Socioeconomic Factors Fuel Global Inequalities in Alzheimer's Disease Burden, Study Finds

An analysis of the global burden and temporal trends of Alzheimer's disease and other dementias (ADODs) reveals significant cross-country inequalities associated with a series of sociodemographic development-related risk factors, such as education, income, fertility, and health expenditure. The new study opens in new tab/window in the American Journal of Preventive Medicine opens in new tab/window, published by Elsevier, calls for the development of targeted prevention and control strategies in different countries.

The burden of ADODs has risen globally over the past three decades. The authors of this first systematic and comprehensive global study analyzing data from 1990 to 2021, including data from the Global Burden of Disease 2021 study and the World Bank, found that there are significant disparities in numbers, rates, and age-standardized rates of disability-adjusted life years across 204 countries and territories.

Lead investigator Ya Fang, MD, PhD, School of Public Health, Xiamen University, China, says, "ADODs currently pose a major global public health challenge. They stand as a leading cause of functional loss and dependence among older individuals worldwide. Yet, to date, there are no definitive treatments capable of fully resolving ADODs. Furthermore, research exploring the relationship between sociodemographic development-related factors and health inequalities associated with ADODs is currently limited. Therefore, we aimed to establish this connection by assessing the impact of sociodemographic development indicators such as education, income, fertility, and health expenditure on ADODs health metrics."

The study found that approximately two-thirds of individuals with ADODs worldwide now live in low- and low-middle income countries, and as populations grow, the number of cases with ADODs in these countries is expected to rise faster than in high-income countries. Therefore, the disease burden of ADODs is believed to be greater in low- and middle-income countries, where individuals are more likely to face poverty and limited access to healthcare. However, even in countries with high sociodemographic development levels, such as Luxembourg, Switzerland, and the United States, despite having relatively comprehensive healthcare systems, the disease burden of ADODs remains high because of the specific distribution of ADOD risk factors in these countries, such as obesity, poor diet, and diabetes.

Another noteworthy finding is that females exhibited a notably higher burden of ADODs than males across all age groups, corroborating previous research that identifies female sex as a risk factor for accelerated cognitive decline. Gender differences in disease may be influenced by reproductive capacity, sex hormones, genetic predisposition, and epigenetics. Females are especially sensitive to hormonal fluctuations, particularly during premenstrual, perinatal, and menopausal periods. Estradiol and progesterone fluctuations during pregnancy impact maternal brain structure and function, such that the reproductive history of women may affect brain aging and disease risk.

Dr. Fang concludes, "This study integrated the Global Burden of Disease 2021 and World Bank data, and to the authors' knowledge is the first systematic and comprehensive study on cross-country inequality associated with a series of sociodemographic development-related factors. Other significant strengths of this study are its long observation period, wide geographical range, and extensive data coverage. Based on the results, it is necessary to further control risk factors of ADODs by promoting a healthy diet and regular exercise for preventing the development of ADODs in developed countries. However, enhancing basic healthcare, improving medical resource access and affordability, and raising ADOD awareness among the public in developing countries are also vital."

Notes for editors

The article is “Disease Burden, Temporal Trends, and Cross-Country Inequality Associated with Sociodemographic Indicators in Alzheimer's Disease and Other Dementias,” by Manqiong Yuan, MS, Lifen Jin, MS, and Ya Fang, PhD (https://doi.org/10.1016/j.amepre.2024.12.011 opens in new tab/window). It appears online ahead of the American Journal of Preventive Medicine, volume 68, issue 4 (April 2025), published by Elsevier.

The article is openly available for 30 days at https://www.ajpmonline.org/article/S0749-3797(24)00445-8/fulltext opens in new tab/window.

Full text of this article is also available to credentialed journalists upon request; contact Astrid Engelen at +31 6 14395474 or [email protected] opens in new tab/window. Journalists wishing to interview the authors should contact Ya Fang, PhD, at [email protected] opens in new tab/window.

This work was supported by the National Key Research and Development Program of China (grant number: 2022YFC3603000), Natural Science Foundation of Xiamen, China (grant number: 3502Z20227014) and National Natural Science Foundation of China (grant number: 82073669).

About the American Journal of Preventive Medicine

The American Journal of Preventive Medicine opens in new tab/window is the official journal of the American College of Preventive Medicine opens in new tab/window and the Association for Prevention Teaching and Research opens in new tab/window. It publishes articles in the areas of prevention research, teaching, practice and policy. Original research is published on interventions aimed at the prevention of chronic and acute disease and the promotion of individual and community health. The journal features papers that address the primary and secondary prevention of important clinical, behavioral and public health issues such as injury and violence, infectious disease, women's health, smoking, sedentary behaviors and physical activity, nutrition, diabetes, obesity, and alcohol and drug abuse. Papers also address educational initiatives aimed at improving the ability of health professionals to provide effective clinical prevention and public health services. The journal also publishes official policy statements from the two co-sponsoring organizations, health services research pertinent to prevention and public health, review articles, media reviews, and editorials. www.ajpmonline.org opens in new tab/window

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