Association between periodontitis and depression severity – A cross-sectional study of the older population in Hamburg

The aim of the current study is to investigate the association between periodontitis (exposure variable) and depression severity (outcome variable) in an older German population. We evaluated data from 6,209 participants (median age 62 years) of the Hamburg City Health Study (HCHS). The HCHS is a prospective cohort study and is registered at ClinicalTrial.gov (NCT03934957). Depression severity were assessed with the 9-item Patient Health Questionnaire (PHQ-9). Periodontal examination included probing depth, gingival recession, plaque index, and bleeding on probing. Descriptive analyses were stratified by periodontitis severity. Multiple linear regression models were adjusted for age, sex, diabetes, education, smoking, and antidepressant medication. Linear regression analyses revealed a significant association between log-transformed depression severity and periodontitis when including the interaction term for periodontitis * age, even after adjusting for age, sex, diabetes, education, smoking and antidepressant medication. We identified a significant association between severe periodontitis and elevated depression severity, which interacts with age. Additionally, we performed a linear regression model for biomarker analyses, which revealed significant associations between depression severity and severe periodontitis with log-transformed inflammatory biomarkers interleukin 6 (IL-6) and high-sensitivity C-reactive protein (hsCRP). In order to identify new therapeutic strategies for patients with depression and periodontal disease, future prospective studies are needed to assess the physiological and psychosocial mechanisms behind this relationship and the causal directionality.