Oral inflammation predicts respiratory disease 10 years later in a Nordic population based study

<bold>Background:</bold> Bleeding gums can be an indication of ongoing inflammation in the oral cavity and may develop into periodontitis if left untreated. The oral inflammatory bacteria may also reach the lungs and affect respiratory health. <bold>Aim:</bold> We aimed to explore whether self-reported gum-bleeding was associated with respiratory disease 10 years later. <bold>Methods:</bold> Data from the Respiratory Health In Northern Europe (RHINE) study with self-reported gum bleeding from 2010-12 (RHINE III) and periodontitis status and respiratory outcomes reported 10 years later (RHINE IV) were available for 8140 participants (median age 62 years). Associations were explored with logistic regression, adjusted for sex, age, smoking and study centre. <bold>Results:</bold> Reporting always or often gum bleeding during toothbrushing in RHINE III increased the odds of reporting chronic bronchitis (cumulative incidence 6%): aOR=2.06 (95% CI: 1.35, 3.13), active asthma (12%): 1.44 (1.05, 1.97), ≥3 asthma symptoms (16%): 2.01 (1.50, 2.68), and COPD (cumulative incidence 2.4%): 2.10 (1.13, 3.88) 10 years later. Among those reporting often/always (n=322) or sometimes (n=1601) gum bleeding in RHINE III, 44% and 31%, respectively, reported periodontitis in RHINE IV. <bold>Conclusion:</bold> High gum bleeding frequency was an important predictor for periodontitis 10 years later. Furthermore, gum bleeding had unexpectedly strong associations with respiratory diseases, and was associated with a higher odds of reporting asthma, COPD, asthma symptoms, and chronic bronchitis. Poor oral hygiene is an easily modifiable risk factor and therefore crucial for public health. Our results support a major preventive potential for improved dental care.