FINAL REPORT:  Shedding Light on Migraine: Exploring Novel Light Metrics as a Trigger of Migraine

Summary

This project sought to identify whether the brightness of light and different wavelengths of light are associated with the onset of episodic migraine and influence migraine pain in the natural setting. For this project, we analyzed data from 79 participants with continuous light exposure for six weeks obtained from wrist-worn actigraphs (small light sensor detectors). We collected information on the timing of headache onset, duration, intensity, associated symptoms, and medications. We also collected daily information on caffeine, alcohol, physical activity, stress, menstrual status, and sleep.

Hypothesis vs. Findings:

In our first aim, we hypothesized that among individuals with episodic migraine, migraine attacks will more likely occur following a period of exposure to higher average brightness compared to a period of lower brightness. Our findings suggest that higher average white light exposure is associated with a 10% higher risk of headache during that same time of day and day of the week. The results did not differ by season or whether participants reported light as a migraine trigger at baseline.

In our second aim, we hypothesized that among individuals with episodic migraine, during an attack, exposure to a higher ratio of blue to green wavelengths would be associated with an average higher pain intensity and longer migraine duration compared to exposure to a lower ratio of blue to green wavelengths. In fact, we found that higher exposure to blue light relative to green light was associated with lower maximal pain intensity.

Unanswered Questions

Our findings indicate that higher average intensity of white light at any level is associated with migraine onset in individuals with episodic migraine. However, we were unable to discern the factors that explain this finding. Specifically, while average light level may indeed directly cause increased risk of a migraine attack, it is possible that average light levels may be related to other triggers. We plan to continue our research to explore shorter periods of exposure as well as exposure to higher intensity of light than we used here. We also plan to examine the influence of circadian timing in association with migraine onset. Future research is needed to determine if interventions that reduce exposure to variations in light can reduce frequency of migraines.

Our findings also indicate that for individuals with episodic migraine, exposure to a higher ratio of blue light relative to green light was associated with lower maximal pain intensity in the natural setting. This finding is in contrast to research in an experimental setting that found that exposure to green light lowers pain intensity. Further research is needed to clarify the extent different frequencies of light impact migraine features (such as pain intensity) in the natural setting, to inform testing interventions that minimize exposure to specific wavelengths of light.

What this Research Means to You

These findings suggest that higher average light exposure during the daytime is associated with migraine onset among individuals with episodic migraine. Whether devices that block light or specific wavelengths of light can reduce migraine occurrence is still unclear. More research is needed so that light interventions that prevent migraine attacks can be found.