Preventing Dementia: The Prevalence of Modifiable Risk Factors in People Attending Ireland's First Brain Health Clinic

Abstract

Cognition exists on a spectrum which ranges from normal cognition, subjective memory complaints (SMC), mild cognitive impairment (MCI) and dementia. Dementia prevalence is rising globally, driven largely by changing population demographics. This poses a significant challenge to healthcare systems worldwide. Despite the rising dementia prevalence, the incidence of dementia is falling in Europe and North America over the last 25 years. This is potentially as an indirect result of improved management cardiovascular risk factors and societal and lifestyle changes. The prodromal period of dementia syndromes which begins in mid-life presents an opportunity to address modifiable risk factors for dementia. It is now acknowledged that on a population level around 45% of all causes of dementia are attributable to modifiable risk factors. Existing memory services must evolve to facilitate brain health interventions for patients with MCI or SMC by identifying and address their individual modifiable risk factors. Aims: 1. To explore existing models for the delivery of brain health interventions and define a clinical service model for a Brain Health Clinic which is integrated into an existing memory service. 2. To quantify the prevalence of modifiable risk factors for dementia in a cohort of patients attending a Brain Health Clinic with a particular focus on cardiovascular risk factors, sensory risk factors and lifestyle factors such as physical activity, sleep and 22 psychosocial well-being. Does the risk factor profile differ between patients with SMC vs MCI? 3. To highlight the potential role of this brain health clinical service in identifying previously undiagnosed modifiable dementia risk factors in patients with MCI and SMC and the scope for intervention to reduce these risk factors on an individual level. Methodology: This thesis includes a prospective cohort study of patients attending the brain health service in Tallaght University Hospital Dublin between March 2022 and April 2024. Patients’ consensus diagnosis of either MCI or SMC was recorded along with whether they had undergone testing for Alzheimer’s Disease (AD) biomarkers. Risk factors were assessed through both biophysical assessments and self-reported questionnaires. Lifestyle risk factors physical activity levels, diet, sleep, depression, social isolation and loneliness were quantified using such as the International Physical Activity Questionnaire (IPAQ), mediterranean diet score tool, Pittsburgh Sleep Quality Index (PSQI), the Epworth sleepiness scale, the hospital anxiety and depression scale (HADS), the Lubben social network scale-6 and the University of California, Los Angeles (UCLS) three-item loneliness scale. The sensory risk factors of poor vision and hearing were screened for using the Peek Acuity smartphone app to generate a LogMAR score and the Siemens HearCheckTM Screener respectively. Cardiovascular risk factors were assessed by measuring blood pressure, random lipid profile and glycosylated haemoglobin. Risk factor profiles were explored using descriptive statistics and compared across cognitive diagnosis and AD biomarkers. Results: In this prospective cohort study there were 118 patients (61% female, median age 71.9 years). Most patients had a MCI diagnosis (79.7%) and of these patients 81.9% were amnestic. Over half of patients in the cohort (n=49, 52.1%) had a lumbar puncture (LP) to assess for AD biomarkers with AD pathology detected in 21 cases. Hypertension was the most prevalent risk factor in patients attending the service, with 46% of patients with known hypertension found to have sub-optimally controlled blood pressure, while 23.7% of patients had newly identified hypertension. Poor sleep was reported by 59.3% of patients. Almost half of patients (48.6%) had low physical activity levels. A possible hearing impairment was identified in 32.6% of patients, with over one fifth of the patient cohort referred to audiology for formal hearing assessment. While there was a similar spread of risk factor profiles across the MCI and SMC patients, patients with SMC had significantly higher rates of loneliness while MCI patients had a significantly higher rate of type two diabetes and depression. Discussion and conclusion: This work is the first to describe a brain health clinic model which has been embedded in an existing memory service with the goal of educating patients with cognitive concerns about their dementia risk, while also quantifying their modifiable risk factor burden. This model enables patients to engage in a personalised prevention plan to improve their overall dementia risk. The wide range of cardiovascular, sensory and lifestyle risk factors which were found in this clinical patient cohort highlight both the risk factor burden in patients with cognitive complaints, but also the opportunity for intervention through personalised prevention. This work outlines a framework which could be implemented in other memory clinical settings to longitudinally follow both cognition and risk factor burden in patients with cognitive concerns who do not meet the criteria for dementia.