In 2015, with 47 million people suffering from Alzheimer’s disease (AD) and dementia, the World Health Organization and Alzheimer’s Disease International recognized AD as a global health priority (1). The prevalence of AD and dementia patients is projected to increase to 131 million in the next three decades (1). Currently, 5.8 million Americans are living with AD and dementia, and this is likely to increase to 13.8 million by 2050 (2). The incidence of AD poses a significant economic burden, including both healthcare and non-healthcare costs. Last year, 305 billion dollars were spent on healthcare and hospice service for dementia patients; an estimated 18.6 billion hours of care were provided to dementia patients by 16 million family members and unpaid care providers (2). Given the enormous financial burden of AD, the outcomes can be worse for people in low and middle income classes. In addition to socioeconomic disadvantage, people with less education have also shown to be at a higher risk for Alzheimer’s development and dementia. Age, genetics and family history are the major risk factors for AD. Although none of these factors can be controlled, there are several other risk factors, including formal education and socioeconomic class, which can be modified to reduce these consequential risk factors. (2).
The relationship between formal education and risk of dementia was first developed in the late 1980s. Research suggests that education, that is time spent in school, increases the “intellectual/cognitive reserve” and decreases the risk of AD and dementia development (3). This cognitive reserve, also known as the brain’s resistance to damage, is the brain’s capability to efficiently use neuronal connection and enable individuals to perform cognitive tasks normally despite brain damage. A study done in China in early 1990 also indicated an inverse correlation between formal education and prevalence of dementia (4). Psychiatric interviews, neurological examinations, psychometric tests, and standardized mental status tests were used for clinical diagnosis of dementia (4). In addition to education, mentally stimulating activities/jobs can also raise cognitive reserve. In a second study, individuals with the APOE-e4 gene, a genetic variant of apolipoprotein E (APOE) gene on chromosome 19 that increases AD risk (5), had less prevalence of dementia if they had more cognitive reserve indicators (6). Dementia was diagnosed using the Diagnostic and Statistical Manual of Mental Disorders and cognitive reserve indicator was generated based on early life education, midlife substantive work complexity, late life leisure activities, and late life social networks (6).
Lower socioeconomic status often reduces the chances of higher educational attainment. Therefore, higher socioeconomic status with higher education may act in synergy and shield against progression of AD development (2). A five year study conducted on 1754 patients with AD concluded that individuals with lower socioeconomic status and disadvantaged neighborhoods had worse 5- year survival rates. Further, patients with higher socioeconomic status in disadvantaged neighborhoods had similar 5- year survival rates as compared to patients with higher socioeconomic status in advantaged neighborhoods. The confounding variables including sex, age, and comorbidities were adjusted before analysis (1). Many individuals from lower socioeconomic class experience poor nutrition, are more likely to smoke, and are more prone to cardiovascular diseases including diabetes, which itself is a massive risk factor for AD development. Besides, lower occupation class increases the likelihood of being exposed to neurotoxic substances, for instance air pollutants and pesticides. Moreover, people from poor economic backgrounds are less likely to afford/receive health care or medical treatments (2).
The above evidence suggests that lower income class and fewer education years can increase the risk of AD and dementia. Therefore, while devising the long term care plan it is important to consider socioeconomic status. Furthermore, it is necessary to develop cheaper AD diagnosis and treatments to improve the quality of life and survival among every strata.
Esurgi is developing a user-friendly AD adjunct diagnostic tool with real-time home accessibility. Previous studies have shown that abnormalities in eye movements (e.g., gaze fixation, saccadic motions) are characteristic of cognitive decline and can be utilized for AD detection (7,8,9). Eye AD is an inexpensive tool that will predict the risk of AD development based on a patient’s saccadic eye movements and can help reduce the healthcare burden.
1. Chen CL, Liang CK, Yin CH, Lin YT, Lee CC, Chen NC. Effects of Socioeconomic Status on Alzheimer Disease Mortality in Taiwan. Am J Geriatr Psychiatry. 02 2020;28(2):205-216. doi:10.1016/j.jagp.2019.06.010
2. 2020 Alzheimer’s disease facts and figures. Alzheimers Dement. Mar 2020;doi:10.1002/alz.12068
3. Sharp ES, Gatz M. Relationship between education and dementia: an updated systematic review. Alzheimer Dis Assoc Disord. 2011 Oct-Dec 2011;25(4):289-304. doi:10.1097/WAD.0b013e318211c83c
4. Zhang MY, Katzman R, Salmon D, et al. The prevalence of dementia and Alzheimer’s disease in Shanghai, China: impact of age, gender, and education. Ann Neurol. Apr 1990;27(4):428-37. doi:10.1002/ana.410270412
5. Alzheimer’s Disease Genetics Fact Sheet. Accessed February 20, 2021. https://www.nia.nih.gov/health/alzheimers-disease-genetics-fact-sheet
6. Dekhtyar S, Marseglia A, Xu W, Darin-Mattsson A, Wang HX, Fratiglioni L. Genetic risk of dementia mitigated by cognitive reserve: A cohort study. Ann Neurol. 07 2019;86(1):68-78. doi:10.1002/ana.25501
7. Beltrán J, García-Vázquez MS, Benois-Pineau J, Gutierrez-Robledo LM, Dartigues JF. Computational Techniques for Eye Movements Analysis towards Supporting Early Diagnosis of Alzheimer’s Disease: A Review. Comput Math Methods Med. 2018;2018:2676409. doi:10.1155/2018/2676409
8. Fernández G, Manes F, Politi LE, et al. Patients with Mild Alzheimer’s Disease Fail When Using Their Working Memory: Evidence from the Eye Tracking Technique. J Alzheimers Dis. 2016;50(3):827-38. doi:10.3233/JAD-150265
9. Boucart M, Bubbico G, Szaffarczyk S, Pasquier F. Animal spotting in Alzheimer’s disease: an eye tracking study of object categorization. J Alzheimers Dis. 2014;39(1):181-9. doi:10.3233/JAD-131331