The amount of data that suggests people who live in polluted places have a higher risk of depression than those who live in locations with cleaner air is increasing, and scientists are finding more and more of it.
However, a new study that was just released on Friday in JAMA Network Open is one of the first to investigate the links between long-term exposure and the increased likelihood of being diagnosed with depression after the age of 64.
The ailment known as depression is a significant one in and of itself. Studies have shown that when it occurs in an older adult, not only may it contribute to problems with the ability to think effectively, but it can also contribute to bodily problems and even mortality.
Previous studies have shown that a fresh diagnosis of depression is significantly less prevalent among older persons than it is among younger groups.
Dr. Xinye Qiu, the co-author of the new study, published Friday in JAMA Network Open. Qiu, a postdoctoral research fellow in the Department of Environmental Health at Harvard T.H. Chan School of Public Health said, “That’s one of the biggest reasons we wanted to conduct this analysis. Surprisingly, we saw a large number of late-onset depression diagnoses in this study.”
Over the study period from 2005 to 2016, the researchers examined data on more than 8.9 million individuals who received their health insurance through Medicare and found that more than 1.52 million of these individuals had been diagnosed with depression. This number probably understates the true prevalence of depression among older individuals because research has shown that it is frequently misdiagnosed in this population.
Qiu and her co-authors examined the residences of each individual with a depression diagnosis and developed models to ascertain the average annual exposure to pollution at each ZIP code. They were able to gauge the individuals' exposure to pollution as a result.
The three types of air pollution that were examined by the researchers were ozone, nitrogen dioxide, and microscopic particulate matter, also known as PM2.5 or particle pollution.
Particle pollution refers to the float-in mixture of solid and liquid droplets. It could seem like smoke, soot, muck, or dust. Ash is another possible form. It is created by vehicles, farms, fires, unpaved roads, building sites, and power plants that use coal and natural gas as fuel.
Because PM2.5 particles are so tiny - one-twentieth the width of a human hair - they can get past the defenses your body normally sets in place to protect itself.
Instead of being expelled from your body as you exhale, it can get stuck in your lungs or enter your circulation. The particles may contribute to respiratory problems in addition to causing irritation and inflammation. Exposure is linked to an increased risk of mental health issues like depression and anxiety, which has long been understood. Exposure can result in heart disease, cancer, or a stroke. Exposure can exacerbate asthma.
The effects of combustion associated with transportation are the most frequent source of nitrogen dioxide pollution. In addition to the burning of fossil fuels like coal, oil, and natural gas, driving a car on the road also releases nitrogen oxides into the air. Exposure can exacerbate airway inflammation, which can also lead to coughing, wheezing, and a decline in lung function.
Pollutant-induced ozone depletion is the main source of smog. It is made at facilities such as refineries, power plants, and autos. Studies that glanced at prolonged exposure found that those who were subjected to greater levels of pollution had a greater likelihood of dying from respiratory disorders. This particular pollutant is notorious for making asthma symptoms worse. According to the American Lung Association, it is one of the pollutants that is "least well-controlled in the United States," and it is also one of the most dangerous pollutants.
The results of the most recent study showed that people with a long history of residing in areas with higher levels of pollution were more likely to be diagnosed with depression. Each of the three pollutants under investigation was connected to a higher risk of late-onset anxiety, even at lower pollution levels.
“So there’s no real threshold, so it means future societies will want to eliminate this pollution or reduce it as much as possible because it carries a real risk,” Qiu let out.
Socioeconomically disadvantaged groups had stronger connections between depression and exposure to particle pollution and nitrogen dioxide than did other groups. According to the findings of the study, this could be in part because adolescents are concurrently subjected to social stress and these bad environmental conditions.
According to the findings of this study, older individuals who already had underlying issues with their heart or lungs were also more susceptible to developing late-in-life depression when exposed to nitrogen dioxide pollution.
The study does have a few shortcomings. The bulk of the people who took part in the study was white, and additional research is required to see whether or not there is a difference between different types of populations.
Because this was a study conducted on an entire population, it is impossible to determine the specific reason why individuals who are exposed to the types of air pollution in question would be at a greater risk of developing depression.
According to the findings of other studies, prolonged exposure to air pollution may hurt the central nervous system, leading to inflammation and triggering cell damage throughout the body.
Studies have shown that certain types of air pollution can also cause the body to release harmful substances. These substances have the potential to damage the blood-brain barrier, which is a network of blood vessels and tissues made up of tissues with closely spaced cells that protect the brain. This can result in feelings of anxiety and depression.
Because being older can harm one's immune system, older persons may be particularly susceptible to the adverse consequences that air pollution can have. Because the neurological foundation for depression is not yet totally understood, additional research will be required to fully comprehend these linkages.
According to the findings of the study, another option is that people who live in polluted places acquire physical difficulties that are related to a deterioration in their mental health.
“Late-life depression should be a geriatric issue that the public and researchers need to be paying more attention to, like on a similar level with Alzheimer’s and other neurological conditions,” stated Qiu.
She is particularly concerned about how the effects of climate change will play out concerning this matter. The findings of the study showed that ozone pollution had a stronger connection to late-onset depression than particle and nitrogen dioxide pollution, both of which are expected to increase as the world warms.
“Because of this concerning effect we are seeing with ozone, it makes more sense for the government to put some regulation on pollution and also climate mitigation because rising temperatures and ozone pollution are definitely linked to each other,” Qiu expressed.
News Source: CNN Health.