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M B Russell

Publications and source records attributed to M B Russell.

At least 37 records · Page 2Linked to original sources
PubMed2000

[The significance of genetic and environmental factors for migraine with aura. A genetic epidemiologic study of Danish twins].

We studied the genetic and environmental influence on migraine with aura (MA) by analysing a twin population. The twin sample consisted of 2,026 monozygotic (MZ) pairs and 3,334 same-gender dizygotic (DZ) pairs recruited from the population-based Danish Twin Register. A total of 211 pairs were identified, of whom 77 were MZ and 134 were DZ. The pairwise concordance rate was significantly higher in MZ-than in DZ-pairs, i.e. 34% and 12%, respectively, emphasizing the importance of genetic factors in MA. However, environmental factors are also important, as the pair wise concordance rate was less than 100% in MZ-pairs. Similarly, the recurrence risk of MA was 50% in MZ- and 21% in DZ-pairs which was a significant difference. In non-twin siblings, the recurrence risk of MA is 27%, which is similar to the recurrence risk in DZ-pairs. This indicates that MA is not developed due to specific environmental factors shared by the twins.

Adult↗
PubMed2000

Multimedia education in headache: the European Neurological Network.

The European Neurological Network is a European Economic Community supported project. The purpose of the project was to develop a multimedia educational tool for general practitioners in order to improve their management of sleep disorders, epilepsy and headache. The project involves approximately one hundred engineers and physicians from Belgium, Denmark, England, Finland, France, Germany, Italy, Portugal and Spain. This paper concerns the multimedia educational tool on headache. The system consists of five different modules, i.e. classification, clinical data, headache tutorial, diagnostic headache diary and nomenclature. It is possible to move between the modules both vertically and horizontally. The headache classification of the International Headache Society is provided in full text as a work of reference. This classification is used world wide and has been adopted by International Classification of Diseases 10 Neurological Adaptation (ICD-10 NA) and the World Health Organisation. The clinical data concentrate on migraine and tension-type headache, the two most common headache disorders, but data on familial hemiplegic migraine, cluster headache, drug-induced headache and secondary headaches are also available. The headache tutorial consists of case records that the user can test their diagnostic abilities on. The diagnostic headache diary is an expert system on headache diagnostics. It can be filled in during a consultation in order to provide the headache diagnosis or it can be printed and used by the headache patient to record headache attacks and medicine consumption. The nomenclature module provides an explanation of words and expressions used in the system.

Education, Medical, Continuing↗
PubMed2000

Possible risk factors and precipitants for migraine with aura in discordant twin-pairs: a population-based study.

The aim of the present study was to detect possible risk factors in migraine with aura (MA) by analysis of discordant twin-pairs. In a recent population-based twin study we established that environmental factors account for approximately 50% of the variation in liability to MA. A cohort of 5,360 same-gender twin-pairs from the general population was screened for migraine. All twin-pairs with possible migraine were interviewed by a physician. A questionnaire provided information about living conditions and lifestyle. Of the 169 discordant twin-pairs 51 were monozygotic and 118 were dizygotic twin-pairs. Several putative risk factors-schooling, education, marital status, smoking status and alcohol consumption-showed no association with MA. The presence of migraine without aura or tension-type headache did not increase the risk of MA. Stress and mental tension, and bright light precipitated attacks of MA in, respectively, 44% and 28% of the twins.

Alcohol Drinking↗
PubMed2000

The diagnostic headache diary--a headache expert system.

The purpose with the headache expert system was to develop a diagnostic and educational tool for the general practitioners (GP), in order to improve their management of headache disorders. This chapter describes the diagnostic headache diary, an expert system intended for education and diagnosing headache disorders. The diagnostic headache diary can be printed and used by headache patients at home to record their headache attacks and medicine consumption by a day to day basis. It can also be used by the GP at the clinic in order to provide the headache diagnoses. The diagnostic headache diary was written in the programming language Delphi and implemented as a stand-alone Windows 95 program. It was integrated as one of five modules in the headache tutorial described in another chapter of this book. The diagnostic headache diary consists of four modules: Patient data, diary, medication and diagnosis. Configured around a database, the diagnostic headache diary allows entries of several patients and search facilities. The diagnostic headache diary was tested and validated by entering expert-diagnosed data from different headache disorders which where compared to the computer generated diagnoses.

Diagnosis, Computer-Assisted↗
PubMed2000

Headache tutorial.

The headache multimedia educational tool for the general practitioners, consists of five different modules, i.e. classification, clinical data, headache tutorial, diagnostic headache diary and nomenclature. It is possible to move between the modules both vertically and horizontally. This paper concerns the headache tutorial. It consist of case records that the user can test his diagnostic abilities on. Each case record is subdivided into an interview by the physician, physical and neurological examination, laboratory test, sum of positive diagnostic elements, suggestions of diagnoses and management. A total of 12 case records are provided. The system will be available on a CD-ROM.

Adult↗
PubMed1999

The relative role of genetic and environmental factors in migraine without aura.

OBJECTIVE: To clarify the relative role of genetic and environmental factors in the etiology of migraine without aura (MO). METHODS: The study population consisted of 5,360 twins, 1,013 monozygotic (MZ) and 1,667 same-gender dizygotic (DZ) twin pairs, from the population-based Danish Twin Registry. A total of 87% completed a simple validated questionnaire screening for migraine. All twin pairs, in whom at least one twin had self-reported migraine or severe headache with accompanying symptoms, were interviewed via telephone by a physician. Ninety percent of the eligible twins were interviewed. Probandwise concordance rates and correlations in liability were calculated, and structural equation model-fitting analyses were applied to quantitate the relative role of genetic and environmental factors in the etiology of MO. RESULTS: The probandwise concordance rate was higher in MZ than DZ twin pairs (0.43 versus 0.31; 95% CI, 0.36 to 0.49 versus 0.26 to 0.36). The correlation in liability was higher in MZ than in DZ twin pairs (0.62 versus 0.41; 95% CI, 0.50 to 0.74 versus 0.29 to 0.53). Structural equation model fitting indicated a highly significant genetic component, because a model with both genetic and environmental components fitted significantly better than a model with only environmental components. The best fitting model implied that the liability to MO resulted from additive genetic effects (61%; 95% CI, 49 to 71%)) and individual-specific environmental effects (39%; 95% CI, 29 to 51%). CONCLUSION: This study indicates that genetic factors play a role in the etiology of migraine without aura. The genetic variability is additive, with a negligible contribution of nonadditive genetic effects. The genetic contributions were similar in men and women despite a higher prevalence in women. Environmental factors are equally important and these factors are individual to the migraineurs.

Adolescent↗
PubMed1999

[Familial occurrence of chronic tension headache].

Chronic tension-type headache occurs in 3% of the Danish population. the aetiology remains an enigma, even though it is one of the most frequent illnesses with chronic pain. A family study indicates the importance of genetic factors. Compared with the general population, first degree relatives (parents, siblings and children) of probands with chronic tension-type headache have a three-fold significantly increased risk of chronic tension-type headache, while spouses had no increased risk. Complex segregation analysis indicates multifactorial inheritance. Thus, a combination of genetic and environmental factors causes chronic tension-type headache.

Adult↗
PubMed1999

Evidence of a genetic factor in migraine with aura: a population-based Danish twin study.

We studied the genetic influence on cause of migraine with aura (MA) by analyzing a twin population. The twin sample consisted of 2,026 monozygotic (MZ) twins and 3,334 same-sex dizygotic (DZ) twins, born from 1953 to 1960, from the population-based New Danish Twin Register. A validated questionnaire was used to screen for migraine, the response rate being 87%, and similar among MZ and DZ twins. All twin pairs with at least 1 twin with possible MA were interviewed by a physician experienced in headache diagnoses. The answers from the questionnaire as well as the zygosity of the twins were blinded for the interviewer. A total of 211 twin pairs were identified, of whom 77 pairs were MZ and 134 pairs were DZ. The lifetime prevalence of MA was 7% and with a male-to-female ratio of 1:1.1. The pairwise concordance rates were significantly higher in MZ (34%) than in DZ twin pairs (12%), emphasizing the importance of genetic factors in MA. However, environmental factors are also important, as the pairwise concordance rate was less than 100% in MZ twin pairs. The recurrence risk of MA was 50% in MZ and 21% in DZ twin pairs. In nontwin siblings, the recurrence risk of MA is 27%, which is similar to the recurrence risk in DZ twins. This indicates that MA is not developed due to specific environmental factors shared by the twins.

Adult↗
PubMed1999

Migraine without aura: a population-based twin study.

To investigate the importance of genetic and environmental factors to the etiology of migraine without aura and to compare the symptomatology of migraine without aura in monozygotic and dizygotic twins, 2,680 twin pairs were recruited from the population-based Danish Twin Registry. Monozygotic (MZ) and same-sex dizygotic (DZ) twin pairs, where at least one twin had self-reported migraine or self-reported severe headache with accompanying symptoms, were telephone interviewed by a physician. The participation rate in the telephone interview was 90%. The pairwise concordance rate was significantly higher in MZ than in DZ twin pairs (28% vs 18%). The probandwise concordance rate was 40% (95% CI, 33-48%) in MZ and 28% (95% CI, 23-33%) in DZ twin pairs. The pairwise concordance rates for the different pain characteristics and accompanying symptoms were not significantly different in MZ and DZ twin pairs. However, comparing all of the pairwise concordance rates of pain characteristics and accompanying symptoms together, MZ twin pairs were significantly more concordant than DZ twin pairs. Our data demonstrate a significant genetic factor in migraine without aura. The size of this factor is modest and the demonstration of susceptibility genes is predicted to be laborious and difficult.

Diseases in Twins↗
PubMed1999

Familial occurrence of chronic tension-type headache.

Chronic tension-type headache (CTTH) assessed by proband report was evaluated in a family study of CTTH. A clinical interview of first-degree relatives by a physician was used as index of validity. Familial occurrence of CTTH in first-degree relatives was also investigated. Patterns of familial aggregation of CTTH were assessed by calculating the population relative risk. A neurological resident carried out all the interviews of probands and their first-degree relatives. The operational diagnostic criteria of the International Headache Society were used. The 122 probands had 377 first-degree relatives. Sensitivity, specificity, predictive values, and chance-corrected agreement rate for the diagnosis CTTH were 68%, 86%, 53% (PVpos), 92% (PVneg), and 0.48, respectively. The low sensitivity of CTTH assessed by proband report indicates that a clinical interview by a physician is necessary in family studies of CTTH. Clinically interviewed parents, siblings, and children had a 2.1 to 3.9-fold significantly increased risk of CTTH compared with the general population. The gender of the probands did not influence the risk of CTTH among first-degree relatives. The significantly increased familial risk of CTTH and no increased risk of CTTH in spouses suggest that a genetic factor is involved in CTTH.

Adolescent↗
PubMed1999

The prevalence and characteristics of migraine in twins from the general population.

We examined whether prevalence, age at onset, and cessation of migraine without aura and migraine with aura are different among twins and singletons. The study population was recruited from the population-based New Danish Twin Register and comprised 2026 monozygotic and 3334 same-sex dizygotic twins born during 1953 to 1960. A simple questionnaire was used to screen for migraine. Twin pairs with at least one twin with possible migraine were interviewed by telephone by two physicians. A total of 1136 twin pairs were included in the telephone interviews. The criteria of the International Headache Society were used for diagnosis. The questionnaire response rate was 87%, and the telephone interview participation rate was 90%. Of the 715 migraineurs, 498 had migraine without aura, 264 had migraine with aura, and 47 had both migraine with and without aura. The lifetime prevalence, age at onset, and cessation of migraine with and without aura did not differ in monozygotic and dizygotic twins. Males and females had a lifetime prevalence of migraine without aura of 7% and 19%, respectively. The female preponderance of migraine without aura was first apparent after aged 14 years; this may be related to an influence of female hormones. The lifetime prevalence of migraine with aura was 7% in males and 8% in females. The observed and expected number of those with both migraine with and without aura was not significantly different, suggesting that migraine without aura and migraine with aura are distinct types of migraine. Males with migraine without aura had a significantly lower mean age at onset than females with migraine without aura (16.5 years versus 21.5 years), while males and females with migraine with aura had similar ages at onset (20.8 years versus 21.8 years). About 20% of the twins had ceased having attacks of migraine with or without aura. More males than females with onset of migraine without aura before aged 15 years had ceased having attacks. The prevalence of migraine without aura and migraine with aura in twins was similar to the prevalence in the general population. Being a twin did not affect age at onset or cessation of migraine. Previous observations on differences of migraine without aura and migraine with aura regarding gender was confirmed.

Adult↗
PubMed1999

The inheritance of migraine with aura estimated by means of structural equation modelling.

Studies of migraine with aura (MA) have shown familial aggregation of the disorder, which cannot be explained by simple mendelian inheritance. The interest in a genetic basis for the disorder has increased after identification of three genetic loci for familial hemiplegic migraine (FHM), which is a rare subtype of MA with autosomal dominant inheritance. Both genetic and environmental factors seem to be important in the expression of MA. To elucidate the molecular pathogenesis of MA, knowledge of the relative role of genetic and environmental factors is essential. Twin studies are a classic way to analyse this. We applied structural equation modelling on MA with twin data obtained from a population based twin register in order to evaluate the effects of genes and environment. The correlation in liability of MA was 0.68 in monozygotic (MZ) and 0.22 in dizygotic (DZ) twin pairs, indicating a high degree of genetic determination in the total variance of liability. The best fitting model combined additive genetic effects and environmental effects that were not shared by the twins. The estimate of heritability was 0.65 and similar in males and females.

Female↗
PubMed1998

[Familial hemiplegic migraine].

Familial hemiplegic migraine (FHM) is a rare subtype of migraine with aura. It is inherited as an autosomal dominant trait. A gene for FHM has been assigned to chromosome 19. This gene codes for a brain-specific calcium channel, and is responsible for FHM in 55% of the FHM families. Other FHM families have been linked to two different locations on chromosome 1. These locations contain possible candidate genes coding for calcium-and potassium channels. Thus FHM is a genetically heterogenous ion channel disorder, which is caused by at least three different genes. About 29% of the FHM families also have cerebellar ataxia, these families have all been linked to chromosome 19. The identification of the genes for FHM may be a key to the identification of the gene/genes for migraine with and without aura.

Chromosome Mapping↗
PubMed1998

Inheritance of chronic tension-type headache investigated by complex segregation analysis.

We investigated the mode of inheritance of chronic tension-type headache in 122 families. The probands were from the Copenhagen Headache Clinic, Denmark. The criteria of the International Headache Society were used. The patterns of segregation of chronic tension-type headache were assessed by complex segregation analysis performed with the computer program POINTER. Of the 122 probands with chronic tension-type headache, 56 had 71 first-degree relatives with chronic tension-type headache. The complex segregation analysis indicates that chronic tension-type headache has multifactorial inheritance.

Age Factors↗
PubMed1998

Altered allelic distributions of the serotonin transporter gene in migraine without aura and migraine with aura.

Allelic variation of the human serotonin transporter gene (HSERT), a highly plausible candidate gene for susceptibility to migraine, was investigated in 266 individuals with migraine, including 173 having migraine without aura (MO), 94 having migraine with aura (MA), 18 with co-occurrence of MO and MA, plus 133 unaffected controls. The distribution of a polymorphism with different forms of a variable tandem number repeat (VNTR) in intron 2 were compared. The MO group had an over-representation of genotypes with two twelve repeat alleles (STin2.12) and a reduction of genotypes containing one ten repeat (STin2.10) compared to controls. The MA group showed a similar pattern, but also a trend towards an increase in genotypes containing the nine repeat allele of the VNTR (STin2.9). Genotypes containing this allele were found in 6.4% of the MA group compared to 2.3% of controls. The group with co-occurrence of MO and MA had a significantly different pattern of overall allele frequency distribution from controls, reflecting a reduction in genotypes containing the STin2.10 allele and a shift both to STin2.9 carriers and to STin2.12 homozygosity. These results support the view that susceptibility to MO and MA has a genetic component, that these disorders are distinct, and that genetic susceptibility may in some cases be associated with a locus at or near the serotonin transporter gene.

Adult↗
PubMed1997

Allelic variation in the serotonin 5-HT2C receptor gene and migraine.

The 5-HT2C (serotonin-2C) receptor has been implicated along with other components of the 5-HT system in the pathophysiology and pharmacotherapy of migraine. To investigate whether the 5-HT2C receptor gene contributes to the risk of migraine we performed an association study of allelic variation at codon 23 (Cys or Ser) of the gene in 242 migraineurs, including 73 with aura, and 129 controls. No differences nor trends in allele or genotype frequencies were seen in the migraineurs compared to the controls. Neither did the frequencies vary significantly in migraineurs with and without aura, or if men and women were analysed separately. In conjunction with an earlier negative linkage study, these data indicate that the 5-HT2C receptor gene does not contribute to the genetic predisposition to migraine.

Alleles↗
PubMed1997

Analysis of 31 families with an apparently autosomal-dominant transmission of migraine with aura in the nuclear family.

We analyzed 31 families selected for an apparently autosomal-dominant mode of inheritance of migraine with aura (MA) in the nuclear family. The nuclear families were expanded with first- and second-degree relatives. All interviews were made by physicians experienced in headache diagnoses. The criteria of the International Headache Society were used. The population relative risk among children in nuclear families was similar to the estimated population relative risk of MA assuming an autosomal-dominant mode of inheritance. The population relative risk tended to decrease among first-degree relatives outside nuclear families and further among second-degree relatives. Both first- and second-degree relatives outside the nuclear families had a statistically significant lower risk of MA than expected. Thus, autosomal-dominant inheritance with or without reduced penetrance was unlikely. Autosomal-recessive inheritance was unlikely because of the unequal sex distribution. Other modes of inheritance were considered as well. Mitochondrial and X-linked inheritance were excluded because of paternal transmission. The female preponderance was too low to explain sex-influenced inheritance. We conclude that MA most likely has a multifactorial inheritance even in high-risk families with MA.

Adolescent↗