Early indicators of primary brain tumours: a population-based study with 10 years' follow-up

BACKGROUND AND PURPOSE

To improve diagnoses of primary brain tumours, knowledge about early indicators is needed. Nationwide Danish health registries were used to conduct a population-based case-control study including all persons diagnosed with a primary brain tumour between 2005 and 2014 in Denmark.

METHODS

All 5135 adults diagnosed with a primary brain tumour in the Danish Cancer Registry were matched to 19 572 general population comparisons from the Danish Civil Registration System. Conditional logistic regression analyses were applied to estimate age- and multivariable-adjusted odds ratios (ORs) for the occurrence of a primary brain tumour up to 10 years after hospital diagnoses or prescription of medications related to nervous system diseases and mental and behavioural disorders.

RESULTS

Increased odds for primary brain tumour after nervous system diseases and mental and behavioural disorders manifested up to 10 years before tumour diagnosis were found. Increased odds were seen especially for hospital contacts for inflammatory nervous system diseases [OR 11.3; 95% confidence interval (CI) 6.5-19.7], epilepsy (OR 9.0; 95% CI 7.6-10.7) and antiepileptic medications (OR 3.6; 95% CI 3.2-4.0), whilst antidementia medications provided a strong, protective association for primary brain tumours (OR 0.5; 95% CI 0.3-0.8).

CONCLUSIONS

Sub-groups of patients diagnosed with or being prescribed certain medications targeting nervous system diseases and mental and behavioural disorders may be at increased risk of being diagnosed with a primary brain tumour. Further studies should disentangle the potential underlying common pathogenetic pathways. The results are important for the development of systematic clinical approaches to ensure early diagnosis of primary brain tumours.

Polymorphisms in the Toll-Like Receptor and the IL-23/IL-17 Pathways Were Associated with Susceptibility to Inflammatory Bowel Disease in a Danish Cohort

BACKGROUND

The inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC), result from the combined effects of susceptibility genes and environmental factors. Previous studies have shown that polymorphisms in the Toll-like receptor (TLR), the apoptosis, the IL-23/IL-17 and the interferon gamma (IFNG) pathways are associated with risk of both CD and UC.

METHODS

Using a candidate gene approach, 21 functional single nucleotide polymorphisms (SNPs) in 15 genes were assessed in a clinical homogeneous group of severely diseased ethnic Danish patients consisting of 624 patients with CD, 411 patients with UC and 795 controls. The results were analysed using logistic regression.

RESULTS

The polymorphisms TLR5 (rs5744174) and IL12B (rs6887695) were associated with risk of CD, and TLR1 (rs4833095) and IL18 (rs187238) were associated with risk of both CD and UC (p<0.05). After Bonferroni correction for multiple testing, the homozygous variant genotype of TLR1 743 T>C (rs4833095) was associated with increased risk CD (OR: 3.15, 95% CI: 1.59-6.26, p = 0.02) and CD and UC combined (OR: 2.96, 95% CI: 1.64-5.32, p = 0.005).

CONCLUSION

Our results suggest that genetically determined high activity of TLR1 and TLR5 was associated with increased risk of both CD and UC and CD, respectively. This supports that the host microbial composition or environmental factors in the gut are involved in risk of IBD. Furthermore, genetically determined high activity of the IL-23/IL-17 pathway was associated with increased risk of CD and UC. Overall, our results support that genetically determined high inflammatory response was associated with increased risk of both CD and UC.

Polymorphisms in the inflammatory pathway genes TLR2, TLR4, TLR9, LY96, NFKBIA, NFKB1, TNFA, TNFRSF1A, IL6R, IL10, IL23R, PTPN22, and PPARG are associated with susceptibility of inflammatory bowel disease in a Danish cohort

BACKGROUND

The inflammatory bowel diseases (IBD), Crohn's disease (CD) and ulcerative colitis (UC), result from the combined effects of susceptibility genes and environmental factors. Polymorphisms in genes regulating inflammation may explain part of the genetic heritage.

METHODS

Using a candidate gene approach, 39 mainly functional single nucleotide polymorphisms (SNPs) in 26 genes regulating inflammation were assessed in a clinical homogeneous group of severely diseased patients consisting of 624 patients with CD, 411 patients with UC and 795 controls. The results were analysed using logistic regression.

RESULTS

Sixteen polymorphisms in 13 genes involved in regulation of inflammation were associated with risk of CD and/or UC (p ≤ 0.05). The polymorphisms TLR2 (rs1816702), NFKB1 (rs28362491), TNFRSF1A (rs4149570), IL6R (rs4537545), IL23R (rs11209026) and PTPN22 (rs2476601) were associated with risk of CD and the polymorphisms TLR2 (rs1816702), TLR4 (rs1554973 and rs12377632), TLR9 (rs352139), LY96 (rs11465996), NFKBIA (rs696), TNFA (rs1800629), TNFRSF1A (rs4149570), IL10 (rs3024505), IL23R (rs11209026), PTPN22 (rs2476601) and PPARG (rs1801282) were associated with risk of UC. When including all patients (IBD) the polymorphisms TLR2 (rs4696480 and rs1816702), TLR4 (rs1554973 and rs12377632), TLR9 (rs187084), TNFRSF1A (rs4149570), IL6R (rs4537545), IL10 (rs3024505), IL23R (rs11209026) and PTPN22 (rs2476601) were associated with risk. After Bonferroni correction for multiple testing, both the homozygous and the heterozygous variant genotypes of IL23R G>A(rs11209026) (OR(CD,adj): 0.38, 95% CI: 0.21-0.67, p = 0.03; OR(IBD,adj) 0.43, 95% CI: 0.28-0.67, p = 0.007) and PTPN22 1858 G>A(rs2476601) (OR(CD,unadj) 0.54, 95% CI: 0.41-0.72, p = 7*10-4; OR(IBD,unadj): 0.61, 95% CI: 0.48-0.77, p = 0.001) were associated with reduced risk of CD.

CONCLUSION

The biological effects of the studied polymorphisms suggest that genetically determined high inflammatory response was associated with increased risk of CD. The many SNPs found in TLRs suggest that the host microbial composition or environmental factors in the gut are involved in risk of IBD in genetically susceptible individuals.

Associations between functional polymorphisms in the NFκB signaling pathway and response to anti-TNF treatment in Danish patients with inflammatory bowel disease

Antitumor necrosis factor-α (TNF-α) is used for treatment of severe cases of inflammatory bowel diseases (IBD), including Crohn's disease (CD) and ulcerative colitis (UC). However, one-third of the patients do not respond to the treatment. Genetic markers may predict individual response to anti-TNF therapy. Using a candidate gene approach, 39 mainly functional single nucleotide polymorphisms (SNPs) in 26 genes regulating inflammation were assessed in 738 prior anti-TNF-naive Danish patients with IBD. The results were analyzed using logistic regression (crude and adjusted for age, gender and smoking status). Nineteen functional polymorphisms that alter the NFκB-mediated inflammatory response (TLR2 (rs3804099, rs11938228, rs1816702, rs4696480), TLR4 (rs5030728, rs1554973), TLR9 (rs187084, rs352139), LY96 (MD-2) (rs11465996), CD14 (rs2569190), MAP3K14 (NIK) (rs7222094)), TNF-α signaling (TNFA (TNF-α) (rs361525), TNFRSF1A (TNFR1) (rs4149570), TNFAIP3(A20) (rs6927172)) and other cytokines regulated by NFκB (IL1B (rs4848306), IL1RN (rs4251961), IL6 (rs10499563), IL17A (rs2275913), IFNG (rs2430561)) were associated with response to anti-TNF therapy among patients with CD, UC or both CD and UC (P ⩽ 0.05). In conclusion, the results suggest that polymorphisms in genes involved in activating NFκB through the Toll-like receptor (TLR) pathways, genes regulating TNF-α signaling and cytokines regulated by NFκB are important predictors for the response to anti-TNF therapy among patients with IBD. Genetically strong TNF-mediated inflammatory response was associated with beneficial response. In addition, the cytokines IL-1β, IL-6 and IFN-γ may be potential targets for treating patients with IBD who do not respond to anti-TNF therapy. These findings should be examined in independent cohorts before these results are applied in a clinical setting.

Secular changes in health care utilization and work absence for migraine and tension-type headache: a population based study

OBJECTIVE

To assess changes in consultation rates, medication use and work absences due to migraine and tension-type headache (TTH) in Denmark over a 12-year period.

METHODS

Surveys of the general population in 1989 and 2001. Medical doctors conducted all headache diagnostic interviews based on ICDH-I and II. The participation rate was 76% (740) in 1989 and 74% (711) in 2001. Headache status was categorized as pure migraine, pure frequent TTH (frequent episodic or chronic TTH), coexisting migraine and frequent TTH, and healthy subjects (no primary headache or only infrequent TTH).

RESULTS

Headache-related consultation rates (OR = 1.6 (1.1-2.2)), especially specialist consultations (OR = 3.6 (2.3-5.6)), increased for all headache groups. Use of prescription medication because of headache increased moderately (OR = 2.1 (1.1-3.9)) while the use of prophylactic medication was stable (OR = 1.1 (0.3-4.0)). Both headache-related (OR = 1.1 (0.7-1.7)) and overall (OR = 0.9 (0.7-1.2)) absence rates were largely unchanged. Headache-related absence rates were higher for subjects with both headache types (OR = 7.5 (4.3-13.1)) or with pure migraine (OR = 3.6 (2.0-6.6)) than for subjects with frequent TTH alone. Triptans users had higher migraine headache frequency and tended to have higher absence rates than non-users. Overall absence rates were higher for subjects with both headache types (OR = 2.3 (1.3-4.0)) or with frequent TTH (OR = 1.9 (1.4-2.7)) than for healthy subjects. Pure migraine was not associated with higher overall absence rates (OR = 1.0 (0.6-1.6)).

CONCLUSION

Despite an increase in headache consultation rates and in use of prescription medication and triptans, no improvement in work absence rates was observed. Consultations, medication use, and absence rates were highest for individuals with both migraine and frequent TTH.

Incidence of primary headache: a Danish epidemiologic follow-up study

The incidence of migraine in a general population has been assessed in few longitudinal studies, and the incidence of tension-type headache has never been assessed. The authors aimed to assess the incidence of migraine and tension-type headache in Denmark by conducting a 12-year follow-up study of a general population (1989-2001). The design and methods of follow-up replicated the baseline study exactly, including use of the International Headache Society's diagnostic criteria and administration of headache diagnostic interviews by a physician. Of 740 persons aged 25-64 years examined in 1989, 673 were eligible in 2001 and 549 (81.6%) participated. The incidence of migraine was 8.1 per 1,000 person-years (male:female ratio, 1:6), and the incidence of frequent tension-type headache was 14.2 per 1,000 person-years (male:female ratio, 1:3). Both rates decreased with age. The incidence of migraine was higher than that previously calculated from cross-sectional studies. Risk factors for migraine were familial disposition, no vocational education, a high work load, and frequent tension-type headache. For tension-type headache, risk factors were poor self-rated health, inability to relax after work, and sleeping few hours per night. The gender difference for tension-type headache differed from that for migraine, and no association with educational level was observed.

Epidemiology of headache

Headache disorders constitute a public-health problem of enormous proportions, with an impact on both the individual sufferer and society. Epidemiological knowledge is required to quantitate the significance of these disorders. The effects on individuals can be assessed by examining prevalence, distribution, attack frequency and duration, and headache-related disability. The socio-economic burden includes both direct costs associated with health care utilization and costs associated with missed work due to sickness absence or reduced efficiency. The individual and socio-economic burden of headaches is substantial. Headache disorders deserve more attention, especially concerning strategies leading to adequate primary prevention, diagnosis and treatment.

The impact of migraine: Epidemiology, risk factors, and co-morbidities

In Western countries, recent community-based studies of migraine prevalence using standardized diagnostic criteria give 1-year prevalence estimates of around 10 to 12%. The prevalence of migraine is age- and gender-dependent. Age at onset of migraine is earlier in boys than in girls. Migraine is two to three times more common in women than in men, with peak prevalence occurring during mid-life in both sexes. Current evidence also indicates that migraine prevalence is higher in Caucasians than in Africans or Asians. In some migraineurs, attacks may be frequent or prolonged, leading to considerable pain and disability. There has been much debate over predisposing factors, which are not sufficient by themselves to cause an attack, as well as precipitants, which immediately precede the attack. However, convincing data are lacking for most of these. Significant associations have been reported between migraine and certain psychiatric disorders, epilepsy, and stroke in women under the age of 45. These findings demonstrate that migraine is common, has a substantial impact on sufferers, and may be associated with other disorders.

Epidemiology and socio-economic impact of headache

Headache disorders constitute a public-health problem of enormous proportions, with an impact on both the individual sufferer and society. Epidemiological knowledge is required to quantitate the significance of these disorders. The effects on individuals can be assessed by examining prevalence, distribution, attack frequency and duration, and headache-related disability. The socio-economic burden includes both direct costs associated with healthcare utilization and costs associated with missed work due to sickness absence or reduced efficiency. The individual and socio-economic burden of headaches is substantial. Headache disorders deserve more attention, especially concerning strategies leading to adequate primary prevention, diagnosis, and treatment.

Basal serum pancreatic polypeptide is dependent on age and gender in an adult population

This study is the first epidemiologically based study of basal levels of serum pancreatic polypeptide (s-PP). The basal level of serum PP has become a field of interest mainly due to the role of PP as an endocrine tumour marker, and as a marker of pancreatic neuroendocrine function after pancreas transplantation and in the case of diabetic autonomic neuropathy. The study population consisted of primarily Caucasian adults representative of a general population living around Copenhagen. Serum pancreatic polypeptide was measured in random serum samples from fasting persons (n = 623), aged 25-64 y, using a monospecific radioimmunoassay. Fasting serum pancreatic polypeptide depended on age and gender. The results demonstrated that fasting pancreatic polypeptide levels increase exponentially with age. Fitted separately for each sex, basal serum pancreatic polypeptide was found to increase by approximately 3% per year of age. Males had higher concentrations of pancreatic polypeptide in serum compared to age-matched females. Normal range and 95% reference intervals are given. The lower limit for the reference interval of the normal range was close to detection limit. We conclude that discrepancies among earlier reports on the fasting levels of serum pancreatic polypeptide are most likely due to lack of adjustment for age and gender. Thus, variation due to age and gender should be considered in evaluating fasting levels of serum pancreatic polypeptide. Whether similar considerations are important when evaluating stimulated serum pancreatic polypeptide levels remains to be elucidated.

The International Headache Society classification of chronic daily and near-daily headaches: a critique of the criticism

The classification of the International Headache Society (IHS) published in 1988 has been positively received throughout the world. However, the classification of headaches occurring daily or almost daily has been criticized repeatedly. This criticisim is discussed in the present review. It is possible to classify virtually all chronic headache patients using the IHS Classification and there seems to be more need for emphasizing a correct application of the classification than for a revision in this regard. The entity of transformed migraine is disputed and so is the existence of hemicrania continua. Neither of these syndromes has been adequately defined nor studied. Chronic daily headache of sudden onset (new persistent daily headache) is not adequately classified at present and should be included as a separate entity in the next edition of the IHS Classification. In a future revision it should also be possible to classify drug-related headache simply on the basis of drug consumption and without mandatory demands for withdrawal. Better longitudinal studies of patients with chronic daily headache are necessary to evaluate finally whether a revision of the classification of these headache syndromes is necessary. Eventually the ongoing discovery of migraine genes is likely to change radically the classification of migraine.

Migraine without aura and migraine with aura are distinct clinical entities: a study of four hundred and eighty-four male and female migraineurs from the general population

The clinical characteristics of migraine without aura (MO) and migraine with aura (MA) were compared in 484 migraineurs from the general population. We used the criteria of the International Headache Society. The lifetime prevalence of MO was 14.7% with a M:F ratio of 1:2.2; that of MA was 7.9% with a M:F ratio of 1:1.5. The female preponderance was significant in both MO and MA. The female preponderance was present in all age groups in MA, but was first apparent after menarche in MO, suggesting that female hormones are an initiating factor in MO, but not likely so in MA. The age at onset of MO followed a normal distribution, whereas the age at onset of MA was bimodally distributed, which could be explained by a composition of two normal distributions. The estimated separation between the two groups of MA was at age 26 years among the females and age 31 years among the males. The observed number of persons with co-occurrence of MO and MA was not significantly different from the expected number. The specificity and importance of premonitory symptoms are questioned, but prospective studies are needed. Bright light was a precipitating factor in MA, but not in MO. Menstruation was a precipitating factor in MO, but not likely in MA. Both MO and MA improved during pregnancy. The clinical differences indicate that MO and MA are distinct entities.

Muscular disorders in tension-type headache

In order to evaluate the diagnostic criteria for muscular disorders in tension-type headache, pericranial muscle tenderness and pressure pain thresholds were studied in a random sample population of 735 adults aged 25-64. In addition, quantitative EMGs were recorded in 547 of these subjects. The correlation between the three diagnostic tests was assessed and the discriminality and cut-off points were analysed using Receiver Operating Characteristics analysis. Local tenderness from the temporal muscles was closely related to the total tenderness scores from 14 pairs of muscles. In chronic tension-type headache, tenderness was positively related to EMG and inversely related to pain thresholds. In the episodic from the total tenderness score was inversely related to pain thresholds, whereas no significant relation to EMG was noted. The Receiver Operating Characteristics curves indicated that tenderness recorded by manual palpation was the most specific and sensitive test, whereas EMG and pain thresholds were of limited diagnostic value. Eighty-seven percent of subjects with the chronic, and 66% of subjects with the episodic form were found to have a "muscular disorder" defined as increased tenderness recorded by either manual palpation or pressure algometry and/or increased EMG levels. However, muscle tenderness increased significantly during pain, so the headache state should be considered in future studies. Suggestions for revision of the present diagnostic criteria for muscular disorders are given.

[Prevalence and sex distribution of different forms of migraine]

The aim of this study was to provide prevalence and sex-ratio of subtypes of migraine diagnosed by neurological interview according to the criteria of the International Headache Society. In all, 3000 males and 1000 females aged 40 years were randomly selected from the Danish population. They received a mailed questionnaire regarding migraine. The questionnaire response rate was 87%. People with self-reported migraine and a random sample of those reporting no migraine were invited to a headache interview, and a physical and a neurological examination. Those not reacting to the invitation were interviewed by telephone. Participation in the interview was 87%. Kappa was 0.77 validating self-reported migraine in the questionnaire against the diagnosis of the clinical interview. Lifetime prevalences of migraine without aura, migraine with aura, migraine aura without headache, and migrainous disorder were 8%, 4%, 1% and 1% in males and 16%, 7%, 3% and 2% in females. Overall lifetime prevalence of any type of migraine was 18%, 12% in males and 24% in females. This is lower than the sum of the prevalences since migraine diagnoses are not mutually exclusive. The male:female ratios of migraine without aura, migraine with aura, migraine aura without headache, and migrainous disorder were approximately 1:2.

Prevalence and sex-ratio of the subtypes of migraine

BACKGROUND

The aim of this study was to provide the prevalence and sex-ratio of subtypes of migraine diagnosed by neurological interview according to the criteria of the International Headache Society.

METHODS

In all, 3000 males and 1000 females aged 40 years were randomly selected from the Danish population. They received a mailed questionnaire regarding migraine. The questionnaire response rate was 87%. People with self-reported migraine and a random sample of those reporting no migraine were invited to a headache interview, and a physical and a neurological examination. Those not reacting to the invitation were interviewed by telephone. Participation at the interview was 87%. Kappa was 0.77 validating self-reported migraine in the questionnaire against the diagnosis of the clinical interview.

RESULTS

Lifetime prevalences of migraine without aura, migraine with aura, migraine aura without headache, and migrainous disorder were 8%, 4%, 1% and 1% in males and 16%, 7%, 3% and 2% in females. Overall lifetime prevalence of any type of migraine was 18%; 12% in males and 24% in females. This is lower than the sum of the prevalences since migraine diagnoses are not mutually exclusive. The male:female ratios of migraine without aura, migraine with aura, migraine aura without headache, and migrainous disorder were approximately 1:2.

CONCLUSIONS

Migraine is more prevalent than previously thought. There was a significant preponderance in females of all the subtypes of migraine except migrainous disorder.

Epidemiology of headache

This thesis is based on nine previously published papers. It represents the first prevalence study of specific headache entities in a representative general population, where the diagnoses are based on a structural interview and examination by a physician using internationally accepted operational diagnostic criteria. The study population was a random sample of 1000 men and women aged 25-64. The participation rate was 76%. The prevalences of the different forms of headache are assessed and the study provides descriptive data concerning symptomatology, precipitating factors, impact of female hormones, use of medical services and work consequences of the headache disorders and describes various factors associated with the disorders. Only half of migraineurs and one-sixth of subjects with tension-type headache consulted their general practitioner because of headache and even less consulted a specialist. These consultation rates reflect the selection of cases that may bias studies in clinic populations. The study supports the notion that migraine and tension-type headache are separate clinical entities and that migraine without aura and migraine with aura are distinct subforms of migraine. Migraine and tension-type headache are sex- and age-dependent disorders with female preponderance and lower prevalence in older age groups. The female preponderance may be explained by clinical factors related to female hormones. There is no clear evidence of any association between sociodemographic variables and migraine or tension-type headache. Tension-type headache is related to a series of psychosocial variables while migraine is not. The results suggest that migraine is primarily a constitutional disorder and tension-type headache a more complex phenomenon influenced by several psychosocial factors. The limitations of cross-sectional data in pointing out risk factors with sufficient certainty are stressed. Longitudinal follow-up studies are the most important challenge in future epidemiological headache research.

Classification of primary headaches

In 1988, the International Headache Society (IHS) classification committee published operational diagnostic criteria for the primary headaches and a broad range of other headache disorders. These criteria have been translated into more than ten languages, providing uniform terminology for clinical practice, multinational clinical trials, and biologic and epidemiologic research. The criteria have also been evaluated in a number of field studies intended to address their generalizability, exhaustiveness, reliability, and validity. In the present publication the IHS criteria for migraine and tension-type headache are presented.

Epidemiology of migraine

The introduction of operational diagnostic criteria for the primary headaches in 1988 has provided new opportunities for comprehensive epidemiologic headache research. In recent years, several studies on the epidemiology of migraine have emerged. This review deals with methodologic considerations and provides a snapshot of the main findings in these studies. The importance of epidemiologic studies in clarifying the natural history of migraine is elucidated.

Migraine prevalence. A review of population-based studies

Obtaining accurate and reliable information on the prevalence of migraine is essential to understanding the burden it places on society. Although the epidemiology of headache has been described in more than 50 population-based studies, only 24 of these have described the gender- and age-specific prevalence of migraine. Essentially five different case definitions have been used in these studies. Variation in the prevalence of migraine among studies is largely due to differences in case definition and in the age and gender distribution of study populations. Among four recent studies that used the diagnostic criteria of the International Headache Society (IHS), a coherent picture emerges. The prevalence of migraine is approximately 6% among men and 15 to 17% among women. Prevalence varies by age, increasing to about age 40 years and declining thereafter in both men and women. The gender ratio also appears to vary by age, increasing from menarche to about age 42 years and declining thereafter. Although the use of the IHS criteria has resulted in a more coherent picture across population-based studies, efforts must be made to assess the reliability and validity of these criteria in population-based samples.

Epidemiology of migraine and tension-type headache

The introduction of operational diagnostic criteria for the primary headaches in 1988 has provided new opportunities for comprehensive epidemiologic headache research. In recent years, several studies on the epidemiology of the primary headaches have emerged. This review deals with methodologic considerations and provides a "snapshot" of the main findings in these studies. The importance of epidemiologic studies in clarifying the natural history of the primary headaches, including the distinction between separate clinical entities, is elucidated.

Presentation of a new instrument: the diagnostic headache diary

A new instrument, the Diagnostic Headache Diary, based on the operational diagnostic criteria of the International Headache Society (IHS), was tested in 61 migraine patients from a headache research clinic using the clinical diagnosis (IHS criteria) for comparison. All patients kept the diary for one to eight months. The clinical and diary diagnosis of migraine with and without aura was the same in, respectively, 72 and 87% of the patients. Nausea, photophobia and phonophobia tended to be more pronounced at the clinical interview. The diary identified 20 more cases of episodic tension-type headache and 15 fewer cases of chronic tension-type headache than the clinical interview. Two blinded observers always made the same IHS diagnoses when interpreting the diagnostic headache diary. A combination of a clinical interview and the diagnostic headache diary gives a qualitatively and quantitatively more precise diagnosis than a clinical interview alone.

Migraine and tension-type headache in a general population: psychosocial factors

In a cross-sectional study of headache disorders in a representative general population, the prevalence of migraine and tension-type headache was assessed in relation to various psychosocial factors. The random sample comprised 1000 25-64 year old men and women of whom 740 attended the investigation. The headache disorders were classified on the basis of a clinical interview, a physical and a neurological examination using the operational diagnostic criteria of the International Headache Society. None of the sociodemographic variables: marital status, cohabitation, educational level, occupational category or employment status were significantly associated with migraine or tension-type headache. In the univariate analyses tension-type headache was significantly associated with a high Neuroticism score on the Eysenck Personality Questionnaire whereas migraine was not. Variables on work conditions and psychosocial factors significantly associated with the headache disorders in univariate analyses were subjected to multivariate analysis. Migraine was significantly associated with exposure to chemicals and fumes at work in women and poor self-appraisal of health in men. In the univariate analyses tension-type headache was significantly related to a series of psychosocial variables. In the multivariate analyses it remained associated with a current feeling of fatigue in both sexes, time-pressure at work in women and exposure to fumes in men.

Interrelations between migraine and tension-type headache in the general population

In a cross-sectional epidemiological survey of a general population, headache disorders were diagnosed according to a structured interview and a neurological examination using the criteria of the International Headache Society. The prevalences and sex distribution of the primary headache disorders were assessed, and characteristics of and interrelationships between different types of headache were analyzed. Severity and frequency of migraine attacks were not correlated, indicating that the migraine attack is an all-or-none phenomenon triggered with an individually variable threshold. Tension-type headache, in contrast, showed increasing severity with increasing frequency, indicating that it is a graded phenomenon. In the previous year, 6% had migraine without aura (previously called "common migraine") and 4% had migraine with aura (previously called "classic migraine"); 63% had episodic tension-type headache and 3% chronic tension-type headache. In women, migraine without aura was twice as prevalent as migraine with aura; in men, an opposite trend emerged. In migraine without aura, pain was more severe than in migraine with aura. Tension-type headache in migraineurs was not significantly more prevalent than in nonmigraineurs and, except for greater frequency and severity, it did not deviate nosographically from pure tension-type headache. Our results support the contention that migraine and tension-type headache are distinct entities, contradict the so-called continuum-severity model, and indicate that the terms combination headache, mixed headache, and interval headache should be avoided.

Impact of headache on sickness absence and utilisation of medical services: a Danish population study

STUDY OBJECTIVE

The aim was to study the extent and type of health service utilisation, medication habits, and sickness absence due to the primary headaches.

DESIGN

This was a cross sectional epidemiological survey of headache disorders in a general population. Headache was diagnosed according to a structured interview and a neurological examination using the criteria of the International Headache Society.

SETTING

A random sample of 25-64 year-old individuals was drawn from the Danish National Central Person Registry. All subjects were living in the Copenhagen County.

PARTICIPANTS

740 subjects participated (76% of the sample); 119 had migraine and 578 had tension type headache.

MAIN RESULTS

Among subjects with migraine 56% had, at some time, consulted their general practitioner because of the migraine. The corresponding percentage among subjects with tension type headache was 16. One or more specialists had been consulted by 16% of migraine sufferers and by 4% of subjects with tension type headache. The consultation rates of chiropractors and physiotherapists were 5-8%. Hospital admissions and supplementary laboratory investigations due to headache were rare (< 3%). Half of the migraine sufferers and 83% of subjects with tension type headache in the previous year had managed with at least one type of drug in the current year. Acetylsalicylic acid preparations and paracetamol were the most commonly used analgesics. Prophylaxis of migraine was used by 7%. In the preceding year 43% of employed migraine sufferers and 12% of employed subjects with tension type headache had missed one or more days of work because of headache. Most common was 1-7 days off work. The total loss of workdays per year due to migraine in the general population was estimated at 270 days per 1000 persons. For tension type headache the corresponding figure was 820. Women were more likely to consult a practitioner than men, whereas no significant sex difference emerged as regards absenteeism from work.

CONCLUSIONS

The impact of the headache disorders on work performance in the general population is substantial, and the disorders merit increased attention.

Migraine with aura and migraine without aura: an epidemiological study

In a cross-sectional study of headache disorders in a representative general population of 1,000 persons the epidemiology of migraine with aura (MA) and migraine without aura (MO) was analysed in relation to sex and age distribution, symptomatology and precipitants. The headache disorders were classified on the basis of a clinical interview as well as a physical and a neurological examination using the operational diagnostic criteria of the International Headache Society (IHS). Lifetime prevalence of MA was 5%, male:female ratio 1:2. Lifetime prevalence of MO was 8%, M:F ratio 1:7. Women, but not men, were significantly more likely to have MO than MA. Neither MA nor MO showed correlation to age in the studied age interval (25-64 years). Premonitory symptoms occurred in 16% of subjects with MA and in 12% with MO. One or more precipitating factor was present in 61% with MA and in 90% with MO. In both MA and MO the most conspicuous precipitating factor was stress and mental tension. Visual disturbances were the most common aura phenomenon occurring in 90% of subjects with MA. Aura symptoms of sensory, motor or speech disturbances rarely occurred without coexisting visual disturbances. The pain phase of MA fulfilled the criteria for MO of the IHS. Headache was, however, less severe and shorter lasting in MA than in MO. Onset at menarche, menstrual precipitation, menstrual problems, influence of pregnancy and use of oral contraceptives all showed some relationship with the presence of MO and less with MA. The present findings suggest that MA and MO share the pain phase.(ABSTRACT TRUNCATED AT 250 WORDS)

Symptomatic and nonsymptomatic headaches in a general population

We assessed the lifetime prevalences of headache disorders in a cross-sectional epidemiologic survey of a representative 25- to 64-year-old general population. We classified the headaches on the basis of a clinical interview and a physical and neurologic examination using the operational diagnostic criteria of the International Headache Society. Lifetime prevalence of idiopathic stabbing headache was 2%, of external compression headache 4%, and of cold stimulus headache 15%. Benign cough headache, benign exertional headache, and headache associated with sexual activity each occurred in 1%. Lifetime prevalence of hangover headache was 72%, of fever headache 63%, and of headache associated with disorders of nose or sinuses 15%. Headaches associated with severe structural lesions were rare. External compression headache, fever headache, headache associated with metabolic disorders, and headache associated with disorders of nose or sinuses all showed significant female preponderance. The symptomatic headaches and headaches unassociated with structural lesions were more prevalent among migraineurs. In subjects with tension-type headache, only hangover headache was overrepresented. There was no association between the headache disorders and abnormal routine blood chemistry or arterial hypertension. In women with migraine, however, diastolic blood pressure was significantly higher than in women without migraine.

A population-based analysis of the diagnostic criteria of the International Headache Society

In 740 representative normal subjects a diagnostic headache interview and a neurological examination provided the necessary information to classify headache disorders according to the operational diagnostic criteria of the International Headache Society (IHS). Sixteen per cent (n = 119) had migraine, 78% (n = 578) tension-type headache. In migraineurs, pain was of a pulsating quality in 78%, severe in 85%, unilateral in 62%, and aggravated by routine physical activity in 96%. Tension-type headache was of a pressing quality in 78%, mild or moderate in 99%, bilateral in 90%, and 72% had no aggravation by physical activity. The accompanying symptoms of nausea, photo- and phonophobia occurred frequently and were usually moderate or severe in migraine subjects, and if present in subjects with tension-type headache, they were usually mild. Only two subjects had unclassifiable headache. The IHS Classification is thus exhaustive. The criteria may be improved by mandatory demands to the criterion of pain intensity leaving other features of pain as supportive for the diagnosis and by including graded severity of accompanying symptoms. A specific proposal is given.

Questionnaire versus clinical interview in the diagnosis of headache

A self-administered questionnaire based on the operational diagnostic criteria of the International Headache Society (IHS) was evaluated in a cross-sectional epidemiological survey of headache disorders. A clinical interview was used as index of validity. Seven hundred and thirteen subjects were included. Sensitivity, specificity, predictive value, and chance-corrected agreement rate for the diagnosis of migraine was 51%, 92%, 50% (PVpos), 93% (PVneg), and 0.43 respectively. Corresponding values for episodic tension-type headache were 43%, 96%, 95% (PVpos), 46% (PVneg), and 0.30; and for chronic tension-type headache 14%, 100%, 100% (PVpos), 97% (PVneg), and 0.24. It is concluded that a questionnaire is not a satisfactory tool in diagnosing headache disorders according to the IHS criteria. The methods of data collection seem to have significant influence on the results. Caution in handling data obtained by means of subjective statements is advocated.

Epidemiology of headache in a general population--a prevalence study

We present the first prevalence study of specific headache entities using the operational diagnostic criteria of the International Headache Society. One thousand 25-64 year old men and women, who lived in the western part of Copenhagen County were randomly drawn from the Danish National Central Person Registry. All subjects were invited to a general health examination focusing on headache and including: a self-administered questionnaire concerning sociodemographic variables, a structured headache interview and a general physical and neurological examination. The participation rate was 76%. Information about 79% of the non-participants showed a slightly differing headache prevalence which was not quantitatively important. The following results in participants are therefore representative of the total sample. The lifetime prevalences of headache (including anybody with any form of headache), migraine, and tension-type headache were 93, 8 and 69% in men; and 99, 25 and 88% in women. The point prevalence of headache was 11% in men and 22% in women. Prevalence of migraine in the previous year was 6% in men and 15% in women and the corresponding prevalences of tension-type headache were 63 and 86%. Differences according to sex were significant with a male: female ratio of 1:3 in migraine, and 4:5 in tension-type headache. The prevalence of tension-type headache decreased with increasing age, whereas migraine showed no correlation to age within the studied age interval. Headache disorders are extremely prevalent and represent a major health problem, which merits increased attention.