Original Article
Prevalence and disability of headache among Norwegian adolescents: A cross-sectional school-based study
Cephalalgia 2015, Vol. 35(13) 1181–1191 ! International Headache Society 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0333102415573512 cep.sagepub.com
Anne-Berit Krogh1, Bo Larsson2,3 and Mattias Linde1,4 Abstract Background: Headache is common in adolescents and affects schoolwork and relations with friends and family. In most previous epidemiological surveys, only the most bothersome headache has been documented. The aim was to determine headache prevalence not only taking into account the most bothersome headache, but also to compare characteristics of the most bothersome and less bothersome headaches, and to investigate headache-related disability. Methods: A cross-sectional school-based study was conducted in which 493 representative adolescents aged 12–18 years were recruited by stratified cluster sampling and interviewed. Headache diagnosis was made according to the new classification system of the International Headache Society (ICHD-3 beta), and the Pediatric Migraine Disability Assessment (PedMIDAS) was used to evaluate disability. Results: The one-year prevalence of any headache type, definite migraine, probable migraine and tension-type headache was 88%, 23%, 13% and 58%, respectively. The point prevalence of any headache was 38%. Nine percent of participants fulfilled criteria for more than one headache diagnosis. The most bothersome headache had a significantly longer duration (p < 0.001) and higher intensity (p < 0.001) than the less bothersome headache, but similar frequency (p ¼ 0.86). Adolescents with headaches lost up to nine days of activity each year, implicating headache as a major health issue. Conclusions: Headaches are very common and disabling among adolescents. The full extent of this health problem is better appreciated if inquiry is not limited to the most bothersome subtypes. Keywords Adolescents, headache, migraine, tension-type headache, prevalence, PedMIDAS Date received: 18 August 2014; revised: 19 October 2014; 18 December 2014; 28 December 2014; accepted: 31 December 2014
Background Headache is one of the most common health problems in adolescents (1,2) and can negatively affect quality of life and lead to impairments in daily functioning such as school performance and recreational activities (3,4). Surveys conducted in different countries and cultures show considerable variation in the estimated prevalence of headache, and a recent review reported an overall median of 5% for oneyear prevalence of headache in adolescents (1). Many studies have considered only the most bothersome headache in adolescence, whereas others have limited the prevalence estimates to strict diagnoses, thereby disregarding the existence of probable migraine (PM) and probable tension-type headache (PTTH) (5,6).
The main objectives of the present epidemiological study were to determine the prevalence of headache, taking into account more than one type of headache
1 Department of Neuroscience, Norwegian University of Science and Technology, Norway 2 Regional Centre for Child and Youth Mental Health and Child Welfare, Central Norway, Norway 3 National Competence Centre for Complex Symptom Disorders. St Olav’s University Hospital, Norway 4 Norwegian Advisory Unit on Headaches, St Olav’s University Hospital, Norway
Corresponding author: Anne-Berit Krogh, Department of Neuroscience, Norwegian University of Science and Technology, N-7489 Trondheim, Norway. Email: [email protected]
1182 in each participant, to compare the differences in the characteristics of the most bothersome and other headaches, and to investigate headache-related disability in adolescents in the general population.
Methods Study population and sample selection The study population was students from secondary schools and high schools in Sør-Trøndelag County in Norway. Sampling was stratified by grade and location. Data were collected in 2011–2012. As of January 1, 2011, Sør-Trøndelag County had 294,066 residents: 173,486 in the city of Trondheim, 83,451 in the inland/ mountain region and 37,129 by the coast (7). To obtain a sample distribution corresponding to the distribution of the population in the county, the schools were initially drawn with the following probabilities: 59% from the urban region, 28% from the inlandmountain region and 13% from coastal municipalities. The study sample was recruited in equal proportions from three grade cohorts from two types of schools: eighth grade (age 12–13 years), 10th grade (age 14–15 years) both from secondary schools, and 12th grade (age 16–18 years) from high schools. There are large differences in school size with more students in schools in urban vs rural areas, and a higher number of schools were therefore needed to be drawn from rural areas to obtain the required number of participants. First we drew what grades we should invite, then the school. Then all the students in the drawnclass level of the current school were invited to attend the study. At the time of the study, there were 74 secondary or high schools in Sør-Trøndelag County. Thirteen of these were invited to participate in the study: four of the 26 schools in an urban area and nine of the 48 schools in a rural (inland/mountain or coastal) area. Of the initial 13 schools invited, seven schools declined to participate in the study and were replaced by seven new schools (four from the inland/ mountain area, one from the coastal area, and two from the urban area). The four schools in urban areas that agreed to participate were two secondary schools (individuals in the eighth and 10th grades) and two high schools (individuals in the 12th grade). Of the latter, one school specialized in vocational training, and one specialized in theoretical sciences. The nine schools in rural areas that agreed to participate were four secondary schools from the coastal region, three secondary schools from the inland/mountain region, one high school from the coastal region, and one high school from the inland/mountain region. Data from the inland/mountain and coastal regions were combined and labeled ‘‘rural.’’
Cephalalgia 35(13)
Recruitment procedure There were 899 eligible students invited to participate in the study. The interviewer (ABK) held an information meeting with principals, inspectors and teachers from each of the selected schools to motivate them to participate in the study. The interviewer met with all students who had been selected for participation, and they also received written information about the study. As an incentive, students were offered a cinema ticket for participation. Norwegian law requires parental consent for children younger than 16 years of age to participate in research; therefore, the interviewer also provided optional meetings for parents with children in these age groups with the purpose of informing them about the study.
Questionnaire and interviews The questionnaire was developed for school-based studies of headache in Sweden (8–10), translated to Norwegian and adapted to the diagnostic criteria from the International Headache Society (IHS) (11). All interviews were conducted face to face by the same experienced nurse in a suitable room at the school during a regular school day and lasted, on average, 20 minutes. As an opening question, the student was asked whether he or she had experienced headache during the past year. For those who answered ‘‘No’’ to this question, the interview stopped. For those who answered ‘‘Yes,’’ a structured interview was conducted to determine the headache characteristics. The researcher asked if the student had experienced more than one type of headache during the last year. If positively endorsed, the characteristics and associated symptoms of headache were documented for up to two headache types. Students were asked to report the frequency, intensity (on a three-point scale: 1 ¼ mild, 2 ¼ moderate, 3 ¼ severe) and duration of episodes, as well as the accompanying symptoms. At the very end of the interview, students were asked to assess the severity of any headache that they had experienced during the interview on a 100 mm visual analog scale (VAS) with the following end points: ‘‘None’’ and ‘‘As bad as it could be’’ (12).
Headache classification Headaches were classified as episodic migraine with or without aura (MA or MwoA), chronic migraine (CM), probable migraine, episodic tension-type headache, infrequent (ITTH) or frequent (FTTH), chronic tension-type headache (CTTH) or medication-overuse headache (MOH) according to the International Classification of Headache Disorders, third edition beta (ICHD-3 beta) (13). PTTH was merged with
1183
Krogh et al. definite TTH. MOH was defined as having any headache (including the most bothersome headache and any other headache) for more than half of the days during the last three months and treating it with medication on at least 10 days per month. Headache that did not fulfill any criteria according to ICHD-3 beta was labeled ‘‘unclassifiable.’’ One of the authors, a neurologist (ML) with extensive experience in the diagnosis and epidemiological research of headache, verified all final diagnoses. The study was conceived at the time criteria of headache classification from the IHS (ICHD-2) (11) was the prevailing set of diagnostic criteria. But information on headache duration was collected in such detail that data could instead be evaluated using the contemporary criteria of headache classification from the IHS (ICHD-3 beta) (13).
Pediatric Migraine Disability Assessment (PedMIDAS) Students were also asked to complete the PedMIDAS, which was developed to assess disability in children and adolescents with chronic pain, including headache, and has been used in clinical studies and epidemiological surveys (14–16). It consists of six questions addressing the number of days totally or partially lost because of headache for the last three months (91 days) in three domains (school, home and social activities). A total score was calculated for each adolescent by summing the number of days reported for each of the items for all headaches as recommended by the creator of the PedMIDAS (14). The PedMIDAS grading system was used to indicate the degree of headache disability. Grade I means little to no disability (0–10), Grade II means mild disability (11–30), Grade III means moderate disability (31–50) and Grade IV means severe disability (>50) (15).
Statistics and data analysis Descriptive data were expressed as means and standard deviations (SD), as the percentage with 95% confidence interval (CI) for continuous variables, and as the median and interquartile range for ordinal variables. The chi-square test was used to examine associations between categorical variables and Pearson productmoment correlations were used to examine associations between continuous variables. Differences between independent group means and medians were examined using Mann-Whitney tests and Kruskal-Wallis tests for ordinal variables. Differences between independent group means and medians were examined using analysis of variance (ANOVA) to examine assosiations between continous variables. The Wilcoxon test was used for paired within-group comparisons. To account for the
risk of mass significance due to statistical comparisons, a highly conservative Bonferroni-adjustment was applied throughout using an alpha lowered to 0.002 (0.05 divided by 25 analyses). IBM SPSS Statistics for Windows version 20 was used for all statistical analyses.
Ethics The Norwegian Ethical Committee for Medical Research and the Norwegian Social Science Data Service approved the research protocol.
Results The flow of participants in the study is presented in Figure 1. Of 899 invited students, written consent was obtained from 519 (58%). Twenty-six of the adolescents did not attend the interview. Of these students, 15 were sick, six did not attend the interview because of an unknown cause, two were on vacation, one withdrew from the study, one had practical studies outside school and one had exams. After the interviews were completed, five students were excluded because they were older than 18 years. Thus, the final study population consisted of 488 adolescents, 57% girls (n ¼ 276) and 43% boys (n ¼ 212), with an age range of 12–18 years. The distributions across grades and school location (urban/rural area) are presented in Table 1.
One-year prevalence of headache Of the 488 participants, 429 reported experiencing a headache in the past 12 months, giving a one-year prevalence of 88% (95% CI, 85–91%; Table 1). The prevalence of headache was significantly (p < 0.001) higher in girls than boys (93% vs 80%), but was similar across grades (p ¼ 0.24) and urban and rural locations (p ¼ 0.057). Of the 488 participants who reported headaches, 7.4% (n ¼ 36, 18 girls, 18 boys) had headaches only associated with another illness such as cold or flu. The one-year prevalence of definite migraine (i.e. MwoA, MA or CM as first or second headache) was 23% (95% CI, 19.3–26.7%), and the one-year prevalence for PM was 13% (95% CI, 10.0–16.0). With Bonferroni adjustment there was no significant difference between girls and boys (p ¼ 0.002), grades (p ¼ 0.47) or urban and rural locations (p ¼ 0.059). The prevalence of migraine subtypes is presented in Table 1. The overall prevalence of any TTH (i.e., ITTH, FTTH, PTTH or CTTH as first or second headache) was 58% (95% CI, 54–62%; Table 1), similar in boys and girls (p ¼ 0.79), across grades (p ¼ 0.15) and in urban and rural locations (p ¼ 0.79). The prevalence of TTH subtypes is presented in Table 1.
1184
Cephalalgia 35(13)
Adolescents invited for participation in the schools in Sør-Trøndelag n = 899 (100%)
Adolescents who consented to participate in the study n = 519 (58%)
Lack of consent n = 380 (42%)
Agreed to participate but did not attend the interview n = 26 (3%)
Adolescents participating in the interview
Excluded because of age over 18 years
n = 493 (55%)
n = 5 (0.5%)
The final study sample n = 488 (54%)
Figure 1. Flow of study participants.
Sixty-five adolescents (45 girls, 20 boys) considered themselves to have more than one type of headache, and 45 of them fulfilled diagnostic criteria for more than one diagnosis. All of the latter reported migraine as the most bothersome headache (23 MA, 14 MwoA, one CM, seven PM). Six adolescents also had definite or PM as the less bothersome headache (four MwoA, two PM). The remaining 39 adolescents with two diagnoses had TTH as the less bothersome headache (26 FTTH, 13 ITTH).
Point prevalence of headache A total of 160 adolescents (38%) experienced headache during the interview. Of these, 104 (65%) rated the severity 20 mm on the VAS, 37 (23%) rated the severity 21–40 mm on the VAS, 12 (8%) rated the severity 41–60 mm on the VAS, and seven (4%) rated the severity > 60 mm on the VAS. The results of analysis of variance (ANOVA) showed no main effects of sex and grade on the VAS score (p ¼ 0.24 and 0.77, respectively) and no sex and grade interaction (p ¼ 0.34). Student’s t-test showed no significant difference between rural and urban locations (p ¼ 0.11).
Frequency of headache The frequency of the most bothersome headache is presented by sex, grade and location of school in Table 2 and by headache diagnoses (also considering any second headache) in Table 3. The frequency of the most bothersome headache (disregarding subtype) was similar between girls and boys (p ¼ 0.022) and across grades (p ¼ 0.004). With Bonferroni adjustment there was no significant difference between the frequencies of the most bothersome headache between grades (p ¼ 0.002 between eighth graders and 10th and 12th graders, and p ¼ 0.67 between 10th and 12th graders). The frequency of the most bothersome headache was similar in urban and rural areas (p ¼ 0.34). Among the 45 adolescents (9% of all participants) who fulfilled ICHD-3 beta criteria for more than one type of headache, there was no significant difference in headache frequency between the most bothersome and the less bothersome headache (p ¼ 0.86). The frequency of the most bothersome headache was 3 days
One to three days
4–
Prevalence and disability of headache among Norwegian adolescents: A cross-sectional school-based study
Cephalalgia 2015, Vol. 35(13) 1181–1191 ! International Headache Society 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav DOI: 10.1177/0333102415573512 cep.sagepub.com
Anne-Berit Krogh1, Bo Larsson2,3 and Mattias Linde1,4 Abstract Background: Headache is common in adolescents and affects schoolwork and relations with friends and family. In most previous epidemiological surveys, only the most bothersome headache has been documented. The aim was to determine headache prevalence not only taking into account the most bothersome headache, but also to compare characteristics of the most bothersome and less bothersome headaches, and to investigate headache-related disability. Methods: A cross-sectional school-based study was conducted in which 493 representative adolescents aged 12–18 years were recruited by stratified cluster sampling and interviewed. Headache diagnosis was made according to the new classification system of the International Headache Society (ICHD-3 beta), and the Pediatric Migraine Disability Assessment (PedMIDAS) was used to evaluate disability. Results: The one-year prevalence of any headache type, definite migraine, probable migraine and tension-type headache was 88%, 23%, 13% and 58%, respectively. The point prevalence of any headache was 38%. Nine percent of participants fulfilled criteria for more than one headache diagnosis. The most bothersome headache had a significantly longer duration (p < 0.001) and higher intensity (p < 0.001) than the less bothersome headache, but similar frequency (p ¼ 0.86). Adolescents with headaches lost up to nine days of activity each year, implicating headache as a major health issue. Conclusions: Headaches are very common and disabling among adolescents. The full extent of this health problem is better appreciated if inquiry is not limited to the most bothersome subtypes. Keywords Adolescents, headache, migraine, tension-type headache, prevalence, PedMIDAS Date received: 18 August 2014; revised: 19 October 2014; 18 December 2014; 28 December 2014; accepted: 31 December 2014
Background Headache is one of the most common health problems in adolescents (1,2) and can negatively affect quality of life and lead to impairments in daily functioning such as school performance and recreational activities (3,4). Surveys conducted in different countries and cultures show considerable variation in the estimated prevalence of headache, and a recent review reported an overall median of 5% for oneyear prevalence of headache in adolescents (1). Many studies have considered only the most bothersome headache in adolescence, whereas others have limited the prevalence estimates to strict diagnoses, thereby disregarding the existence of probable migraine (PM) and probable tension-type headache (PTTH) (5,6).
The main objectives of the present epidemiological study were to determine the prevalence of headache, taking into account more than one type of headache
1 Department of Neuroscience, Norwegian University of Science and Technology, Norway 2 Regional Centre for Child and Youth Mental Health and Child Welfare, Central Norway, Norway 3 National Competence Centre for Complex Symptom Disorders. St Olav’s University Hospital, Norway 4 Norwegian Advisory Unit on Headaches, St Olav’s University Hospital, Norway
Corresponding author: Anne-Berit Krogh, Department of Neuroscience, Norwegian University of Science and Technology, N-7489 Trondheim, Norway. Email: [email protected]
1182 in each participant, to compare the differences in the characteristics of the most bothersome and other headaches, and to investigate headache-related disability in adolescents in the general population.
Methods Study population and sample selection The study population was students from secondary schools and high schools in Sør-Trøndelag County in Norway. Sampling was stratified by grade and location. Data were collected in 2011–2012. As of January 1, 2011, Sør-Trøndelag County had 294,066 residents: 173,486 in the city of Trondheim, 83,451 in the inland/ mountain region and 37,129 by the coast (7). To obtain a sample distribution corresponding to the distribution of the population in the county, the schools were initially drawn with the following probabilities: 59% from the urban region, 28% from the inlandmountain region and 13% from coastal municipalities. The study sample was recruited in equal proportions from three grade cohorts from two types of schools: eighth grade (age 12–13 years), 10th grade (age 14–15 years) both from secondary schools, and 12th grade (age 16–18 years) from high schools. There are large differences in school size with more students in schools in urban vs rural areas, and a higher number of schools were therefore needed to be drawn from rural areas to obtain the required number of participants. First we drew what grades we should invite, then the school. Then all the students in the drawnclass level of the current school were invited to attend the study. At the time of the study, there were 74 secondary or high schools in Sør-Trøndelag County. Thirteen of these were invited to participate in the study: four of the 26 schools in an urban area and nine of the 48 schools in a rural (inland/mountain or coastal) area. Of the initial 13 schools invited, seven schools declined to participate in the study and were replaced by seven new schools (four from the inland/ mountain area, one from the coastal area, and two from the urban area). The four schools in urban areas that agreed to participate were two secondary schools (individuals in the eighth and 10th grades) and two high schools (individuals in the 12th grade). Of the latter, one school specialized in vocational training, and one specialized in theoretical sciences. The nine schools in rural areas that agreed to participate were four secondary schools from the coastal region, three secondary schools from the inland/mountain region, one high school from the coastal region, and one high school from the inland/mountain region. Data from the inland/mountain and coastal regions were combined and labeled ‘‘rural.’’
Cephalalgia 35(13)
Recruitment procedure There were 899 eligible students invited to participate in the study. The interviewer (ABK) held an information meeting with principals, inspectors and teachers from each of the selected schools to motivate them to participate in the study. The interviewer met with all students who had been selected for participation, and they also received written information about the study. As an incentive, students were offered a cinema ticket for participation. Norwegian law requires parental consent for children younger than 16 years of age to participate in research; therefore, the interviewer also provided optional meetings for parents with children in these age groups with the purpose of informing them about the study.
Questionnaire and interviews The questionnaire was developed for school-based studies of headache in Sweden (8–10), translated to Norwegian and adapted to the diagnostic criteria from the International Headache Society (IHS) (11). All interviews were conducted face to face by the same experienced nurse in a suitable room at the school during a regular school day and lasted, on average, 20 minutes. As an opening question, the student was asked whether he or she had experienced headache during the past year. For those who answered ‘‘No’’ to this question, the interview stopped. For those who answered ‘‘Yes,’’ a structured interview was conducted to determine the headache characteristics. The researcher asked if the student had experienced more than one type of headache during the last year. If positively endorsed, the characteristics and associated symptoms of headache were documented for up to two headache types. Students were asked to report the frequency, intensity (on a three-point scale: 1 ¼ mild, 2 ¼ moderate, 3 ¼ severe) and duration of episodes, as well as the accompanying symptoms. At the very end of the interview, students were asked to assess the severity of any headache that they had experienced during the interview on a 100 mm visual analog scale (VAS) with the following end points: ‘‘None’’ and ‘‘As bad as it could be’’ (12).
Headache classification Headaches were classified as episodic migraine with or without aura (MA or MwoA), chronic migraine (CM), probable migraine, episodic tension-type headache, infrequent (ITTH) or frequent (FTTH), chronic tension-type headache (CTTH) or medication-overuse headache (MOH) according to the International Classification of Headache Disorders, third edition beta (ICHD-3 beta) (13). PTTH was merged with
1183
Krogh et al. definite TTH. MOH was defined as having any headache (including the most bothersome headache and any other headache) for more than half of the days during the last three months and treating it with medication on at least 10 days per month. Headache that did not fulfill any criteria according to ICHD-3 beta was labeled ‘‘unclassifiable.’’ One of the authors, a neurologist (ML) with extensive experience in the diagnosis and epidemiological research of headache, verified all final diagnoses. The study was conceived at the time criteria of headache classification from the IHS (ICHD-2) (11) was the prevailing set of diagnostic criteria. But information on headache duration was collected in such detail that data could instead be evaluated using the contemporary criteria of headache classification from the IHS (ICHD-3 beta) (13).
Pediatric Migraine Disability Assessment (PedMIDAS) Students were also asked to complete the PedMIDAS, which was developed to assess disability in children and adolescents with chronic pain, including headache, and has been used in clinical studies and epidemiological surveys (14–16). It consists of six questions addressing the number of days totally or partially lost because of headache for the last three months (91 days) in three domains (school, home and social activities). A total score was calculated for each adolescent by summing the number of days reported for each of the items for all headaches as recommended by the creator of the PedMIDAS (14). The PedMIDAS grading system was used to indicate the degree of headache disability. Grade I means little to no disability (0–10), Grade II means mild disability (11–30), Grade III means moderate disability (31–50) and Grade IV means severe disability (>50) (15).
Statistics and data analysis Descriptive data were expressed as means and standard deviations (SD), as the percentage with 95% confidence interval (CI) for continuous variables, and as the median and interquartile range for ordinal variables. The chi-square test was used to examine associations between categorical variables and Pearson productmoment correlations were used to examine associations between continuous variables. Differences between independent group means and medians were examined using Mann-Whitney tests and Kruskal-Wallis tests for ordinal variables. Differences between independent group means and medians were examined using analysis of variance (ANOVA) to examine assosiations between continous variables. The Wilcoxon test was used for paired within-group comparisons. To account for the
risk of mass significance due to statistical comparisons, a highly conservative Bonferroni-adjustment was applied throughout using an alpha lowered to 0.002 (0.05 divided by 25 analyses). IBM SPSS Statistics for Windows version 20 was used for all statistical analyses.
Ethics The Norwegian Ethical Committee for Medical Research and the Norwegian Social Science Data Service approved the research protocol.
Results The flow of participants in the study is presented in Figure 1. Of 899 invited students, written consent was obtained from 519 (58%). Twenty-six of the adolescents did not attend the interview. Of these students, 15 were sick, six did not attend the interview because of an unknown cause, two were on vacation, one withdrew from the study, one had practical studies outside school and one had exams. After the interviews were completed, five students were excluded because they were older than 18 years. Thus, the final study population consisted of 488 adolescents, 57% girls (n ¼ 276) and 43% boys (n ¼ 212), with an age range of 12–18 years. The distributions across grades and school location (urban/rural area) are presented in Table 1.
One-year prevalence of headache Of the 488 participants, 429 reported experiencing a headache in the past 12 months, giving a one-year prevalence of 88% (95% CI, 85–91%; Table 1). The prevalence of headache was significantly (p < 0.001) higher in girls than boys (93% vs 80%), but was similar across grades (p ¼ 0.24) and urban and rural locations (p ¼ 0.057). Of the 488 participants who reported headaches, 7.4% (n ¼ 36, 18 girls, 18 boys) had headaches only associated with another illness such as cold or flu. The one-year prevalence of definite migraine (i.e. MwoA, MA or CM as first or second headache) was 23% (95% CI, 19.3–26.7%), and the one-year prevalence for PM was 13% (95% CI, 10.0–16.0). With Bonferroni adjustment there was no significant difference between girls and boys (p ¼ 0.002), grades (p ¼ 0.47) or urban and rural locations (p ¼ 0.059). The prevalence of migraine subtypes is presented in Table 1. The overall prevalence of any TTH (i.e., ITTH, FTTH, PTTH or CTTH as first or second headache) was 58% (95% CI, 54–62%; Table 1), similar in boys and girls (p ¼ 0.79), across grades (p ¼ 0.15) and in urban and rural locations (p ¼ 0.79). The prevalence of TTH subtypes is presented in Table 1.
1184
Cephalalgia 35(13)
Adolescents invited for participation in the schools in Sør-Trøndelag n = 899 (100%)
Adolescents who consented to participate in the study n = 519 (58%)
Lack of consent n = 380 (42%)
Agreed to participate but did not attend the interview n = 26 (3%)
Adolescents participating in the interview
Excluded because of age over 18 years
n = 493 (55%)
n = 5 (0.5%)
The final study sample n = 488 (54%)
Figure 1. Flow of study participants.
Sixty-five adolescents (45 girls, 20 boys) considered themselves to have more than one type of headache, and 45 of them fulfilled diagnostic criteria for more than one diagnosis. All of the latter reported migraine as the most bothersome headache (23 MA, 14 MwoA, one CM, seven PM). Six adolescents also had definite or PM as the less bothersome headache (four MwoA, two PM). The remaining 39 adolescents with two diagnoses had TTH as the less bothersome headache (26 FTTH, 13 ITTH).
Point prevalence of headache A total of 160 adolescents (38%) experienced headache during the interview. Of these, 104 (65%) rated the severity 20 mm on the VAS, 37 (23%) rated the severity 21–40 mm on the VAS, 12 (8%) rated the severity 41–60 mm on the VAS, and seven (4%) rated the severity > 60 mm on the VAS. The results of analysis of variance (ANOVA) showed no main effects of sex and grade on the VAS score (p ¼ 0.24 and 0.77, respectively) and no sex and grade interaction (p ¼ 0.34). Student’s t-test showed no significant difference between rural and urban locations (p ¼ 0.11).
Frequency of headache The frequency of the most bothersome headache is presented by sex, grade and location of school in Table 2 and by headache diagnoses (also considering any second headache) in Table 3. The frequency of the most bothersome headache (disregarding subtype) was similar between girls and boys (p ¼ 0.022) and across grades (p ¼ 0.004). With Bonferroni adjustment there was no significant difference between the frequencies of the most bothersome headache between grades (p ¼ 0.002 between eighth graders and 10th and 12th graders, and p ¼ 0.67 between 10th and 12th graders). The frequency of the most bothersome headache was similar in urban and rural areas (p ¼ 0.34). Among the 45 adolescents (9% of all participants) who fulfilled ICHD-3 beta criteria for more than one type of headache, there was no significant difference in headache frequency between the most bothersome and the less bothersome headache (p ¼ 0.86). The frequency of the most bothersome headache was 3 days
One to three days
4–
