The physiological influence of oral health on healthy ageing: a longitudinal analysis of two epidemiological cohort studies

近年来，在英国和其他发达国家，老年人(即65岁及以上的人)的比例急剧上升。在英国，预计到2050年，每四个人中就有一个人的年龄在65岁或以上[1]。医学上的进步和预防保健方面的知识延长了寿命。然而，衰老通常与糖尿病、慢性阻塞性肺病和痴呆症等慢性病和健康状况有关，这些疾病和健康状况可能会对生活质量产生重大影响。因此，日益增长的老龄化人口具有健康和公共卫生方面的影响；促进“健康老龄化”是一项重大的公共卫生挑战。健康老龄化指的是最佳的身体和认知功能，慢性病的延迟发病，以及老年人的社会福祉[2]。口腔健康是整体健康的重要组成部分，因此，促进健康老龄化的努力也需要认识到老年人口腔健康的负担。口腔健康状况是最普遍的健康状况，其风险随着年龄的增长而显著增加，构成了健康不良的主要负担[3]。在一项基于人群的英国老年男性研究中，%的人牙齿很少(21颗)，43%的人患有活动性牙周疾病，超过三分之一的人口干[4]。由于牙槽骨的吸收和假牙口炎的并发症，用假牙替换牙齿在老年人中也是有问题的。口腔疾病也非常昂贵，2010年全球每年的直接治疗费用(牙科服务)估计为2980亿美元[6]。一些研究报告指出，口腔健康问题与老年人的一些健康结局有关，如残疾和身体功能[8]、虚弱[9]、心血管疾病[10]、死亡率(Friedman 2016)和代谢综合征[11]，以及慢性疾病的标志物，如炎症、止血和心脏生物标志物[12]。口腔健康不良还与饮食和营养有关。口腔干燥和牙齿脱落影响咀嚼能力和食物选择，导致避免咀嚼难以咀嚼的食物(水果、蔬菜、肉类)，导致饮食不佳和关键营养素缺乏[5]。然而，由于牙槽骨的吸收和假牙口炎的并发症，用假牙替换牙齿在老年人中也是有问题的。一些研究还报告或建议2型糖尿病与口腔健康不良之间存在双向关联[13-15]。尽管老年人口腔健康问题的风险和负担越来越大，但很少有研究从纵向上调查口腔健康对健康和福祉(慢性病和生活质量)的影响，因此，口腔健康影响老年人生活质量的机制尚未得到很好的证实。[8]和[9]进行了横断面分析，以确定口腔健康不良对关键健康措施的影响。他们发现，口腔健康状况不佳与虚弱、身体功能和残疾有关。有必要进行纵向分析，以帮助更好地理解这些联系和潜在途径。该项目将使用长期跟踪的大型纵向数据集来研究与年龄相关的健康状况(包括慢性病，如2型糖尿病)和口腔健康指标(特别是口干和假牙佩戴)之间的联系的生理机制。明确老年人口老龄化的潜在途径和中介途径，将有助于提高老龄人口的健康水平。

In recent years there has been a dramatic increase in the proportion of older people (i.e., people aged 65 years and above) in the UK and other advanced countries. In the UK it is projected that by the year 2050 one in four people will be 65 years or above 65 years [1]. Advancement in medicine and knowledge in preventive care has led to prolonged life. However, aging is usually associated with chronic diseases and health conditions such as diabetes, chronic obstructive pulmonary disease, and dementia which can have a substantial impact on quality of life. The increasing aging population therefore has health and public health implications; it is a critical public health challenge to promote 'healthy aging'. Healthy aging refers to optimal physical and cognitive functioning, delayed onset of chronic diseases, and social wellbeing in older age [2]. Oral health is a critical component of overall health and therefore efforts to promote healthy ageing also need to recognise the burden of oral health in older people. Oral health conditions are the most widely prevalent health conditions, and their risks increase substantially with age, constituting a major burden of ill-health [3]. In a population-based study of older British men, 64% had few teeth (<21 teeth), 43% had active periodontal (gum) disease and over a third had dry mouth [4]. Replacement of teeth with dentures is also problematic in older people due to resorption of the alveolar bone and complications of denture stomatitis [5]. Oral diseases are also very costly, with an estimated global yearly direct cost of treatment (dental services) to be US$298 billion in 2010 [6]. and £3.4 billion/year in England[7].Several studies have reported that oral health problems are associated with a number of health outcomes in older populations - such as, disability and physical function [8], frailty [9], cardiovascular diseases [10], mortality (Friedman 2016) and metabolic syndrome [11] - as well as with markers of chronic conditions, such as inflammatory, hemostactic and cardiac biomarkers [12].Poor oral health has also been linked to diet and nutrition. Dry mouth and tooth loss influence chewing ability and food selection, leading to the avoidance of foods that are difficult to chew (fruit, vegetables, meat) resulting in poor diet and deficiencies in key nutrients [5]. However, replacement of teeth with dentures is also problematic in older people due to resorption of the alveolar bone and complications of denture stomatitis [5]. Some studies also report or suggest a two-way association between type 2 diabetes and poor oral health [13-15]. Despite the increasing risks and burden of oral health problems among older people, few studies have investigated the influence of oral health on health and wellbeing (chronic conditions and quality of life) longitudinally and as such the mechanisms through which oral health influence quality of life of older populations is not well established. [8] and [9] conducted a cross sectional analysis to determine the influence of poor oral health on key health measures. They found that poor oral health was associated with frailty [9], physical function and disability [8]. There is the need for a longitudinal analysis to help better understand the associations and the underlying pathways. This project will use large longitudinal datasets with a long follow up period to examine the physiological mechanisms underpinning the association between age related health conditions (includes chronic diseases, such as type 2 diabetes mellitus) and oral health markers, particularly dry mouth and denture wearing. A clear understanding of the underlying and mediating pathways will help to improve the health of aging population.