The chronobiology of migraine: a systematic review

Abstract

Background: The paroxysmal nature of migraine is a hallmark of the disease. Some patients report increased attack frequency at certain seasons or towards the end of the week, while others experience diurnal variations of migraine attack onset. This systematic review investigates the chronobiology of migraine and its relation to the periodicity of attacks in existing literature to further understand the oscillating nature of migraine.

Main body: PubMed and Embase were systematically searched and screened for eligible articles with outcome measures relating to a circadian, weekly or seasonal distribution of migraine attacks. We found that the majority of studies reported morning hours (6 am-12 pm) as the peak time of onset for migraine attacks. More studies reported Saturday as weekly peak day of attack. There was no clear seasonal variation of migraine due to methodological differences (primarily related to location), however four out of five studies conducted in Norway reported the same yearly peak time indicating a possible seasonal periodicity phenomenon of migraine.

Conclusions: The findings of the current review suggest a possible role of chronobiologic rhythms to the periodicity of migraine attacks. Future studies are, however, still needed to provide more knowledge of the oscillating nature of migraine.

Keywords: Migraine; chronobiology; circadian; periodicity; seasonal; weekly.

Fig. 1

Flow diagram of the review process

Fig. 2

Circadian (24-hour) distribution of migraine attack onset peak interval for the included studies (n = 15). One study reported migraine attack onset at any time of the day [32] and thus was not included in the figure. Horizontal black lines indicate the reported time range where most migraine attacks began as reported by the individual studies. Black dot was applied if studies reported a specific peak time. Broken lines were applied for three studies where specific time clocks were unreported [3, 23, 43]. Thus, reporting of early morning hours was estimated to 5 am–8 am [3], morning hours was estimated to 6 am–12 pm [43] and after noon was estimated to 12 pm–12 am [23]. n: total sample size

Fig. 3

Weekly distribution of migraine attacks. The number of studies reporting migraine attack frequency peak on each day of the week. Three studies found that attacks were equally distributed throughout the week [19, 25, 42]. One study found that there were fewer migraine attacks on Sundays compared to other days of the week [25]. n: total sample size

Fig. 4

Seasonal distribution of migraine attacks. Horizontal black lines indicate the reported time of year for peak in migraine attack frequency. Broken lines represent estimated dates based on definition of the polar light season in Tromsø (May 21st –July 21st ) [27] as exact dates were not specified by authors. Four studies on the seasonal distribution reported no peak of migraine attack frequency throughout the year [–21]. Black dot indicates peak date. n: total sample size, N: north (latitude), E: east (longitude), W: west (longitude), MA: migraine with aura. MO: migraine without aura. CL: confidence level. *Data only obtained by those who answered yes to experiencing a seasonal variation of migraine attacks. **Results estimated from figure. Increased headache frequency in spring is more prevalent for MA compared to MO patients. *** This study followed patients for two consecutive years. In the first year, there was no pattern in regard to distribution of migraine attack frequency. In the subsequent year, there was however a monthly variation of attack frequency with a peak in March. **** Temperature sensitive patients showed migraine attack frequency peak in winter and non-temperature sensitive patients had more migraine attacks during spring