New research has found a positive association between air pollution and dementia, supporting the findings of previous studies. The latest research study used data from the Clinical Practice Research Database to compare dementia diagnoses by zip code, finding that those in higher polluted areas were more likely to eventually develop the disease.
Learn more about the study and the insight it gives us into the relationship between air pollution and dementia.
Air Pollution and Dementia
A new study from the United Kingdom has found that high levels of air pollution are associated with an increased risk of dementia. Most studies evaluating the long-term effects of air pollution are focused on cardiovascular health, however, more recently, studies are finding associations between pollution and dementia. This study, published online in BMJ Open, is the first of its kind from the U.K.
Researchers used data from the Clinical Practice Research Database (CPRD). The CPRD is a large primary care database that collects anonymous patient data and has been doing so since 1987. Using data from 130,978 adults between the ages of 50-79 with no recorded history of dementia, researchers linked air pollution measures with the anonymous data using the residential postcode. Adjustments were made for age, body mass index, ethnicity, sex and smoking.
Lead author of the study, Iain Carey, M.D., summarized the findings, saying, “We found that older patients across London who were living in areas with higher air pollution were more likely to be diagnosed with dementia in subsequent years.”
Researchers were able to relate the type of air pollution to the risk of dementia, finding that there was a positive exposure-response relationship between dementia risk and all measures of pollution, except for one. Taking the data further, researchers attempted to quantify how much air pollution can raise the risk of dementia. To do this, they assumed what would happen if all patients in the study have been exposed at the levels associated with the bottom 20%, finding the difference to be 7%.
Dr. Carey explains, “We calculated how much of the dementia was attributable to pollution (NO2), by assuming what would happen if all patients in the study had instead been estimated to have been exposed at the levels associated with the bottom 20%. The difference between this theoretical scenario and what we observed gave us an attributable risk of 7%.”
Minimizing Air Pollution for Better Brain Health
He cautioned “Since this is an observational study, it only tells us there may be a possible link between air pollution and dementia. There may be many factors involved, only some of which we were able to account for. We also have to consider our limitations, such as uncertainty around personal exposure, where we assume that traffic pollution levels at somebody’s address can adequately represent their long-term exposure,” he added. “There are also valid concerns about the under-diagnosing of dementia on electronic patient records.”
While study authors acknowledge that their findings only show a correlation and not causation, they do say that these, “findings are another reason to minimize exposure to air pollution.”
To minimize exposure to air pollution, try to avoid traveling during rush hour, refrain from burning candles and have good ventilation when cleaning and cooking.
Have you seen the impact of air pollution on brain health? Share your thoughts on the possible correlation between air pollution and dementia with us in the comments below.