Abstract
This study was performed to determine if there were a time of year that children were more likely to transition into a chronic daily headache. We retrospectively reviewed records of 103 patients with chronic migraine and 104 patients with new daily persistent headache. Of these, 56 chronic migraine and 92 new daily persistent headache patients were able to identify the specific month in which they began to experience daily headaches. Thirty-nine percent of new daily persistent headache patients had an onset of daily headache in either September or January, months traditionally associated with the start of the school semester in the United States. Only a single patient reported onset in May or June. Data for the transition from episodic to chronic migraine also showed higher rates in September and January, but did not reach statistical significance. These data demonstrate the higher rates of new daily persistent headache onset during school start months and question what factors may be responsible for this association.
The seasonal variance of onset of chronic daily headache in pediatric patients is poorly understood. Chronic daily headache is described as having headaches that occur more days than not with no underlying pathology and is divided into subtypes. Two frequent forms of chronic daily headache seen in children are chronic migraine and new daily persistent headache. Chronic migraine is described by the International Classification of Headache Disorders (Third Edition) as a headache occurring ≥15 days per month for more than 3 months, which has migraine features ≥8 days per month. 1 Chronic migraine has been shown to impact 1.7% of children and 1.5% of adolescents. 2 New daily persistent headache occurs more frequently in children than adults and is characterized by an abrupt onset often associated with infection and mild to moderate pain that is typically bilateral and described as pressing or tightening. 3
A study of 6- to 7-year-old children suggested that starting school is stressful for children and they experience more frequent episodes of existing headache during the first year of school. 4 It has been reported that school stress is the greatest precipitating factor of migraine in junior high school children. 5 Another study found that in children migrainous and nonmigrainous headache was associated with stress at school, bullying, and problems dealing with other children. 6
The goal of this study was to examine the seasonal trends of chronic daily headache onset in school children. As a result of clinical observation and the literature cited above, it was hypothesized that there would be increased numbers of chronic migraine and new daily persistent headache onset in the months that children start or return to school.
Methods
This was a retrospective study of school-aged children who were evaluated for headache by a pediatric headache specialist at a national referral center. Patients were identified from a database of chronic headache patients. Using the most recent patient records available in the database, 103 records of patients diagnosed with chronic migraine and 104 records of patients diagnosed with new daily persistent headache were retrospectively reviewed. No charts had to be excluded as all of the records reviewed were of patients who had experienced an onset of chronic headache while they were school-aged and enrolled in school and therefore met our inclusion criteria.
A thorough chart review was conducted on all patient charts looking for pre-established variables. These included information regarding age, gender, headache onset, and psychosocial variables associated with headache. Information concerning school and psychosocial factors was primarily obtained via a standardized institutional survey completed by the children and/or their parents at the time of their appointment.
Several statistical tests were performed separately for the chronic migraine and new daily persistent headache data sets. First, chi-square analysis was performed to determine if there was a significant difference in the month of headache onset. After obtaining these results, the months with the greatest number of headache onset were combined, and statistical tests were performed separately for the chronic migraine and new daily persistent headache data sets to determine if any of the school and psychosocial variables were significantly different for headaches that started in these months. A P value of <.05 was used to determine statistical significance. This retrospective review received institution approval (14-004906) from the Mayo Clinic.
Results
Data were collected on 207 children, 154 (74.3%) were female and 62 (30.0%) were from within the state (Minnesota). The mean age of patients (at the time of the appointment) was 14.4 years, with a standard deviation of 2.6. Within the chronic migraine group, 56 patients (54.4%) could identify the exact month their chronic headache started, compared to 92 (88.5%) of patients with new daily persistent headache. Only these patients who could identify the month their chronic headache started were used in the remainder of this analysis, and the following data and analysis pertain only to them. The 56 chronic migraine patients included 44 females (78.6%), and the average age (at the time of the appointment) was 14.8 years, with a standard deviation of 2.14. The 92 new daily persistent headache patients included 60 females (65.2%), and the average age (at the time of the appointment) was 14.0 years, with a standard deviation of 2.8.
The monthly trend of headache onset is summarized in Table 1 and Figure 1. The new daily persistent headache monthly data as a whole was statistically significant; in addition, individual months January and September had a significant increase in headache onset (P ≤ .01), whereas May had a significant decrease in headache onset (P ≤ .01). The chronic migraine monthly data as a whole and for individual months showed a similar trend but were not statistically significant. However, in Figure 1 it is apparent that chronic headache onset was greatest in the fall (September and October) and winter (December and January).
This polar plot demonstrates that September and January are months that NDPH most frequently start (P < .01). A similar but nonsignificant trend is seen for the transition to chronic migraine. NDPH, new daily persistent headache. CM, chronic migraine.
Month of Headache Onset in Pediatric Patients With Chronic Daily Headache.
The psychosocial factors reported at the time of a chronic migraine patient’s appointment are summarized in Figure 2. The most common psychosocial variables reported by chronic migraine patients included sleep difficulty (56.7%), difficulty concentrating (48.1%), and no psychosocial factors (48.0%). “No psychosocial factors” indicates that a patient responded “none” to a survey question asking if they were angry, anxious, irritable/restless, lonely, sad, or out of control. Significantly fewer patients in the school start month group answered “none” to this question than those in the not school start month group (P = .048). There were no other significant differences between the 2 groups. The psychosocial factors reported at the time of a new daily persistent headache patient’s appointment are summarized in Figure 3. The most common psychosocial variables reported by new daily persistent headache patients included sleep difficulty (59.8%), difficulty concentrating (56.1%), and no psychosocial factors (51.3%). There were no significant differences in psychosocial variables between the school start and not school start new daily persistent headache groups.
This graph represents positive responses to a standardized intake questionnaire for patients whose new daily persistent headache began in September or January, versus those whose headache started in the other 10 months. No significant differences were seen between these groups.
This graph represents positive responses to a standardized intake questionnaire for patients whose chronic migraine started in September or January, versus those whose headache started in the other 10 months. Patients who transformed into chronic migraineurs in school start months were less likely to report being angry, anxious, irritable/restless, lonely, sad or out of control.
Discussion
This study examined the seasonal impact on onset of two subtypes of chronic daily headache, chronic migraine and new daily persistent headache, in school children through a retrospective chart review of patients seen at a tertiary care center. Approximately 54% of chronic migraine and 89% of new daily persistent headache patients were able to identify an exact month that they began experiencing chronic daily headache and were included in the seasonal analysis. Chronic migraine patients generally experience a progressive onset of chronic daily headache in which episodic migraine gradually transforms into chronic migraine; whereas, new daily persistent headache patients typically experience an abrupt onset of chronic daily headache, often associated with a physical or psychological stress. 3
The seasonal results of new daily persistent headache supported the hypothesis that there would be an increase in chronic daily headache onset in the months that children start or return to school. There was a significant increase in new daily persistent headache onset in the months most students in the study started or returned to school after summer break (September) and returned to school after winter break (January). The onset of new daily persistent headache in these months was greater than in any other month of the year. Approximately 39% of all new daily persistent headache started in these 2 months. The seasonal results of chronic migraine were less profound and did not reach significance. The lower number of chronic migraine patients who were included in this part of the study could account for this. However, January and September were some of the most frequent months patients reported an onset of chronic migraine.
There are two studies that addressed a similar question; that is, when are pediatric patients with migraine most likely to present to the emergency room? In one study from the University of Pittsburgh, emergency room visits for migraine reached a peak in September and October with a nadir in May and June. 7 Another study looked at a national database of emergency room visits for headache, finding that higher rates of pediatric emergency room visits occur in January (odds ratio 1.92) and September (odds ratio 1.64), and lower rates occur in April (odds ratio 0.42). 8
But why is there an increased number of chronic daily headache onsets when school starts? Data about psychosocial variables reported in an intake survey at the time of the appointment was reviewed to try to explain this (Figures 2 and 3). Pediatric pain and headache has been associated with school stress and other psychosocial factors in multiple studies. 9 -12 A high number of chronic migraine and new daily persistent headache patients did report psychosocial factors that could attribute to their headache, such as school problems and sleep difficulty. Overall, there were few differences in the frequency of psychosocial variables between the patients whose chronic daily headache started during school start months and those whose chronic daily headache started at another time. The only significant difference found was fewer patients in the chronic migraine school start month group answered “none” to a question asking if they were angry, anxious, irritable/restless, lonely, sad, or out of control than those in the chronic migraine not school start month group.
Therefore, the reason why starting school causes children to experience a greater onset of new daily persistent headache remains unclear. Possible reasons this current set of data could not address are changes in sleep patterns associated with the start of school and changes in activity associated with a school schedule. A challenge was the retrospective nature of this study. The intake survey was completed at the time of the patient’s appointment, which was often months or even years after the patient experienced an onset of chronic daily headache. Another limitation of this study was the low number of chronic migraine patients who could identify the exact month their headache started. Factors that affect sleep, busy schedules or anxiety likely play a role in the transformation to chronic headache in select patients. However, our methods were not able to detect these concerns in patients in our total population.
This study identifies a positive association between onset of new daily persistent headache and the transition months when a young person is going from a summer or winter break to the start of school. On an individual patient level, this may offer further insight into trigger factors for chronic headache. Further clarification of these phenomena may improve our understanding of the transition to chronic headache.
Footnotes
Author Contributions
KJM was involved in the design of the study and writing of the manuscript. LRG was involved in the study design, data collection, and writing of the manuscript.
Declaration of Conflicting Interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Ethical Approval
This study was approved (14-004906) by the IRB of Mayo Clinic.