Sexual dimorphism in periodontal inflammation: A cross-sectional study

Background: The purpose of the present study was to evaluate the role of sexual dimorphism (SD) in the clinical manifestation of plaque-induced periodontal inflammation by analyzing the association between patient-related factors and the full-mouth prevalence of bleeding on probing (BOP%) within 2 cohorts of male and female individuals. Methods: Data on BOP (dichotomously recorded as present/absent after the assessment of probing depth [PD]) were retrospectively obtained from the files of adult patients undergoing a first periodontal visit at a University center. Two multiple regression models (1 for males, 1 for females) were built with BOP% as the dependent variable and patient-related factors (i.e., age; smoking status; daily cigarette consumption; history of diabetes diagnosis; number of teeth present; proportion of sites with PD ≥ 5 mm around teeth) as independent variables. Results: In males (n = 212), BOP% was 5.9% lower in smokers compared to non-smokers (p = 0.021). In females (n = 389), BOP% increased by 1.6% for each 10-year increase in age (p = 0.046). The proportion of sites with PD ≥ 5 mm showed a strongly significant, positive association with BOP% irrespective of biological sex (p < 0.001). Conclusion: SD manifested as a sex-dependent diversity in the association between patient-related factors and periodontal inflammation expressed as BOP%. While smoking determined a lower BOP% only in males, aging was associated with increased BOP% only in females. Plain Language Summary: Gingival bleeding upon mechanical stimulation of the bottom of the gingival sulcus/pocket with a periodontal probe (bleeding on probing [BOP]) is suggestive of the presence of an inflammatory infiltrate induced by dental plaque within the gingival tissue. The prevalence of BOP within the dentition (BOP%) has a diagnostic relevance, being one of the main parameters to discriminate between periodontal health and disease. Also, BOP% informs the probability for a patient to either develop destructive form of periodontal disease (i.e., periodontitis) or manifest periodontitis progression. Based on the documented influence of biological sex on the incidence, traits, and/or progression rate of several diseases, which goes under the name of sexual dimorphism (SD), the effect of SD was investigated in relation to the factors that were previously associated with BOP% in a cohort of patients with heterogeneous periodontal conditions undergoing their first periodontal visit. Interestingly, SD manifested as a sex-dependent diversity in the association between patient-related factors and periodontal inflammation expressed by BOP%. While smoking determined a lower BOP% only in males, aging was associated with increased BOP% only in females. The present findings may find potential applications in personalized periodontal medicine and inspire future studies in this field.