AIM: To ascertain whether healthy lifestyles are associated with periodontal diseases in two large-scale surveys in the US (National Health and Nutrition Examination Survey - NHANES) and the UK Biobank. METHODS: 9854 US adults and 111 679 UK adults were included in the analyses. A healthy lifestyle score (HLS), ranging between 0 and 5, was calculated based on the reported number of healthy behaviours, including never smoking, no heavy alcohol consumption, top third of leisure-time physical activity, higher dietary quality, and ideal sleep duration. The prevalence of periodontal diseases was the primary outcome in both surveys. In the NHANES, periodontal status was assessed through a full-mouth periodontal examination, while in the UKB, only self-reported periodontal status was available. RESULTS: Multiple regression analyses confirmed that the presence of at least 2-3 healthy behaviours (vs. 0-1) was associated with lower odds of overall and severe periodontitis (ORs 0.5, 0.4-0.6
p <
.002 and 0.5, 0.3-0.8
p = .003, respectively) in the NHANES, and of bleeding gums (OR = 0.9, 0.8-1.0
p = .092) and loose teeth (OR = 0.6, 0.5-0.7
p <
.002) in UKB. This association increased when considering prevalence of 4-5 healthy behaviours (vs. 0-1) in both the NHANES (periodontitis: OR = 0.3, 0.2-0.4
p <
.002
severe periodontitis: OR = 0.1, 0.01-0.2
p <
.002) and the UKB (bleeding gums: OR = 0.8, 0.7-0.9
p <
.002
loose teeth: OR = 0.5, 0.4-0.6
p <
.002). Mediation analyses revealed how these protective associations could be partially mediated (1-14%) by differences in biomarkers of systemic inflammation (white blood cells and neutrophils count as well as C-reactive protein). CONCLUSIONS: Adoption of healthy lifestyle behaviours is associated with a lower prevalence of periodontal diseases within two large population-based samples. This relationship exhibits a dose-response pattern, implying that greater adherence to healthy habits leads to a more significant protective effect against the odds of periodontal diseases. Additionally, our findings suggest that this protective effect is, in part, mediated by reductions in systemic inflammation.