Abstract

Aim: Some studies have shown that there is a relationship between smoking and metabolic syndrome (MetS), while other studies have not found an association. Considering the importance of this issue, the aim of this study was to review all the studies related to smoking and its relationship with MetS and to update the information. Subject and methods: PubMed, Scopus, and Web of Science were searched to identify studies on the association between smoking and MetS published from January 1, 2000, through August 13, 2023. The pooled odds ratio (OR) and relative risk (RR) and the 95 confidence intervals were used to measure the association between smoking and MetS by adopting a random-effects meta-analytic model. Quality appraisal was undertaken using the Newcastle–Ottawa Scale. Results: A total of 78 studies were included. Regarding the association between smoking and MetS, the pooled RR for current smoking among cohort studies was 1.51 95% CI: 1.15, 1.99 and the pooled OR for current smoking among cross-sectional studies was 1.12 95% CI: 1.07, 1.17. For the relationship between smoking dose and MetS, the pooled OR for subgroups with 10 or more cigarettes/day was 1.57 95% CI: 1.04, 2.38, but no association was found between subgroups with less than 10 cigarettes/day and MetS (1.17 95% CI: 0.99, 1.38). For the association between duration of smoking and MetS, the pooled OR for subgroups with 10 or more years of smoking was 1.17 95% CI: 1, 1.39, while no association was found between subgroups with less than 10 years of smoking and MetS (0.96 95% CI: 0.80, 1.16). Conclusion: Our analysis shows a statistically significant relationship for current smoking among cohort and cross-sectional studies and between smoking dose and duration of smoking and MetS, where the likelihood of MetS increases with dose and duration. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.