Relationship between Frailty, Oral Health and General Health of Older People

Abstract

Dentate older people are vulnerable to oral diseases like dental caries, periodontitis and consequently, tooth loss. Dental caries, periodontitis and tooth loss not only have local effects on the dentition and tooth-supporting tissues but also may impact frailty and several chronic diseases. This thesis contributes to the current state of knowledge on the evidence on the relationship between oral health and the general health in older people and how frailty status impacts oral health and oral health behaviours. The specific aims of the thesis were to: a) review and appraise the evidence on the longitudinal associations between oral health and major chronic diseases in older people through a systematic review of the literature; b) to describe the longitudinal associations between oral health condition and the major chronic diseases in community-dwelling older people and assess the impact of poor oral health on chronic diseases in this population c) to determine what aspects of oral health are worse in frail, compared to non-frail, older men; d) determine whether frailty in older men is associated with poorer oral health and lower levels of dental service utilisation; To address the first and second aims, a systematic review of longitudinal studies on the relationship between oral health and the four leading causes of death in the older Australian population was conducted. MEDLINE, EMBASE and Scopus databases were searched for published literature up to October 2019 using predefined search strategy (age > 65 and cohort design). A total of 4839 records were identified in the initial database search but only 11 were selected for qualitative analysis. Two studies found that a lower number of teeth was associated with increased risk of dementia (hazard ratio [HR]: 1.85 (95% CI 1.04-3.31), HR: 2.20 (95% CI: 1.1-4.5)), and one study did not show any significant association among oral health status and dementia onset. Four studies found significant associations between tooth loss or lack of posterior occlusal support and an increased likelihood of developing cognitive impairment (OR: 3.31 (95% CI: 1.07–10.2), OR: 1.61 (95% CI 1.03–2.49), OR 2.39 (95% CI: 1.48–3.86), beta estimate: –5.6955 (0.9194) P < 0.0001). One study reported that swallowing difficulties and denture wearing during sleep were independently associated with an approximately 2.3-fold higher risk of incident pneumonia. Another showed that the increase in teeth with periodontal pockets was associated with increased mortality from pneumonia in older people (HR: 3.9 (95%CI 1.1-13.9). Two studies explored the associations between oral health and cancer and cardiovascular diseases mortality during a 4-year follow up period. In both studies, impaired dentition with poor masticatory ability was an independent risk factor for cardiovascular disease mortality (HR: 1.83 (95% CI: 1.12-2.98), HR: 4.60 (95% CI: 1.01–21.1)) but not cancer mortality. The systematic review concluded that, overall, in community-dwelling older adults, there is evidence of a longitudinal relationship between poor oral health and cognitive disorders, respiratory diseases and cardiovascular mortality but not with specific cardiovascular diseases or cancer. However, the findings should be interpreted with caution given the heterogeneity between studies, particularly concerning the definition of the exposure and the most relevant outcomes. To address the third and fourth aims, cross sectional data from the Concord Health and Ageing in Men Project were used. Australian men aged 70 years or older participated in the study. Data on 601 participants with both frailty status and oral health information were collected between 2015 and 2016. There were significant associations between frailty and dentition status (odds ratio [OR]: 2.49, 95% confidence interval [CI]: (1.17‐5.30), and frailty and active coronal decayed surfaces (ACDS) (OR: 3.01, CI: 1.50‐6.08) but only the frailty association with ACDS remained significant after adjusting for confounders (adjusted OR: 2.46, CI: 1.17‐5.18). There was no association between frailty and dental service utilisation and frailty and self-rated oral health. In summary, frailty was independently associated with the presence of dental caries. However, dental service utilisation and other oral health markers were not significantly associated with frailty after adjusting for confounders. From the results presented in the chapters of this thesis, important conclusions can be observed: a) there is some evidence of longitudinal relationships between poor oral health and cognitive disorders, respiratory diseases and respiratory and cardiovascular mortality but not cardiovascular disease and cancer in community-dwelling older men; b) the analysis of CHAMP data showed that frailty was independently associated with the presence of the active coronal dental caries in community-dwelling older Australian men. However, frailty was not independently associated with any other oral health conditions, dental service utilisation and self-rated oral health. In combination, the finds of the research conducted for this thesis strongly suggest that a far greater emphasis in the education of dental personnel should be placed on the principles of understanding the ageing of individuals, chronic diseases and the mechanisms underlying the development of frailty and its impact on personal and public health aspects of oral health care.