HEALTHY LIFESTYLES FOR HEALTHY GUMS Towards the implementation of lifestyle modifications to improve oral and general health

Unhealthy lifestyles are at the root of the global burden of non-communicable diseases, which account for approximately 41 million deaths (71%) globally each year. Unhealthy lifestyle behaviours, such as poor nutrition, physical inactivity, alcohol/tobacco use, poor sleep quality, and high psychological stress, constitute the multiple determinants of “health” together with genetics, environment, and access to medical care. Over the past several years, there has been an increased interest in evaluating the benefit of adhering to healthier lifestyle behaviours in the development of morbidity and mortality. From a biological standpoint, the detrimental impact of unhealthy lifestyles on systemic health may be mainly ascribed to the induction of a state of low-grade systemic inflammation and to the overproduction of reactive oxygen species, leading to oxidative stress. Evidence is still scarce about the independent and the combined effects of lifestyles on periodontitis onset, severity, and treatment outcomes. Therefore, the aim of the present PhD project was to investigate the association between lifestyles, both independently and combined, and periodontal diseases using cross-sectional and longitudinal study designs. The thesis includes results from different research studies. Chapters 1 and 3 are based on observational evidence collected from a University-based sample regarding the association between adherence to Mediterranean diet, physical activity level, perceived stress, and sleep quality. Chapter 2 analysed the divergent association between leisure-time and occupational physical activity with periodontitis using a nationally representative sample of the US population. Chapter 4 analysed the dose-response relationship between the number of healthy lifestyles and periodontitis in two large-scale epidemiological studies from the US and the UK. Finally, Chapter 5 shows experimental data deriving from a case-series of participants from the same population with periodontitis and analysis of pre-post non-surgical periodontal therapy.