Blood levels of B vitamin amino acids linked to dementia risk after air pollution exposure.
Blood levels of B vitamin amino acids linked to dementia risk after air pollution exposure.
The Link Between Air Pollution and Dementia: Understanding the Mechanisms
Scientists have long reported a link between air pollution and the risk of developing dementia. However, until recently, the mechanisms underlying this association have remained largely unknown. A new study published in the journal Neurology sheds some light on this issue, providing valuable insights into how air pollution influences the development of dementia.
Dr. Giulia Grande, a co-author of the study and a postdoctoral researcher at the Karolinska Institute in Stockholm, Sweden, explains, “In this study, we found that two types of vitamin B-related amino acids played a role in increasing or decreasing the risk of dementia caused by air pollution.”
In their research, the team analyzed the impact of fine particulate matter, or PM2.5, which is a common air pollutant, on the risk of dementia. They also examined the levels of two amino acids associated with vitamin B, namely methionine and homocysteine.
Methionine is an essential amino acid involved in normal brain functions and is commonly found in foods such as meat, fish, dairy products, beans, and eggs. On the other hand, homocysteine is an amino acid produced in the cells, which can be transformed into methionine through a reaction requiring vitamin B12 and folate. Homocysteine is essential for red blood cell formation and healthy cell growth and function.
The study involved over 2,500 adults, with an average age of 73, living in central Stockholm. The participants were followed for up to 12 years using interviews, questionnaires, and blood tests. Of the total participants, 376 individuals developed dementia during the study.
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Researchers measured the annual average levels of PM2.5 at the participants’ home addresses. The individuals who developed dementia had an average exposure to PM2.5 pollution of 8.4 micrograms per cubic meter (µg/m3), only slightly higher than the 8.3 µg/m3 exposure for those who did not develop dementia.
It is worth noting that these annual average levels of PM2.5 were relatively low compared to the European average of 13.8 µg/m3. However, researchers still found that the risk of dementia increased by 70% for every one µg/m3 increase in PM2.5 exposure during the five years leading up to the study.
Furthermore, the study revealed that approximately half of the increased risk of dementia associated with PM2.5 pollution resulted from an interaction between air pollution and high homocysteine levels or low methionine levels.
Dr. Grande highlights the significance of these findings, saying, “Our results indicate that raised homocysteine levels and low methionine values played a role in determining the dementia risk related to air pollution. However, they also show that a substantial direct effect of air pollution on dementia exists, suggesting that air pollution affects the development of dementia through multiple pathways.”
While these findings provide valuable insights, it is important to acknowledge certain limitations within the study. It focused solely on the small Kungsholmen district of Stockholm and had limited comparisons regarding air pollutants. Therefore, further research is necessary to gain a more comprehensive understanding of the biological mechanisms underlying the brain damage caused by air pollution.
Now, let’s test your knowledge with a quick question: What is one of the first symptoms of Alzheimer’s disease? Take a guess!
The U.S. Environmental Protection Agency offers more information on PM2.5 and its impacts on health.
Source: Neurology, news release, July 19, 2023
