Physiologic Recovery After Smoking Cessation: A Systematic Review of Inflammatory and Cardiovascular Biomarker Changes.

Cigarette smoking remains a major modifiable contributor to cardiovascular morbidity and mortality through mechanisms involving systemic inflammation, oxidative stress, endothelial dysfunction, dyslipidemia, and hematologic abnormalities. Although the long-term cardiovascular benefits of smoking cessation are well-established, the temporal pattern of biologic recovery following cessation remains incompletely understood. This systematic review synthesized current evidence regarding the reversal of cardiovascular risk biomarkers after smoking cessation, with emphasis on the timing and magnitude of biomarker normalization. A comprehensive search of PubMed, Embase, Scopus, and Cochrane CENTRAL identified studies published between January 1990 and May 2024 evaluating biomarker changes following smoking abstinence. Eligible studies included randomized controlled trials, prospective clinical studies, and observational investigations involving adults who achieved smoking abstinence for at least seven days. Risk of bias was assessed using the Cochrane Risk of Bias 2 (RoB 2) tool and the Risk of Bias in Nonrandomized Studies-of Interventions (ROBINS-I) instrument, and findings were synthesized narratively because of methodological heterogeneity. Ten studies comprising 2,750 participants met the inclusion criteria. Biomarker recovery followed a staged temporal pattern, with oxidative stress markers improving within one to two weeks, inflammatory biomarkers declining over approximately two to 12 weeks, and lipid and hematologic parameters improving more gradually over three to eight months. However, substantial heterogeneity in study design, cessation interventions, biomarker selection, and follow-up duration limited direct cross-study comparability. Adjunctive interventions, including antioxidant supplementation and exercise, appeared to enhance biomarker recovery in selected populations. Overall, smoking cessation was associated with progressive improvement in multiple cardiovascular risk pathways, supporting its critical role in cardiovascular prevention and highlighting the potential value of biomarker-guided approaches in future risk-reduction strategies.