Do menthol smokers inhale more nicotine and toxins?
The pattern of results we have observed suggest that it may not be a simple effect of menthol causing smokers to inhale more smoke. Rather, we have proposed that in circumstances requiring the smoker to reduce their cigarette consumption (e.g. when price increases affect affordability in a low-income smokers) menthol enables the smoker to increase the amount of smoke and nicotine they inhale per cigarette, by reducing the harshness.
Now clearly manufacturers of menthol cigarettes have an interest in this issue. In particular, the Lorrilard Tobacco Company, who depend on sales of Newport cigarettes for most of their profits, have an interest. So I was interested to read a paper by Dr Daniel Heck of Lorrilard Tobacco Company, on biomarkers of smoke exposure on menthol and nonmenthol smokers.
The study recruited 54 monthol smokers and 58 non-menthol smokers, provided them with preference-matched standard menthol or nonmenthol for a 1-week study period and menthol smokers were also given free menthol cigarettes for 2 weeks prior to the study period to allow them to acclimatize to the study menthol cigarettes.
For one day at the start of the one week study period and another day at the end, participants were allowed to smoke normally but blood and urine was taken in order to measure a variety of indicators of smoke exposure. The main result was that there were no consistent differences in markers of smoke exposure between menthol and nonmenthol smokers.
I am not writing to dispute the findings or even the measures used in the study (although Id have preferred if blood nicotine concentration had been measured). Rather I want to point out some characteristics of the study population and study procedures that make it unsurprising that they didn’t find any differences.
First of all, the study sample smoked an average of 27 cigarettes per day (both menthol and nonmenthol smokers). This a very high cigarette consumption, and extremely unusual for current African American menthol cigarette smokers. Just for comparison, among smokers attending our clinic (who are heavier than average smokers), AA menthol smokers smoked under 16 cigarettes per day.
Secondly, providing the sample of menthol smokers with free access to the study menthol cigarettes for 3 weeks, including the study week, detracts from the financial reality facing many smokers just now, and could have altered the way they smoked the cigarettes.
It is a pity this study did not recruit a more representative sample of US smokers and allow them to smoke their own, paid-for cigarettes.
Heck JD. Smokers of menthol and nonmenthol cigarettes exhibit similar levels of biomarkers of smoke exposure. Cancer Epidemiol Biomarkers Prev. 2009 Feb;18(2):622-9.