Late-life depression begins after age 60, and isn’t usually associated with previous psychiatric history in the patient or their family. It’s also more likely than Early-life depression to have associated cognitive impairment and physical illness. It’s believed to be a type of vascular depression. Vascular depression is caused by damage to capillaries in the lungs and brain. This leads to chronic low oxygen levels and leakage of blood in some areas of the brain. These, in turn, lead to inflammation and autoimmune activation, which can lead to depression.

An investigation published in JAMA, researchers found a relationship between exposure to air pollutants and late-onset depression in the United States. The researchers collated non-personally identifiable Medicare data on patients diagnosed with EPA data on air pollutants. The pollutants examined were PM 2.5, NO2, and Ozone (O3). The statistical examination showed that even normal levels of these pollutants were associated with independent chance increases in late-life depression of 0.91%, 0.61%, and 2.13%.

Previous studies have found air pollutants to be associated with increased likelihoods of kidney and liver disease, as well as Alzheimer’s disease. It’s also been shown that people of all ages living in areas with high particulate pollution can experience impacts on brain structure and reduced cognitive ability. Individuals should take these factors into account when choosing where to live, and governments should use them when considering air quality standards.