Abstract
Background
Headaches are often under-diagnosed in adolescents. The aim of this study was to examine the one-year prevalence of primary headaches among high school students in the city of Zagreb, the capital of Croatia.
Methods
This was a population-based, cross-sectional study. A total of 2350 questionnaires consisting of questions on demographic data, the presence and clinical characteristics of headaches were distributed among students in eight high schools; 2057 (87.5%) questionnaires were eligible for analysis.
Results
The mean age of the students was 17.2 ± 1.2 years; 50.2% were female. The prevalence of recurrent headache was 30.1% (620/2057), girls 35.1%, boys 25.2%. Among students with headache, 291 (46.9%) had migraine, and 329 (53.1%) had tension-type headaches (TTHs). The mean frequency of headaches was 5.66 per month in girls and 4.42 in boys; mean duration of a headache attack was 8.94 hours in girls and 8.37 hours in boys (NS). Unilateral headache was present in 31.6%, throbbing quality in 22.6%, dull in 34.4% of students; 22.4% had severe intensity and 70.3% moderate. Nausea was present in 4.0% always and in 14.7% frequently (girls 18.8%), photophobia in 41.3%, phonophobia in 63.2%, osmophobia in 23.9% (NS among genders). Almost 30% of students were disabled and stayed at home, more frequently boys. Girls (33.4%) were more likely to take drugs for every attack; number per month was 3.7. The results of this study showed that the prevalence of migraine among adolescents in Croatia was 16.5% for girls and 11.8% for boys; the prevalence of TTH was 18.4% for girls and 13.4% for boys.
Conclusions
The prevalence of self-reported headache among high school students in Zagreb is relatively high. Significant gender differences in frequency and clinical characteristics were observed. Primary headaches among adolescents are an important public health problem and should receive more attention from school and health authorities.
Introduction
Headache is the most frequent neurological complaint in adults, resulting in a reduction of quality of life in most sufferers. Epidemiological studies have documented that headache can be a serious health problem in children as well. Studies on the prevalence of headaches among adolescents have been carried out in several countries. Reported lifetime prevalence rates for all types of headache in children and adolescents range from 19% to 93% and the prevalence of recurrent headaches ranges from 29.1% to 52.2% (1–6). The one-year prevalence of migraine ranges from 6.3% to 21.3% (1,3,4,7–15), and the estimated one-year prevalence of tension-type headache (TTH) ranges from 5.1% to 25.9% (1,3,4,9–14). Nonclassifiable headache is reported in 4.8% to 27% of children and adolescents (3,4,9). Chronic migraine is present in 0.8% of adolescents (16,17). Higher prevalence rates are found for girls of all age groups and for all headache categories than for boys; the prevalence of migraine increases with age (4,10,11).
This was the first study on the prevalence of headaches among adolescents in Croatia.
The aim of this study was to examine the one-year prevalence of recurrent primary headaches and their clinical characteristics among high school students in the city of Zagreb and to compare our data with recent epidemiological studies from other countries.
Patients and methods
This was a population-based, cross-sectional study conducted in Zagreb, the capital city of the Republic of Croatia, conducted in April 2008. The school system in Croatia is as follows: all children who turn 6 years old by April 1 are enrolled in a junior school that is obligatory and lasts eight years. In the next four years (not obligatory) the student can enroll in a high school, vocational school or art school that lasts four years or they can enroll in a trade school that lasts three years. After high school, students may enroll in a university and receive a bachelor’s degree (three years), master’s degree (five years) or PhD (six years). There are 76 high schools in Zagreb (20 public high schools, 34 vocational schools, eight art schools, 20 private high schools and four high schools for students with special needs). In the 2008–2009 school year a total of 177,799 adolescents were enrolled in high school, of these 89,101 were girls. A pre-notice letter was sent to principals of eight high schools in Zagreb who were thereafter contacted by phone to receive additional information on the purpose of the survey. The high schools were selected by random choice (three gymnasiums, three vocational schools, one private school and one art school) from different parts of Zagreb (urban and suburban). The principal of one high school refused to participate (no specific explanation was given). After the consent of the school principals, a total of 2350 questionnaires were distributed among students in these eight high schools (87 classes). At the beginning of a school class, in the presence of the teacher and our novices, the students were asked to complete a multiple choice questionnaire. The questionnaire was explained to them, section by section. It was emphasized that only students who have recurrent headaches with certain characteristics (these were explained to them as it was written in the questionnaire) should complete the whole questionnaire. After the quality control process, 2057 (87.5%) questionnaires were suitable for analysis (incomplete or inappropriate questionnaires were excluded). Our sample of respondents consisted of adolescents between 14 and 18 years old, which is a more uniform group as opposed to other studies that included children between 7 and 15 years; we deliberately avoided inclusion of pre-pubertal children in order to achieve a more uniform sample group. To avoid sample bias, all students in a class were asked to complete the questionnaire (studies that were conducted via telephone have shown that nonresponders were parents of children without headache, which might have led to an overestimation of headache prevalence) (9).
Three novices (MS, DA, RB) from our Neurology Department explained to the students the purposes of the survey and how to fill in the questionnaire. The questionnaire consisted of demographic data and questions regarding the presence and clinical characteristics of headaches. The first question after demographic data was: “Do you suffer from recurrent headaches, especially headaches that are burdensome to you?” Only students who had recurrent headaches (i.e. they notice the presence of the headache and they feel that the headache disables them in what they are doing) were asked to complete the questionnaire. In addition, we asked the students to describe their headaches in terms of localization, quality, intensity, presence of nausea, photo-, phono-, osmophobia, frequency and duration.
Furthermore, we asked the students whether they have to take a rest because of the headache as well as the necessity and number of medications for relief and the medications’ efficacy. The last question focused on the possible precipitating factors of the student’s headache. Headache type was determined according to the International Classification of Headache Disorders, second edition (ICHD II) criteria (18). The diagnosis of migraine was given if a student declared that: a) she or he had at least five attacks of headache; b) attacks lasted four to 72 hours; c) the headache had at least two of the following characteristics: unilateral location; moderate to severe intensity; the headache is pulsating at least half of the time; and pain is aggravated by routine physical activity; d) at least one of the following: nausea with or without vomiting; photophobia and phonophobia ± osmophobia (see Table 5 in Appendix). We have not given separate diagnoses for definite migraine and probable migraine based on this questionnaire, therefore we regarded these students as one group.
The diagnosis of TTH was given if a student declared that he or she had at least 10 attacks of headache lasting 30 minutes to seven days followed by at least two of the following: bilateral location, pressing quality, mild to moderate intensity, not aggravated by routine physical activity; the headache was accompanied neither by nausea and vomiting; slight photophobia or phonophobia may be present (see Table 5 in Appendix).
The Croatian Society for Neurovascular Disorders of the Croatian Medical Association has recently published the Evidence Based Guidelines for Treatment of Primary Headaches update 2012 (19); however, these guidelines refer only to adult headache sufferers.
The study was approved by the ethics committee of the University Hospital Sestre Milosrdnice, Zagreb.
Statistical analysis
Data analysis was performed using the STATISTICA version 7.1 (StatSoft Inc, Tulsa, OK, USA). Quantitative variables were summarized as mean and standard deviation (SD) and categorical variables on a nominal scale were summarized as a number (%). In the statistical analysis, the chi-square test was used to compare distribution of categorical variables between subgroups, Student’s t-test or Mann-Whitney U-test were used to compare quantitative variables depending on distribution and scale. Univariate and multivariate logistic regression analysis was used to identify the odds (odds ratios (ORs) with 95% confidence intervals (CIs)) for having a headache according to associated risk factors. Statistical significance was considered for all tests as two sided at p < 0.05 without adjustments for multiplicity.
Results
Demographic data and prevalence
Demographic data.
TTH: tension-type headache; df: degree of freedom.
The results of this study showed that the prevalence of migraine and probable migraine among adolescents in Croatia was 16.5% for girls and 11.8% for boys; the prevalence of TTH was 18.4% for girls and 13.4% for boys (χ2 = 0.0002, df = 1, p = 0.98).
Headache characteristics
Headache characteristics.
Most responders stated that they have a dull headache, followed by a combination of a dull and throbbing headache. The localization of headache was more frequently unilateral, and the intensity was moderate (in most responders) or severe. Nausea was rarely or never present; if present, data show that girls more frequently have nausea (χ2 = 8.090; df = 3; p < 0.045). Phonophobia (63.2%) was more frequently present than photophobia (41.3%) or osmophobia (23.9%) (not significant (NS) among genders, respectively; χ2 = 0.329, df = 1, p = 0.56; χ2 = 2.926, df = 1, p = 0.08; χ2 = 1.585, df = 1, p = 0.2).
Almost 30% of adolescents during headache were disabled and stayed home, needing bed rest; more frequently boys, χ2 = 11.92, df = 2, p < 0.006.
Therapy
Therapy.
Total relief was declared by 30% of responders, no relief was present in 25.5%, whereas partial relief was declared by 50.3% of girls and 35.3% of boys, χ2 = 17.52, df = 2, p < 0.002. More than half of the responders never consulted a physician for their headache, 22.6% consulted a physician once and 15.5% several times.
Self-reported causes of headaches
Self-reported triggers for headache in adolescents.
NA: not applicable.
Data on missing answers (percentage is given in parentheses) are as follows: age at headache onset 54 (8.7), frequency two (0.3), presence of photophobia, phonophobia and osmophobia 17 (2.7), headache frequency two (0.3), possible cause of headache 14 (2.3). The question about pain character and localization was set in one question; there were four (0.6) missing answers. However, the majority of students filled in the data on pain character but not on the localization as well.
A multivariate analysis denoted the significantly associated odds for headache as follows: female gender (OR = 1.61, 95% CI 1.32–1.96, p < 0.001) and life satisfaction level (OR for range of satisfied to not satisfied at all = 7.73, 95% CI 4.72–12.67, p < 0.001), showing higher odds as completely unsatisfied.
Discussion
Headache prevalence and characteristics
The one-year prevalence of recurrent headache in our study is in line with most similar studies (1,2,3,9,13). The age of headache onset showed later onset in our population of adolescents (13.1 ± 2.3 for girls and 12.5 ± 1.2 for boys) compared to German data (7.8 years girls, 7.3 years boys); both studies show significantly earlier age of headache onset in boys (9).
According to ICHD II criteria, among our students with recurrent headaches, 46.9% had migraine, and 53.1% had TTH. Increasing age, female gender, low socioeconomic status of the family, low education level of the mother, positive family history of headache and children living in single-parent households each has a significant effect on the presence of headaches in children (8,9,13,15,20). Follow-up studies have observed that migraine changes over time, especially in adolescents (12,21–24). It is often difficult to categorize the type of headache in children because of the significant overlap of symptoms that meet both criteria for migraine without aura and TTH; in follow-up studies a trend toward a decrease of overlapping symptoms at the second examination performed two to five years after the first one has been noted (21). Several studies showed that the first diagnosis of headache type was subject to change in a follow-up period of four years; one-fifth of children and adolescents diagnosed with migraine on first examination will report symptoms typical of TTH after four years and the same was observed for TTH (12,19,24). When “strict” International Headache Society (IHS) criteria are used, the prevalence of migraine tends to be lower; therefore the “modified criteria” that usually change the item “duration of headache” are applied (headache attacks of < 4 hours of duration are included) (2). In our study, we have included students in the migraine group if they stated that they have a pulsating headache at least half of the time. That and the criteria of headache duration < 4 hours could have led to an overestimation of migraine prevalence in our study. Inconsistencies among studies make it difficult to compare prevalence rates across studies because there is no established definition of the terms “frequent” or “recurrent,” which are most often used to define the presence of headaches. In a recent study the best diagnostic items for migraine in children and adolescents were moderate or severe intensity, pain aggravation by physical activity, pulsating quality and for TTH no photophobia, no nausea, no aggravation by physical activity, mild or moderate intensity and nonpulsating quality (5). In our study, we have strictly adhered to the ICHD II criteria for TTH. The results of our study showed that the prevalence of migraine among adolescents in Croatia was 16.5% for girls and 11.8% for boys; the prevalence of TTH was 18.4% for girls and 13.4% for boys. In most studies migraine is rated as the most disabling headache, with the highest average intensity, highest frequency and more frequent use of medication (9). In our study, adolescents suffering from headache mostly had a moderate to severe, unilateral, dull or a combination of dull and throbbing headache, more often accompanied by phonophobia than photophobia, followed by osmophobia. More than 70% of students had nausea rarely or never. As mentioned earlier, the higher prevalence of migraine in our study could be the result of “modified criteria” i.e. the inclusion of headaches that were less than four hours in duration if medication was taken and were pulsating at least half of the time. Nevertheless, we believe that whenever possible, headache type should be recognized because migraine is associated with more pain and the presence of physical symptoms, as similar studies show (9).
A study from Germany showed that headache is the most frequent type of pain among children and adolescents, followed by abdominal pain, limb pain and back pain (25). Furthermore, this study showed that children with back pain, limb pain and abdominal pain visited a doctor more often than did those with headache; in contrast, children and adolescents with headache reported taking medication because of pain more often than did those with other pain types. In our study, more than half of responders never consulted a physician for their headache, which was somewhat lower than in a similar study from Germany, as was the percentage of adolescents taking medication for their headache (9). A study from Italy showed that none of the adolescents suffering from headache had visited a doctor (26). A study from the United States showed that 40% of adolescents visited a health care provider and less than one in five reported taking medications to prevent headache (17). In our study almost one-third of respondents said that they always have to take medication for their headache and the rest of them take medications rarely or never. The reasons for these variations among studies could be due to cultural differences and access to health care providers (i.e. health care system in a certain country).
Self-medication is common in chronic daily headache sufferers (14). Headache during childhood has a high risk of persisting into adulthood (27); therefore it is important to give adequate management to adolescents with recurrent and severe headaches.
The leading self-perceived triggers for headache, especially for migraine, among adolescents were stress, lack of sleep and too much school work (6,26,28,29). In contrast, the statistical analysis in another study identified alcohol and coffee consumption, smoking, neck pain, stress and physical inactivity as risk factors for headache (6). In our study the self-reported precipitating factors for headache were as follows: lack of sleep, “problems with school,” climate changes, while menstruation was in fourth place for girls.
Absenteeism from school and quality of life
Absenteeism from school among children and adolescents because of headache was more frequent than for other pain disorders (43%) (25). Absenteeism was also higher in the migraine group compared to the TTH group (13). In our study, 24% of girls and 37.6% of boys stayed in bed when having a headache, and further 74.3% of girls and 61.2% of boys needed rest. Our study showed that almost one-third of adolescents stayed at home and needed bed rest because of their headache.
Adolescents with migraine reported clinically significant impairment in health-related quality of life compared to their nonmigraine peers, independent of psychiatric comorbidities (7). Studies show that there was also a close association between headache frequency and the number of other physical complaints as well as physical and psychiatric morbidity later in life (9,30,31). Considering that children and adolescents with recurrent headache were predisposed to chronic headache in their adult life (32), brings us to the conclusion that adolescent headache is a serious condition that needs immediate and serious attention in its early stage. It is especially important to detect youngsters with headaches in whom the medications do not achieve relief, which seems to be the case in one-quarter of our respondents.
Limitations of the study
Limitations of this study are as follows: the survey was performed only in the capital city of Croatia, which might not be a representative sample of all Croatian adolescents, since the majority of the respondents were from urban areas and a minority from rural areas. Furthermore, the proportion of students with migraine might be somewhat different if we conducted a face-to-face interview. The most common reasons for patients not meeting the standard ICHD-II criteria were the requirement of unilateral location, headache duration and number of associated symptoms; if these were modified probably a higher percentage of patients would receive the diagnosis of migraine (33). And third, this was a cross-sectional not a longitudinal study.
Our study was the first study of this kind in Croatia among adolescents and it has shown that the prevalence of self-reported headache among high school children in Zagreb city is relatively high. Pain among children and adolescents is an important public health problem and should receive more attention from school and health authorities. This study shows that we need to promote the management of headache in educational programs to enhance the communication between students, teachers, family physicians and members of the family. It is also important to offer adolescents who suffer from headache an early appropriate management program in order to prevent chronic headache in later life.
Clinical implication
The prevalence of migraine among adolescents in Croatia is 16.5% for girls and 11.8% for boys; the prevalence of tension-type headache (TTH) is 18.4% for girls and 13.4% for boys. The prevalence of recurrent headache was 30.1% (girls 35.1%, boys 25%). Almost 30% of students were disabled and stayed at home; more frequently boys. Girls (33.4%) are more likely to take drugs for every headache attack. Primary headaches among adolescents are an important public health problem and should receive more attention from school and health authorities.
Footnotes
Funding
This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors.
Conflict of interest
None declared.