Temperature variation and the incidence of cluster headache periods: A nationwide population study.
BACKGROUND
Cluster headache (CH) is well known to show a seasonal predilection; however, the impact of temperature and other meteorological factors on cluster periods (or bouts) has not been established.


METHODS
This nationwide survey included 758 patients with episodic CH retrieved from the Taiwan National Health Insurance Research Database from 2005 to 2009. Corresponding meteorological recordings were obtained from the Central Weather Bureau. A case-crossover study design was used to investigate the association between cluster periods and meteorological factors.


RESULTS
A total of 2452 episodes of cluster periods were recorded. The cluster periods were most frequent in the autumn and least frequent in the winter. Seasonal changes from winter to spring and from autumn to winter also increased the frequency of cluster periods. The risk of cluster periods increased when there was a higher mean temperature on event days (odds ratio (OR), 1.014, 95% confidence interval (CI), 1.005-1.023, p = 0.003) or within seven to 56 days. Either an increase or a decrease in temperature (0.05℃/day) following a warm period (mean temperature ≥26℃) was associated with the onset of cluster periods. In contrast, a greater increase in temperature (0.15℃/day) following a cold period (mean temperature < 21℃) was needed to evoke cluster periods. No such associations were found following moderate periods (21℃ ≤mean temperature <26℃).


CONCLUSIONS
Our study shows that temperature is associated with precipitating or priming cluster periods. The influence depends on the temperature of the preceding periods.
Faculty of Medicine, National Yang-Ming University School of Medicine, Taiwan Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taiwan.
Y-Jung
YJ
Lee
Department of Medicine, Taipei City Hospital Heping Fuyou Branch, Taiwan Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taiwan.
Yung-Tai
YT
Chen
Faculty of Medicine, National Yang-Ming University School of Medicine, Taiwan Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taiwan.
Shuo-Ming
SM
Ou
Division of Nephrology, Department of Medicine, Taipei Veterans General Hospital, Taiwan Institute of Clinical of Medicine, National Yang-Ming University, Taipei, Taiwan.
Szu-Yuan
SY
Li
Faculty of Medicine, National Yang-Ming University School of Medicine, Taiwan Department of Psychiatry, Taipei Veterans General Hospital, Taiwan.
Albert C
AC
Yang
School of Health Care Administration, Taipei Medical University.
Chao-Hsiun
CH
Tang
Faculty of Medicine, National Yang-Ming University School of Medicine, Taiwan Department of Neurology, Neurological Institute, Taipei Veterans General Hospital, Taiwan Institute of Brain Science and Brain Research Center, National Yang-Ming University, Taiwan sjwang@vghtpe.gov.tw.
Shuu-Jiun
SJ
Wang
Headache; cluster headache; cluster periods; meteorological factors; seasons