Global Dementia Rates Hit Women Harder Across Eighteen Countries
Women developed dementia at higher age-standardized rates than men across diverse populations, a meta-analysis published on October 12 in JAMA Neurology showed. Researchers examined harmonized individual-level data from 22 population-based longitudinal cohorts spanning 18 countries and six continents.
The study tracked 38,418 adults aged 60 to 102 who did not have dementia at baseline. Recruitment began between 1990 and 2011, with follow-up assessments concluding through 2021 across a median of four waves. Over the course of the study, 3001 participants developed all-cause dementia.
Income Disparities Shape Regional Incidence Figures
Age- and sex-standardized incidence rates of all-cause dementia were higher in low- and middle-income countries than in high-income countries. The rate reached 13.6 per 1000 person-years in low- and middle-income regions compared with 8.3 in high-income areas. When broken down by sex within those income brackets, the incidence was 15.3 versus 9.3 among women and 12.6 versus 7.5 among men.
Globally, the age- and sex-standardized incidence of all-cause dementia stood at 9.7 per 1000 person-years. This figure equated to approximately 11.4 million new dementia cases worldwide in 2023. Regional variations showed the highest rates in Latin America at 13.1 and Asia at 13, while Oceania recorded the lowest at 7.6, though those regional differences were not statistically significant.
Projections Point to Double the Cases by 2050
Assuming that age- and sex-specific incidence rates remain stable, researchers applied the data to projected population figures for the year 2050. That calculation yielded an incidence rate of 11.7 per 1000 person-years, corresponding to 24.7 million new cases globally. The projected 2050 rate breaks down to 12.8 among women and 10.5 among men.
Study authors noted that these projections rely on the assumption that age-sex-specific incidence and country-income classifications will remain constant over time. Additional methodological limitations included varying diagnostic criteria, assessment methods, and large heterogeneity in pooled estimates. The analysis also carried potential interval-censoring bias and underrepresentation of institutionalized older adults, people with lower socioeconomic status, and specific ethnic or rural groups.
Targeted Prevention Strategies Required for Underserved Settings
Ashleigh S. Vella, PhD, from the Centre for Healthy Brain Ageing at the Discipline of Psychiatry and Mental Health within the School of Clinical Medicine at the University of New South Wales in Sydney, Australia, led the research. The National Institute on Aging provided funding for the study.
The observed sex- and income-stratified differences, together with substantial cross-country variation, highlight the need for targeted equitable prevention strategies and expanded diagnostic and care capacity, particularly for women and in underresourced settings,
the authors wrote.
Frequently Asked Questions About Global Dementia Projections
Which regions recorded the highest and lowest dementia incidence rates?
Latin America recorded the highest age-standardized incidence at 13.1 per 1000 person-years, followed closely by Asia at 13. Oceania recorded the lowest rate at 7.6, though researchers noted those regional differences were not statistically significant.
How many participants and cohorts were included in the research?
The meta-analysis evaluated 38,418 adults without dementia at baseline, drawn from 22 population-based longitudinal cohorts across 18 countries or territories spanning six continents.
What total number of new dementia cases is projected for 2050?
Researchers calculated that if incidence rates remain stable, the 2050 global population will experience 24.7 million new dementia cases, translating to an incidence rate of 11.7 per 1000 person-years.
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