Do smokers have a different gingival crevicular fluid cytokine/chemokine profile than nonsmokers in clinically healthy periodontal sites? A systematic review and meta-analysis

Abstract

Objectives: Assessing the evidence and comparing the levels of cytokines in gingival crevicular fluid (GCF) of periodontal healthy sites of smokers and nonsmokers.

Materials and methods: Seven databases were surveyed for observational studies up to April 8, 2021. Studies comparing cytokine levels on GCF in periodontally healthy sites of smokers vs. nonsmokers were included in the study. The risk of bias was evaluated using NIH (2014) tool. For meta-analyses, levels in GCF were analyzed, followed by evidence certainty assessment using the GRADE approach.

Results: Eighteen studies were included for qualitative evaluation, and eight were included in meta-analysis. Qualitatively, despite high heterogeneity and risk of bias observed among the studies, most of them presented no significant difference in the gingival crevicular cytokine fluid levels between groups. Regarding meta-analyses, interleukin-8 (IL-8) and superoxide dismutase (SOD) levels in GCF were analyzed. The significant difference was observed only in SOD levels, where heavy smokers had lower levels compared to nonsmokers (MD - 30.06 [- 40.17, - 19.96], p = 0.07, 95%CI), as well as light smokers had lower levels compared to nonsmokers (MD - 15.22 [- 16.05, - 14.39], p < 0.00001, 95%CI).

Conclusion: No distinct GCF cytokine profiles were detected for smokers and non-smokers. However, despite the limitations observed in the included studies, lower levels of SOD were identified in smokers.

Clinical relevance: Indicating a distinct GCF profile of cytokines in periodontal healthy smokers may help to understand the mechanism whereby smoking may affect the host response.

Keywords: Biomarkers; Gingival crevicular fluid; Periodontium; Smokers.