Supporting data for "The Mediating and Moderating Factors in the Association between Tooth Loss and Cognitive Decline"

Dementia has emerged as significant public health concerns, with Alzheimer's disease (AD) constituting the predominant subtype. AD has already impacted 24 million people and is forecasted to double every two decades until the year 2040. The management and financial burden of AD, including the support required for affected patients, pose significant challenges to individuals, families, and the healthcare system.

Teeth are an essential part of the stomatognathic system and are pivotal for an individual's overall quality of life. Loss of teeth can diminish chewing ability, potentially causing malnutrition, speech challenges, decreased self-confidence, and limited social engagement. In the past ten years, tooth loss has turn into a significant worldwide issue because of its potential link to cognitive decline. Nevertheless, the interplay between tooth loss and neurocognitive performance, along with the possible mechanism, is still not well explored.

To bridge this gap in understanding, we initially reassessed the prevailing epidemic patterns of AD and edentulism, respectively. Study results revealed that the prevalence rates of AD in China have grown by 28% from 1990 to 2021, with a projected 60% rise expected by 2040. Regarding edentulism, the diminution in the annual percentage change in prevalence, incidence, and Disability-Adjusted Life Years (DALY) rates confirmed the achievement of previous interventions from 1990 to 2021. Nevertheless, due to the aging population, a significant burden of edentulism persists, as reflected by an increasing prevalence rate which is expected to persist over the next twenty years.

Following this, we conducted a systematic review to explore the interplay between missing teeth and reduced cognitive capacity. The findings from longitudinal studies indicated that missing teeth could be a possible contributing factor for cognitive impairment. Subsequently, we examined two demographic studies obtaining data from the National Health and Nutrition Examination Survey (NHANES) to assess the impact of cholesterol levels and dietary inflammation on the interconnection between missing teeth and reduced cognitive function. Both studies confirmed strong relationship among tooth loss and cognitive capacity. The first study revealed that high-density lipoprotein cholesterol (HDL-C) levels functioned as a mediator in the relationship between impaired dentition and cognitive capacity. The second study demonstrated that changes in dietary patterns caused by tooth loss facilitate cognitive impairment, a process that can be moderated by serum albumin levels.

Building upon these discoveries, we delved deeper into the influence of tooth loss on metabolic and dietary profiles concerning cognitive performance within the Hong Kong population. The outcomes demonstrated an interplay between impaired dentition and cognitive performance, highlighting that controlling glucose levels could mitigate the impacts of tooth loss on cognitive function regardless of dietary habits. Notably, cholesterol, CRP, and albumin did not show significant involvement in shaping the connection between tooth loss and cognitive function.

This thesis represents the initial in-depth assessment of potential mediating factors in the link between tooth loss and cognitive performance. The results could serve as a basis for forthcoming research exploring the complex relationship between impaired dentition and neurodegenerative conditions.