New Research Connects Air Pollution Exposure to Motor Neurone Disease Risk

Long-term exposure to air pollution could increase a person’s risk of developing motor neurone disease and accelerate its progression, according to new research. MND encompasses a group of diseases that target and destroy the upper and lower motor neurones, causing progressive muscle weakness, paralysis and eventually respiratory failure. There is no cure. What exactly triggers the ultimately fatal disease continues to evade researchers, but a growing body of research suggests environmental exposures such as air pollution may be a risk factor contributing to its onset. While past research has indicated possible links between air pollution exposure and increased risk of developing neurodegenerative diseases more broadly, there has been limited focus on MND. Researchers from Karolinska Institutet in Sweden sought to determine whether long-term exposure to air pollution could increase the risk of developing MND. They also wanted to investigate the effects of this exposure on the rate of functional decline as the disease progresses. The researchers gathered data from 1463 MND patients, 1768 of their siblings, and 7310 members of the general population with similar demographics. Then they measured their exposure to four main air pollutants at their residential addresses over average time periods of one, three, five and 10 years. What they found was increased relative risks of MND ranging from 20 to 30 per cent, depending on the pollutant. “However, the associations appeared to be slightly stronger for the 10-year exposure window, shedding light on the accumulated risk of poor air quality,” the study said. Long-term exposure post-diagnosis also accelerated functional decline and the risk of mortality. “A faster loss of motor and respiratory functions . . . was also evident among patients with MND with a higher 10-year average exposure to all PMs,” the study said. It suggests air pollution could be a driver of the the neurodegenerative condition, even in countries where exposure to such pollution remains relatively low, such as Sweden. The researchers acknowledged some limitations in their study, including further information about air pollution in different locations, the sources of particular pollutants, and lack of data between 2020 and 2022 due to the COVID-19 pandemic. But they reiterated that their findings serve as another piece of the puzzle towards the treatment and prevention of MND. “These results highlight the public health importance of improving air quality to reduce the risk of neurodegenerative diseases and to improve the outcome of patients with these disease,” the study said.