The purpose of the study was to establish population level estimates for biomarkers of cigarette smoke exposure to serve as a baseline against potential changes in exposure upon switching to a potentially modified risk tobacco product.

A meta-analysis of data published 2008-2018 was conducted to estimate population levels for blood Carboxyhemoglobin (COHb), a biomarker for CO, and urinary Nicotine Equivalents (NEQs), a biomarker of nicotine exposure.  The population level estimate for smokers was established for the two biomarkers. This estimate was compared to that from two other groups, non-smokers and former smokers, to determine whether a statistical difference existed in comparison to these groups.

The population level estimate for smokers was found to be significantly different from non-smokers and former smokers. The smoker population was clearly identified from the non-smokers and former smokers for both COHb and NEQs. Population level estimates for non-smokers were not significantly different from former smokers (cessation group).