Michael Siegel reported earlier in the week how a new study has claimed that secondhand smoke exposure causes poor performance academically. The first point of common-sense is to simply ask if SHS causes poor academic performance, how come active smoking has positively beneficial effects on the brain and concentration, and how did we ever evolve with people smoking for our entire history?
As you might have guessed, the study was a crock of shit, as it simultaneously measured self-reported secondhand smoke exposure and self-reported academic performance. In other words, people estimated how much passive smoke exposure they had (I couldn't ever quantify that, could you?) and also stated their academic performance. Not exactly rigorous science by any stretch of the imagination. So how much did their performance suffer? "Students exposed to SHS at home 1 to 4 and 5 to 7 days per week were 14% (95% CI, 5%-25%) and 28% (15%-41%)"
So, uh, hardly at all. Averages of 14 and 28%? Come on now. No real scientist would ever genuinely consider that noteworthy, so what's the agenda here?
If exposure to SHS could impair the students’ academic performance and hence reduce their chances to succeed, then home smokers are depriving the students’ human rights to higher education stipulated in the Universal Declaration of Human Rights—Right to Education (Article 26), which states 'higher education shall be equally accessible to all on the basis of merit.'
Tobacco control advocates, educators, and human right advocators can also make use of our evidence to negotiate an expansion of smoke-free legislation to the home environment.
Ahhhh. The tried and tested "for the sake of the children" argument. Or, put in a real context, " we have no evidence whatsoever that tobacco smoke impairs academic performance or cognitive ability, so we'll tug at the heart-strings instead." Although it must be noted that the study author is using the term "evidence" incredibly loosely, and it's admitted by the researchers that there was a significant margin of error:
Although restricting our analyses to nonsmokers only should have largely reduced the confounding effects of unfavorable lifestyle factors associated with smoking, residual confounding cannot be ruled out because of the crude self-reported measures of socioeconomic status and unmeasured lifestyle factors.
In other words, they were unaccounted variables that could, and most certainly would, have affected the results - and if the results were affected, then there would be no "evidence" to push for a home smoking ban, and that just won't do at all. Moreover, as Siegel notes:
In addition, there are other important confounding variables, such as parental involvement with the child's education. In other words, there are many reasons why children who are more heavily exposed to secondhand smoke may do poorer in school, and the study cannot adequately rule out these alternative explanations.Siegel makes another excellent point, that "because the study is cross-sectional, it cannot establish whether the academic performance problems might have predated the secondhand smoke exposure." What he means is, no base level of performance was taken. It's all well and good comparing smoke-exposed to non-smoke-exposed children, but without comparing the same child's performance before and after exposure began nothing is actually being measured at all.
Therefore, it is mystifying why the study goes ahead and concludes that the observed association in the study is attributable to a direct, causal effect of secondhand smoke exposure.
If a child typically scored 70-90% on tests, then was exposed to secondhand smoke and his grades went down to 40-50%, and all other variables had been accounted for e.g. general change in attitude towards studies, then a case could exist for secondhand smoke impairing academic performance. As it stands, however, all we have is more pseudo-science, political bullshit printed in a journal to win support.