Effects of smoke-free workplace legislation on heart attacks

There is no doubt whatsoever that exposure to other people’s tobacco smoke pollution, over a long period of time, can cause various diseases (as summarized in a previous posts):
Health effects of Tobacco Smoke Pollution. 8/6/07 http://www.healthline.com/blogs/smoking_cessation/2007/08/health-effects-of-tobacco-smoke.html
Sidestream cigarette smoke more toxic than mainstream smoke. 8/8/07 http://www.healthline.com/blogs/smoking_cessation/2007/08/sidestream-cigarette-smoke-more-toxic.html
Make yours a smoke-free home. 08/10/07
http://www.healthline.com/blogs/smoking_cessation/2007/08/make-yours-smoke-free-home.html

Since the growing implementation of workplace smoking bans (with bars restaurants etc being workplaces) there have been a number of reports from around the world finding that the rate of hospitalizations for acute myocardial infarction (MI: a “heart attack”) decreases significantly in areas where these smoking bans are implemented.

These studies have sometimes been based on very small geographic regions and a relatively small number of MIs. For example, a widely reported study published in the BMJ in 2004 found that in Helena, Montana, the number of hospitalizations for MI fell from 40 per half-year before the workplace smoking ban to 24 in the six months the law was in effect. The MI hospitalization rate increased slightly in a part of Montana outside Helena, and increased again (to 38) in Helena when the workplace smoking ban was lifted http://www.bmj.com/cgi/content/full/328/7446/977 .

This month a much larger study found that there were 3814 fewer hospital admissions (an 8% drop) for MIs in New York state in 2004 than would have been expected without the smoke-free workplace legislation implemented in 2003 in New York. http://www.ajph.org/cgi/content/abstract/97/11/2035

One question raised by these findings is whether the effects are caused primarily by fewer MIs in smokers who reduce or quit smoking because of the ban on smoking in workplaces, or whether it is primarily caused by fewer MIs in non-smokers who are no longer having to breath air polluted by tobacco smoke.

Another study published this month suggests that the effect is almost exclusively in non-smokers. This study by Drs Seo and Torabi of Indiana University carefully compared the number of hospitalizations in one Indiana county (Monroe) that implemented increasingly strict smoke-free workplace legislation, with another very similar county that did not pass such legislation (Delaware county). They found that in Monroe county the number of non-smoking MI admissions fell from 17 to 5, whereas it fell from 18 to 16 over the same time period in Delaware. The number of smokers admitted with MIs stayed about the same in both counties. This suggests that the reductions in MIs following these smoking bans is due to the reduction in the cardiotoxic effects of inhaling tobacco smoke pollution in non-smokers (For some reason the authors excluded MIs in people with other pre-existing risk factors such as high BP or cholesterol. I’m not sure why, so if you know, please explain it to me).

While none of the studies finding reduced MIs following smoke-free workplace legislation are perfect, and many are based on a very small number of cases, they are telling a fairly consistent story. The only way the data could fall this way by chance (rather than due to a “real” effect) would be if there was a systematic publication bias (i.e. people doing similar studies with different results not publishing them) or a systematic bias in the research process (e.g. researchers “cherry-picking” the time-frames chosen for comparisons to exclude “data blips” that don’t fit with the claimed results). While such biases do sometimes enter into the research process my inclination is to believe the results when they are almost all pointing in the same direction. So if you are aware of any studies of this issue that found different results, please let me know. But in the mean time the main conclusions appear to be:

1. Non smokers exposed to other people’s tobacco smoke pollution have increased risks of suffering a heart attack.

2. Implementing comprehensive smoke-free workplace legislation not only allows people to work in a safer workplace, it results within a year in a reduced number of non-smokers suffering from heart attacks.

3. If making workplaces smoke-free reduces heart attacks, making homes smoke-free will likely have the same effect.

Have a happy and smoke-free Thanksgiving.

Labels: ETS, foulds, myocardial infarction, tobacco smoke pollution

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Make yours a smoke-free home

My previous two posts focused on the harmful effects of exposure to tobacco smoke pollution (ETS or SHS). It is clear that inhaling air contaminated by smoke from other people’s tobacco smoke can harm your health. As always, the risk is related to the cumulative dose and so the riskiest places are those in which we spend most time. The primary reason for legislation banning smoking in public places is actually to protect the people for whom that place is their workplace. While it could be argued that spending a couple of hours in a restaurant where someone else has smoked is unlikely to cause you a serious illness (notwithstanding the fact that some people can have asthma attacks or other illnesses triggered by relatively brief exposure), there is no doubt that a waitress spending forty or more hours in that environment every week will have a significant risk of contracting a serious illness caused by the smoke exposure. So the case for protecting workers in bars, restaurants, casinos and all other workplaces from tobacco smoke pollution is very clear and very strong.

Of course, other than the workplace, the other place we spend most time is our home. The home is also the place that children spend most of their time. Largely for these reasons, more and more households are deciding to be smoke-free as well. The proportion of households with smoke-free home rules in the United States ("No one is allowed to smoke anywhere inside your home,") increased significantly, from 43% during 1992--1993 to 72% in 2003. In 2003, 32% of households with a smoker living there had a smoke-free rule, as compared with 72% of households with no resident smokers.

So it is now the norm in the United States for a household to have a policy that no-one smokes indoors, and around a third of households with smokers were already implementing such a rule in 2003. The reasons are clear:
- tobacco smoke contains thousands of toxins.
- the concentration of some of these toxins in the air increases over time
- it is clear that exposure to tobacco smoke pollution increases the risk of serious illnesses
- smokers who live in smoke-free households are more likely to quit
- in addition, allowing smoking in the house increases the risk that children will be exposed and may become smokers themselves

So if you live in a household without any smokers, but without a smoke-free policy, its time to sit down with the family and agree on having one. and how it will be implemented on occasions when people may want to smoke (a houseparty, a home-repair worker, a visiting family-member who smokes etc).

Likewise, if you live with a smoker and currently allow smoking in the home, perhaps its time to make a change. Most smokers nowadays are aware of at least some of the effects of tobacco smoke pollution and therefore understand the rationale for having a smoke-free home and car. Most of the year it is no great hardship for the smoker to do their smoking outside. Sitting down with the people you live with and providing a heartfelt reason for making the household smoke-free may not meet with as much resistance as you might think.

Helpful information on smoke-free homes is available at:
http://www.epa.gov/smokefre/pledge/

Further information including smoke-free cars can be found at:
http://www.smokefreezone.org/

The latest data on the proportion of smoke-free homes in the United States can be found at: http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5620a3.htm

Labels: ETS, nicotine addiction cigarette, pollution, SHS, smoking tobacco

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Sidestream cigarette smoke more toxic than mainstream smoke

In my last post about tobacco smoke pollution I mentioned the puzzling fact that although exposure to tobacco smoke pollution (TSP or ETS or SHS) gives about 1-5% of the smoke dose of active smoking, it gives a proportionately bigger increase in some disease risks. This fact has caused some to be rather skeptical about the evidence on tobacco smoke pollution and health. But just this month a new paper has been published by Drs Suzaynn Schick and Stan Glanz at University of California at San Francisco, that sheds some new light on this.

One of the main carcinogens in cigarette smoke is known as NNK (as its long chemical name is almost unpronounceable!). Previous studies have shown that there is a 3-4 times higher concentration of NNK in sidestream smoke (the smoke released from a burning cigarette into the air between puffs) than in mainstream smoke (the smoke inhaled by the smoker). But the new paper by Drs Schick and Glanz went further. They analyzed tobacco industry documents dating back to the 1980s that showed that Philip Morris tobacco company (which was, at that time, denying the harmfulness of exposure to environmental tobacco smoke) had conducted studies that not only measured these effects, but uncovered the mechanism behind it (continued reaction of nicotine, nitrogen oxides and other smoke chemicals). These studies also showed that while the smoke ages as it hangs in the air in a room where someone has smoked, the concentration of NNK actually increases another 2-4 times! So the net effect is that the concentration of NNK per unit of sidestream smoke hanging around in the air in a room hours after the smoker has left, may be 10 times greater than the concentration per unit of smoke the smoker inhaled directly from the cigarette. This type of finding may be a part of the explanation of why exposure to tobacco smoke pollution is more harmful than we might expect from the simple amount of smoke being inhaled.

Of course the tobacco company that discovered these results (Philip Morris, makers of Marlboro) did not expend much effort to share them with the public. Rather, it has taken painstaking research by public health scientists to piece together the evidence from tobacco industry documents and publish them in a peer-reviewed journal.

This gives yet more reason to ensure that people (and pets) in public spaces should not be exposed to tobacco smoke pollution, and to make sure your home environment is smoke-free.

This link takes you to the original journal report:
http://cebp.aacrjournals.org/cgi/content/abstract/16/8/1547

Labels: ETS, pollution, SHS, Smoking, tobaco

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Health effects of Tobacco Smoke Pollution

Tobacco smoke pollution (TSP), also known as, “environmental tobacco smoke (ETS)” or “secondhand smoke (SHS)” is the tobacco smoke that enters the environment as a result of (a) sidestream smoke, that comes directly from the burning tip of the tobacco product without having been exhaled by the smoker and (b) mainstream smoke, that has been exhaled by the smoker.

As tobacco smoke is one of the most potent toxic compounds, tobacco smoke pollution can impact on many health problems, even at low levels of exposure. It is estimated that at least 50,000 deaths are attributable to second hand smoke each year in the United States (California Air Resources Board, [CAR] 2005). The list below contains some of the most common health effects of that have been causally linked to TSP.

Developmental Effects
Low birthweight
Sudden Infant Death Syndrome (SIDS)
Pre-term delivery

Respiratory Effects
Acute lower respiratory tract infections in children (e.g., bronchitis and pneumonia)
Asthma induction and exacerbation in children and adults
Chronic respiratory symptoms in children
Middle ear infections in children

Carcinogenic Effects
Lung cancer
Nasal sinus cancer
Breast cancer in younger, primarily pre-menopausal women

Cardiovascular Effects
Coronary artery disease

With cardiovascular diseases being associated with a very high proportion of overall deaths, factors that increase risk of cardiovascular mortality have a substantial societal impact. TSP results in smoke exposure of about 1% of typical active smoking, but increases cardiovascular risk by 30%. Recent evidence suggests that policy regarding TSP can have substantial effects on cardiovascular events. A study conducted in Helena, Montana found that implementation of a comprehensive local ordinance on clean air was related to a 40% reduction in admissions for acute myocardial infarction, which subsequently rebounded after the ordinance was suspended (Sargent, Shephard, Glantz, 2004). This study demonstrates the potential health benefit of establishing smoke-free environments.

It has been demonstrated that non-smokers have statistically greater risk of lung cancer if their spouses are smokers. Meta-analyses show the increased risk of lung cancer was about 25% greater than expected in women and 35% greater in men if their spouses smoked (National Cancer Institute, 1999).

So what can you do to avoid exposure to Tobacco Smoke Pollution? Firstly, if you live in a state that has yet to implement legislation requiring public places to be smoke-free, then make a point of only going to bars and restaurants that are smoke-free and let the owner know how much you appreciate it. Each state produces a list of smoke-free venues.
Secondly, while you can’t necessarily control every environment, one important environment that you may be able to control is your own home. So make sure that you and your family are not exposed to toxic tobacco smoke pollution at home by making your home a Smoke-Free Home. I’ll talk more about smoke-free homes in my next post.

For an extremely comprehensive report on the effects of Tobacco Smoke Pollution, see the 2006 report launched by Surgeon General Carmona (now a member of the board here at Healthline). http://www.surgeongeneral.gov/library/secondhandsmoke/

For an interesting report on the effects on heart attack rates when a city in Montana passed smoke-free environment legislation (plus a commentary by CDC) see:
http://www.bmj.com/cgi/content/full/328/7446/977?maxtoshow=&HITS=10&hits=10&RESULTFORMAT=&fulltext=helena+ets&searchid=1&FIRSTINDEX=0&resourcetype=HWCIT

Labels: ETS, nicotine addiction cigarette smoking tobacco, nicotine regulation reduction smoking smokeless, pollution, SHS

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