Measuring the impact of England’s public smoking ban on infant mortality

A PHS 795 student draws our attention to a quasi-experimental study examining the impact of England’s comprehensive public smoking ban on infant birth weight and mortality. Although it is true that an interrupted time series design is relatively weak, the magnitude of this intervention as a nationwide policy and the strength of the biological mechanisms connecting maternal smoking to these outcomes gives a whole lot of weight to its conclusion (why it was published in a high impact journal like Nature). Our student writes:

In July 2007, England passed a nationwide, comprehensive smoking ban. Since then, virtually all work and public places have been smoke-free. A few studies have looked at the positive impacts of this on adult health, in terms of direct smoking as well as second-hand smoke.

This research article from 2015 uses a quasi-experimental design to look at the effect of England’s smoke-free legislation on perinatal survival. As we’ve learned in this class, exposures during early stages of the life course can have the biggest impacts on lifetime health. This study looked at death certificates for all births between 1995 and 2011: over 52,000 stillbirths and over 10 million live-births were examined. They found the smoking ban caused a near-immediate reduction in stillbirths, low birth weight, and neonatal mortality for the study group.

Despite being one of the largest studies to investigate this topic, there are some inherent limitations to this type of analysis. How does the experimental design used here relate to the quasi experimental methods discussed with Dr. Remington? Are there other experimental designs that might be reasonable to examine the relationship between smoking bans and health benefits?

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4 thoughts on “Measuring the impact of England’s public smoking ban on infant mortality

  1. This is a great article and a topic in which I am particularly interested. I wrote a paper last semester on the positive effects of the statewide smoking ban here in Wisconsin, and it seems those effects are mirrored worldwide. Although the article did cite some limitations to this type of experimental design, it is hopeful to see research being conducted to address this issue. It is fascinating to see that the smoking ban caused a near-immediate reduction in stillbirths, low birth weight, and neonatal mortality for the study group. This article reminded me of the in-class lecture by Deborah Ehrenthal and her research on the determinants of health across the life course. The critical period model of her research cites exposure at a specific point in time can affect the individual for a lifetime. I think of the link between mother and baby and what the long-term consequences of smoking can have on the child. Since there can be an accumulation of risks, further research on this topic seems vital to not only preventing neonatal mortality, but also to mitigating the harmful effects over a lifetime.

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  2. I also really enjoyed Prof. Ehrenthal’s lecture, and didn’t realize how little I knew about different effects on a baby’s development depending on the time and duration of exposure during gestation. This study’s authors made the related point that “improvements in perinatal outcomes are likely mediated via reductions in maternal SHS exposure as well as active maternal smoking”, which would be an interesting distinction to try to study. The two factors (maternal smoking and SHS exposure) are obviously correlated; the socioecological model as discussed in the Martinez-Donate lecture helped me consider the forms those correlations could take (specifically, the example about smoking policy changes in the military). I expect social networks and friendships play an important role in how women feel about smoking during pregnancy, and likely affect a woman’s choices and exposures, in a way that’s similar to determinants of smoking among service members. I agree with Joe that more research to clarify the links between the smoking ban and neonatal health outcomes would be valuable.

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  3. Very interesting study and finding. While I believe the conclusions from the study are likely credible, it would have been nice to see how the change in infant mortality compared to trends in regions that did not have a smoking ban in the same time period. Adding a control from a similar region (from another part of the UK that has not banned smoking in public areas) would have served as a useful comparison.

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  4. As other have mentioned this was a great read, thanks for sharing. Am I the only PHS 795 student who struggles with smoking bans on a philosophical level? I find that whenever we ban a legal activity in a public place my libertarian leanings show themselves. Why ban smoking in places like restaurants when people could simply decide to eat somewhere else if they didn’t want to be exposed to smoke? Is it because smoking is absolutely, 100% proven to be harmful? If that’s the case, then why not make smoking illegal, full stop? I imagine this is where some people would claim that an all out ban on cigarettes would infringe on people’s rights too much, but I can’t see that being any less true when applied to private businesses. I can’t quite find the line where government should want to intervene.

    This article did chip away at my position just a little bit because, as we’ve learned, the health of the mother can determine her child’s health in the earliest stages of pregnancy, so it may be smart to limit everyone’s exposure to cigarette smoke everywhere a potential mother might travel. But, again, how much responsibility is on the mother and how much is on the government is something I struggle with.

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