Filtering the evidence

Here are some highlights from a study on filtered cigarettes and cancer, published Monday in the Journal of the National Cancer Institute:

As cigarette designs have changed over the past five decades to include ventilation holes in the filters, rates of a particular type of lung cancer, adenocarcinoma, have increased relative to other types of lung cancer.

When filter ventilation was first adopted in the 1960s, it was thought to create a safer cigarette by decreasing the amount of nicotine and tar a smoker takes in each time he inhales. It turns out filter ventilation also does some less salutary things that no one foresaw, including increasing cancer-causing smoke toxicants and increasing the amount of smoke a smoker takes in.

The study authors recommend the U.S. Food and Drug Administration consider banning cigarette filter ventilation. The authors write, “given a lack of evidence for countervailing harms, ending filter ventilation could be a ‘no regrets’ action that would benefit public health.”

The authors cannot definitively prove a causal relationship between filter ventilation and increased adenocarcinoma (or other) lung cancer risk. However, senior author Peter D. Shields says if ventilation holes “have the potential harm, the FDA can act, even if the science is not perfect.”

I offer up these pieces of information as a non-scientist. It’s fascinating to me that people who are scientists are so keen to recommend banning something without proof the thing in question actually causes the harm they’re trying to prevent or reduce.

On the other hand, one might argue if the FDA acted to inform the public of the risk caused by cigarettes many decades ago, back when the science on the causal relationship between smoking and lung cancer wasn’t perfect, an untold number of lives could have been saved.

If you fail to regulate because you’re waiting for better evidence, well, that leaves open the chance people will get hurt by the unregulated product or activity. But if you regulate without waiting for perfect science — or at least sufficient robust proof of causality — it’s possible you’ll be causing more harm with the regulation than by letting things be, isn’t it?

The examples of this phenomenon are many and include … ventilated filters. Let’s not forget, the very thing the study authors are now suggesting banning with “no regret(s)” — ventilation holes — were introduced as a means of improving health and saving lives.

Thus, there’s a group of highly trained scientists bemoaning the unintended consequences of an insufficiently researched and insufficiently thought-out change, which they suggest should be rectified by another change before the cause-and-effect relationships of the complicated cycle are fully understood. I suppose if we simply required cigarette manufacturers to inform consumers the ventilated filters look to be harmful, smokers could decide for themselves if that mattered enough to them to seek or demand unventilated alternatives.

But given cigarette smokers are people who continue to smoke despite reams of evidence that it’s extremely bad for their health and a great deal of social pressure to stop, it’s hard to imagine them getting picky about the details of their filters based on which type of lung cancer they might ultimately get. They’re still smoking because they can’t quit (most likely) or they really, really, really don’t care. Either way, the prospect of dying of adenocarcinoma instead of small-cell lung cancer is unlikely to be a major motivator.

And maybe that’s worth taking into account. If the goal is reducing lung cancer deaths, might not studies of smokeless alternatives (Snus, smokeless cigarettes, e-cigarettes) be a better use of research money? This is