Residents in the Southeastern states of Kentucky, Tennessee, Alabama, and Mississippi are more prone to developing dementia, with a 25% higher risk compared to other parts of the United States.

Researchers from California have created a worrisome map that illustrates dementia rates in 10 different regions across the country. They found that areas in the Mid-Atlantic such as Pennsylvania, New Jersey, and West Virginia exhibit the lowest rates, serving as a reference point for the rest of the nation.

Following the Southeast, the regions with the next highest incidences of dementia are found in the northwestern states of Alaska and Idaho, as well as around the Rocky Mountain states like Colorado and Montana, both showing a 23% increased risk.

Southwestern states like California were 13 percent more likely to develop the condition, while those in northeast states like New York were the least likely with a seven percent increased risk.

The researchers, from the University of California San Francisco (UCSF), said the disparities are most likely due to socioeconomic factors like quality of education and exposure to environmental toxins. 

They said while more research is needed, the findings show which areas of the country are most vulnerable to dementia and where efforts should be targeted for education, prevention and therapies.

Dr Kristine Yaffe, senior study author, said: ‘The study underscores the need to understand regional differences in dementia and the importance of region-specific prevention and intervention efforts.’ 

Around 8 million adults in the US have some form of dementia and 500,000 are diagnosed every year. 

Experts estimate cases will grow by 1 million per year by 2060, while some research suggests 12.7million patients could be diagnosed by 2050.

This could be due to cases being underreported, a growing aging population and surging rates of diseases like heart disease and obesity, which can weaken blood vessels in the brain and lead to dementia.

Alzheimer’s is the most common form with about 6million cases. 

The new study, published Monday in JAMA Neurology, evaluated records from 1.2million veterans over 65 who sought care at a Veterans Affairs (VA) health system between 1999 and 2021. 

The researchers used VA data to compare dementia rates among veterans in 10 regions in the US. 

On average, participants were followed for 13 years.  

The average participant age was 74, and 98 percent were men. About 86 percent were white. 

The average age of dementia diagnosis overall in the US is 83. 

The team divided participants by 10 geographic regions defined by the CDC: the Northeast, Great Lakes, Mid-Atlantic, South Atlantic, Southeast, South, Midwest, Rocky Mountains, Southwest and Northwest. 

The Mid-Atlantic – which includes Delaware, Washington DC, Maryland, Pennsylvania, Virginia, West Virginia, New Jersey – was used as a baseline because it had the lowest dementia rate of 11 per 1,000 people.

The researchers found 14 in every 1,000 participants in the Southeast had dementia, a 25 percent increased risk over the Mid-Atlantic.

The Northwest – Alaska, Idaho, Oregon and Washington state – and Rocky Mountain – Colorado, Montana, North Dakota, South Dakota, Utah and Wyoming – both had dementia rates of 13 per 1,000.

This put those areas at a 23 percent increased risk over the Mid-Atlantic.  

People living in Arizona, California, Hawaii and Nevada – the Southwest region – were at a 13 percent increased risk, with a rate of 12 per 1,000. The Midwest and Great Lakes regions were also around 13 percent. 

The Northeast region had the smallest increase compared to the Mid-Atlantic with a dementia rate of 12 per 1,000 people and a seven percent greater risk. 

The researchers pointed to socioeconomic factors influencing regional risks, especially in southeastern states. 

Dr Christina Dintica, first study author and postdoctoral scholar of psychiatry at UCSF, said: ‘Quality of education, early life conditions, and environmental exposures may be among those factors.’ 

States like Kentucky and Mississippi also have high rates of conditions like diabetes, heart disease and obesity, all of which can damage blood vessels in the brain and trigger full-body inflammation that can kill brain cells. 

They also have high concentrations of industrial factories releasing chemicals like heavy metals and gases linked to dementia. 

Military veterans in general are also at a higher risk of dementia overall due to higher rates of traumatic brain injuries (TBIs), which can damage brain cells and blood vessels in the brain.

Some TBIs may also increase amounts of tau and amyloid proteins in the brain, which are known to cause Alzheimer’s disease. 

Post-traumatic stress disorder (PTSD) is also most common in veterans. The condition is thought to trigger inflammation in the brain and damage the brain’s memory structures. 

Veterans over 70, such as those in the study, were also more likely to have been exposed to Agent Orange, a mixture of herbicides used by the US military during the Vietnam War. 

Previous research suggests people exposed to Agent Orange were twice as likely to develop dementia as those who were not exposed due to inflammation and brain cell death.

The study had several limitations, including only focusing on veterans and the vast majority of participants being men.