Terrible Science or Terrible Articles?

Is Second Hand Smoke Harmful?

I’ll start off by saying the only good thing that appears to have come out of Donald Trump becoming president of the US is that since he labels everything as ‘Fake News’, if it diminishes his character in any way, the issue of actual fake news is being addressed. This is something that has been around for quite some time. My belief is that the biggest use of fake news is to ‘prove’ pseudoscience and parade it as though it is fact, such as Trumps take on climate change. Scientific communication plays one of the biggest roles in fake news today.

An article I come across in the Slate titled: ‘We Used Terrible Science to Justify Smoking Bans’. Now, When I hear the phrase ‘Terrible Science’ my mind goes straight towards homeopathy, anti-GMOs and general pseudoscience. It doesn't tend to lean towards rigorously peer reviewed scientific literature. In 2007 in the UK the smoking ban came into place, prohibiting people from smoking in any enclosed public area and the workplace. Jacob Grier, the author of the article, states that the research used to come to the conclusion allowing the ban is ‘flawed’. He argues that more recent research shows that there is no health benefits of people inhaling second hand smoke.

Scientifically speaking, not just using the one study he has used to determine this ironic conclusion, is that there is a scientific consensus; second hand smoke does have a negative impact on health. As seen in a review by the CDC and many meta-analyses. Granted, all in all, statistically the effect of adverse health upon exposure to second hand smoke is overall, small. However, the list of negative effects are serious, including strokes and heart attacks as well as cancer. When I say ‘statistically small’, if you have read the CDC link posted, you will see that that CDC approximates that 2,500,000 non-smokers have died due to exposure to second hand smoke since 1964. In terms of overall population levels, over that period of time, the effects are statistically small. Still, that is 2,500,000 people who could have possibly survived. Grier focuses his biased review of the literature on basically playing down the effects of second hand smoke exposure, saying the health benefits since the ban are exaggerated and suggesting that some of the data is made up. He also uses non-scientific articles to back up saying there is no link between lung cancer and second hand smoke and other articles that prove his point.

"A decade later, comprehensive smoking bans have proliferated globally. And now that the evidence has had time to accumulate, it’s also become clear that the extravagant promises made by anti-smoking groups—that implementing bans would bring about extraordinary improvements in cardiac health—never materialized."

I’d like to point out here that these studies do materialise if you search for them correctly. The studies he uses are aimed at specific incidences, such as acute myocardial infarction (AMI) in a study using ‘about’ 4 million inhabitants. We are looking at the whole picture here, he is, in effect, asking two questions: 'was the smoking ban based on flawed science'? and 'has the smoking ban had a positive effect on overall health'? Sadly for him, even this study he quotes doesn’t prove his case, as the authors conclude:

“Our study, based on a population of about 4 million inhabitants, suggests that smoke-free policies may result in a short-term reduction in admissions for AMI.”

Where are the reviews?

With journalists like this, I notice a pattern. Everything that doesn’t fit his view is either biased by the researchers or flat out made up. They tend to focus on the little picture, picking up studies here and there and criticising the wrong things in them. I say this in almost every blog, in science we absolutely love systematic-reviews. Imagine a systematic review as a building, such as an ‘information architecture’ of evidence based science, you start out with one or two studies (or blocks) and that gives you a direction in which way your building will go (negative or positive). More scientists add research blocks, and these collate together. After years of work you have a beautiful architecture with different wings, some studies will show positive results, some will show negative. Now, you can pick a building block to prove your point, such as saying “there are no adverse effects to health from second hand smoke exposure” - that one study will prove your point, and there are probably others. To bring this together, at the top of your architecture you want something grand. Something someone will look at, think of this as your systematic review. This is collating all your data from your overall structure to answer a very important question, is the building stable, or do we need to add more?

That is exactly what Cochrane do. You will have seen me talk about Cochrane before and how they are the ‘gold standard’ of systematic reviews. They love criticism, even more than myself. They even run a Silverman Prize targeted at rewarding people who do a good critique at pointing out what they have done wrong. So, it wasn’t surprising that a Cochrane review published in 2016 looked into the evidence behind second hand smoking was absent from Griers ‘review of evidence’. This is the second review carried out by them with the same title, this re-relaese is an update of the data including 77 more studies. They concluded that:

“Since the first version of this review was published, the current evidence provides more robust support for the previous conclusions that the introduction of a legislative smoking ban does lead to improved health outcomes through reduction in SHS for countries and their populations. The clearest evidence is observed in reduced admissions for acute coronary syndrome. There is evidence of reduced mortality from smoking-related illnesses at a national level. There is inconsistent evidence of an impact on respiratory and perinatal health outcomes, and on smoking prevalence and tobacco consumption.”

There are also reviews here, here and here. Again, each one conveniently missed off the cherry-picked data in the article. We need to consider the reductions in negative health outcomes based on population, the systematic reviews conclude that there is definitely negative outcomes from second hand smoke exposure. Given the weight of these reviews and the CDC estimation of the amount of deaths from exposure to second hand smoke, there is substantial evidence to back this banning of smoking. I can not see where this ‘flawed data’ is residing.

Conclusion

If you are going to read up on an subject, read up on both sides. Don’t read one study and go on a witch-hunt looking for only studies that confirm that study and so-forth. More so, don’t give reporters like this the power to mislead you. Read up on both sides, that is exactly what I have done for this blogpost for the last week. I didn’t just read the reviews and say ‘well, he's wrong’. I read the other side to see why they may be issues and if there are issues, what are they? The truth is in this article, the author claims that the effects on health since the ban are exaggerated and wrote a biased article looking only at the few published works that went against the grain.