American Journal of Emergency Medicine 33 (2015) 409–413
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Original Contribution
Meteorologic parameters and migraine headache: ED study Mustafa Yilmaz, MD a,⁎, Mehtap Gurger, MD a, Metin Atescelik, MD a, Mustafa Yildiz, MD a, Sukru Gurbuz, MD b a b
Department of Emergency Medicine, Firat University School of Medicine, Elazig, Turkey Department of Emergency Medicine, Inonu University School of Medicine, Malatya, Turkey
a r t i c l e
i n f o
Article history: Received 1 December 2014 Received in revised form 24 December 2014 Accepted 24 December 2014
a b s t r a c t Aim: Migraine is common in society and is one of the primary causes of chronic headache with episodes. In this study, we aimed to determine the role of meteorologic parameters and moon phase on triggering migraine attacks and effects on the number of patients presenting to the emergency department with migraine headaches. Materials and Methods: Patients admitted to the emergency department due to a migraine headache during a 1year period were studied retrospectively. Correlation between moon phases, pressure, temperature, humidity, wind speed values of meteorologic observation, and recording station located in the same city and daily number of patients was analyzed. Results: A total of 3491 patients, of whom 72% (n = 2518) were women, were enrolled. The average daily number of patients was 9.6 ± 4 (3-24). A statistically significant correlation was found between the number of daily patients and daily maximum temperature (P = .005), mean temperature (P = .013), minimum temperature (P = .041), and daily temperature change (P = .003). In addition, a negative correlation was found between the daily number of patients presenting to the emergency department and daily relative humidity (in percentage; P = .031). No significant relationship was found between moon phases and the number of patients. Conclusion: We have determined that the number of patients admitted to the emergency department with migraine headache has increased with high temperature and low humidity and that there is no relationship between the number of patients and moon phases. © 2014 Elsevier Inc. All rights reserved.
1. Introduction Migraine, most common disease in the community, is one of the primary causes of chronic headache with periods of remission and exacerbations. It is seen in about 12% of population, and it is more common in women [1,2]. Migraine causes individuals to limit their daily activities because it has attacks that last for hours and even days, and these attacks cause occasional severe headaches [3,4]. Although causes that trigger migraine attacks and their mechanisms of action are not fully identified, many internal (personal) or external (environmental) factors such as hormonal changes, menstrual periods, emotional stress, hunger, fatigue, odors, noise, and sleep pattern changes trigger a migraine attack or cause an increase in headaches [5]. Identification and avoidance of the factors that trigger or aggravate migraine attacks constitutes the first and most important step in the prevention of migraine attacks. Because avoidance of trigger factors can significantly decrease severity or frequency of attacks, studies for identifying factors that trigger migraine attacks continue [6,7]. The results of the studies that examine whether
⁎ Corresponding author. Department of Emergency Medicine, Firat University Faculty of Medicine, 23200 Elazig, Turkey. Tel.: +90 424 2370000/1443. E-mail addresses: [email protected] (M. Yilmaz), [email protected] (M. Gurger), [email protected] (M. Atescelik), [email protected] (M. Yildiz), [email protected] (S. Gurbuz). http://dx.doi.org/10.1016/j.ajem.2014.12.056 0735-6757/© 2014 Elsevier Inc. All rights reserved.
there is a relationship between migraine attacks and meteorologic parameters, an external cause, are different, so this suggests that the mystery of this issue is still unsolved and further studies are needed. Although positive correlations between migraine and bright snow cover, atmospheric pressure, wind, and temperature have been reported, some meteorologic parameters have been shown to have negative correlation or even no relationship. Hence, those results reveal the difference between the results of studies [7–13]. In the literature, the number of studies examining the correlation between the meteorologic parameters and the number of emergency department patients presenting with migraine attack is very low [14,15]. In our study, we also aimed to investigate whether meteorologic parameters affect the daily number of patients admitted to the emergency department with migraine headaches. In addition, we also investigated whether the daily number of patients with migraine attacks is affected according to moon phases. Our study differs from several previous studies because there are no subjective records such as headache diaries, personal comments are avoided by not making individual interviews, and a more objective evaluation was done. In addition, we aimed to determine the effect of our regional weather variables on the number of patients admitted to the emergency department with a migraine attack and share the results because most studies examining the effects of meteorologic parameters on migraine headache have different results.
410
M. Yilmaz et al. / American Journal of Emergency Medicine 33 (2015) 409–413
300 250
Patients
200 150 100 50 0 1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
hours* Female
Male
Fig. 1. The number of patients presenting to the emergency department by hours (*1 = 0100-0159; 2 = 0200-0259; 3 = 0300-0359 … etc).
2. Materials and methods 2.1. Study patients A total of 3491 patients older than 18 years who admitted to emergency department of a regional hospital located in Turkey between January 1 and December 31, 2013, with a headache that is consistent with migraine and whose diagnosis were encoded as G-43 from International Classification for Diseases, 10th Revision coding system were retrospectively evaluated. Patients who had other diseases causing headache (hypertension, subarachnoid bleeding, sinusitis, trauma, etc) were excluded from the study. Patients with recurrent hospital visits due to migraine attacks in 1 year were also included in the study. 2.2. Meteorologic data Daily average-maximum-minimum (max-min) temperature (in degrees Celsius), atmospheric pressure (in millibars), humidity (in percentage), and wind speed (in meters per second) values were obtained from meteorologic observation and recording station located in the same city. Also daily max-min difference of atmospheric pressure and temperature was calculated. In addition, for each month, moon phases were enrolled in the study as new moon, first quarter, full moon, last quarter, and other days. For each moon phase (new moon, first quarter, full moon, last quarter), 1 day before and 1 day after were also included. Thus 3day data were assessed for each moon phase. Number of patients in the days including each moon phase for a year was identified, and correlation between moon phases and number of patients admitted to the emergency department with a migraine headache was examined. 2.3. Statistical analysis Statistical Package for the Social Sciences (SPSS 21, Chicago, IL) statistical software was used for data analysis. Numerical variables were expressed as mean ± SD and categorical variables as percentage. Independent-sample t test or 1-way analysis of variance was used for numerical data analysis and χ2 test for categorical variables analysis. Pearson correlation test was used to determine the relationship between the numerical parameters. P b .05 was considered statistically significant.
(3491/176 909) who admitted to the emergency department within 1 year. Seventy-two percent (n = 2518) of patients were female, and the average age of all patients was 36 ± 11 years. There was no difference between men and women according to the mean age (P N .05). The average daily number of patients was 9.6 ± 4 (3-24). Regarding the time of day, migraine attacks were highest between 2000 and 2100 hours, and a total of 367 patients (270 female and 97 male) with migraine headaches were admitted to emergency department. Also, it was found that more migraine patients were admitted to the emergency department in the evening compared with other times of the day. Fifty-five percent (n = 1921) of all migraine patients were admitted to emergency department in the evening between 1700 and 2359.More than half (73.5%; n = 1412) of these patients were female. Arrival times of the patients by sex are shown in Fig. 1. Most of the female patients had migraine attacks on Sunday (16.6%) and Saturday (15.3%). Most of the male patients were admitted to emergency department on Tuesday (15.4%) and Sunday (15.2%) (Fig. 2). Most of the patients were admitted to emergency department with a migraine headache in October (10.5%) and November (10.6%). The number of patients presenting to the emergency department by month was presented in Fig. 3. Statistically significant correlations were found between the daily number of patients and daily maximum temperature (P = .005), mean temperature (P = .013), minimum temperature (P = .041), and daily temperature change (P = .003). A negative correlation was found between the number of patients presenting to the emergency department and daily average relative humidity (P = .031). The relationship between daily number of patients and average temperature (minimum, average, and maximum) and the relationship between daily number of patients and average relative humidity are shown in Figs. 4 and 5. No statistically significant correlation was found between the daily number of patients presenting to the emergency department and daily maximum-minimum, mean pressure, and daily pressure changes (P N .05). Although a positive correlation was seen between the number of patients with migraine and daily average wind speed (in meters per second), this was not statistically significant (P N .05). The correlation between the daily number of patients and weather variables is shown in Table. No significant correlation was found between the number of patients with migraine headaches and moon phases (P N .05). We also compared the moon phases and the number of patients for 4 seasons, but it did not provide a meaningful result.
3. Results 4. Discussion A total of 3491 patients who admitted to the emergency department with migraine headaches for a period of 12 months were included in our study. Patients with migraine headaches constituted 1.97% of all patients
Causes that trigger migraine attacks are not elucidated and internal or external factors play a role. The effects of changes in meteorologic
M. Yilmaz et al. / American Journal of Emergency Medicine 33 (2015) 409–413
411
450 400 350
Patients
300 250 200 150 100 50 0 Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Days Female
Male
Fig. 2. The number of patients admitted to the emergency department with migraine headache by days.
300
250
Patient
200
150
100
50
0
Months Female
Male
Fig. 3. The number of patients admitted to the emergency department with migraine headache by months.
Fig. 4. The relationship between daily number of patients and average temperatures (maximum, average, and minimum temperature).
412
M. Yilmaz et al. / American Journal of Emergency Medicine 33 (2015) 409–413
Fig. 5. The relationship between the daily number of patients and average relative humidity.
parameters, one of the external factors, on migraine attacks were investigated several times and different results were obtained. Migraines are known to be triggered by multi factorial reasons and studies to identify these trigger reasons continue. Pathophysiological mechanisms of changes in the weather in causing headaches are not exactly known [16]. We found in our research that the number of patients who were admitted to the emergency department because of migraine headaches is more in the days when the temperature increases and humidity decreases. There have been published studies in the literature showing that high relative humidity increases frequency of migraine attacks [12,17]. In 2 studies on patients admitted to the emergency department with migraine headaches, no relationship has been reported between humidity and the number of patients with migraine attacks [14,15]. Meanwhile Gomersall and Stuart [9] found similar results to our study showing a negative correlation with humidity in his study with data obtained from headache diaries of 56 patients. Hence, increase in the number of patients with migraine attacks is seen with low humidity. Increase in the frequency of migraine attacks with increase in temperature is supported by many studies [14,18,19]. Nevertheless, there are publications showing that the temperature increase or decrease has no relationship with migraine headaches [12,15]. In recent years, Hoffmann et al [17] showed increased frequency of migraine headaches in a study conducted at low temperature. The results of the 2 studies are different in which patients with migraine headaches admitted to the emergency department were selected and there were many patients [13,14]. Villeneuve et al [15] reported no association between the number of patients presenting to the emergency department with migraine attacks and temperature in their study on 4039 patients. In a study by Mukamal et al [14] on 7054 patients, they concluded similarly to our
study that the number of patients with migraine headaches increases with temperature rise. In the same study, it was also shown that every 5°C increase increases headache risk by 7.5%, and this is parallel with our result of increase in the number of patients admitted to the emergency department with increased daily temperature changes. Although there are studies [18,19] showing that migraine attacks increase with high atmospheric pressure, our results are similar to the results of studies showing no relationship between migraine headache and atmospheric pressure [14,15,17,20]. In addition, there are studies showing that migraine attacks increase with low atmospheric pressure [9,12]. Results published by several authors on possible effects of meteorologic parameters such as relative humidity, air temperature, and atmospheric pressure are different. This situation suggests that meteorologic parameters alone do not have a direct effect on the number of patients presenting to the emergency department with a migraine headache, but suggesting that other trigger factors play role together with weather parameters. Stress disorders, changes in sleeping character, or insomnia is known to trigger headaches often [5,21,22]. Stress is a process resulting from interaction with social or natural environment. As there is a common belief that stress is increased during full moon, we have included possible relationship between the number of patients who referred to the emergency department with migraine headaches and moon phases. Although acute behavioral disorders, tendency to violence in psychiatric patients [21,23], and sleep disorders [24] have been reported to be more during full moon in several publications, we did not find a significant relationship between moon phases and the number of patients admitted to the emergency department with migraine headaches.
5. Conclusion Table Comparison of meteorologic data with the daily number of patients
No. of patients/d
Maximum temperature Minimum temperature Mean temperature Max-min temperature Mean relative humidity Maximum pressure Minimum pressure Mean pressure Max-min pressure Mean windy rate
r (Pearson correlation)
P
0.146 0.107 0.130 0.153 −0.113 0.01 0.029 0.021 −0.066 0.008
.005 .041 .013 .003 .031 .848 .585 .685 .212 .880
Different results were obtained from studies examining the relationship between meteorologic parameters and migraine headaches. Therefore, as a result of our study in which we investigated the effect of regional meteorologic parameters on the number of patients admitting to emergency department with migraine headache, we have detected that the number of patients admitting to the emergency department with migraine headaches increase with high temperature and low humidity. In addition, we have concluded that there is no relationship between moon phases and the number of patients admitting to the emergency department with migraine headaches. Further studies are needed for a more detailed description of factors that trigger migraine attacks and affect the number of migraine attack patients.
M. Yilmaz et al. / American Journal of Emergency Medicine 33 (2015) 409–413
6. Study limitations Other trigger factors that cause migraine attacks in patients cannot be questioned and the exact time of headache start cannot be determined as our study is retrospectively conducted.
References [1] Lipton RB, Bigal ME. The epidemiology of migraine. Am J Med 2005;118(1):3S–10S. [2] Pietrobon D, Moskowitz MA. Pathophysiology of migraine. Annu Rev Physiol 2013; 75:365–91. [3] Bigal ME, Rapoport AM, Lipton RB, Tepper SJ, Sheftell FD. Assessment of migraine disability using the migraine disability assessment (MIDAS) questionnaire: a comparison of chronic migraine with episodic migraine. Headache 2003;43(4):336–42. [4] Bera SC, Khandelwal SK, Sood M, Goyal V. A comparative study of psychiatric comorbidity, quality of life and disability in patients with migraine and tension type headache. Neurol India 2014;62(5):516–20. [5] Kelman L. The triggers or precipitants of the acute migraine attack. Cephalalgia 2007;27(5):394–402. [6] Spierings EL, Ranke AH, Honkoop PC. Precipitating and aggravating factors of migraine versus tension-type headache. Headache 2001;41(6):554–8. [7] Zivadinov R, Willheim K, Sepic-Grahovac D, Jurjevic A, Bucuk M, Brnabic-Razmilic O, et al. Migraine and tension-type headache in Croatia: a population-based survey of precipitating factors. Cephalalgia 2003;23(5):336–43. [8] Cooke LJ, Rose MS, Becker WJ. Chinook winds and migraine headache. Neurology 2000;54(2):302–7. [9] Gomersall JD, Stuart A. Variations in migraine attacks with changes in weather conditions. Int J Biometeorol 1973;17(3):285–99.
413
[10] Osterman PO, Lövstrand KG, Lundberg PO, Lundquist S, Muhr C. Weekly headache periodicity and the effect of weather changes on headache. Int J Biometeorol 1981;25(1):39–45. [11] Osterman PO, Lundberg PO, Lundquist S, Lövstrand KG, Muhr C. Weekly periodicity of headache and the effect of changes in weather on headache. Ups J Med Sci Suppl 1980;31:23–6. [12] Prince PB, Rapoport AM, Sheftell FD, Tepper SJ, Bigal ME. The effect of weather on headache. Headache 2004;44(6):596–602. [13] Vaitl D, Propson N, Stark R, Walter B, Schienle A. Headache and sferics. Headache 2001;41(9):845–53. [14] Mukamal KJ, Wellenius GA, Suh HH, Mittleman MA. Weather and air pollution as triggers of severe headaches. Neurology 2009;72(10):922–7. [15] Villeneuve PJ, Szyszkowicz M, Stieb D, Bourque DA. Weather and emergency room visits for migraine headaches in Ottawa, Canada. Headache 2006;46(1):64–72. [16] Zebenholzer K, Rudel E, Frantal S, Brannath W, Schmidt K, Wöber-Bingöl C, et al. Migraine and weather: a prospective diary-based analysis. Cephalalgia 2011;31(4): 391–400. [17] Hoffmann J, Lo H, Neeb L, Martus P, Reuter U. Weather sensitivity in migraineurs. J Neurol 2011;258(4):596–602. [18] Alstadhaug KB, Salvesen R, Bekkelund SI. Seasonal variation in migraine. Cephalalgia 2005;25(10):811–6. [19] Walach H, Betz HD, Schweickhardt A. Sferics and headache: a prospective study. Cephalalgia 2001;21(6):685–90. [20] Wilkinson M, Woodrow J. Migraine and weather. Headache 1979;19(7):375–8. [21] Owen C, Tarantello C, Jones M, Tennant C. Lunar cycles and violent behaviour. Aust N Z J Psychiatry 1998;32(4):496–9. [22] Siniatchkin M, Riabus M, Hasenbring M. Coping styles of headache sufferers. Cephalalgia 1999;19(3):165–73. [23] Calver LA, Stokes BJ, Isbister GK. The dark side of the moon. Med J Aust 2009; 191(11–12):692–4. [24] Turányi CZ, Rónai KZ, Zoller R, Véber O, Czira ME, Ujszászi A, et al. Association between lunar phase and sleep characteristics. Sleep Med 2014;15(11):1411–6.
Contents lists available at ScienceDirect
American Journal of Emergency Medicine journal homepage: www.elsevier.com/locate/ajem
Original Contribution
Meteorologic parameters and migraine headache: ED study Mustafa Yilmaz, MD a,⁎, Mehtap Gurger, MD a, Metin Atescelik, MD a, Mustafa Yildiz, MD a, Sukru Gurbuz, MD b a b
Department of Emergency Medicine, Firat University School of Medicine, Elazig, Turkey Department of Emergency Medicine, Inonu University School of Medicine, Malatya, Turkey
a r t i c l e
i n f o
Article history: Received 1 December 2014 Received in revised form 24 December 2014 Accepted 24 December 2014
a b s t r a c t Aim: Migraine is common in society and is one of the primary causes of chronic headache with episodes. In this study, we aimed to determine the role of meteorologic parameters and moon phase on triggering migraine attacks and effects on the number of patients presenting to the emergency department with migraine headaches. Materials and Methods: Patients admitted to the emergency department due to a migraine headache during a 1year period were studied retrospectively. Correlation between moon phases, pressure, temperature, humidity, wind speed values of meteorologic observation, and recording station located in the same city and daily number of patients was analyzed. Results: A total of 3491 patients, of whom 72% (n = 2518) were women, were enrolled. The average daily number of patients was 9.6 ± 4 (3-24). A statistically significant correlation was found between the number of daily patients and daily maximum temperature (P = .005), mean temperature (P = .013), minimum temperature (P = .041), and daily temperature change (P = .003). In addition, a negative correlation was found between the daily number of patients presenting to the emergency department and daily relative humidity (in percentage; P = .031). No significant relationship was found between moon phases and the number of patients. Conclusion: We have determined that the number of patients admitted to the emergency department with migraine headache has increased with high temperature and low humidity and that there is no relationship between the number of patients and moon phases. © 2014 Elsevier Inc. All rights reserved.
1. Introduction Migraine, most common disease in the community, is one of the primary causes of chronic headache with periods of remission and exacerbations. It is seen in about 12% of population, and it is more common in women [1,2]. Migraine causes individuals to limit their daily activities because it has attacks that last for hours and even days, and these attacks cause occasional severe headaches [3,4]. Although causes that trigger migraine attacks and their mechanisms of action are not fully identified, many internal (personal) or external (environmental) factors such as hormonal changes, menstrual periods, emotional stress, hunger, fatigue, odors, noise, and sleep pattern changes trigger a migraine attack or cause an increase in headaches [5]. Identification and avoidance of the factors that trigger or aggravate migraine attacks constitutes the first and most important step in the prevention of migraine attacks. Because avoidance of trigger factors can significantly decrease severity or frequency of attacks, studies for identifying factors that trigger migraine attacks continue [6,7]. The results of the studies that examine whether
⁎ Corresponding author. Department of Emergency Medicine, Firat University Faculty of Medicine, 23200 Elazig, Turkey. Tel.: +90 424 2370000/1443. E-mail addresses: [email protected] (M. Yilmaz), [email protected] (M. Gurger), [email protected] (M. Atescelik), [email protected] (M. Yildiz), [email protected] (S. Gurbuz). http://dx.doi.org/10.1016/j.ajem.2014.12.056 0735-6757/© 2014 Elsevier Inc. All rights reserved.
there is a relationship between migraine attacks and meteorologic parameters, an external cause, are different, so this suggests that the mystery of this issue is still unsolved and further studies are needed. Although positive correlations between migraine and bright snow cover, atmospheric pressure, wind, and temperature have been reported, some meteorologic parameters have been shown to have negative correlation or even no relationship. Hence, those results reveal the difference between the results of studies [7–13]. In the literature, the number of studies examining the correlation between the meteorologic parameters and the number of emergency department patients presenting with migraine attack is very low [14,15]. In our study, we also aimed to investigate whether meteorologic parameters affect the daily number of patients admitted to the emergency department with migraine headaches. In addition, we also investigated whether the daily number of patients with migraine attacks is affected according to moon phases. Our study differs from several previous studies because there are no subjective records such as headache diaries, personal comments are avoided by not making individual interviews, and a more objective evaluation was done. In addition, we aimed to determine the effect of our regional weather variables on the number of patients admitted to the emergency department with a migraine attack and share the results because most studies examining the effects of meteorologic parameters on migraine headache have different results.
410
M. Yilmaz et al. / American Journal of Emergency Medicine 33 (2015) 409–413
300 250
Patients
200 150 100 50 0 1
2
3
4
5
6
7
8
9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
hours* Female
Male
Fig. 1. The number of patients presenting to the emergency department by hours (*1 = 0100-0159; 2 = 0200-0259; 3 = 0300-0359 … etc).
2. Materials and methods 2.1. Study patients A total of 3491 patients older than 18 years who admitted to emergency department of a regional hospital located in Turkey between January 1 and December 31, 2013, with a headache that is consistent with migraine and whose diagnosis were encoded as G-43 from International Classification for Diseases, 10th Revision coding system were retrospectively evaluated. Patients who had other diseases causing headache (hypertension, subarachnoid bleeding, sinusitis, trauma, etc) were excluded from the study. Patients with recurrent hospital visits due to migraine attacks in 1 year were also included in the study. 2.2. Meteorologic data Daily average-maximum-minimum (max-min) temperature (in degrees Celsius), atmospheric pressure (in millibars), humidity (in percentage), and wind speed (in meters per second) values were obtained from meteorologic observation and recording station located in the same city. Also daily max-min difference of atmospheric pressure and temperature was calculated. In addition, for each month, moon phases were enrolled in the study as new moon, first quarter, full moon, last quarter, and other days. For each moon phase (new moon, first quarter, full moon, last quarter), 1 day before and 1 day after were also included. Thus 3day data were assessed for each moon phase. Number of patients in the days including each moon phase for a year was identified, and correlation between moon phases and number of patients admitted to the emergency department with a migraine headache was examined. 2.3. Statistical analysis Statistical Package for the Social Sciences (SPSS 21, Chicago, IL) statistical software was used for data analysis. Numerical variables were expressed as mean ± SD and categorical variables as percentage. Independent-sample t test or 1-way analysis of variance was used for numerical data analysis and χ2 test for categorical variables analysis. Pearson correlation test was used to determine the relationship between the numerical parameters. P b .05 was considered statistically significant.
(3491/176 909) who admitted to the emergency department within 1 year. Seventy-two percent (n = 2518) of patients were female, and the average age of all patients was 36 ± 11 years. There was no difference between men and women according to the mean age (P N .05). The average daily number of patients was 9.6 ± 4 (3-24). Regarding the time of day, migraine attacks were highest between 2000 and 2100 hours, and a total of 367 patients (270 female and 97 male) with migraine headaches were admitted to emergency department. Also, it was found that more migraine patients were admitted to the emergency department in the evening compared with other times of the day. Fifty-five percent (n = 1921) of all migraine patients were admitted to emergency department in the evening between 1700 and 2359.More than half (73.5%; n = 1412) of these patients were female. Arrival times of the patients by sex are shown in Fig. 1. Most of the female patients had migraine attacks on Sunday (16.6%) and Saturday (15.3%). Most of the male patients were admitted to emergency department on Tuesday (15.4%) and Sunday (15.2%) (Fig. 2). Most of the patients were admitted to emergency department with a migraine headache in October (10.5%) and November (10.6%). The number of patients presenting to the emergency department by month was presented in Fig. 3. Statistically significant correlations were found between the daily number of patients and daily maximum temperature (P = .005), mean temperature (P = .013), minimum temperature (P = .041), and daily temperature change (P = .003). A negative correlation was found between the number of patients presenting to the emergency department and daily average relative humidity (P = .031). The relationship between daily number of patients and average temperature (minimum, average, and maximum) and the relationship between daily number of patients and average relative humidity are shown in Figs. 4 and 5. No statistically significant correlation was found between the daily number of patients presenting to the emergency department and daily maximum-minimum, mean pressure, and daily pressure changes (P N .05). Although a positive correlation was seen between the number of patients with migraine and daily average wind speed (in meters per second), this was not statistically significant (P N .05). The correlation between the daily number of patients and weather variables is shown in Table. No significant correlation was found between the number of patients with migraine headaches and moon phases (P N .05). We also compared the moon phases and the number of patients for 4 seasons, but it did not provide a meaningful result.
3. Results 4. Discussion A total of 3491 patients who admitted to the emergency department with migraine headaches for a period of 12 months were included in our study. Patients with migraine headaches constituted 1.97% of all patients
Causes that trigger migraine attacks are not elucidated and internal or external factors play a role. The effects of changes in meteorologic
M. Yilmaz et al. / American Journal of Emergency Medicine 33 (2015) 409–413
411
450 400 350
Patients
300 250 200 150 100 50 0 Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Days Female
Male
Fig. 2. The number of patients admitted to the emergency department with migraine headache by days.
300
250
Patient
200
150
100
50
0
Months Female
Male
Fig. 3. The number of patients admitted to the emergency department with migraine headache by months.
Fig. 4. The relationship between daily number of patients and average temperatures (maximum, average, and minimum temperature).
412
M. Yilmaz et al. / American Journal of Emergency Medicine 33 (2015) 409–413
Fig. 5. The relationship between the daily number of patients and average relative humidity.
parameters, one of the external factors, on migraine attacks were investigated several times and different results were obtained. Migraines are known to be triggered by multi factorial reasons and studies to identify these trigger reasons continue. Pathophysiological mechanisms of changes in the weather in causing headaches are not exactly known [16]. We found in our research that the number of patients who were admitted to the emergency department because of migraine headaches is more in the days when the temperature increases and humidity decreases. There have been published studies in the literature showing that high relative humidity increases frequency of migraine attacks [12,17]. In 2 studies on patients admitted to the emergency department with migraine headaches, no relationship has been reported between humidity and the number of patients with migraine attacks [14,15]. Meanwhile Gomersall and Stuart [9] found similar results to our study showing a negative correlation with humidity in his study with data obtained from headache diaries of 56 patients. Hence, increase in the number of patients with migraine attacks is seen with low humidity. Increase in the frequency of migraine attacks with increase in temperature is supported by many studies [14,18,19]. Nevertheless, there are publications showing that the temperature increase or decrease has no relationship with migraine headaches [12,15]. In recent years, Hoffmann et al [17] showed increased frequency of migraine headaches in a study conducted at low temperature. The results of the 2 studies are different in which patients with migraine headaches admitted to the emergency department were selected and there were many patients [13,14]. Villeneuve et al [15] reported no association between the number of patients presenting to the emergency department with migraine attacks and temperature in their study on 4039 patients. In a study by Mukamal et al [14] on 7054 patients, they concluded similarly to our
study that the number of patients with migraine headaches increases with temperature rise. In the same study, it was also shown that every 5°C increase increases headache risk by 7.5%, and this is parallel with our result of increase in the number of patients admitted to the emergency department with increased daily temperature changes. Although there are studies [18,19] showing that migraine attacks increase with high atmospheric pressure, our results are similar to the results of studies showing no relationship between migraine headache and atmospheric pressure [14,15,17,20]. In addition, there are studies showing that migraine attacks increase with low atmospheric pressure [9,12]. Results published by several authors on possible effects of meteorologic parameters such as relative humidity, air temperature, and atmospheric pressure are different. This situation suggests that meteorologic parameters alone do not have a direct effect on the number of patients presenting to the emergency department with a migraine headache, but suggesting that other trigger factors play role together with weather parameters. Stress disorders, changes in sleeping character, or insomnia is known to trigger headaches often [5,21,22]. Stress is a process resulting from interaction with social or natural environment. As there is a common belief that stress is increased during full moon, we have included possible relationship between the number of patients who referred to the emergency department with migraine headaches and moon phases. Although acute behavioral disorders, tendency to violence in psychiatric patients [21,23], and sleep disorders [24] have been reported to be more during full moon in several publications, we did not find a significant relationship between moon phases and the number of patients admitted to the emergency department with migraine headaches.
5. Conclusion Table Comparison of meteorologic data with the daily number of patients
No. of patients/d
Maximum temperature Minimum temperature Mean temperature Max-min temperature Mean relative humidity Maximum pressure Minimum pressure Mean pressure Max-min pressure Mean windy rate
r (Pearson correlation)
P
0.146 0.107 0.130 0.153 −0.113 0.01 0.029 0.021 −0.066 0.008
.005 .041 .013 .003 .031 .848 .585 .685 .212 .880
Different results were obtained from studies examining the relationship between meteorologic parameters and migraine headaches. Therefore, as a result of our study in which we investigated the effect of regional meteorologic parameters on the number of patients admitting to emergency department with migraine headache, we have detected that the number of patients admitting to the emergency department with migraine headaches increase with high temperature and low humidity. In addition, we have concluded that there is no relationship between moon phases and the number of patients admitting to the emergency department with migraine headaches. Further studies are needed for a more detailed description of factors that trigger migraine attacks and affect the number of migraine attack patients.
M. Yilmaz et al. / American Journal of Emergency Medicine 33 (2015) 409–413
6. Study limitations Other trigger factors that cause migraine attacks in patients cannot be questioned and the exact time of headache start cannot be determined as our study is retrospectively conducted.
References [1] Lipton RB, Bigal ME. The epidemiology of migraine. Am J Med 2005;118(1):3S–10S. [2] Pietrobon D, Moskowitz MA. Pathophysiology of migraine. Annu Rev Physiol 2013; 75:365–91. [3] Bigal ME, Rapoport AM, Lipton RB, Tepper SJ, Sheftell FD. Assessment of migraine disability using the migraine disability assessment (MIDAS) questionnaire: a comparison of chronic migraine with episodic migraine. Headache 2003;43(4):336–42. [4] Bera SC, Khandelwal SK, Sood M, Goyal V. A comparative study of psychiatric comorbidity, quality of life and disability in patients with migraine and tension type headache. Neurol India 2014;62(5):516–20. [5] Kelman L. The triggers or precipitants of the acute migraine attack. Cephalalgia 2007;27(5):394–402. [6] Spierings EL, Ranke AH, Honkoop PC. Precipitating and aggravating factors of migraine versus tension-type headache. Headache 2001;41(6):554–8. [7] Zivadinov R, Willheim K, Sepic-Grahovac D, Jurjevic A, Bucuk M, Brnabic-Razmilic O, et al. Migraine and tension-type headache in Croatia: a population-based survey of precipitating factors. Cephalalgia 2003;23(5):336–43. [8] Cooke LJ, Rose MS, Becker WJ. Chinook winds and migraine headache. Neurology 2000;54(2):302–7. [9] Gomersall JD, Stuart A. Variations in migraine attacks with changes in weather conditions. Int J Biometeorol 1973;17(3):285–99.
413
[10] Osterman PO, Lövstrand KG, Lundberg PO, Lundquist S, Muhr C. Weekly headache periodicity and the effect of weather changes on headache. Int J Biometeorol 1981;25(1):39–45. [11] Osterman PO, Lundberg PO, Lundquist S, Lövstrand KG, Muhr C. Weekly periodicity of headache and the effect of changes in weather on headache. Ups J Med Sci Suppl 1980;31:23–6. [12] Prince PB, Rapoport AM, Sheftell FD, Tepper SJ, Bigal ME. The effect of weather on headache. Headache 2004;44(6):596–602. [13] Vaitl D, Propson N, Stark R, Walter B, Schienle A. Headache and sferics. Headache 2001;41(9):845–53. [14] Mukamal KJ, Wellenius GA, Suh HH, Mittleman MA. Weather and air pollution as triggers of severe headaches. Neurology 2009;72(10):922–7. [15] Villeneuve PJ, Szyszkowicz M, Stieb D, Bourque DA. Weather and emergency room visits for migraine headaches in Ottawa, Canada. Headache 2006;46(1):64–72. [16] Zebenholzer K, Rudel E, Frantal S, Brannath W, Schmidt K, Wöber-Bingöl C, et al. Migraine and weather: a prospective diary-based analysis. Cephalalgia 2011;31(4): 391–400. [17] Hoffmann J, Lo H, Neeb L, Martus P, Reuter U. Weather sensitivity in migraineurs. J Neurol 2011;258(4):596–602. [18] Alstadhaug KB, Salvesen R, Bekkelund SI. Seasonal variation in migraine. Cephalalgia 2005;25(10):811–6. [19] Walach H, Betz HD, Schweickhardt A. Sferics and headache: a prospective study. Cephalalgia 2001;21(6):685–90. [20] Wilkinson M, Woodrow J. Migraine and weather. Headache 1979;19(7):375–8. [21] Owen C, Tarantello C, Jones M, Tennant C. Lunar cycles and violent behaviour. Aust N Z J Psychiatry 1998;32(4):496–9. [22] Siniatchkin M, Riabus M, Hasenbring M. Coping styles of headache sufferers. Cephalalgia 1999;19(3):165–73. [23] Calver LA, Stokes BJ, Isbister GK. The dark side of the moon. Med J Aust 2009; 191(11–12):692–4. [24] Turányi CZ, Rónai KZ, Zoller R, Véber O, Czira ME, Ujszászi A, et al. Association between lunar phase and sleep characteristics. Sleep Med 2014;15(11):1411–6.
