Although dementia may be caused by a variety of factors, scientists have been looking at a somewhat unexpected possible variable: air pollution. Several studies have been done examining the link between dementia and air pollution, and while more research needs to be done, it’s worth taking a closer look.
Dementia is a general term to describe the group of symptoms that are associated with memory loss and other cognitive deficits that impair every day functioning.1 It is caused by damage to brain cells; when the brain cells aren’t able to communicate effectively, memory, cognition, and functioning are all affected. Alzheimer’s is a type of dementia.
What is air pollution?
Air pollution is defined as a mixture of natural and man-made substances in the air.2 Since we breathe in the air, pollution can affect our bodies. When you breathe in the air, these tiny particles of pollution can settle in the lung tissue or get into the bloodstream, triggering an immune response that includes inflammation – which has been linked to neurological conditions. There are two general categories of air pollution: outdoor air pollution and indoor air pollution. Outdoor air pollution includes noxious gases, tobacco smoke, ozone, and fine particles from burning fossil fuels.2 Indoor air pollution includes tobacco smoke, gases, allergens, mold, pollen, materials like asbestos, and household products and chemicals.2 Air pollution has been associated with a variety of illnesses, including lung and respiratory diseases, adverse pregnancy outcomes, cardiovascular diseases, and death.2
Air pollution and dementia
Given air pollution’s effect on other parts of the body, it’s not a stretch to study if it affects the neurological system as well. A retrospective cohort study in London found a positive exposure-response relationship between dementia, particularly Alzheimer’s disease, and all levels of air pollution except ozone.3 A group of scientists in the US studied whether long-term exposure to air pollution is associated with dementia. They used 15 years of Medicare records and tracked health conditions and outcomes, along with the Environmental Protection Agency’s (EPA) air quality monitoring network. This study found that even a small increase in exposure to air pollutants can increase the risk of developing dementia, and monitoring air pollution and air quality has positive effects on health.4 Counties that had to comply with air quality regulations had lower rates of Alzheimer’s disease than counties that did not have such regulations.5 Multiple studies have found similar associations, and more research needs to be done as well. Despite this, the associations between air pollution and illness, including dementia, are strong.
Air pollution may be getting worse in many American cities, especially with the loosening of federal regulations regarding environmental safeguards. This can have a variety of effects, including a significant effect on health, particularly for older individuals. It’s not always clear whether the air you’re breathing is clean or not, and so the way to help safeguard public health is to strengthen and enforce air pollution standards.
While there’s not much you can do about outside air pollution (aside from moving to an area with less traffic or far away from power plants or factories), if you’re concerned about indoor air pollution, ask your doctor about what you can do to help minimize your exposure. Not smoking cigarettes indoors (or at all), using natural cleaning supplies, and making sure your home is well-ventilated can all help to reduce indoor air pollution.6 This, along with a healthy lifestyle and regular doctor visits can help you stay healthy and may reduce your risk of developing dementia.
What Is Dementia? Alzheimer’s Association. https://www.alz.org/alzheimers-dementia/what-is-dementia 2019. Accessed July 17, 2019.
Air Pollution. National Institute of Environmental Health Sciences. https://www.niehs.nih.gov/health/topics/agents/air-pollution/index.cfm Last Reviewed May 2, 2019. Accessed July 17, 2019.
Carey IM, Anderson HR, Atkinson RW, Beevers SD, Cook DG, Strachan DP, et al. Are noise and air pollution related to the incidence of dementia? A cohort study in London, England. BMJ Open.2018; 8. doi: http://dx.doi.org/10.1136/bmjopen-2018-022404 Accessed July 18, 2019.
Bishop KC, Ketcham JD, Kuminoff NV. Hazed and confused: The effect of air pollution on dementia. National Bureau of Economic Research Working Paper. 2018. Doi: 10.3386/w24970. Accessed July 18, 2019.
Reuben A. The evidence is strong: Air pollution seems to cause dementia. Wired. https://www.wired.com/story/air-pollution-dementia/ May 9, 2019. Accessed July 18, 2019.
17 Simple Ways to Prevent Air Pollution in Your Home. Cleveland Clinic. https://health.clevelandclinic.org/17-simple-ways-prevent-air-pollution-home/ 2015. Accessed July 18, 2019.