How Age and Other Demographics Affect Alzheimer's and Dementia Risk

According to our research team’s analysis of the latest available data:

• The typical age range for an Alzheimer’s diagnosis is 75-84. The average age of diagnosis for all forms of dementia is 83.7.
• The risk of an Alzheimer’s diagnosis doubles every 5 years after age 65.
• By age 85, the risk of diagnosis rises to more than 1 out of 3.

Read on to learn more about diagnosis rates by age.

There are 54.1 million seniors over the age of 65 in the United States, according to the Administration for Community Living’s 2020 Profile of Older Americans. According to the Alzheimer’s Association’s data from the same year, Alzheimer’s affects:

• 3% (900,000) of the 31.5 million seniors 65-74
• 17% (2.72 million) of the 16 million seniors 75-84
• 32% (2.1 million) of the 6.6 million seniors 85+

Life expectancy after an Alzheimer’s diagnosis is generally between three and 11 years, according to the Mayo Clinic. However, some people may continue to live with the disease for 20 years or longer, as noted by the Mayo Clinic. The older someone is at diagnosis, the shorter their life expectancy, noted the BrightFocus Foundation.

• Regardless of the age of diagnosis, female dementia patients typically live 1 1/2 years longer with the disease than their male counterparts. It’s unknown why this is, but it may be related to female patients being more likely to seek out medical assistance, as noted by the BrightFocus Foundation.
• Symptoms of early-onset Alzheimer’s, also called younger onset Alzheimer’s, typically develop between someone’s 30s and 50s. Limited data is available for people diagnosed with Alzheimer’s before the age of 65. Around 200,000 Americans have early-onset Alzheimer’s.
• Seniors diagnosed after the age of 65 live an average of four to eight years after a diagnosis, according to the Alzheimer’s Association.
• Seniors diagnosed between the ages of 70-79 have an average life expectancy of seven years.
• Seniors 90+ live an average of two to three years after a diagnosis, according to the BrightFocus Foundation.

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The BrightFocus Foundation reports that there are roughly 500,000 new cases of Alzheimer’s each year. According to the Alzheimer’s Association, the projected number of people 65+ with Alzheimer’s disease in 2025 is 7.2 million.

It’s important to note that Americans who will turn 65 in the next decade are economically, socially, and culturally different than the seniors who came before them, as noted by the Alzheimer’s Association. As such, the following information below is reflective of the older adults who have come before and may not reflect what will happen to adults in the future. Alzheimer’s disease and other dementia research is continually evolving.

• Race/ethnicity. The Alzheimer’s Association reports that 19% of Black seniors and 14% of Hispanic seniors have Alzheimer’s, compared to 10% of Caucasian seniors.
• Sex/gender. The Alzheimer’s Association notes that 6.5 million seniors over 65 have Alzheimer’s and that 4 million are women and 2.5 million are men. The Aging, Demographics, and Memory Study (ADAMS) cites that out of a group of 229 Alzheimer’s patients, 71.5% were women while 28.5% were men.
• Marital status. Unmarried people, including the divorced or widowed, are at an increased risk of Alzheimer’s disease, according to the National Center for Biotechnology Information at the National Institutes of Health. According to the Centers for Disease Control and Prevention, social isolation increases dementia risk by 50%.
  Children may affect women’s Alzheimer’s risk, but more research is needed. Time noted two studies with opposing conclusions: One indicated a decreased risk of Alzheimer’s for women who gave birth to more than three children, while the other noted an increased risk for women who gave birth to more than five children.
• Socioeconomic status. The Alzheimer’s Association notes that low socioeconomic status may negatively affect an individual’s cognitive screening rate. Language barriers and lower education levels may make it difficult to distinguish normal aging from dementia or a mild cognitive impairment (MCI). Some research suggests that carriers of the e4 allele of the APOE gene (which increases the risk of Alzheimer’s disease), who also had a lower childhood socioeconomic status, experienced greater cognitive decline. This possible outcome is noted in the journal Social Science & Medicine.
• Education attainment. More years of formal education decreases the risk of an Alzheimer’s diagnosis, as noted by the Alzheimer’s Association. Johns Hopkins Medicine notes this as well: Between 2000 and 2012, dementia rates fell, while the length of formal education for seniors over 65 increased from 12 to 13 years on average.