Evaluation and meta-analysis of HTP testing methods in harm reduction

Abstract

This paper presents a comprehensive literature review to evaluate and synthesize heated tobacco product (HTP) testing methodologies and quantify differences in aerosol emissions versus conventional cigarettes to inform harmonized, health-relevant standards. The review systematically examines scientific publications, regulatory documents, and industrial reports published over the past decade to assess current practices in the mechanical, chemical, and toxicological evaluation of HTPs A systematic review and meta-analysis following PRISMA searched Scopus/Google Scholar through July 2025, screened studies against predefined inclusion criteria, and extracted analytes, instruments, and outcomes; 26 eligible studies were analyzed using Review Manager and JASP with random-effects modeling (REML). Based on studies, HTP aerosols showed large reductions in harmful and potentially harmful constituents relative to cigarette smoke, frequently exceeding 80–90% for key classes; the pooled effect size indicated an ≈88.18% reduction with moderate heterogeneity, and funnel-plot symmetry suggested low publication bias. HTPs consistently produce lower toxicant emissions than conventional cigarettes. However, cross-study variability in devices, puffing regimens, and collection/analytic methods limits direct comparability, underscoring the need for standardized, validated HTP-specific protocols. The findings recommend that regulators and labs could elaborated to adopt harmonized HTP puffing and aerosol-collection methods based on product used specificity to improve product emission robustness and eventual the risk assessment for consumer protection.