Associations between numbers of teeth and serum cytokine levels in Japanese adults: A cross-sectional study from PROST.

Objectives: Previous studies have reported decreased number of teeth to be associated with poorer quality of life in elderly people. Cardiovascular disease, diabetes and rheumatoid disease were found to be correlated to number of lost teeth, which may represent an aspect of periodontal health. Periodontal infection elevates the concentration of serum high sensitivity C-reactive protein (hsCRP) and interleukin-6 (IL-6). Therefore, we hypothesized that serum concentrations of hsCRP and proinflammatory cytokines may be associated with number of teeth in adults.
Methods: The Project in Sado for Total Health (PROST) is an observational cohort study that is currently being conducted at Sado General Hospital, Niigata Prefecture, Japan. A cross-sectional analysis was performed with 493 participants aged 50-89 years. Dialysis patients were excluded. Serum concentrations of hsCRP, IL-1β, IL-6, and TNF-α were measured. Number of teeth were counted by two dental hygienists.
Results: Multiple linear regression analysis revealed that number of teeth was significantly associated with serum IL-1β and IL-6 levels, but not with hsCRP or TNF-α, after adjustment with age, smoking and habitual alcohol drinking. The higher concentrations of proinflammatory cytokines with decreased number of teeth might be associated with worse conditions of systemic health.
Conclusions: Numbers of teeth were associated with serum IL-1b and IL-6 levels in Japanese adults aged 50 years and older.