Analytic dataset and Stata code for biomarker-specific meta-analysis of exposure after switching from cigarettes to e-cigarettes

This repository contains the clean analytic dataset and Stata code used for the biomarker-specific random-effects meta-analysis of changes in human biomarkers of exposure after complete switching from combustible cigarettes to e-cigarettes, or exclusive e-cigarette use after cigarette smoking. The dataset includes 47 biomarker-specific effect estimates across ten biomarkers from seven study-level sources. Biomarkers include tobacco-specific nitrosamines, volatile organic compound metabolites, carbon monoxide markers and the polycyclic aromatic hydrocarbon marker 1-hydroxypyrene. Effect estimates are expressed as ratios of means, with corresponding log ratios of means, standard errors, derivation notes and study-level identifiers. The repository includes a clean public analytic dataset, data dictionary, README file and Stata do-file that reproduces the biomarker-specific pooled estimates, heterogeneity statistics, sensitivity analysis excluding approximate or reconstructed estimates, and forest plots. Raw Stata log/output files are not included because all results can be regenerated by running the supplied code. This repository contains the analytic dataset for the quantitative meta-analysis only. It is not the full extraction database for all studies included in the broader systematic review.