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What Percentage Does Dementia Affect?: Statistics, Risk Factors, and Global Impact

4 min read

According to the World Health Organization (WHO), over 55 million people worldwide were living with dementia in 2021. This article explores in detail what percentage does dementia affect, breaking down prevalence by age, region, and risk factors based on current data from reputable health organizations.

Quick Summary

Dementia prevalence is strongly linked to age, with rates rising significantly after age 65. The condition affects millions worldwide and disproportionately impacts women and those in low- and middle-income countries. Lifestyle factors and underlying health conditions are also significant contributors to risk.

Key Points

  • Prevalence Varies by Age: The risk and percentage of dementia diagnoses rise dramatically with age, with rates in individuals 85 and older being significantly higher than in the 65-74 age group.

  • Dementia is a Global Issue: Over 55 million people worldwide had dementia in 2021, and this figure is projected to increase substantially.

  • Disparities Exist in Affected Demographics: Older Black and Hispanic Americans are more likely to develop dementia compared to older White adults.

  • Dementia vs. Alzheimer's Disease: Alzheimer's is the most common type of dementia, but other forms like vascular dementia and Lewy body dementia also contribute to the overall statistics.

  • Modifiable Risk Factors Can Lower Risk: Up to 40% of dementia cases may be preventable or delayed by addressing factors such as physical inactivity, smoking, and untreated health conditions.

  • Growing Economic and Societal Burden: With the increase in cases, the economic costs associated with dementia and the reliance on unpaid caregivers are also rising significantly.

  • Underdiagnosis is a Global Problem: A substantial percentage of dementia cases go undiagnosed, particularly in low- and middle-income countries, limiting access to care and support.

  • Projections Indicate Rapid Growth: Without major breakthroughs, the number of individuals with dementia is projected to increase significantly in the coming decades due to aging populations.

In This Article

Prevalence of Dementia in the United States and Worldwide

The prevalence of dementia varies significantly by age and region. While age is the strongest known risk factor, it is important to remember that dementia is not a normal or inevitable part of aging. Several national and international health organizations track these statistics to inform public health initiatives.

United States Dementia Statistics

Based on recent data from sources like the CDC and Columbia University, the percentage of older adults affected by dementia varies considerably based on age group.

  • Older Adults (65 and older): A study published in 2022 found that nearly 10% of U.S. adults aged 65 and older have dementia. A separate 2024 report from the CDC found that 4.0% of non-institutionalized adults aged 65 and older had a diagnosed dementia.
  • Age-Specific Increases: The rate increases sharply with age. In 2024, the CDC reported a diagnosed prevalence of 1.7% for ages 65–74, rising to 13.1% for those 85 and older. Another study cites a lifetime risk of 42% for Americans over 55 to eventually develop dementia.
  • Demographic Disparities: Risk is not evenly distributed across the population. Older Black Americans and Hispanic individuals are at a higher risk of developing dementia compared to older White adults.

Global Dementia Statistics

Global figures also reflect a substantial and growing burden of dementia, particularly in developing nations.

  • Worldwide Cases: In 2021, the WHO reported approximately 57 million people living with dementia globally.
  • Geographic Distribution: More than 60% of people with dementia live in low- and middle-income countries, and this proportion is projected to rise.
  • Gender Differences: Women are disproportionately affected by dementia, accounting for two-thirds of all cases globally. This is partly due to women generally living longer than men.
  • New Cases: Every year, there are nearly 10 million new cases of dementia worldwide.

Types of Dementia and Associated Statistics

Dementia is a general term, and many different conditions can cause it. Alzheimer's disease is the most common cause, but other types also contribute to the overall statistics.

  • Alzheimer's disease: The most common form of dementia, accounting for an estimated 60–70% of all cases.
  • Vascular dementia: The second most common type, typically caused by problems with blood flow to the brain, such as after a stroke. It accounts for about 5–10% of cases.
  • Dementia with Lewy bodies (DLB): Characterized by abnormal protein deposits called Lewy bodies and accounts for a smaller percentage of cases.
  • Frontotemporal dementia (FTD): A group of disorders affecting the frontal and temporal lobes, more common in younger people.
  • Mixed dementia: Often, individuals with Alzheimer's also have brain changes from another type of dementia, such as vascular dementia. This is especially common at advanced ages.

Key Modifiable Risk Factors

While some risk factors like age and genetics are non-modifiable, The Lancet Commission suggests that addressing certain lifestyle factors could prevent or delay up to 40% of dementia cases.

  • Lifestyle choices: These include physical inactivity, smoking, excessive alcohol consumption, and diet high in unhealthy fats.
  • Underlying health conditions: Uncontrolled high blood pressure (hypertension), diabetes, and high cholesterol are all linked to an increased risk.
  • Social and mental engagement: Low social contact, less education, and depression are associated with a higher risk of dementia.
  • Traumatic brain injury (TBI): Moderate to severe head injuries can increase the risk of developing dementia.

Comparison of Dementia vs. Alzheimer's Disease

Characteristic Dementia Alzheimer's Disease
Definition An umbrella term for a collection of symptoms, including memory loss, communication problems, and impaired thinking. The most common specific cause of dementia, accounting for 60-70% of cases.
Cause Caused by a variety of conditions, diseases, or injuries that damage brain cells. Primarily caused by the accumulation of specific protein plaques (beta-amyloid) and tangles (tau) in the brain.
Progression Symptoms can worsen over time, but the rate and pattern depend on the underlying cause. Some types may have temporary or treatable causes. A slowly progressive, irreversible brain disease that begins many years before symptoms emerge.
Symptoms Wide range of possible symptoms; loss of memory alone is usually insufficient for diagnosis. Early symptoms often include forgetting recent events, followed by more severe memory loss and communication problems.
Treatment Treatments vary by cause; some conditions like vitamin deficiencies may be reversible. No cure, but medications can temporarily improve symptoms or slow cognitive decline.

Conclusion: Understanding the Broad Impact of Dementia

Dementia is a widespread and growing public health concern, affecting a significant portion of the global and U.S. population, especially as the average age increases. The percentage of people affected by dementia is not a single number but a dynamic statistic that escalates with age, showing stark disparities across different demographic groups. By understanding which percentage does dementia affect, and how its prevalence increases with age and other risk factors, policymakers, healthcare providers, and individuals can better prepare for its growing impact. While age is a primary risk factor, the role of modifiable factors like diet, exercise, and social engagement offers hope for risk reduction and prevention efforts. Continual research and awareness are critical for early diagnosis, treatment, and support for those impacted by this complex condition.

Frequently Asked Questions

In 2021, there were an estimated 57 million people living with dementia worldwide, according to the World Health Organization. The number of people affected is projected to rise to 139 million by 2050.

No, women are disproportionately affected by dementia. Globally, women account for two-thirds of all dementia cases. This is partly due to women's generally longer life expectancy.

No, dementia is an overarching term for a group of symptoms that affect memory, thinking, and social abilities. Alzheimer's disease is the most common cause of dementia, contributing to 60-70% of cases, but other conditions can also cause it.

Age is the strongest risk factor for dementia, with the risk increasing exponentially after age 65. For example, a 2024 CDC report shows a prevalence of 1.7% for adults ages 65-74, which jumps to 13.1% for those 85 and older.

Yes, research suggests that addressing certain modifiable risk factors can potentially prevent or delay a significant percentage of dementia cases. These include maintaining physical activity, eating a healthy diet, not smoking, and managing other health conditions.

Yes, demographic differences are observed in dementia risk. In the U.S., older Black Americans and older Hispanic individuals are more likely to have dementia compared to older white adults.

Dementia carries a significant economic burden. In 2019, the global cost of dementia was estimated at US$ 1.3 trillion, with about half of that attributable to care provided by unpaid, informal caregivers.

References

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Medical Disclaimer

This content is for informational purposes only and should not replace professional medical advice. Always consult a qualified healthcare provider regarding personal health decisions.