Abstract
Purpose of Review
Previous studies have indicated a possible link between the prevalence of cluster headache (CH) and sunlight exposure. However, this theory has yet to be tested systemically. In this article, we aim to examine how latitude affects the prevalence and phenotypes of CH.
Recent Findings
To our knowledge, there is by far no article describing the effect of latitude on disease phenotype; thus, we performed a literature review. We noted positive effects of latitude on 1-year prevalence, the proportion of chronic CH, and the proportion of miosis and/or ptosis.
Summary
Latitude may affect the phenotypic presentations of cluster headache, probably partially mediated via temperature and sunlight variations. Still, other factors, such as environmental exposure to smoking and the genetic difference between the Eastern and Western populations, may participate in the pathogenesis and clinical manifestations of CH.
Similar content being viewed by others
Avoid common mistakes on your manuscript.
Introduction
Cluster headache (CH) is a primary headache disorder listed under the category of trigeminal autonomic cephalalgia (TAC), as defined by the International Classification Headache Disorders, 3rd edition (ICHD-3) [1]. CH is characterized by severe pain and the featured cranial autonomic symptoms (CAS), including unilateral lacrimation, conjunctival injection, rhinorrhea, nasal congestion, eyelid edema, forehead and facial sweating, miosis, and ptosis [1]. Though not listed among the diagnostic criteria, patients with CH present attacks periodically at a specific time within a day, i.e., the circadian rhythm, or within a year, i.e., the circannual rhythm. Thus, CH is also nicknamed the “alarm headache.” The hypothalamus, a structure that participates in day-night circadian regulation and sensing seasonal variation, has been proposed to play a central role in regulating the periodic presentations [2].
Latitude is a geographic coordinate related to several geometric measurements, such as temperature or sunlight variation [3]. One well-known example of how latitude affects a disease is through the study of multiple sclerosis, in which the disease is more prevalent among residents who live at a higher latitude [4]. Moreover, other autoimmune diseases, such as the latitude-dependent autoimmune diseases (LDADs), also showed a positive correlation between latitude and disease prevalence [5]. Among these disorders, a lowered vitamin D level at a higher latitude was commonly proposed to be one of the disease-causing mechanisms [4].
Previous studies have suggested a possible link between sunlight exposure and the prevalence of CH; moreover, seasonal preferences of bouts have also been reported in clinical studies [6]. Since latitude is the geographical coordinate that could affect sunlight variation [3], we hypothesized that there is a correlation between the clinical presentations of CH and latitude. Thus, we aimed to perform a literature review to decipher how geographic factors affect disease phenotype.
Methods
Literature Search
A literature review was performed with the PubMed database, and a selection diagram with PRISMA 2020 was utilized to identify eligible articles in our analysis (Fig. 1) [7]. In the searching step, the terms “Cluster headache” with Medical Subject Headings (MeSH) and “Epidemiology” were used (Query string: (Cluster headache [MeSH]) AND (Epidemiology)). The articles were searched up to November 24th, 2023, and there were no limitations to the year of publication or language of the publications.
A total of 321 studies were identified from PubMed, and their titles and abstracts were screened by one of the authors [Y.C.L.] independently. Two hundred and seventy-seven studies were excluded in the first step for the following reasons: (1) 267 studies with unrelated content, (2) three with no identified geographic regions or were multi-country studies that a specific geographic coordinate could not be defined, (3) six with no available full text, and (4) one without an English abstract. This resulted in 44 studies being assessed in the next step.
In the second step, a nested selection process was performed; that is, we searched the references from the selected articles to encompass a broader collection of the literature. We first divided the 44 articles into two main categories, by whether they were “meta-analysis or review article” (N = 10) or not (N = 34). We extracted all of the references from the ten articles assigned to the first category, and a second literature selection process was performed by screening their titles and abstracts. Initially, a total of 914 references were found. After 889 articles being excluded with specific reasons (Fig. 1), 25 articles survived this selection process. For the 34 articles listed in the second category, four articles were excluded for reasons specified in Fig. 1, and 30 articles survived. Lastly, we also searched our database from previous studies, and additional 10 studies, which are different from the previous 55 studies, were selected. Finally, a total of 65 studies were included for data extraction [6, 8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36,37,38,39,40,41,42,43,44,45,46,47,48,49,50,51,52,53,54,55,56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71].
Prevalence Study
To investigate the relationship between disease prevalence and latitude, studies based on community population were selected. Since the bout frequency for most studies reported an average of 1 bout per year, and in Asian studies, the frequency is even lower [72], the actual headache prevalence might be underestimated if the study timeframe was short. Thus, we reported both the 1-year prevalence and lifetime prevalence separately among those studies based on their study designs or the content of questionnaires. Among the 22 studies recruited for data extraction, two were deemed ineligible for analysis and further excluded. A study from Addis Ababa, Ethiopia, reported 3 patients over 231 participants in the general population [37], which makes the lifetime prevalence of 1.2%. However, considering that this community encompassed only 400 households, and there were an average of four people in a household, the prevalence might be overestimated due to their close relationships. In another Swedish study [24], the prevalence was around 0.2% (48/31,750); however, since the population was based on a twin study, we excluded this article for the potential overestimation of the prevalence. Moreover, to deal with studies from the same community (two studies from San Marino [21, 33] and two from Stockholm, Sweden [8, 25]), only the studies with a larger population enrolled were kept [8, 21]. After selection, a total of 18 articles were enrolled for the prevalence study [8, 14, 16, 19, 21, 27, 30, 34,35,36, 38, 51,52,53, 55, 62, 67, 68].
Clinical Presentations
To investigate the relationship between clinical presentations of CH and latitude, we collected the studies providing at least one clinical phenotype, and the phenotypes were extracted. Both community- and hospital-based studies were enrolled. We enrolled all the studies, including episodic CH (eCH) or chronic CH (cCH). Moreover, if the studies provided only the data in subgroups (i.e., females and males) rather than the total population, we performed simple statistics to restore the data for the entire population by the patient numbers provided in the studies. A total of 57 articles were enrolled for final analysis [6, 9,10,11,12,13,14,15, 17, 18, 20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35,36, 38,39,40,41,42,43,44,45,46,47,48,49,50, 54, 56,57,58,59,60,61,62,63,64,65,66,67,68,69,70,71]. Since the reported clinical data differed from study to study, we did not exclude studies with duplicated cities in the initial step, and we enrolled as many studies as possible. However, during analysis, to avoid over-estimation, if a variable was available in multiple studies from the same city, the studies with the largest number of enrolled CH patients were kept due to a higher accuracy in a larger sample size. Therefore, the number of the studies differed in the analysis of each variable.
Regarding the analysis for cCH, since the selected articles spanned the timeframe before and after the implement of ICHD-3, the definition of cCH differed; thus, for the analysis regarding the proportion of cCH, we examined both conditions with (1) all studies enrolled, and (2) ICHD-3 subgroups alone. Moreover, since previous studies have suggested a strong correlation between smoking and cCH as well as a discrepancy between Eastern and Western populations, we adjusted both factors in the analysis of cCH [72,73,74].
In a previous study, the authors indicated a discrepancy of clinical presentations between Western and Eastern countries [72]. In this study, the studies from Western countries had a significantly higher latitude than those from Eastern countries. Therefore, for variables other than cCH, we adjusted this factor in the regression model for items that showed significance in Spearman’s correlation test. This study listed North and South American and Egyptian articles [67] as studies from Western countries.
Neuropsychiatric Comorbidities
To examine the psychiatric comorbid conditions of cluster headaches, we investigated the contents of our collected literature. Though there were several studies describing psychological symptoms including depression, anxiety, and sleep disturbances, the methods and the assessment tools varied. After initial screening, 9 articles were enrolled [13, 17, 18, 26, 38, 42, 43, 49, 71]. An additional 7 articles were selected from reference screening [75,76,77,78,79,80,81]. Three studies were excluded due to no defined geographic boundaries [76, 80, 81]. For studies reporting depression, 7 reported the proportion of depression among the patients [13, 38, 42, 71, 75, 77, 79], and another four, all from Seoul, Korea, used the Patient Health Questionnaire-9 (PHQ-9) to assess the severity of depression [18, 26, 49, 78]. For anxiety, one reported the proportion of anxiety [18], one reported the proportion of “nervous disease” [13], and another four Korean studies reported the General Anxiety Disorder-7 (GAD-7) scores [18, 26, 49, 78] in participants. Two studies reported the total score of the Hospital Anxiety and Depression Scale (HADS) [17, 43]. Two studies reported suicidal attempts [17, 38]. Other assessment methods for psychological disorders included the Perceived Stress Scale 4 (PSS-4) in two studies [18, 26], EQ-5D in two studies [18, 26], and sleep conditions in one study [17]. Considering that (1) this manuscript is not a narrative review article, (2) the data of most psychological comorbidities assessments remained scarce, and (3) the studies reporting PHQ-9 and GAD-7 were located in the same city, we included only the proportion of depression in our final analysis [13, 38, 42, 71, 75, 77, 79].
Latitude Definition
In this study, we defined the latitudes mostly from the communities’ locations. If a specific community was not indicated, the hospitals where the research were carried out were used as surrogates. For studies utilizing multicenter registries, we examined their study designs, and if > 50% of the patients could be located in a defined region, the studies were enrolled after a vote between the authors. However, for studies with a multi-nation design, the articles were omitted. Other conditions were discussed case by case within the authors whether the article should be kept or not. We defined the latitude of each location by an online website (https://www.latlong.net/).
Statistics
The results were analyzed with R (R Core Team, 2019). For statistical analysis, non-parametric methods were carried out due to a relatively small sample size. For the correlation between latitude and the variables, Spearman’s correlation test was used. Linear regression was carried out to estimate the effect gradient on latitudinal change and to adjust for potential confounding factors. To test the differences between binary categories, such as the higher or lower latitude groups, the Wilcoxon rank sum test was applied. A significance level of all the statistics in our study was set at p value < 0.05 in a two-tailed test.
Results
A total of 65 articles with available full text in English were qualified for analysis. Among these articles, 18 articles reported prevalence, and 57 reported clinical profiles. The average latitude from the Western studies was significantly higher than that in the Eastern studies (Western: median = 43.3°, range = 8.1°–67.3°; Eastern: median = 34.7°, range = 3.1°–39.9°, p = 0.007).
Nine articles with 1-year prevalence encompassed a latitude ranging from 3.1° to 59.3° (median = 35.7°) and nine articles with lifetime prevalence ranging from 40.3° to 63.4° (median = 43.9°) (Table 1). Both the 1-year prevalence (rho = 0.57, p = 0.121) and lifetime prevalence (rho = 0.35, p = 0.359) of CH showed positive trends with the latitude, but the statistical significances were not reached. Of note, if the significant outlier (800/100,000) [67] from Egypt on 1-year prevalence was removed, the correlation between latitude and 1-year prevalence becomes statistically significant (rho = 0.74, p = 0.046), and for every degree of increased latitude, the 1-year prevalence rate increased 1.69/100000 (p = 0.038). There was no significant East–West difference for 1-year prevalence (p = 0.643).
A total of 40 studies reported the proportion of cCH, and the latitudes of these studies ranged from 25.0° to 61.9° (median = 44.8°) (Table 2). After removal of duplicate cities, there was a significantly positive correlation between the proportion of cCH and latitude (rho = 0.54, p < 0.001) in 19 cities, and for every one degree increase in latitude, the proportion of cCH increased 0.5% (p = 0.0003). If both smoking and East–West category were adjusted, there were no significant effect for latitude (p = 0.134), smoking rate (p = 0.365), or East–West category (p = 0.058). Among the 9 studies utilizing ICHD-3 for diagnosing cCH, the correlation between the proportion of cCH and latitude remained significantly positive (rho = 0.76, p = 0.007), and for every one degree increase in latitude, the proportion of cCH increased 0.7% (p = 0.007). After adjustment, there were no significant effect for latitude (p = 0.503), smoking rate (p = 0.536), nor East–West category (p = 0.174).
The proportion of male patients showed a non-significant negative correlation with latitude (rho = − 0.15, p = 0.385) (Table 2). The age in the study was significantly older in patients who dwelled in higher latitudes (rho = 0.519, p = 0.008), while the age at disease onset did not (rho = 0.34, p = 0.109). Though for every degree increase in latitude, the age in the study postponed by 0.19 years (p = 0.008), we did not find a correlation between diagnostic delay and latitude (rho = 0.19, p = 0.544). We also noted an increased trend of smoking rate among patients living in higher altitudes (rho = 0.52, p for rho = 0.024), and smoking rate increased by 0.5% for every degree increase of latitude (p = 0.027). There is no correlation between latitude and drinking rate (rho = 0.16, p = 0.613).
The latitude distribution of the 57 articles enrolled for clinical features ranged from 21.2° to 67.3° (median = 43.9°) (Table 2) There is no significant correlation between latitude and attack frequencies (rho = 0.26, p = 0.416), attack duration (rho = 0.08, p = 0.811), bout frequencies (rho = 0.24, p = 0.539), or bout duration (rho = 0.07, p = 0.812). For circadian and circannual rhythm and nocturnal attacks, the studies ranged from 25.0° to 67.3° (median = 37.6°). There is no significant correlation between latitude and circadian rhythm (rho = − 0.18, p = 0.555), circannual rhythm (rho = − 0.44, p = 0.276), or nocturnal attacks (rho = 0.57, p = 0.186).
For cranial autonomic symptoms, lacrimation remained the most commonly reported symptom (76.7%), and was followed by conjunctival injection (62.6%), rhinorrhea (56.6%), nasal congestion (48.5%), facial sweating (28.2%), eyelid edema (25.9%), ptosis (30.3%), and miosis (19.5%). Ptosis (rho = 0.70, p = 0.002) and miosis (rho = 0.56, p = 0.045) both showed significantly positive correlations with latitude. For every degree increase in latitude, there was a 1.3% increase in ptosis (p = 0.002) and a 0.7% increase in miosis (p = 0.045) (Table 2). The proportions of other symptoms, including lacrimation (rho = 0.23, p = 0.365), conjunctival injection (rho = − 0.03, p = 0.926), nasal congestion (rho = 0.31, p = 0.266), rhinorrhea (rho = 0.12, p = 0.661), facial sweating (rho = 0.38, p = 0.167), and eyelid edema (rho = 0.06, p = 0.846), were not correlated with latitude.
Among the accompanying symptoms, nausea (rho = − 0.69, p = 0.012) had a negative correlation with latitude. For every degree of increased latitude, the proportion of nausea decline by 0.7% (p = 0.012) (Table 2). Meanwhile, there is no significant correlation for vomiting (rho = − 0.59, p = 0.095), photophobia (rho = 0.46, p = 0.115), or phonophobia (rho = − 0.01, p = 0.964). We also did not find a correlation between the proportion of depression and latitude (rho = 0.50, p = 0.258).
For the factors that reached significant level on correlation analysis, after East–West category was adjusted, the significance for 1-year prevalence, proportion of cCH, smoking rate, ptosis, miosis, and nausea did not present for both latitude and East–West category (Suppl. Table 1).
Discussion
In our study, we showed that (1) the 1-year prevalence, (2) smoking rate, (3) the proportion of cCH, either diagnosed by ICHD-3 alone or not, and (4) the proportion of miosis and/or ptosis were positively correlated with latitude. However, we did not discover a correlation between circadian rhythm, circannual rhythm, or the frequencies of nocturnal attacks with latitude. This study encompasses literature with populations located in tropical, temperate, and arctic zones and with latitudes spanning from 3.1° to 67.3°, providing several clinical insights into CH. To our knowledge, the correlation between CH prevalence and latitude has not been systematically investigated previously.
Currently, the actual prevalence of CH remains uncertain. In this study, we updated the median 1-year prevalence to be around 64/100,000 and the lifetime prevalence to be 99.6/10,000, which resembled the data from a widely accepted meta-analysis in 2008, which reported a 1-year prevalence of 53/100,000 and a lifetime prevalence 124/100,000 [82]. We noticed that both 1-year prevalence and lifetime prevalence had positive correlations with the latitude, though the trends were insignificant. However, after we removed a potential outlier, the correlation between latitude and 1-year prevalence became significant. For other primary headaches, data from migraine showed the lifetime prevalence ranging from 2.6 to 6.9% in six cities located between 0° to 25° and 12.5% to 26.5% in seven cities located higher than 30° latitude, which resembled our results [83]. The mechanism of how latitude affects the prevalence of CH was not well studied, and here, we proposed three plausible mechanisms, including (1) vitamin D deficiency, (2) the variation of total sunshine hours, and (3) the variation of temperature. First, vitamin D deficiency has been proposed as a major pathomechanism for latitude-related diseases such as multiple sclerosis, psychiatric disorders, and primary headache disorders [4, 83,84,85]. In a Korean study (Seoul, 37.53° N), though the rate of vitamin D deficiency was high for patients with CH (92.8%), this level was not significantly different from normal controls. Moreover, the level did not differ between cluster or remission periods [86]. In Scandinavian countries located in high latitudes, though exposed to less UVB radiation, the prevalence of vitamin D deficiency is lower than expected possibly due to a higher consumption of salmon and trout in their diets [87]. Thus, both studies showed that vitamin D deficiency could not fully explain the latitude-related prevalence of CH. Recently, genetic studies on CH have provided further evidence. In a recently published GWAS study, a single-nucleotide polymorphism (SNP) (rs12121134) near DUSP10 was proposed to be related to CH, while this gene was also reported to be associated with vitamin D-related pathway [88, 89]. However, in a Greek genetic study, the authors examined three loci for the vitamin D receptor gene (VDR), and none of them showed a significant association with CH [90]. Another Swedish study examined a SNP (rs2228570) as in the Greek study also revealed negative results [91]. Taking the above findings together, the vitamin D pathway alone cannot fully explain the correlation between the prevalence of CH and latitudes. Second, it has been reported that the incidence of CH is inversely related to sunshine hours in a Taiwanese study [6, 83]. However, the total daylight hours in a year are distributed equally throughout the latitudes if the local weather conditions, such as cloudy days, were not taken into consideration [3, 92]. What is related to the latitude is the variation of sunlight [3]. Thus, for the Taiwanese study, the more appropriate explanation of the results might be due to the larger sunlight variation in Northern Taiwan [6]. Due to the scarce evidence on this topic, this hypothesis required further confirmation. A third explanation is the effect of temperature and its variation. A Greek study has shown that the average temperature is negatively correlated with both the latitude and the prevalence of daily headaches [93], though the study was not specific to CH. Moreover, another study reported that cluster attacks were more commonly presented during weather transitions, including seasonal and temperature changes [94]. Geographic evidence revealed a negative correlation between latitude and the absolute temperature, while a positive correlation was seen between the amplitude of temperature variation and latitude [3, 95, 96]. Taking the evidence together, we proposed that the larger temperature alteration, as well as the colder weather at higher latitudes, might be a factor that triggers CH. Since the hypothalamus is well-recognized as a center for temperature homeostasis and acts as a critical role in the pathomechanism of CH, how the climate at a higher latitude interacts with the function of the hypothalamus requires further clarification [2, 97].
It is now widely accepted that smoking is a risk factor for CH as well as the chronification of headaches, and their causal relationships were confirmed by a GWAS study utilizing Mendelian randomization [74]. We noticed that there was a higher smoking rate among patients in higher latitudes; however, this might be confounded by other factors since it is unreasonable to propose one’s smoking habit is affected by latitude. It has been reported that the smoking rates among Eastern studies (44.1% to 73.1%) were lower than the Western studies (67% to 88.3%), which resembled our results [72]. Since the Western studies selected in this study had a significantly higher latitude than the Eastern countries, after the adjustment was made, the significance of the effect of latitude disappeared. Thus, we proposed that the smoking rate remained largely affected by cultural or genetic differences between Eastern and Western populations [98].
Among the populations enrolled in this study, the proportion of cCH was significantly higher in those dwelled in higher latitudes, either the condition was diagnosed by all sorts of definition or by ICHD-3 alone. Several studies have suggested that smoking, a well-recognized risk factor for cCH, released cadmium and nicotine and disrupts the normally functioned hypothalamus-pituitary axis (HPA) [99, 100]. Moreover, though the hallmark of cCH is a loss of circannual periodicity or that bout lasted more than 9 months per year, we did not notice a longer bout duration or a loss of circadian presentation to be correlated with a higher latitude in this study. We believed that both environmental (smoking) and genetic factors concomitantly contribute to the chronification of CH. This hypothesis required further studies to examine their interactions.
Miosis and ptosis were both the results of sympathetic dysfunction, while lacrimation, conjunctival congestion, rhinorrhea, nasal congestions, or eyelid edema were due to activation of the parasympathetic reflex [101]. In this study, latitude correlated well with miosis and ptosis, but not with symptoms contributed by parasympathetic activation. We proposed two main mechanisms for this finding, including (1) the effect of temperature, and (2) the preserved hibernation habit. For the first hypothesis, previous studies showed that the prevalence of ptosis is correlated with age, diabetes, and high blood pressure and that the latter two diseases had inverse correlations with latitude, which might be the result of the lower ambient temperature at higher latitudes [102,103,104]. Some studies have suggested that miosis and ptosis were caused by the dysfunction of intracranial sympathetic nerves due to the dilatation of carotid arteries [105]. In an animal study, the carotid artery showed reversible vasodilatation by cooling from 37 to 4 ℃ to preserve cerebral blood flow [106]. These results could partially explain the higher prevalence of ptosis or miosis in colder places. For the second hypothesis, in animals dwelled at higher latitudes, they decreased their sympathetic tones and increased parasympathetic tones to prepare for hibernation during winter [107]. The results of the alteration of the autonomic nervous system during hibernation resembled the clinical features of CH and could to some degree echo the higher prevalence of CH in high-latitude residents. Both the hypotheses that a colder temperature and the adjustment of the autonomic nervous system during hibernation partly explained the higher presentation of miosis/ptosis at higher latitudes.
Depression has been reported to be more prevalent among CH patients than normal subjects [75]. However, we cannot find a significant relationship between the proportion of depression and latitude among CH patients. Our finding is in line with previous evidence that the relationship between depression and latitude was conflicting [108,109,110]. Due to the scarce data on CH patients, further investigation is required.
To sum up, we believe that the pathomechanism of CH remains multifactorial, which includes environmental, genetic, and bio-social factors. In this study, we have shown that latitude affects the prevalence of CH, the proportion of cCH, and symptoms related to sympathetic dysfunction. This might be due to the effect of environmental factors, such as the ambient temperature or sunlight exposure. Secondly, the discrepancies between Eastern and Western studies might have complicated our results [72]. Nevertheless, since the significant effect of latitude disappeared after adjusting for this factor in most variables, different genetic backgrounds among Eastern or Western populations remained a plausible explanation in this study. Lastly, it has been a widely acknowledged concept that smoking can cause CH or cCH [73, 74]. Though not widely explored in this study, smoking still represents an important bio-social factor in shaping the phenotypes of CH.
There are several limitations of this study. First, the number of studies enrolled for each variable was small, and therefore, this study is under-powered. However, we have done our best to explore as many studies as possible. Second, in each study enrolled, the methodology, the population included, the conducting periods, as well as the way to describe the clinical presentation differed, and these factors impede us from collecting a larger data more precisely. Third, for countries that span a wide range of latitudes i.e., the USA or China, though we assumed that the study population of a defined hospital were mostly residents near the location and had made our best to search for the enrolled population, still, conditions such as self-referral from a distant region could exist, especially in tertiary medical centers. Fourth, the enrolled study for clinical assessment encompassed only a small range of latitudes (21.2°–67.3°) for analysis, and the data of the countries in the tropical region and Asia remains lacking.
Conclusions
This study showed that the 1-year prevalence, the proportion of chronic CH, as well as ptosis and mitosis were positively correlated with latitudinal change. Both temperature and sunlight variation at higher latitudes are plausible causes, and further studies are required for confirmation.
Data Availability
Data is provided within the manuscript.
References
Headache Classification Committee of the International Headache Society (IHS) The International Classification of Headache Disorders, 3rd edition. Cephalalgia. 2018;38(1):1–211. https://doi.org/10.1177/0333102417738202. PMID: 29368949.
May A, Schwedt TJ, Magis D, Pozo-Rosich P, Evers S, Wang SJ. Cluster headache Nat Rev Dis Primers. 2018;4:18006. https://doi.org/10.1038/nrdp.2018.6.
Hut RA, Paolucci S, Dor R, Kyriacou CP, Daan S. Latitudinal clines: an evolutionary view on biological rhythms. Proc Biol Sci. 2013;280(1765):20130433. https://doi.org/10.1098/rspb.2013.0433.
Wood H. Multiple sclerosis: Latitude and vitamin D influence disease course in multiple sclerosis. Nat Rev Neurol. 2017;13(1):3. https://doi.org/10.1038/nrneurol.2016.181.
Parnell GP, Schibeci SD, Fewings NL, Afrasiabi A, Law SPL, Samaranayake S, et al. The latitude-dependent autoimmune disease risk genes ZMIZ1 and IRF8 regulate mononuclear phagocytic cell differentiation in response to vitamin D. Hum Mol Genet. 2019;28(2):269–78. https://doi.org/10.1093/hmg/ddy324.
Lin KH, Wang PJ, Fuh JL, Lu SR, Chung CT, Tsou HK, et al. Cluster headache in the Taiwanese—a clinic-based study. Cephalalgia. 2004;24(8):631–8. https://doi.org/10.1111/j.1468-2982.2003.00721.x.
Page MJ, McKenzie JE, Bossuyt PM, Boutron I, Hoffmann TC, Mulrow CD, et al. The PRISMA 2020 statement: an updated guideline for reporting systematic reviews. BMJ. 2021;372:n71. https://doi.org/10.1136/bmj.n71.
Steinberg A, Josefsson P, Alexanderson K, Sjostrand C. Cluster headache: prevalence, sickness absence, and disability pension in working ages in Sweden. Neurology. 2019;93(4):e404–13. https://doi.org/10.1212/WNL.0000000000007787.
Imai N, Kitamura E. Differences in clinical features of cluster headache between drinkers and nondrinkers in Japan. PLoS ONE. 2019;14(11):e0224407. https://doi.org/10.1371/journal.pone.0224407.
Ofte HK, Berg DH, Bekkelund SI, Alstadhaug KB. Insomnia and periodicity of headache in an arctic cluster headache population. Headache. 2013;53(10):1602–12. https://doi.org/10.1111/head.12241.
Lee MJ, Park JW, Chu MK, Moon HS, Chung PW, Chung JM, et al. Treatment pattern and response for cluster headache in Korea: a prospective multicenter observation study. Cephalalgia. 2023;43(4):3331024231159627. https://doi.org/10.1177/03331024231159627.
Vikelis M, Rapoport AM. Cluster headache in Greece: an observational clinical and demographic study of 302 patients. J Headache Pain. 2016;17(1):88. https://doi.org/10.1186/s10194-016-0683-0.
Lund N, Petersen A, Snoer A, Jensen RH, Barloese M. Cluster headache is associated with unhealthy lifestyle and lifestyle-related comorbid diseases: Results from the Danish Cluster Headache Survey. Cephalalgia. 2019;39(2):254–63. https://doi.org/10.1177/0333102418784751.
Sjaastad O, Bakketeig LS. Cluster headache prevalence. Vaga study of headache epidemiology. Cephalalgia. 2003;23(7):528–33. https://doi.org/10.1046/j.1468-2982.2003.00585.x.
Fourier C, Ran C, Steinberg A, Sjostrand C, Waldenlind E, Belin AC. Sex differences in clinical features, treatment, and lifestyle factors in patients with cluster headache. Neurology. 2023;100(12):e1207–20. https://doi.org/10.1212/WNL.0000000000201688.
Katsarava Z, Dzagnidze A, Kukava M, Mirvelashvili E, Djibuti M, Janelidze M, et al. Prevalence of cluster headache in the Republic of Georgia: results of a population-based study and methodological considerations. Cephalalgia. 2009;29(9):949–52. https://doi.org/10.1111/j.1468-2982.2008.01836.x.
Liaw YC, Wang YF, Chen WT, Chen SP, Wu JW, Chen ST, et al. Sex-related differences in cluster headache: a hospital-based study in Taiwan. Cephalalgia. 2022;42(14):1532–42. https://doi.org/10.1177/03331024221120054.
Chung PW, Lee MJ, Park JW, Sohn JH, Kim BK, Chu MK, et al. Differences of cluster headache on the basis of sex in the Korean Cluster Headache Registry. Headache. 2019;59(10):1722–30. https://doi.org/10.1111/head.13637.
Haimanot RT, Seraw B, Forsgren L, Ekbom K, Ekstedt J. Migraine, chronic tension-type headache, and cluster headache in an Ethiopian rural community. Cephalalgia. 1995;15(6):482–8. https://doi.org/10.1046/j.1468-2982.1995.1506482.x.
Imai N, Yagi N, Kuroda R, Konishi T, Serizawa M, Kobari M. Clinical profile of cluster headaches in Japan: low prevalence of chronic cluster headache, and uncoupling of sense and behaviour of restlessness. Cephalalgia. 2011;31(5):628–33. https://doi.org/10.1177/0333102410391486.
Tonon C, Guttmann S, Volpini M, Naccarato S, Cortelli P, D’Alessandro R. Prevalence and incidence of cluster headache in the Republic of San Marino. Neurology. 2002;58(9):1407–9. https://doi.org/10.1212/wnl.58.9.1407.
Kikui S, Danno D, Takeshima T. Clinical profile of chronic cluster headaches in a regional headache center in Japan. Intern Med. 2023;62(4):519–25. https://doi.org/10.2169/internalmedicine.9557-22.
Petersen AS, Lund N, Jensen RH, Barloese M. Real-life treatment of cluster headache in a tertiary headache center—results from the Danish Cluster Headache Survey. Cephalalgia. 2021;41(5):525–34. https://doi.org/10.1177/0333102420970455.
Ekbom K, Svensson DA, Pedersen NL, Waldenlind E. Lifetime prevalence and concordance risk of cluster headache in the Swedish twin population. Neurology. 2006;67(5):798–803. https://doi.org/10.1212/01.wnl.0000233786.72356.3e.
Ekbom K, Ahlborg B, Schele R. Prevalence of migraine and cluster headache in Swedish men of 18. Headache. 1978;18(1):9–19. https://doi.org/10.1111/j.1526-4610.1978.hed1801009.x.
Cho SJ, Lee MJ, Kim BK, Moon HS, Chung PW, Sohn JH, et al. Clinical features of chronic cluster headache based on the third edition of the International Classification of Headache Disorders: a prospective multicentre study. PLoS One. 2019;14(8):e0221155. https://doi.org/10.1371/journal.pone.0221155.
Jurno ME, Pereira BSR, Fonseca FAS, Teixeira GA, Maffia LQ, Barros MRA, et al. Epidemiologic study of cluster headache prevalence in a medium-size city in Brazil. Arq Neuropsiquiatr. 2018;76(7):467–72. https://doi.org/10.1590/0004-282X20180065.
Taga A, Russo M, Manzoni GC, Torelli P. Familial cluster headache in an Italian case series. Neurol Sci. 2015;36(Suppl 1):141–3. https://doi.org/10.1007/s10072-015-2147-8.
Felicio AC, Bichuetti DB, Santos WA, Godeiro Junior CO, Marin LF, Carvalho DS. Epidemiology of primary and secondary headaches in a Brazilian tertiary-care center. Arq Neuropsiquiatr. 2006;64(1):41–4. https://doi.org/10.1590/s0004-282x2006000100009.
Torelli P, Beghi E, Manzoni GC. Cluster headache prevalence in the Italian general population. Neurology. 2005;64(3):469–74. https://doi.org/10.1212/01.WNL.0000150901.47293.BC.
Xie Q, Huang Q, Wang J, Li N, Tan G, Zhou J. Clinical features of cluster headache: an outpatient clinic study from China. Pain Med. 2013;14(6):802–7. https://doi.org/10.1111/pme.12101.
Dong Z, Di H, Dai W, Pan M, Li Z, Liang J, et al. Clinical profile of cluster headaches in China—a clinic-based study. J Headache Pain. 2013;14(1):27. https://doi.org/10.1186/1129-2377-14-27.
D’Alessandro R, Gamberini G, Benassi G, Morganti G, Cortelli P, Lugaresi E. Cluster headache in the Republic of San Marino. Cephalalgia. 1986;6(3):159–62. https://doi.org/10.1046/j.1468-2982.1986.0603159.x.
Katsarava Z, Obermann M, Yoon MS, Dommes P, Kuznetsova J, Weimar C, et al. Prevalence of cluster headache in a population-based sample in Germany. Cephalalgia. 2007;27(9):1014–9. https://doi.org/10.1111/j.1468-2982.2007.01380.x.
Black DF, Swanson JW, Stang PE. Decreasing incidence of cluster headache: a population-based study in Olmsted County. Minnesota Headache. 2005;45(3):220–3. https://doi.org/10.1111/j.1526-4610.2005.05048.x.
Evers S, Fischera M, May A, Berger K. Prevalence of cluster headache in Germany: results of the epidemiological DMKG study. J Neurol Neurosurg Psychiatry. 2007;78(11):1289–90. https://doi.org/10.1136/jnnp.2007.124206.
Mengistu G, Alemayehu S. Prevalence and burden of primary headache disorders among a local community in Addis Ababa, Ethiopia. J Headache Pain. 2013;14(1):30. https://doi.org/10.1186/1129-2377-14-30.
Crespi J, Gulati S, Salvesen Ø, Bratbak DF, Dodick DW, Matharu MS, et al. Epidemiology of diagnosed cluster headache in Norway. Cephalalgia Reports. 2022;5. https://doi.org/10.1177/25158163221075569.
Gaul C, Christmann N, Schroder D, Weber R, Shanib H, Diener HC, et al. Differences in clinical characteristics and frequency of accompanying migraine features in episodic and chronic cluster headache. Cephalalgia. 2012;32(7):571–7. https://doi.org/10.1177/0333102412444012.
Monta A, Redon S, Fabre C, Donnet A. A retrospective observation on 105 patients with chronic cluster headache receiving indomethacin. Neurol Sci. 2021;42(10):4175–82. https://doi.org/10.1007/s10072-021-05114-4.
Lund N, Barloese M, Petersen A, Haddock B, Jensen R. Chronobiology differs between men and women with cluster headache, clinical phenotype does not. Neurology. 2017;88(11):1069–76. https://doi.org/10.1212/WNL.0000000000003715.
Allena M, De Icco R, Sances G, Ahmad L, Putorti A, Pucci E, et al. Gender differences in the clinical presentation of cluster headache: a role for sexual hormones? Front Neurol. 2019;10:1220. https://doi.org/10.3389/fneur.2019.01220.
de Coo IF, Wilbrink LA, Ie GD, Haan J, Ferrari MD. Aura in cluster headache: a cross-sectional study. Headache. 2018;58(8):1203–10. https://doi.org/10.1111/head.13344.
Ko CA, Lin GY, Ting CH, Sung YF, Lee JT, Tsai CK, et al. Clinical features of cluster headache: a hospital-based study in Taiwan. Front Neurol. 2021;12:636888. https://doi.org/10.3389/fneur.2021.636888.
Genovese A, Taga A, Rausa F, Quintana S, Manzoni GC, Torelli P. Clinical features of cluster headache in relation to age of onset: results from a retrospective study of a large case series. Neurol Sci. 2019;40(Suppl 1):193–4. https://doi.org/10.1007/s10072-019-03801-x.
Lademann V, Jansen JP, Evers S, Frese A. Evaluation of guideline-adherent treatment in cluster headache. Cephalalgia. 2016;36(8):760–4. https://doi.org/10.1177/0333102415612774.
Negro A, Sciattella P, Spuntarelli V, Martelletti P, Mennini FS. Direct and indirect costs of cluster headache: a prospective analysis in a tertiary level headache centre. J Headache Pain. 2020;21(1):44. https://doi.org/10.1186/s10194-020-01115-4.
Moon HS, Cho SJ, Kim BK, Lee MJ, Chung PW, Sohn JH, et al. Field testing the diagnostic criteria of cluster headache in the third edition of the International Classification of Headache Disorders: a cross-sectional multicentre study. Cephalalgia. 2019;39(7):900–7. https://doi.org/10.1177/0333102419837159.
Lee MJ, Cho SJ, Park JW, Chu MK, Moon HS, Chung PW, et al. Temporal changes of circadian rhythmicity in cluster headache. Cephalalgia. 2020;40(3):278–87. https://doi.org/10.1177/0333102419883372.
Manzoni GC, Terzano MG, Bono G, Micieli G, Martucci N, Nappi G. Cluster headache–clinical findings in 180 patients. Cephalalgia. 1983;3(1):21–30. https://doi.org/10.1046/j.1468-2982.1983.0301021.x.
Alders EE, Hentzen A, Tan CT. A community-based prevalence study on headache in Malaysia. Headache. 1996;36(6):379–84. https://doi.org/10.1046/j.1526-4610.1996.3606379.x.
Mitsikostas DD, Thomas A, Gatzonis S, Ilias A, Papageorgiou C. An epidemiological study of headache among the Monks of Athos (Greece). Headache. 1994;34(9):539–41. https://doi.org/10.1111/j.1526-4610.1994.hed3409539.x.
Rasmussen BK, Jensen R, Schroll M, Olesen J. Epidemiology of headache in a general population–a prevalence study. J Clin Epidemiol. 1991;44(11):1147–57. https://doi.org/10.1016/0895-4356(91)90147-2.
Ekbom K, Svensson DA, Traff H, Waldenlind E. Age at onset and sex ratio in cluster headache: observations over three decades. Cephalalgia. 2002;22(2):94–100. https://doi.org/10.1046/j.1468-2982.2002.00318.x.
Munoz M, Dumas M, Boutros-Toni F, Coquelle D, Nicolas A, Ndzanga E, et al. Prevalence of headache in a representative sample of the population in a French department (Haute-Vienne-Limousin). Headache. 1993;33(10):521–3. https://doi.org/10.1111/j.1526-4610.1993.hed3310521.x.
Sjostrand C, Waldenlind E, Ekbom K. A follow-up study of 60 patients after an assumed first period of cluster headache. Cephalalgia. 2000;20(7):653–7. https://doi.org/10.1111/j.1468-2982.2000.00104.x.
Manzoni GC, Micieli G, Granella F, Tassorelli C, Zanferrari C, Cavallini A. Cluster headache—course over ten years in 189 patients. Cephalalgia. 1991;11(4):169–74. https://doi.org/10.1046/j.1468-2982.1991.1104169.x.
Steinberg A, Fourier C, Ran C, Waldenlind E, Sjostrand C, Belin AC. Cluster headache—clinical pattern and a new severity scale in a Swedish cohort. Cephalalgia. 2018;38(7):1286–95. https://doi.org/10.1177/0333102417731773.
Manzoni GC, Taga A, Russo M, Torelli P. Age of onset of episodic and chronic cluster headache—a review of a large case series from a single headache centre. J Headache Pain. 2016;17:44. https://doi.org/10.1186/s10194-016-0626-9.
Bhargava A, Pujar GS, Banakar BF, Shubhakaran K, Kasundra G, Bhushan B. Study of cluster headache: a hospital-based study. J Neurosci Rural Pract. 2014;5(4):369–73. https://doi.org/10.4103/0976-3147.139987.
Moon HS, Park JW, Lee KS, Chung CS, Kim BK, Kim JM, et al. Clinical features of cluster headache patients in Korea. J Korean Med Sci. 2017;32(3):502–6. https://doi.org/10.3346/jkms.2017.32.3.502.
Monteiro-Pereira JM, Maio R, Calheiras JM. Cluster headache prevalence in a general population. Cluster headache and related conditions. Oxford: Oxford University Press; 1999.
Murtaza M, Kisat M, Daniel H, Sonawalla AB. Classification and clinical features of headache disorders in Pakistan: a retrospective review of clinical data. PLoS ONE. 2009;4(6):e5827. https://doi.org/10.1371/journal.pone.0005827.
Gesztelyi G, Bereczki D. Primary headaches in an outpatient neurology headache clinic in East Hungary. Eur J Neurol. 2004;11(6):389–95. https://doi.org/10.1111/j.1468-1331.2004.00800.x.
Torelli P, Cologno D, Cademartiri C, Manzoni GC. Application of the International Headache Society classification criteria in 652 cluster headache patients. Cephalalgia. 2001;21(2):145–50. https://doi.org/10.1046/j.1468-2982.2001.00185.x.
El Amrani M, Ducros A, Boulan P, Aidi S, Crassard I, Visy JM, et al. Familial cluster headache: a series of 186 index patients. Headache. 2002;42(10):974–7. https://doi.org/10.1046/j.1526-4610.2002.02226.x.
El-Sherbiny NA, Masoud M, Shalaby NM, Shehata HS. Prevalence of primary headache disorders in Fayoum Governorate. Egypt J Headache Pain. 2015;16:85. https://doi.org/10.1186/s10194-015-0569-6.
Shahbeigi S, Fereshtehnejad SM, Mohammadi N, Golmakani MM, Tadayyon S, Jalilzadeh G, et al. Epidemiology of headaches in Tehran urban area: a population-based cross-sectional study in district 8, year 2010. Neurol Sci. 2013;34(7):1157–66. https://doi.org/10.1007/s10072-012-1200-0.
Wang Y, Zhou J, Fan X, Li X, Ran L, Tan G, et al. Classification and clinical features of headache patients: an outpatient clinic study from China. J Headache Pain. 2011;12(5):561–7. https://doi.org/10.1007/s10194-011-0360-2.
Al-Hashel J, Ibrahim I, Youssry D, Ahmed SF, Goadsby P. Cluster Headache in Kuwait: a hospital-based study. Front Neurol. 2019;10:573. https://doi.org/10.3389/fneur.2019.00573.
Riess CM, Becker WJ, Robertson M. Episodic cluster headache in a community: clinical features and treatment. Can J Neurol Sci. 1998;25(2):141–5. https://doi.org/10.1017/s0317167100033758.
Peng KP, Takizawa T, Lee MJ. Cluster headache in Asian populations: similarities, disparities, and a narrative review of the mechanisms of the chronic subtype. Cephalalgia. 2020;40(10):1104–12. https://doi.org/10.1177/0333102420923646.
Chung PW, Kim BS, Park JW, Sohn JH, Lee MJ, Kim BK, et al. Smoking history and clinical features of cluster headache: results from the korean cluster headache registry. J Clin Neurol. 2021;17(2):229–35. https://doi.org/10.3988/jcn.2021.17.2.229.
Winsvold BS, Harder AVE, Ran C, Chalmer MA, Dalmasso MC, Ferkingstad E, et al. Cluster headache genomewide association study and meta-analysis identifies eight loci and implicates smoking as causal risk factor. Ann Neurol. 2023;94(4):713–26. https://doi.org/10.1002/ana.26743.
Liang JF, Chen YT, Fuh JL, Li SY, Liu CJ, Chen TJ, et al. Cluster headache is associated with an increased risk of depression: a nationwide population-based cohort study. Cephalalgia. 2013;33(3):182–9. https://doi.org/10.1177/0333102412469738.
Choong CK, Ford JH, Nyhuis AW, Joshi SG, Robinson RL, Aurora SK, et al. Clinical characteristics and treatment patterns among patients diagnosed with cluster headache in U.S. Healthcare Claims Data. Headache. 2017;57(9):1359–74. https://doi.org/10.1111/head.13127.
Robbins MS, Bronheim R, Lipton RB, Grosberg BM, Vollbracht S, Sheftell FD, et al. Depression and anxiety in episodic and chronic cluster headache: a pilot study. Headache. 2012;52(4):600–11. https://doi.org/10.1111/j.1526-4610.2011.02024.x.
Ji Lee M, Cho SJ, Wook Park J, Kyung Chu M, Moon HS, Chung PW, et al. Increased suicidality in patients with cluster headache. Cephalalgia. 2019;39(10):1249–56. https://doi.org/10.1177/0333102419845660.
Jurgens TP, Gaul C, Lindwurm A, Dresler T, Paelecke-Habermann Y, Schmidt-Wilcke T, et al. Impairment in episodic and chronic cluster headache. Cephalalgia. 2011;31(6):671–82. https://doi.org/10.1177/0333102410391489.
Joshi S, Rizzoli P, Loder E. The comorbidity burden of patients with cluster headache: a population-based study. J Headache Pain. 2017;18(1):76. https://doi.org/10.1186/s10194-017-0785-3.
Louter MA, Wilbrink LA, Haan J, van Zwet EW, van Oosterhout WP, Zitman FG, et al. Cluster headache and depression. Neurology. 2016;87(18):1899–906. https://doi.org/10.1212/WNL.0000000000003282.
Fischera M, Marziniak M, Gralow I, Evers S. The incidence and prevalence of cluster headache: a meta-analysis of population-based studies. Cephalalgia. 2008;28(6):614–8. https://doi.org/10.1111/j.1468-2982.2008.01592.x.
Prakash S, Mehta NC, Dabhi AS, Lakhani O, Khilari M, Shah ND. The prevalence of headache may be related with the latitude: a possible role of Vitamin D insufficiency? J Headache Pain. 2010;11(4):301–7. https://doi.org/10.1007/s10194-010-0223-2.
Menon V, Kar SK, Suthar N, Nebhinani N. Vitamin D and depression: a critical appraisal of the evidence and future directions. Indian J Psychol Med. 2020;42(1):11–21. https://doi.org/10.4103/IJPSYM.IJPSYM_160_19.
Leary PF, Zamfirova I, Au J, McCracken WH. Effect of latitude on vitamin D levels. J Am Osteopath Assoc. 2017;117(7):433–9. https://doi.org/10.7556/jaoa.2017.089.
Sohn JH, Chu MK, Park KY, Ahn HY, Cho SJ. Vitamin D deficiency in patients with cluster headache: a preliminary study. J Headache Pain. 2018;19(1):54. https://doi.org/10.1186/s10194-018-0886-7.
Kampman MT, Brustad M. Vitamin D: a candidate for the environmental effect in multiple sclerosis—observations from Norway. Neuroepidemiology. 2008;30(3):140–6. https://doi.org/10.1159/000122330.
O’Connor E, Fourier C, Ran C, Sivakumar P, Liesecke F, Southgate L, et al. Genome-wide association study identifies risk loci for cluster headache. Ann Neurol. 2021;90(2):193–202. https://doi.org/10.1002/ana.26150.
Jimenez-Martinez M, Stamatakis K, Fresno M. The dual-specificity phosphatase 10 (DUSP10): its role in cancer, inflammation, and immunity. Int J Mol Sci. 2019;20(7). https://doi.org/10.3390/ijms20071626.
Papasavva M, Vikelis M, Siokas V, Katsarou MS, Dermitzakis E, Raptis A, et al. VDR Gene polymorphisms and cluster headache susceptibility: case-control study in a Southeastern European Caucasian population. J Mol Neurosci. 2022;72(2):382–92. https://doi.org/10.1007/s12031-021-01892-w.
Jennysdotter Olofsgard F, Ran C, Qin Y, Fourier C, Sjostrand C, Waldenlind E, et al. Investigating vitamin D receptor genetic markers in a cluster headache meta-analysis. Int J Mol Sci. 2023;24(6). https://doi.org/10.3390/ijms24065950.
Holtkamp G. The Sunniest and Darkest Places on Earth. Scilogs. https://web.archive.org/web/20091027044102/http://www.scilogs.eu/en/blog/spacetimedreamer/2009-06-15/the-sunniest-and-darkest-places-on-earth.
Mitsikostas DD, Tsaklakidou D, Athanasiadis N, Thomas A. The prevalence of headache in Greece: correlations to latitude and climatological factors. Headache. 1996;36(3):168–73. https://doi.org/10.1046/j.1526-4610.1996.3603168.x.
Lee YJ, Chen YT, Ou SM, Li SY, Yang AC, Tang CH, et al. Temperature variation and the incidence of cluster headache periods: a nationwide population study. Cephalalgia. 2014;34(9):656–63. https://doi.org/10.1177/0333102413520083.
Boychenko S, Voloshchuk V, Kuchma T, Serdyuchenko N. Long-time changes of the thermal continentality index; the amplitudes and the phase of the seasonal temperature variation in Ukraine. Geofizicheskiy Zhurnal. 2018;40(3):81–96. https://doi.org/10.24028/gzh.0203-3100.v40i3.2018.137175.
Chown SL, Sinclair BJ, Leinaas HP, Gaston KJ. Hemispheric asymmetries in biodiversity—a serious matter for ecology. PLoS Biol. 2004;2(11):e406. https://doi.org/10.1371/journal.pbio.0020406.
Osilla EV, Marsidi JL, Shumway KR, et al. Physiology, temperature regulation. [Updated 2023 Jul 30]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2024. Available from: https://www.ncbi.nlm.nih.gov/books/NBK507838/.
Jafari A, Mahdizadeh M, Peyman N, Gholian-Aval M, Tehrani H. Exploration the role of social, cultural and environmental factors in tendency of female adolescents to smoking based on the qualitative content analysis. BMC Womens Health. 2022;22(1):38. https://doi.org/10.1186/s12905-022-01617-0.
Torelli P, Manzoni GC. What predicts evolution from episodic to chronic cluster headache? Curr Pain Headache Rep. 2002;6(1):65–70. https://doi.org/10.1007/s11916-002-0026-5.
Rozen TD. Linking cigarette smoking/tobacco exposure and cluster headache: a pathogenesis theory. Headache. 2018;58(7):1096–112. https://doi.org/10.1111/head.13338.
Silvestro M, Tessitore A, Orologio I, Battista G, Siciliano M, Tedeschi G, et al. Cluster headache pathophysiology: what we have learned from advanced neuroimaging. Headache. 2022;62(4):436–52. https://doi.org/10.1111/head.14279.
Hashemi H, Khabazkhoob M, Emamian MH, Yekta A, Jafari A, Nabovati P, et al. The prevalence of ptosis in an Iranian adult population. J Curr Ophthalmol. 2016;28(3):142–5. https://doi.org/10.1016/j.joco.2016.04.005.
Staples JA, Ponsonby AL, Lim LL, McMichael AJ. Ecologic analysis of some immune-related disorders, including type 1 diabetes, in Australia: latitude, regional ultraviolet radiation, and disease prevalence. Environ Health Perspect. 2003;111(4):518–23. https://doi.org/10.1289/ehp.5941.
Cabrera SE, Mindell JS, Toledo M, Alvo M, Ferro CJ. Associations of blood pressure with geographical latitude, solar radiation, and ambient temperature: results from the Chilean health survey, 2009–2010. Am J Epidemiol. 2016;183(11):1071–3. https://doi.org/10.1093/aje/kww037.
Drummond PD. Mechanisms of autonomic disturbance in the face during and between attacks of cluster headache. Cephalalgia. 2006;26(6):633–41. https://doi.org/10.1111/j.1468-2982.2006.01106.x.
Mustafa S, Thulesius O. Cooling-induced carotid artery dilatation: an experimental study in isolated vessels. Stroke. 2002;33(1):256–60. https://doi.org/10.1161/hs0102.101545.
Milsom WK, Zimmer MB, Harris MB. Regulation of cardiac rhythm in hibernating mammals. Comp Biochem Physiol A Mol Integr Physiol. 1999;124(4):383–91. https://doi.org/10.1016/s1095-6433(99)00130-0.
Patten SB, Williams JV, Lavorato DH, Wang JL, Bulloch AG. Major Depression prevalence increases with latitude in Canada. Can J Psychiatry. 2017;62(1):62–6. https://doi.org/10.1177/0706743716673323.
Levitt AJ, Boyle MH. The impact of latitude on the prevalence of seasonal depression. Can J Psychiatry. 2002;47(4):361–7. https://doi.org/10.1177/070674370204700407.
Partonen T, Partinen M, Lonnqvist J. Frequencies of seasonal major depressive symptoms at high latitudes. Eur Arch Psychiatry Clin Neurosci. 1993;243(3–4):189–92. https://doi.org/10.1007/BF02190726.
Acknowledgements
This work was supported by the Brain Research Center, National Yang Ming Chiao Tung University.
Funding
Open Access funding enabled and organized by National Yang Ming Chiao Tung University
Author information
Authors and Affiliations
Contributions
Y.C.L. wrote the main manuscript text and prepared the tables and figures. All authors reviewed the manuscript.
Corresponding author
Ethics declarations
Conflict of Interest
Both S.J. Wang and S.P. Chen own a position on editorial board at Current Pain and Headache Reports. YC Liaw declare no potential conflicts of interest. SJ Wang reports grants and personal fees from Novartis Taiwan, personal fees from Daiichi-Sankyo, grants and personal fees from Eli-Lilly, personal fees from AbbVie/Allergan, personal fees from Pfizer Taiwan, and personal fees from Biogen Taiwan, outside the submitted work.
Human and Animal Rights and Informed Consent
This article does not contain any studies with human or animal subjects performed by any of the authors.
Additional information
Publisher's Note
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Supplementary Information
Below is the link to the electronic supplementary material.
Rights and permissions
Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/.
About this article
Cite this article
Liaw, YC., Chen, SP. & Wang, SJ. The Prevalence and Clinical Phenotypes of Cluster Headache in Relation with Latitude. Curr Pain Headache Rep 28, 427–438 (2024). https://doi.org/10.1007/s11916-024-01229-3
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11916-024-01229-3