A Systematic Review and Meta-Analysis on Human Biomarkers of Exposure from Heated Tobacco Products Compared to Conventional Cigarettes among Adult Smokers

Abstract

Introduction: The health effects of Heated Tobacco Products (HTP), which are noncombustible alternatives to Conventional Cigarettes (CC), may be assessed by the measurement of Biomarkers of Exposure (BoE). Methods: This meta-analysis aims to compare the BoE levels between HTP and CC. Systematic computerized search was performed using Pubmed, Google Scholar, and Cochrane database. The studies included randomized controlled trials that evaluated the effectiveness of HTP compared to CC in reducing human BoE. Two reviewers independently appraised each study. Any disparity in assessment was settled by an independent adjudicator. Results: Data from the trials included in this study (N=1,193) showed that there was a significant difference in the levels of BoEs between HTP and CC. The levels of carboxyhemoglobin [-2.0 (95% CI -3.08 to -0.92), Z=3.64, p=0.00001], 4-aminobiphenyl [- 1.67 (95% CI -2.36 to -0.99), Z=4.80, p=0.00001], 3-hydroxypropylmercaptapuric acid [-1.09 (95% CI -1.54 to -0.63), Z=4.70, p= 0.00001], N-nitrosonornicotine [-0.95 (95% CI -1.49 to - 0.41), Z=3.46, p=0.0005], 4-(methylnitrosamino)-1-(3-pyridyl)- 1-butanol [-1.30 (95% CI - 1.72 to -0.89), Z=6.18, p=0.00001], Total Nicotine Equivalents [-0.85 (95% CI -1.36 to -0.34), Z=3.24,p=0.001], Benzo[a]pyrene [-1.70 (95% CI -2.08 to -1.33), Z=8.92, p=0.00001], and Sphenylmercapturic acid [-1.18 (95% CI -1.36 to -0.99), Z=12.36, p= 0.0001] among the participants were significantly reduced in those who used HTP as compared to those who smoked CC. Conclusion: The study showed that the use of HTP could significantly reduce exposure to harmful substances compared to CC using BoEs that are assessed to be most suitable and practical for tobacco product regulation.