Prevalence and Incidence

Alzheimer Disease

Prevalence 

According to the Alzheimer’s Association (2023), approximately 6.7 million Americans aged 65 and older are living with Alzheimer’s, with women making up nearly two-thirds of the affected population. The prevalence of Alzheimer disease increases dramatically with age.

• Ages 65-74: Approximately 3% of individuals in this age group have Alzheimer disease. 

• Ages 75-84: The prevalence increases to about 17% of people in this age group. 

• Ages 85+: Around 32% of individuals aged 85 and older are living with Alzheimer’s disease. 

Gender Differences

Women are more likely to develop Alzheimer disease than men. This is partly due to women’s longer life expectancy, but there may also be biological or hormonal factors that contribute to the higher prevalence in women. 

Geographic Variability 

Prevalence varies by region due to differences in population demographics, healthcare systems, and diagnostic practices. Higher prevalence rates are often seen in high-income countries with aging populations. 

Global Prevalence 

Alzheimer’s disease is the most common cause of dementia worldwide. According to the World Health Organization (WHO), it is estimated that over 55 million people globally live with dementia, with Alzheimer disease accounting for about 60-70% of all cases. As the global population ages, the number of individuals affected by AD is expected to rise significantly.

Incidence

Similar to prevalence, the incidence of Alzheimer disease rises significantly with age. 

• Ages 65-74: The incidence of Alzheimer disease is relatively low in this age group but still significant. 

• Ages 75-84: The incidence increases, with around 7 to 8 new cases per 1,000 individuals per year in this age group. 

• Ages 85+: The incidence is highest in this group, with about 15-20 new cases per 1,000 individuals per year. 

Gender Differences

Women also have a higher incidence of Alzheimer compared to men, primarily due to their longer life expectancy. Women aged 85 and older are significantly more likely to develop Alzheimer disease than men of the same age. 

Ethnic and Racial Variability 

In the United States, studies have shown that African Americans and Hispanics are at higher risk for developing Alzheimer disease compared to non-Hispanic whites, with incidence rates higher in these populations. Genetic and environmental factors likely contribute to these disparities. 

Global Incidence 

The global incidence of Alzheimer disease is increasing as the population ages. An estimated 10 million new cases of dementia are diagnosed worldwide each year, with Alzheimer contributing to a significant portion of those cases.  

Conclusion

Prevalence of Alzheimer disease rises sharply with age, particularly affecting individuals over 65. Women are more likely to develop Alzheimer, and prevalence rates are expected to increase globally as the population ages. 

Incidence rates also rise with age, with the highest new case rates seen in those over 85. The incidence of Alzheimer is higher among women, and certain ethnic groups, such as African Americans and Hispanics, face a higher risk compared to non-Hispanic whites.