Sunday, May 30, 2021

Things that “Everyone Knows”


Among the things that “everyone knows” because it is just so damned obvious is that smoking impairs your sense of smell. Yet when one tabulates the studies looking at tobacco use and odor perception, the conventional wisdom crumbles more easily than the ash on a Macanudo. 

I wrote about this in What the Nose Knows, and studies since then have confirmed my skepticism: some find a link, others don’t.

A newly published “scoping review” collated the results of over 700 studies, seeking statistical associations between “social determinants of health” and olfactory function. They found some significant links (e.g., exposure to environmental and occupational toxins), but “the associations between olfactory dysfunction and education level and lifestyle factors such as smoking and drinking seem to be much more elusive.” (Translation: “we know those factors matter, we just couldn’t find convincing evidence.”)

How much more elusive was smoking as a factor? This elusive:

Of the 28 studies that examined smoking, 12 demonstrated significant positive correlation between smoking status and [olfactory dysfunction].

In other words, the majority of studies (16/28) found no link. The conventional wisdom is still batting less than .500.

The study discussed here is “Association between social determinants of health and olfactory function: a scoping review,” by Joel James, Avraham M. Tsvik, Sei Y. Chung, John Usseglio, David A. Gudis, Jonathan B. Overdevest, published in International Forum of Allergy and Rhinology published online May 28, 2021.

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