Air pollution could be linked with increased migraine activity, study finds

NEW DELHI: Exposure to air pollution could be associated with an increased migraine activity, according to a study.

Both a short-term and cumulative exposure to air pollution were tied to increased migraine activity, as were climate factors such as heat and humidity, findings published in the journal Neurology suggest.

"These results help us to better understand how and when migraine attacks occur," author Ido Peles, of Ben-Gurion University of the Negev in Be'er Sheva, Israel, said.

"They suggest that for people who have a susceptibility to migraine to begin with, environmental factors may play two roles: intermediate-term factors such as heat and humidity may modify the risk for attacks, while short-term factors such as spikes in pollution levels may trigger attacks," Peles said.

Over 7,000 people with a migraine problem who lived in Be'er Sheva in the Negev desert were followed for an average of 10 years.

Researchers looked at the participants' daily exposure to air pollution from traffic, industry and dust storms, and weather conditions.

How often and when people visited the hospital or a primary care office with an acute migraine were analysed and compared to the pollution and weather conditions on that day and up to seven days earlier -- pollution effects may take a few days to affect the body, the team said.

The day with the highest number of hospital or clinic visits was noted to have elevated levels of air pollution, compared to the average over the study period -- PM10, including dust particles, was 119.9 microns per cubic metre, compared to an average of 57.9 microns per cubic metre during the study.

PM2.5 levels were 27.3 microns per cubic metre, compared to an average of 22.3 microns per cubic metre during the study. Participants having a cumulative exposure to high levels of PM2.5 were nine per cent more likely to have high use of migraine drugs, the researchers found.

Level of nitrogen dioxide (NO2), a gas released mostly from traffic emissions, was 11.2 parts per billion, compared to an average of 8.7 parts per billion. People with a cumulative exposure to high levels of NO2 were found to be 10 per cent more likely to have high use of migraine drugs, compared to those without.

The day with the fewest visits to the hospital or clinic also had lower than average pollution levels, the researchers said.

Further, climate conditions were found to amplify the effects of pollutants.

High temperatures and low humidity were found to amplify the effects of NO2, while cold and humid conditions intensified the effects of PM2.5.

"These findings highlight opportunities for anticipating what care will be needed," Peles said.

"As climate change intensifies the frequency of heat waves, dust storms and pollution episodes, we will need to integrate these environmental risk factors into our guidance for people with migraine," the author said.

"When high-risk exposure periods are in the forecast, doctors can advise people to limit their outdoor activity and use air filters, take short-term preventative medications and start using their migraine drugs at the first sign of a problem to ward off attacks," Peles said.