Do you live in a region considered a dementia hot spot, or a region of the country with elevated rates of dementia? The risk of dementia varies surprisingly across the United States; there are significant geographic disparities in the rates of diagnoses, with people in certain areas seeing dementia rates as much as 25% higher than the baseline.
Of course, dementia is a common medical condition among older Americans, with as many as one in 10 adults 65 and over having the disease, whether mild or severe. This means millions suffer from the condition already, and, with the aging of the baby boomer population, an estimated 9 million people in the U.S. could have dementia by 2030.
Here’s where dementia rates are the lowest, and highest, along with some details on potential reasons why people in some areas may be more likely than others to develop serious memory issues.
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Dementia hot spots: the areas with the highest and lowest risks of dementia
Researchers at the University of California, San Francisco, conducted a large-scale study of more than 1.2 million older veterans enrolled in the VA medical system from 1990 to 2021. Participants were studied for a period of 12.6 years, and dementia rates were calculated per 1,000 person-years.
The data, which was published in JAMA Neurology, revealed that the lowest rates of dementia occurred in the mid-Atlanta region. Within this region of the country, which includes Delaware, Maryland, New Jersey, Pennsylvania, Virginia, Washington, DC, and West Virginia, there were 11.2 cases of dementia per 1,000 person-years.
Since this region had the lowest incidence rates, it became the baseline against which other regions were compared, revealing shocking geographic disparities. Specifically:
- The Southeast region had dementia rates 25% higher than the mid-Atlantic baseline
- Both the Northwest and Rocky Mountain regions saw 23% higher rates
- Incidence rates in the South were 18% higher
- Rates were 13% higher in the Southwest
- Both the Midwest and South Atlanta had 12% higher rates
- Rates were 7% higher in the Northeast and the Great Lakes
Researchers accounted for other factors affecting dementia risks, such as age, rates of cardiovascular disease, race, and rural versus urban living, as rural areas tend to see higher rates of dementia. Even after adjusting for these factors, the regional differences persisted.
These differing rates of dementia risk are illustrated on the map below, which compares nine U.S. regions with the Mid-Atlantic.
Why are the geographic disparities so stark?
This study did not provide conclusive answers as to why there is such significant regional variation in dementia diagnoses. However, study authors put forth several potential theories to help explain the discrepancy.
“Quality of education, early life conditions, and environmental exposures may be among those factors,” said Christina Dintica, PhD, and one of the study authors.
Past research has also suggested that factors such as labor market conditions, environmental hazards, structural racism, and overall adult health and mortality can make an impact.
Still other studies have shown that the difference in diagnosis rates can be largely explained by differences in health systems rather than by an actual disparity in dementia rates — meaning that just because more people are diagnosed in a particular location does not mean that more people have the condition, just that more people are likely to seek help or doctors are more likely to identify the issue.
Untangling geography as a risk factor is challenging, even in small hot spots. For example, Starr County, Texas, near the Mexican border, has a dementia rate that is double that of the U.S. average of those on Medicare, affecting about one in five people, according to The Atlantic. It’s unclear whether the county’s exposure to pollution is responsible or if the numerous risk factors that accumulate in a poor community with a strained health care system are to blame.
Researchers have made clear that further scientific examination is necessary to provide more clarity on the reasons for the disparities. They also suggest that simply being aware of the disparate risk levels can be helpful to policymakers and potential future dementia patients.
“These results underscore the influence of regionally patterned risk factors or diagnostic practices, highlighting the importance of tailored health care strategies, public health initiatives, and policy reforms,” the study states.
The good news: reducing your dementia risk
While news of geographic disparities in dementia rates is disturbing, moving isn’t likely to be a solution to cut your risk if you are an older adult. Whatever the environmental or other factors that you’ve been exposed to are likely already baked in.
The good news (yes, there is some good news here) is that you can still reduce your risk. According to the Lancet Commission on Dementia Prevention, up to 45% of dementia cases are preventable. Here are the fourteen ways the Commission recommends to protect your brain and reduce your risk.
- Complete your secondary education.
- Address hearing loss by getting a hearing aid.
- Lower your cholesterol if it is elevated.
- If you have been diagnosed with depression, get treatment.
- Avoid traumatic brain injury by wearing helmets, seatbelts and avoiding falls.
- Aim for 75 minutes (at the very minimum) of aerobic activity per week.
- Avoid type 2 diabetes or get treatment for diabetes and pre-diabetes.
- Don’t smoke, or quit if you are a smoker.
- Treat high blood pressure.
- Maintain a healthy weight.
- If you drink, do so only in moderation.
- Avoid social isolation and loneliness.
- Keep your eyes and vision healthy.
- Reduce your exposure to air pollution by monitoring your local air quality index and limiting your outdoor activities on days with poor air quality. This is especially important if you live in areas affected by wildfires. The real estate listing company, Redfin, has published property-level air quality data, so you can see your home’s overall risk. Just scroll down to the climate section on your home’s page and click on “air factor.”
Other studies have recommended keeping your mind active with games, puzzles, and lifelong learning.
Taking these steps is a lot easier than packing your bags and moving, and they can be one of the best options you have for keeping your mind sharp as you age.