(Montreal) Significant exposure to second-hand smoke is associated with severe headaches or migraines in people who have never smoked, indicates a study recently published by Chinese researchers.
However, the same association was not seen with modest exposure to second-hand smoke.
“What is very interesting,” said Doctor François Perreault, of the CHUM headache clinic, “is above all that they measured the levels of cotinine, the metabolite of tobacco, which means that we can really see to what extent exposure to tobacco influences migraine. »
The researchers in fact noted a positive association between a blood level of cotinine which oscillated between 1 and 10 ng/mL and intense headaches or migraines. The same association was not seen when blood cotinine levels ranged from 0.05 to 0.99 ng/mL.
However, the study does not quantify the intensity of these migraines or headaches, emphasized Dr. Perreault. The researchers simply asked their participants if they had suffered from a migraine or headache in the past few days, nothing more.
The intensity of a migraine can vary greatly, recalled Dr. Perreault, ranging from moderate pain that still has a functional impact to a migraine so intense that it is impossible to leave the house.
“Migraine intensity is not correlated (in this study), but we know that severe headaches can be caused (by second-hand smoke),” he said.
The study also does not specify whether it was a one-off or prolonged exposure to second-hand smoke. The measurement of cotinine in the blood, on the other hand, is an interesting data, he estimated, since it is much more objective than an estimate, for example, of the time spent in a smoky room.
People who live with migraines know straight away that they need to avoid strong odors that could trigger their illness.
In the case of nicotine, explained Dr. Perreault, we are talking about a substance with inflammatory properties. And when we know that the brain, during a migraine attack, is already overwhelmed by a wave of inflammatory substances which overstimulate the pain receptors, we understand the importance of not adding more.
“Nicotine will trigger the release of other inflammatory factors which cause a kind of vasodilation, and we know that this dilation causes even more pain,” he explained.
“This dilation releases other inflammatory factors, so it’s a kind of vicious circle (which) promotes all this inflammatory soup in which the brain is bathed. »
This study sets the stage for other research that will delve deeper into the association between second-hand smoke and migraines, said Dr. Perreault.
“It would be interesting to see if prolonged secondary exposure to high levels of nicotine promotes migraine chronicity. Does this ultimately encourage the development of major migraines? » he asked.
The findings of this study were published by the medical journal Headache.
