Lightning and its association with the frequency of headache in migraineurs: An observational cohort study

Aim: The aim of this article is to determine if lightning is associated with the frequency of headache in migraineurs. Methods: Participants fulfilling diagnostic criteria for International Headache Society-defined migraine were recruited from sites located in Ohio (n = 23) and Missouri (n = 67). They recorded headache activity in a daily diary for three to six months. A generalized estimating equations (GEE) logistic regression determined the odds ratio (OR) of headache on lightning days compared to non-lightning days. Other weather factors associated with thunderstorms were also added as covariates to the GEE model to see how they would attenuate the effect of lightning on headache. Results: The mean age of the study population was 44 and 91% were female. The OR for headache was 1.31 (95% confidence limits (CL); 1.07, 1.66) during lighting days as compared to non-lightning days. The addition of thunderstorm-associated weather variables as covariates were only able to reduce the OR for headache on lightning days to 1.18 (95% CL; 1.02, 1.37). The probability of having a headache on lightning days was also further increased when the average current of lightning strikes for the day was more negative. Conclusion: This study suggests that lightning represents a trigger for headache in migraineurs that cannot be completely explained by other meteorological factors. It is unknown if lightning directly triggers headaches through electromagnetic waves or indirectly through production of bioaerosols (e. g. ozone), induction of fungal spores or other mechanisms. These results should be interpreted cautiously until replicated in a second dataset.