The South Bronx has been known to suffer from poor air quality and health inequality for decades, but now that scourge can be linked to another public health problem: Alzheimer’s disease. According to data from the Coalition of New York State Alzheimer’s Association Chapters, more than 426,500 New Yorkers aged 65 and older have the condition. New York is second among the five states with the highest projected prevalence of Alzheimer’s, at 12.7% — and at 16.6%, Bronx county has the highest prevalence in the state.
These statistics take on new meaning with the findings of a study released in November 2024 by the Dementia Risk Reduction Project showing that three of 12 risk factors that may influence dementia risk are smoking, air pollution, and diabetes. The Bronx has the second-highest percentage of adult smokers at 11.7%, slightly behind Staten Island at 12%.
Research indicates that air quality in the South Bronx is poor because of factories, industry, and thousands of trucks moving through the community emitting nitrogen oxide. The Dementia Risk Reduction Project found that prolonged exposure to air pollution significantly raises dementia risk.
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“Studies have shown that fine particulate matter — a component of air pollution — can penetrate the body and reach the brain,” said Dr. Chris Vercammen. “While the precise relationship between air pollution and dementia is still being studied, researchers have found that this particulate matter can lead to chronic inflammation throughout the body, including within the brain itself.”
Vercammen explained that this inflammation can be damaging to brain cells and may contribute to cognitive decline. In addition, certain chemical air pollutants can have toxic effects on both the body and brain cells, potentially leading to cognitive impairment.
Prevalence of diabetes among New York City residents also makes the results of this study significant, with approximately 16% of Bronx residents being diagnosed with the ailment, the highest rate by county in the state. Elevated fasting plasma glucose (FPG) levels, a marker of diabetes, are linked to an increased risk of dementia, with an approximately 25% increase in risk even at prediabetes levels and a 50% increase in risk at the threshold for diabetes diagnosis.
“People with diabetes have consistently elevated blood sugar over time, which can damage your blood vessels, lead to chronic inflammation, and contribute to atherosclerosis, all of which can have a negative impact on your brain,” said Dr. Raj Dasgupta. He added that insulin resistance, often linked to an elevated FPG, can also interfere with how brain cells communicate and clear out harmful proteins. All of this increases the risk of neurodegeneration, making conditions like Alzheimer’s more likely. As blood glucose levels increase further, dementia risk continues to rise.
Rising diabetes rate combined with prolonged exposure to air pollution make it easy to understand why Alzheimer’s disease is a growing problem in New York City.
“By understanding and influencing dementia risk factors, we can disrupt dementia,” said Sarah Lock, AARP senior vice president for policy and executive director of the Global Council on Brain Health (GCBH). “We can use this information to promote healthier brains and empower people to lower their own risks, potentially delaying dementia onset and fostering healthy aging. This research aims to give older Americans more quality time with loved ones. Through this first-of-its kind research endeavor, AARP hopes to glean and share information on the relationship between potential risks and dementia and how can we can reduce those risks for older Americans.”
This study has even greater implications for Black and Brown New York City residents. In the Bronx, where pollution is the highest, the racial makeup is 56.6% Hispanic and 28.2% Black. Coupled with statistics showing that 14.5% of New Yorkers diagnosed with diabetes are Black,and 11.7% are Hispanic, the risk of Black and Brown New Yorkers is clearly greater. In addition, Black Americans with Alzheimer’s are more likely to be diagnosed later.
With emerging research, it becomes more obvious that diagnosis and treatment of Alzheimer’s and dementia in New York City is a health equity issue. “If these are issues that disproportionately affect communities of color, and these issues are tied to increased risk of dementia, then you can put that together and say communities of color are more impacted because the underlying factors of how and where people live expose us to higher levels of risk,” said Doris Phildor, MPH, health system director of the Alzheimer’s Association, NY.
The reporting for this article was supported by a journalism fellowship from the Gerontological Society of America, Journalists Network on Generations, and Commonwealth Fund.