By Dara Jamieson, MD
Assistant Professor of Clinical Neurology,
Weill Cornell Medical College

Dr. Jamieson reports no financial relationships relevant to this field of study.

SYNOPSIS: For about 13% of patients with migraine, a change in weather may be a trigger for some headaches; however, there is no specific perturbation in meteorological measures that is likely to predict a headache.

SOURCE: Hoffmann J, et al. The influence of weather on migraine – are migraine attacks predictable? Ann Clin Transl Neurol 2015;2:22-28.

In 2011, Hoffmann et al published a pilot analysis of the headache diaries of 20 Berlin migraineurs, correlating migraine attack frequency and severity to atmospheric air pressure, temperature, and relative air humidity. In six patients, the attack prevalence and pain intensity were associated with a lower temperature and higher humidity. As an expansion on this earlier data, the headache diaries of 100 migraineurs were retrospectively examined by the same investigators to assess the correlation of headaches with change in weather. Weather data included hourly recordings of atmospheric pressure, temperature, and relative humidity in years 2006 and 2007. These three weather measures, in 4-hour intervals over 12 consecutive months, and their variation within the 24 hours preceding a migraine attack, as noted in the patient diaries, were analyzed. For migraineurs showing a positive correlation between the meteorological measures and headache attacks, logistic regression analysis was used to assess the predictability of a migraine attack based on the meteorological information. Small monthly variations in migraine frequency were noted, with more events recorded in January, May, and July and fewer headaches noted in the months of November, August, and March. Migraines were slightly more likely to occur on Tuesday and Wednesday, than on Sunday. Migraines were twice as likely to occur in the early morning between 4 a.m. and 8 a.m., as compared to later in the evening between 8 p.m. and midnight. Because the pooled analysis for the 100 patients did not reveal a significant correlation between the meteorological variables and migraines, the patients’ diaries were analyzed individually. Significant migraine correlation with weather was found in 13 patients; however, significant values in the weather parameters or their changes did not follow a predictable pattern. The correlation between migraines seemed to be with a perturbation in the weather pattern, rather with than any specific increase or decrease in the specific meteorological measures. Even in weather-sensitive migraineurs, a migraine attack could not be consistently predicted based on the weather patterns measured in this study.

COMMENTARY

Migraine is a complex brain disorder, with episodic head pain that can occur spontaneously or can be triggered by environmental conditions that reflect the individual predilections of patients. Some triggers are endorsed by many patients (e.g., alcohol) and others are unique to the point of oddness (e.g., leather shoes). Frequently, patients report a correlation between migraine headaches and change in weather. In a review published in 2013, appropriately entitled “Migraine and triggers: Post hoc ergo propter hoc?” Hoffman and Recober reviewed the available literature and concluded that the “clinical and experimental data seem to indicate that in a subgroup of migraineurs, the incidence of migraine attacks may be associated with low temperature, high relative humidity, and low atmospheric pressure.”1 However, Hoffman and his colleagues based this conclusion on their small pilot study published in 2011,2 whose early results did not predict the less conclusive results of their recent analysis of more data. This current study found a relatively small percentage (13%) of migraineurs had weather sensitivity, without a reliable forecast of the specific directions of the change that was likely to trigger an attack.

Despite much patient headache diary documentation and physician questioning about triggers of migraine attacks, the vast majority of headaches are triggered by what I characterize as “chaos in the universe.” But, the effect of weather perturbations on migraine headaches is best described by the “butterfly effect,” whereby a small change in the initial conditions leads to a complex sequence of events that eventually produces a significantly different outcome. Had the butterfly not flapped its wings when and where it did, the tornado, days later, might not have achieved its eventual strength and location. Weather changes do not cause the migraine headache to occur, and the headache might have occurred even without the atmospheric pressure, temperature, and humidity changes. However, there is some weather contribution to the characteristics and timing of a particular migraine headache, with a stronger influence in certain inexplicably vulnerable migraineurs. The obvious problem for the weather-sensitive headache sufferers is that the lack of predictability means that migraineurs get asked about a weather trigger, but nobody tells them what to do about it.

REFERENCES

1. Hoffmann J, Recober A. Migraine and triggers: Post hoc ergo propter hoc? Curr Pain Headache Rep 2013;17:370.

2. Hoffmann J, et al. Weather sensitivity in migraineurs. J Neurol 2011;258:596-602.