Long-term air pollution exposure associated with late-onset depression in older adults: study

Story at a glance

• Research has linked air pollution to mental health emergencies and depression.

• A new study found that greater exposure to particulate matter and other pollutants increases the risk of older adults being diagnosed with depression later in life.

• This was found especially in the case of socioeconomically disadvantaged individuals.

Long-term exposure to air pollution is associated with higher risk of late-onset depression in older adults, according to a study published in the journal JAMA Network Open.

Researchers looked at data from 2005 to 2016 for nearly 9 million older adults on Medicare, more than 1.5 million of whom had their first diagnosis of depression later on in life.

Based on where they resided, some people had more long-term exposure to air pollution, including from fine particulate matter PM2.5, nitrogen dioxide and ozone. This group was found to have a higher risk of later-onset depression than people who were not as exposed to air pollution.

The results showed that each 5 unit increase of air pollution of PM2.5, nitrogen oxide and ozone was associated with a 0.91, 0.61 or 2.13 percent increased risk of depression, respectively.

The researchers found that people who were exposed to nitrogen dioxide and had comorbidities, like Alzheimer’s disease, dementia or congestive heart failure, were at even higher risk of depression.

The study also highlights the contributing factor of socioeconomic status. “Socioeconomically disadvantaged individuals were observed to be at a much higher risk of latelife depression in this study,” write the authors. “They are simultaneously exposed to both social stress and poor environmental conditions, including air pollution.”

One limitation of the study is that most of the people included were white. In addition, the air pollution estimates were based on modeled data and cover the area of each zip code, where the distribution of pollutants may be uneven.

These findings add to other research that has indicated a link between air pollution and mental health conditions. For example, long term air pollution exposure has been linked with anxiety and depression. Evidence also suggests that, on days with high air pollution concentration, hospitals have increased visits to emergency departments for psychiatric reasons.