Scandinavian and North American Moist Snuff and Periodontitis: A Systematic Review and Meta-Analysis.

AIM To answer the focused PECOS question: in humans (P), what is the effect of Scandinavian or North American moist snuff (MS) (E), in comparison to non-use (C), in terms of periodontitis (O) as demonstrated in clinical studies (S)? METHODS Electronic databases (MEDLINE, EMBASE and Cochrane) and grey literature were searched for relevant studies reporting clinical and/or patient-reported periodontal outcomes. Qualitative and quantitative syntheses (random-effects meta-analysis with pooled odds ratios [ORs] or effect sizes [ESs] and 95% confidence intervals [CIs]) were performed to determine the associations between MS use and primary (periodontitis) or secondary outcomes (gingival recession, gingivitis). Risk of bias (Newcastle-Ottawa scale) and certainty of evidence (GRADE) were assessed. RESULTS Twenty-two mostly cross-sectional studies from Sweden (n = 11), the United States (n = 10) and Norway (n = 1) were included. MS use was most frequently associated with buccal recession. Qualitatively, an association between MS use and periodontitis (n = 16) was judged to be unlikely. Based on studies with high clinical heterogeneity, no significant associations were found between MS use and periodontitis (n = 2 [12,775 participants], OR = 1.49 [CI: 0.71-3.16]), recessions (n = 9 [3719 participants], ES = -0.04 [CI: -0.98 to 0.90]) or gingivitis (n = 3 [1429 participants], ES = 0.09 [CI: -0.36 to 0.55]). The certainty of evidence was judged to be very low. CONCLUSION The current evidence, mostly based on cross-sectional studies and very low certainty, suggests that Scandinavian or North American MS use is not associated with periodontitis. PROSPERO CRD42023417652.