 Of this
group, women were significantly more likely than men to report to being
“bothered a lot” by cigarette smoke.
A national survey in 1999 reported that 72% of all
respondents were bothered by SHS to some degree, with this figure being even
higher for nonsmokers, at 85%.19 A majority of
Maori (62%) and Pacific respondents (76%) also reported that SHS was bothersome.
This survey also found that 78% of respondents agreed that “smoking should
not be allowed in any workplace where nonsmokers have to work”. Similarly,
97% of respondents favoured some form of smoking restrictions in restaurants,
cafés and foodhalls; and 79% some form of restriction in bars.
A national survey in 2001
reported that 83% of Maori surveyed and 85% of all respondents agreed that
people have a right to smoke-free workplaces. Only 7% of Maori and 8% of all
respondents disagreed with this.28
DiscussionThe international literature
provides strong evidence that SHS is a carcinogen and increases the risk of
cardiovascular disease and respiratory illnesses. Although the specific data on
workplace SHS exposure and adverse health outcomes are limited, it is
biologically plausible that SHS poses a similar hazard in indoor workplaces to
that in settings in which the impact is better established (ie, for spouses of
smokers exposed in home environments).
Despite the evidence detailed in major reviews and from
toxicological work highlighting the relative hazard of
SHS,29 some authors still dispute aspects of
the hazard posed by SHS. For example, Bailar30
and others have found it hard to understand that low levels of SHS impact on
cardiovascular health (despite the available data indicating direct
physiological effects of such exposure31). Some
of the criticism of the evidence for the hazards of SHS has come from within
particular disciplinary groups that lack a public health context (eg,
mathematics and experimental toxicology32,33).
Policy makers should consider such critiques in the light of the overall weight
of evidence, and the assessments made by international health authorities such
as the International Agency for Research on Cancer (which considers SHS a proven
carcinogen1).
In the absence of changes in legislation, or substantial
changes in smoking prevalence, enforcement or education since 1996, the national
survey data suggest that at least 30% of workers are currently exposed to SHS at
lunch and tea breaks. Also, at least 15% are exposed to SHS during working
hours. However, the lack of more recent national survey data makes these
estimates tentative. It is plausible that other tobacco control efforts have had
some impact on SHS workplace exposure since the mid 1990s, given the ongoing
annual decline in per capita tobacco consumption (down by about 22% between 1996
and 200134). This trend to lower per capita
consumption (while smoking prevalence has stayed at 25–26% of the adult
population since 1991) would probably decrease the daily
level of exposure to SHS, rather than
the proportion of the working
population exposed to SHS.
The New Zealand national survey data and data from studies
of the hospitality sector, strongly suggest that the expansion of smoke-free
workplaces can reduce the exposure of workers to SHS. This picture is consistent
with the substantial international evidence for the effectiveness of
interventions to reduce smoking in workplaces and public places.
35–38 One of these
reviews37 concluded that in addition to smoking
bans and restrictions reducing exposure to SHS in the workplace, such
interventions appear to reduce tobacco consumption and increase smoking
cessation.
The impact of further workplace controls in New Zealand is
likely to be beneficial for businesses as well as for workers. New Zealand
surveys indicate that bars and restaurants would receive more
patronage.39,40 One review of studies in the
United States37 reported that smoking
restrictions do not have an adverse economic effect on businesses (including
bars and restaurants) or on tourism. Indeed, the impact on businesses of
smoke-free bar and restaurant laws can be
positive.41–43 The business benefits
include decreases in worker sickness and accidents, labour turnover,
productivity losses, legal risks and insurance, cleaning, ventilation and legal
compliance costs.44–49 Compliance with
smoke-free regulations has been reported to be high in various United States and
Australian settings.50–52
The main options to protect workers from SHS are the
voluntary limitation of smoking in workplaces by either management or workers,
and legislation to limit such smoking. There is evidence that voluntary
limitation is much less effective than legislation in reducing SHS
exposure.53–55 Also, one review reported
that totally smoke-free workplaces had about twice the effect on tobacco
consumption and smoking prevalence as policies that allowed smoking in some
areas.38
Improving ventilation has been suggested as an option for
reducing the hazard posed by SHS in workplaces. However, experimental work has
revealed that ventilation to control SHS is not
feasible,56 and that eye and nasal irritations
are observed at very low levels of SHS (ie, corresponding to a fresh air
dilution volume of >3000 m3 per
cigarette).57
There is currently draft legislation before the New Zealand
Parliament to extend the scope of smoke-free workplaces (and possibly to make
all bars and restaurants smoke free). The evidence detailed in this review would
support such legislation on public health and economic grounds. Yet to maximise
the impact of any new legislation, the government and health authorities should
consider various supplementary options:
1) Funding mass media campaigns in the near future to
further educate workers and the public about the hazards of SHS in the
workplace. Such campaigns should be particularly aimed to the audiences of
low-income workers, and Maori and Pacific peoples, due to their greater
likelihood of being at risk from SHS. Use of campaigns would facilitate both
self enforcement and easier enforcement of new legislation. In particular, they
could help inform members of the New Zealand hospitality industry. Many in this
industry, especially those managing clubs and bars, have indicated concerns
about the effects of any legislation to ban smoking in licensed
premises.58
2) Supporting employers with smoking cessation interventions
for their staff (eg, encouraging use of the Quitline and providing financial
support for smoking cessation, using the proven methods described in new smoking
cessation guidelines for New
Zealand59).
3) Actively exposing and countering tobacco industry
misinformation concerning the risks associated with SHS (as documented in a
recent New Zealand review60).
4) Improving tobacco control in general, particularly with
greater use of mass media campaigns, publicity for the Quitline, and the further
use of quit and win contests.
5) Regular monitoring of the exposure of workers to SHS, of
workers’ attitudes to and knowledge of the effects of SHS, and of the
economic impact of policy interventions. Additional research in the New Zealand
setting could address the impact of SHS on both workers and non-workers for
health conditions that are particularly relevant to this country. These
conditions include asthma and meningococcal disease.
In summary, the international literature provides strong
evidence that SHS is a carcinogen, and that it increases the risk of
cardiovascular disease and respiratory illnesses. Furthermore, the available
data on workplace exposure to SHS are strongly suggestive that this hazard is a
significant threat to the health of exposed workers.
The New Zealand data are consistent with the extensive
international evidence, that smoke-free policies in workplaces can improve
health protection for workers. However, in this country there are many workers
still exposed to significant levels of SHS. The exposure is estimated to cause
around 100 deaths annually. This workplace health risk may soon be addressed by
new and stronger smoke-free environments legislation. Nevertheless, there are a
range of feasible additional actions that the health sector can take to enhance
the impact of such important legislation – including running a mass media
campaign on the hazard posed by SHS.
Author information:
Nick Wilson, Public Health Physician, Wellington; George Thomson, Department of
Public Health, Wellington School of Medicine, University of Otago
Acknowledgements: We
thank Professor Alistair Woodward, Dr Kevin Dew, Dr Sarah Hill and the two
anonymous reviewers for helpful comments on the draft.
Correspondence: Dr
Nick Wilson, 367A Karori Road, Wellington. Fax: (04) 476 3646; email:
nwilson@actrix.gen.nz
References:
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