The doctoral dissertation in the field of Oral health, cognition and dementia will be examined at the Faculty of Health Sciences at Kuopio campus. The public examination will be streamed online.
What is the topic of your doctoral research? Why is it important to study the topic?
This doctoral project studied the association between poor oral health and risk of cognitive decline and dementia. Dementia is a public health concern, and its prevalence is projected to surpass 130 million by 2050. It has been suggested that up to 45% of dementia cases could be prevented by modulation of modifiable risk factors. In this regard, poor oral health is a novel research topic.
What are the key findings or observations of your doctoral research?
This was the first project to address oral health in relation to cognition in the Finnish adult population. It separately assessed both milder cognitive decline and dementia against several oral health predictors including some previously unproved measures, e.g., posterior tooth loss, posterior occlusal pairs and chewing ability. Across both outcomes, several oral health predictors were found to be important. Tooth loss, posterior occlusal pairs loss, chewing difficulty, deepened periodontal pockets, and bleeding on probing, significantly increased risk of cognitive decline. For dementia, tooth loss, posterior tooth and occlusal pairs loss were important. Associations were independent of potential confounders, including baseline cognition and dentures, and after accounting for reverse causality bias. The effect of tooth loss and related variables was more consistent and robust, especially for dementia, and was independent of dentures, highlighting the importance of natural teeth preservation and maintenance of healthy dentition.
How can the results of your doctoral research be utilised in practice?
In practice, these results highlight the importance of oral health for healthy cognition and consolidates the findings related to the impact of oral health beyond the oral cavity. It also provides ground for more in depth research on the topic including into the underlying mechanisms and probable role of oral or dental rehabilitation in dementia prevention regimens.
Clinically, natural teeth preservation and maintenance of occlusal support and stability are important for dementia prevention. This includes maintenance of healthy periodontium, which is the primary cause of tooth loss in older adults. Oral/dental healthcare professionals are well placed to identify early and drastic changes in oral health especially among the at-risk population (older adults) and provide preventive, therapeutic and rehabilitative interventions. It has also been suggested that oral health might infer a higher risk of cognitive impairment via common risk factors, e.g., diabetes and poor nutrition, thereby maintenance of healthy oral cavity could decrease the risk of cognitive impairment by improving overall health.
What are the key research methods and materials used in your doctoral research?
This project includes a systematic review and meta-analysis, and 3 original publications based on data from Finnish Health 2000 (H2000) and Health 2011 (H2011) Surveys.
The systematic review consisted of 47 longitudinal studies which investigated the impact of periodontitis/poor periodontal health and tooth loss on cognitive decline/impairment and dementia. Both outcomes were separately analysed.
In the studies based on H2000 and H2011 Surveys, several oral health measures were assessed for their association with baseline cognitive performance, 11-year cognitive decline, and 15-year incident dementia.
At H2000, oral health was assessed clinically, radiographically, and via questionnaires. Cognitive performance at H2000 and H2011 surveys was conducted via selected cognitive tests from CERAD neuropsychological battery. Participants with baseline dementia and/or other conditions affecting cognition were excluded.
The doctoral dissertation of Sam Asher, MPH, entitled Periodontal health, tooth loss, and risk for cognitive decline and dementia will be examined at the Faculty of Health Sciences. The Opponent in the public examination will be Professor Björn Klinge of Karolinska Institutet, and the Custos will be Professor Liisa Suominen of the University of Eastern Finland. The public examination will be held in English.
For further information, please contact:
Sam Asher, MPH, samash@uef.fi, 0442489821
