Intramedullary spinal cord and filum tumours-long-term outcome: single institution case series

BACKGROUND

Intramedullary spinal cord tumours are rare and account for about 2-4% of primary CNS tumours. Ependymomas and astrocytomas are most frequent. The aim of this study was to evaluate the long-term neurological outcome, quality of life (QoL), survival, need for additional treatment and frequency of neuropathic pain in a patient group treated at a tertiary university hospital.

METHOD

Retrospective descriptive study of 52 long-term survivors with intramedullary or filum tumours consenting to participate in this study. Fifty-six operations were performed in 48 patients. Clinical and radiological follow-up period was 113 and 117 months, respectively.

RESULTS

Good neurological outcome (ASIA score D or E, modified McCormick grade 1 or 2) was achieved in 88%. We found two negative prognostic factors in regards of severe disability which were large craniocaudal tumour size (p = 0.004) and histologic verified astrocytomas (p = 0.002). SF-36 results showed significantly lower results on all five subdomains concerning physical function, whereas scores for mental health and role emotional showed no significant differences compared to Norwegian norms. Ten patients including all astrocytoma patients, one primitive neuroectodermal tumour and three recurrent tumours of filum terminale had adjuvant therapy. None of the patients with intramedullary ependymoma had adjuvant therapy. Neuropathic pain was present in 54% of patients at the last follow-up.

CONCLUSION

This series shows that good results can be obtained with surgery for intramedullary tumours, even without perioperative neurophysiological monitoring. Multicentre studies are needed for further evaluation of negative and positive prognostic factors to further improve outcome.

Diving and long-term cardiovascular health

Background

Short-term cardiovascular effects from ambient pressure exposure are known. However, long-term cardiovascular effects from diving in humans have been less studied.

Aims

To examine possible long-term cardiovascular health effects from occupational diving.

Methods

We compared the prevalence of cardiovascular disease in former divers to non-divers. We obtained data on male former divers with a certificate valid for professional diving after 1980, from the Norwegian Diver 2011 project, and matched data on the general male population from the HUNT3 Survey. We also compared former divers with high and low grades of diving exposure.

Results

Data were available on 768 former divers. The prevalence of self-reported high blood pressure in former divers who often omitted a dive-free day after 3 days of strenuous diving was 28% compared with 18% in those who rarely violated these regulations [relative risk (RR) 1.47, confidence interval (CI) 1.01–2.15]. Also, the prevalence of myocardial infarction/angina pectoris was 11% in divers with >150 professional dives/year compared with 4% in divers with ≤50 professional dives/year [RR adj. 2.91 (CI 1.23–6.87)] and 16% in divers with >2000 air dives in total relative to 3% in divers with ≤2000 dives [RR adj. 3.05 (CI 1.47–6.34)].

Conclusions

The prevalence of some cardiovascular symptoms and diseases may be higher in male former divers than in the general population. Diving might have adverse long-term cardiovascular effects. Whether this is associated with diving per se or strenuous physical activity requires further studies.

Pregnancy outcome in partners of male professional divers in Norway

BACKGROUND

Diving is associated with both acute and long-term effects in several organ systems. Reduced semen quality after extreme diving and a reduced proportion of males in the offspring of divers have previously been reported.

AIMS

To study pregnancy outcomes in partners of professional male divers.

METHODS

The cohort of divers registered with the Norwegian Inshore Diving Registry was linked to the Medical Birth Registry of Norway (MBRN).

RESULTS

In total, 6186 male divers had 10395 children registered in the MBRN during the study period. Of these, 52% were boys, compared to 51% in the general population. The partners of a subgroup of divers who were most likely to be occupationally exposed at the time of conception reported that early miscarriage was more frequent (27%) than in the general population (21%; relative risk 1.21, 95% confidence interval 1.05-1.39). Otherwise, there was a lower risk of adverse pregnancy outcomes such as preterm birth, stillbirth, low birthweight, small for gestational age and low Apgar score compared to the general population. Birthweight above 4000g was more frequent.

CONCLUSIONS

We observed no reduced sex ratio in the offspring of occupational divers. Except for an increase in self-reported early miscarriage in the partners of exposed divers, we observed no excess risk of any of the adverse perinatal pregnancy outcomes studied.

Mortality among professional divers in Norway

BACKGROUND

Diving operations are technically complex, and the underwater environment poses a high risk of fatal or near miss accidents. Furthermore, long-term effects of diving on bone, the central nervous system and the lung have been observed in divers who have not experienced any diving-related accidents.

AIMS

To compare total and cause-specific mortality among Norwegian professional divers by class of diving certificate, relative to the general population.

METHODS

Data on mortality were obtained for divers in the Norwegian Inshore Diving Registry, which comprises data on all divers with a certificate valid for professional diving after 1980. By August 2010, 5526 male divers born between 1950 and 1990 were identified, 3130 of whom were fully certified professional divers. The rest of the Norwegian male population born in the same period (1 604 147) served as referents. Data on mortality were obtained by linkage to the Cause of Death Registry.

RESULTS

Mortality was 23 per 1000 in professional divers and 24 per 1000 in referents. The hazard ratio was 0.79 (confidence interval [CI] 0.63-0.997). Diving-related accidents and suicide were the most common causes of death among divers. Both were significantly more common among divers with the higher level diving certificates.

CONCLUSIONS

Overall, mortality in professional divers was lower than that of the general population. However, professional divers had a higher risk of dying from work-related accident or suicide.

No changes in lung function after a saturation dive to 2.5 MPa with intermittent reduction in $$ P_{{{{\rm O}}_{{{\rm 2}}} }} $$ during decompression

Decompression stress and exposure to hyperoxia may cause a reduction in transfer factor of the lung for carbon monoxide and in maximal aerobic capacity after deep saturation dives. In this study lung function and exercise capacity were assessed before and after a helium-oxygen saturation dive to a pressure of 2.5 MPa where the decompression rate was reduced compared with previous deep dives, and the hyperoxic exposure was reduced by administering oxygen intermittently at pressures of 50 and 30 kPa during decompression. Eight experienced divers of median age 41 years (range 29-48) participated in the dive. The incidence of venous gas microemboli was low compared with previous deep dives. Except for one subject having treatment for decompression sickness, no changes in lung function or angiotensin converting enzyme, a marker of pulmonary endothelial cell damage, were demonstrated. The modified diving procedures with respect to decompression rate and hyperoxic exposure may have contributed to the lack of changes in lung function in this dive compared with previous deep saturation dives.

Electroencephalography and magnetic resonance imaging in neurological decompression sickness

The purpose of this study was to evaluate the use of electroencephalography (EEG) and magnetic resonance imaging (MRI) in the clinical evaluation of acute decompression sickness (DCS) in the central nervous system (CNS). Twenty-one patients treated because of acute DCS in the CNS during 1999-2001 were included, 15 patients with clinical cerebral DCS and five with clinical spinal cord DCS. Seven patients had abnormalities in their EEG, five with cerebral DCS and two with spinal cord DCS. MRI showed high intensity lesions in the spinal cord in four patients with clinical spinal cord DCS and in one with clinical cerebral DCS. Cerebral lesions were not identified by MRI in any patient. In conclusion, EEG showed unspecific abnormalities in only one third of the cases. Conventional MRI with a 1.5 T scanner may be of help in the diagnosis of DCS in the spinal cord, but not in the brain. EEG and MRI have low sensitivity in the diagnosis of acute DCS in the CNS. Recompression treatment of DCS should still be guided by clinical neurological examination and assessment of symptoms.

[Botulinum toxin A--effect on spasticity]

BACKGROUND

Severe spasticity may lead to problems of movement and function, pain and hygiene, and may be difficult to treat. A team of neurologists and physiotherapists evaluated the effect of botulinum toxin A (BTX-A) on spasticity.

MATERIAL AND METHODS

Ten patients with central nervous disorders were included in this study. Function, pain and personal hygiene were assessed before and after injections with BTX-A.

RESULTS

Nine patients experienced improvement of function and/or pain relief. One patient had improved perception in his hand, and one patient needed only two injections to stop a vicious circle. The effect varied from patient to patient. It seemed that patients with some preserved motor control in the spastic limb could use it to learn more appropriate movement strategies.

INTERPRETATION

We recommend that doctors and physiotherapists work together to identify muscle groups that need to be targeted for injection and evaluate consequences of the treatment. Injections with BTX-A should be combined with physiotherapy.

[Patients with traumatic spinal cord injuries at the department of neurology, Haukeland Hospital 1952-99]

BACKGROUND

We wanted to study the cause and the segmental level of traumatic spinal cord injuries.

MATERIAL AND METHODS

All 238 patients (208 men) with traumatic spinal cord injuries admitted to the Department of Neurology, Haukeland University Hospital in Bergen, Norway, from 1952 to 1999 were included. Data were obtained from medical files and studied retrospectively.

RESULTS

The initial clinical level of injury was the cervical spine in 50% of the patients, the thoracic spine in 33%, and the lumbar spine in 18%. Falling (45%) and road accidents (35%) were the main causes. The mean annual number of patients with traumatic spinal cord injuries increased from three in 1952-60 to eight in 1991-99; there was an increase in high cervical injuries among those older than 60. The proportion of work-related traumatic spinal cord injuries was 42% in 1952-74 and 26% in 1975-99.

INTERPRETATION

Although there has been a reduction of work-related spinal cord injuries, there is still a potential for further prevention, especially among persons of more than 60 years of age.

Multiple sclerosis: a modifying influence of HLA class I genes in an HLA class II associated autoimmune disease

Multiple sclerosis (MS) is a presumed autoimmune disease of the central nervous system, shown to be associated with the HLA class II haplotype DRB1*15,DQB1*06. Carrying the HLA class II haplotype DRB1*15,DQB1*06 increases the risk of MS by 3.6. By adopting a polymerase chain reaction (PCR)-based typing technique for HLA class I and class II genes, 200 Swedish MS patients and 210 Swedish healthy controls were analysed for their HLA alleles. Additional HLA class I alleles that increase and decrease the genetic susceptibility to MS were identified. The HLA-A*0301 allele increases the risk of MS (odds ratio=2.1) independently of DRB1*15,DQB1*06. HLA-A*0201 decreases the overall risk (odds ratio= 0.52) and the presence of A*0201 reduces the risk of MS for DRB1*15,DQB1*06 carriers from 3.6 to 1.5. Our findings are the first to identify a major modulating effect of HLA class I alleles on the susceptibility to a human autoimmune disease; a phenomenon that has previously only been observed in animal models.

Multiple sclerosis in North Norway, and first appearance in an indigenous population

This study was performed to determine the prevalence of multiple sclerosis (MS) in 1993 and annual incidence rates 1983-1992, and to examine whether the disease occurs among the Sami people. According to earlier reports the two northernmost counties of Norway, Troms and Finnmark with 225,000 inhabitants, have a relatively low prevalence of MS: 20.6 per 100,000 in 1973 and 31.5 in 1983. Also no person who is of pure Sami heritage (i.e., with both parents speaking Sami natively) has been found with the disease. Except for the introduction of magnetic resonance imaging as a diagnostic tool, there has been no significant change in the neurological service in the area during the past 20 years. Files of patients with the diagnosis of MS were reviewed, and questionnaires were sent to all patients alive on the prevalence day of 1 January 1993. The prevalence in 1993 was 73.0 per 100,000. The mean crude annual incidence rate was 3.5 per 100,000 during the period 1983-1992 compared with 3.0 during 1974-1982. In 1983 there were no pure Sami among the MS patients, but one had a Sami father. On 1 January 1993 there were three patients with both Sami parents and three with only one Sami parent, which is a rate that is still lower than would be expected if the prevalence of MS among the Sami were similar to that in the rest of the Norwegian population. The study shows that the incidence of MS in Troms and Finnmark has been increasing over the past 10 years, but is still lower than on the western coast and in the eastern part of Norway. The lowest incidence is found in Finnmark, where the Sami population is highest. During the past 10 years MS has also been diagnosed among the Sami population.

Altered antibody pattern to Epstein-Barr virus but not to other herpesviruses in multiple sclerosis: a population based case-control study from western Norway

OBJECTIVE

The prevalence of anti-EBV antibodies was studied in a group of 144 patients with multiple sclerosis and 170 age, sex, and area matched controls from the county of Hordaland, western Norway. The prevalence of three other herpesviruses, herpes simplex virus (HSV), varicella zoster virus (VZV), and cytomegalovirus (CMV), were also included.

METHODS

Antibodies to various virus antigens were determined by enzyme linked immunosorbent assay (ELISA) and indirect immunfluorescence (IIF) in serum samples from 144 patients with multiple sclerosis and 170 controls.

RESULTS

All of the 144 patients with multiple sclerosis had IgG antibodies to EBV compared with 162 of 170 controls (p=0.008). The frequency of IgG antibodies to EBV capsid antigen (VCA), nuclear antigen (EBNA), and early antigen (EA) was significantly higher in patients with multiple sclerosis compared with the controls (p<0.000001, p=0.01, and p<0.0001 respectively). The presence of antibodies was independent of the initial course of the disease and the disease activity at the time of blood sampling. The prevalence of IgG antibodies to HSV, CMV, and VZV did not differ between cases and controls.

CONCLUSION

The results suggest a role for EBV in the aetiology of multiple sclerosis.

Epileptic seizures in patients with multiple sclerosis. Is the prognosis of epilepsy underestimated?

The exact prevalence of epileptic seizures in patients with multiple sclerosis (MS) is still a matter of some controversy. In a population-based, unselected group of 423 patients with MS we identified 17 (4.02%) with epileptic seizures. The mean age at onset of MS was 25.2 years and at onset of epilepsy 32.6 years. A prevalence of 'active epilepsy', i.e. seizures within the last 5 years, was estimated to 3.2%. The prevalence of epilepsy in our MS population is much higher than should be expected when compared to lifetime prevalence of epilepsy in corresponding age groups. The occurrence of convulsive status epilepticus is also higher than expected, and suggests a rather serious prognosis. Thus, drug treatment should be considered after the first epileptic seizure.

[Central nervous pain in patients with spinal cord injury. Medical and surgical treatment]

About 50% of patients with spinal cord injury suffer from persistent central neurogenic pain. The authors review the case of a patient with traumatic paraplegia who developed persistent central neurogenic pain. The pain was described as burning in the buttock area, icing in the rectum area and as lancinating pain to the lower extremities. The combination of amitryptilin and morphine had a slight, short-term effect, but the pain did not respond to treatment with simple analgetica, dextropropoxyphen or ketobemidone, neither administered alone nor in combination with tricyclic antidepressants, carbamazepine or baclophen. Transcutanous nerve stimulation and acupuncture had no effect. The patient was operated on by means of the computer-assisted dorsal root entry zone (DREZ)-microcoagulation technique 2.5 years after the trauma. This technique is described in brief. The prevalence and classification of neurogenic pain, and possible medical and surgical treatment, are also discussed.

Multiple sclerosis and cancer in Norway. A retrospective cohort study

INTRODUCTION

During the extended course of multiple sclerosis (MS) there are ample opportunities for the patients to develop other illnesses including cancer, a potential long-term complication of the immunosuppressive drug treatment in MS.

MATERIAL AND METHODS

A retrospective cohort study was done to estimate the relative risk of cancer in a population of MS-patients from three Norwegian counties by record linkage with the Cancer Registry of Norway. The cohort comprised 1271 MS-patients, 530 men and 741 women, identified in five longitudinal population-based incidence studies. The reporting of cancer cases has been compulsory in Norway since 1952.

RESULTS

We found 73 cancer cases (standardized incidence ratio (SIR) = 0.86, 95% CI 0.68-1.09). Mean follow-up time was 18.4 years. A significant excess of breast cancers was observed (SIR = 1.70, 95% CI 1.05-2.60). A non-significant excess of cancer in the urinary tract was observed. No significantly increased risk in hematologic and lymphatic malignancies or malignant brain tumors was observed. The incidence of cancer of the digestive organs was significantly lower than expected (SIR = 0.51, 95% CI 0.24-0.93).

CONCLUSION

Overall, the study indicates that an MS-patient is not at any unusual risk for subsequent development of cancer compared to the normal population.

Multiple sclerosis and chronic inflammatory diseases. A case-control study

INTRODUCTION

Disease associations may provide useful etiological leads in relation to diseases of unknown cause.

MATERIAL AND METHODS

We conducted a hospital-based case-control study of 155 MS patients and 200 controls in Hordaland County, Norway to investigate the possible association between MS and autoimmune diseases.

RESULTS

The MS patients had a statistically significant more frequent coexistence of rheumatoid arthritis, psoriasis, and goitre when compared to the controls (OR = 2.96; 95% CI 1.23-7.66). This difference persisted when analysing the definite MS cases separately (OR = 2.90; 95% CI 1.10-7.96). The familial occurrence of chronic inflammatory diseases was not significantly different in cases and controls. A significant increased risk to develop MS occurred in first degree relatives of MS patients (OR = 12.58; 95% CI 1.73-552).

CONCLUSION

Acknowledging the low figures, the uncertain estimates with large confidence intervals, and thus the obvious role of chance in this study, the results might indicate that a generalized, genetically controlled problem of the immune system could result in aggregates of the reported diseases, all of which are partly characterized by aberrations of the immune system.

Bladder, bowel and sexual dysfunction in patients with multiple sclerosis--a cohort study

A population-based cohort study focusing on bladder, bowel and sexual dysfunction in MS-patients was performed. The total cohort under study comprised 209 patients. The duration of the disease was nine to 19 years. A total of 57.5% reported some to major bladder dysfunction. The corresponding figures of bowel and sexual dysfunction were 41.3% and 51% respectively. The dysfunction increased with higher age, higher age at onset of MS, duration and course of the disease. The most unfavourable course of the disease was the relapsing remittent secondary progressive form, where almost 70% became worse during an eight year's observation period, in contrast to patients with the relapsing remittent form, where less than 30% became worse. The study shows that a high number of MS patients is in need of a neuro-urological work-up, and that effort should be made to prevent or delay a secondary progressive course of the disease.

Cerebrospinal fluid in the diagnosis of multiple sclerosis: a consensus report

The Committee of the European Concerted Action for Multiple Sclerosis (Charcot Foundation) organised five workshops to discuss CSF analytical standards in the diagnosis of multiple sclerosis. This consensus report from 12 European countries summarises the results of those workshops. It is hoped that neurologists will confer with their colleagues in clinical chemistry to arrange the best possible local practice. The most sensitive method for the detection of oligoclonal immunoglobulin bands is isoelectric focusing. The same amounts of IgG in parallel CSF and serum samples are used and oligoclonal bands are revealed with IgG specific antibody staining. All laboratories performing isoelectric focusing should check their technique at least annually using "blind" standards for the five different CSF and serum patterns. Quantitative measurements of IgG production in the CNS are less sensitive than isoelectric focusing. The preferred method for detection of blood-CSF barrier dysfunction is the albumin quotient. The CSF albumin or total protein concentrations are less satisfactory. These results must be interpreted with reference to the age of the patient and the local method of determination. Cells should be counted. The normal value is no more than 4 cells/microliters. Among evolving optional tests, measurement of the combined local synthesis of antibodies against measles, rubella, and/or varicella zoster could represent a significant advance if it offers higher specificity (not sensitivity) for identifying chronic rather than acute inflammation. Other tests that may have useful correlations with clinical indices include those for oligoclonal free light chains, IgM, IgA, or myelin basic protein concentrations.

Elevated cerebrospinal fluid proteins in sciatica caused by disc herniation

We carried out a study of cerebrospinal fluid (CSF) proteins in 180 patients with sciatica caused by lumbar disc herniation to elucidate further the degree and mechanisms of protein elevations. The 63 controls were patients with tension headache or migraine without aura. The CSF/serum albumin ratios were higher in the patients (mean 8.84, SD 5.16) than in the controls (mean 5.60, SD 2.33). Similar differences were found for the CSF/serum IgG ratios and the CSF-total proteins. The CSF/serum albumin ratios, CSF/serum IgG ratios and the CSF-total protein concentrations were higher in men than in women among the patients. We suggest that the significant difference in ratio parameters between patients and controls indicates a leak of plasma albumin, most likely IgG, into the CSF in patients with sciatica. The leak was more pronounced in men. Also in the control group the CSF/serum albumin and CSF/serum IgG ratios were higher in men.

Absence of HTLV-1 related sequences in MS from high prevalence areas in western Norway

In Western Norway, long-term follow up epidemiological studies have revealed significant increases in the incidence and prevalence rates of multiple sclerosis (MS) in stable populations, indicating the impact of exogenous factors. In this study 183 MS patients and 102 controls from high prevalence areas in Western Norway were investigated for human T-lymphotropic virus type I (HTLV-1) related sequences by polymerase chain reaction. Using primers targeting the gag, pol and env genes in the HTLV-1 provirus genome, no amplification products were detected in the 183 MS patients or 102 controls. The results strongly suggest that neither HTLV-1 nor a closely related retrovirus participate in the aetiology of MS.

Organic solvents and multiple sclerosis: a case-control study

A case-control study of multiple sclerosis (MS) has been carried out in western Norway. The study included 93% of the patients who had clinical onset of MS in the county of Hordaland during the years 1976-86 (N = 155) and 200 controls, marginally matched for age, sex and residence. There was no statistically significant difference between MS patients and controls with regard to exposure to organic solvents, exposure to the combination organic solvents and welding or to organic solvents and other chemical compounds.

Infections in childhood and adolescence in multiple sclerosis. A case-control study

A case-control study on multiple sclerosis was conducted in Western Norway during the years 1986-1988. Included were 155 persons with multiple sclerosis and 200 controls, marginally matched according to age, sex and area of residence. The mean age at measles infection was for the cases 6.6 years and for the controls 5.7 years (p = 0.06). The cases had more frequently experienced bronchitis and/or pneumonia in the age group 11-15 years (OR = 3.20, 95% confidence interval 0.96-10.63). Tonsillectomies were reported more frequently by the cases. The odds ratio was especially high for those treated at age 0-6 years (OR = 3.44, 95% confidence interval 1.63-7.27). The results are consistent with the idea of MS as an age-dependent, host-immune response to infection during childhood or adolescence.

Early prognostic factors for disability in multiple sclerosis, a European multicenter study

The effects of initial clinical variables on short-term prognosis are analyzed in a cross-sectional study of 574 multiple sclerosis patients from 7 centers in 5 European countries. Patients with a primary progressive course had a 2.3 higher mean disability score (EDSS) than the primary remittent group after a mean duration of disease of 6.6 years. High age at onset was associated with a primary progressive course, and was also related to increased risk of a rapid shift to a secondary progressive course. Among the remittent patients without a secondary progressive course a high age at onset was significantly correlated to a higher disability score. In the whole remittent group the presence of pyramidal and cerebellar symptoms at onset predicted both a high disability score and a rapid shift to a secondary progression, while the effect was reverse for sensory and visual symptoms. No difference between the sexes was found.

Clustering of residence of multiple sclerosis patients at age 13 to 20 years in Hordaland, Norway

Geographic and temporal variation and migration studies point to an exogenous agent in the etiology of multiple sclerosis. If infectious etiology is involved, space-time clustering would also be expected. The authors analyzed 381 patients with a clinical onset of multiple sclerosis between 1953 and 1987 in the county of Hordaland, Norway. Patients within the same birth cohort had lived significantly closer to each other than would be expected during ages 13-20 years, with peak clustering at age 18 years (p = 0.002). Clustering was also shown between patients in pairs comprised of one individual with initial remittent disease and the other with chronic progressive course of disease, suggesting a similar etiology for both clinical patterns. Clustering between cases with widely divergent dates of clinical onset provides evidence of marked variation in latency. No similar clustering was observed in age-, sex-, and area-matched hospital controls without multiple sclerosis, and no clustering was found among the cases when using fixed number of years before onset. These results are compatible with a common infectious agent, such as the Epstein-Barr virus, acquired in adolescence in genetically vulnerable persons who are also not protected by an infection acquired before this age of susceptibility. Susceptibility could be related to the route of transmission or to other age-related covariates or it may be hormonally mediated.

Incidence of multiple sclerosis in Hordaland, western Norway: a fluctuating pattern

The incidence of multiple sclerosis (MS) was studied in the county of Hordaland, western Norway. A significant increase in incidence in the period 1958-1987, a decline followed by a gradual increase in mean age at onset, geographic differences in time trends and a biphasic pattern revealed by a birth cohort analysis support the theory of real time-space fluctuations in the incidence of MS over time.

Multivariate analyses of factors associated with unemployment in people with multiple sclerosis

Variables at onset of multiple sclerosis (MS) as predictors of time to unemployment have been studied using multivariate survival (time-to-response) analyses. The study consisted of 79 patients with MS diagnosed in the two most northern counties of Norway between 1974-82. Diagnostic category, age at onset, sex, county, symptom groups, course of disease and occupation groups were identified as possible prognostic variables. Forty one patients (51%) were unemployed at last follow up. None of the 15 patients with probable or possible MS were unemployed due to MS. The multivariate analyses selected the nonremittent course or heavy physical work and age over 30 at onset as high risk factors associated with early unemployment.

Antibodies in sera from Norwegian multiple sclerosis patients and the general population reacting with HTLV-1. A pilot study

By using enzyme-linked immunosorbent assay, Western blot and passive agglutination we have performed a pilot study involving the testing of 349 sera from the general population of 3 coastal regions in southern Norway, 230 sera from multiple sclerosis patients from western Norway, 109 age- and sex-matched controls and 34 sera from patients with other neurological diseases, for antibodies to HTLV-I. About 2% and 4% of sera from the general population had antibodies reacting with HTLV-I in ELISA and Adult T-cell Leukemia Antigen by agglutination, respectively, whereas about 8% and 5% of the multiple sclerosis sera had such antibodies. In the general population antibodies were more frequent among young individuals and there appeared to be some prevalent regional differences. Western blot confirmatory tests showed that in some instances antibodies reacted with the gag proteins, in particular p19. The results obtained in this study do not indicate an association between HTLV-I and multiple sclerosis, although at this stage we cannot rule out that another retrovirus is involved.

Optic neuritis in the two northernmost counties of Norway. A study of incidence and the prospect of later development of multiple sclerosis

A study of the incidence of uncomplicated optic neuritis (ON) in the period 1972-1984 and the subsequent risk of later developing of multiple sclerosis (MS) was performed in the two northernmost counties of Norway. The incidence of ON was stable during the period. Of the 36 ON patients available to follow-up, 42% later developed MS. Mean time from debut of ON to the next symptom of MS was 2.2 years, median 1 year. There was one ethnic Lapp among the ON patients. The number of Lapps in the area is estimated to be about 26,000.

Prognostic factors for life expectancy in multiple sclerosis analysed by Cox-models

To determine if such factors as first symptom, sex, age at onset and initial clinical course have any influence on life expectancy of multiple sclerosis patients, a survival analysis from date of diagnosis for 598 MS-patients in Norway was performed. To study the effect of all the variables simultaneously we used the Cox proportional hazards regression model with incomplete data. Median survival time was 27 years after diagnosis. The variable which most strongly predicted the duration of the disease was age at onset. High age at onset and a progressive course of the disease were correlated with a more unfavourable prognosis. The onset symptom, vertigo, was also correlated with a shorter life expectancy. No significant effect of sex was found. We found in this material an indication of improved survival over the study period.

Multiple sclerosis in the two northernmost counties of Norway

The prevalence of MS in the two northernmost counties of Norway increased from 20.6 per 100,000 in 1973 to 31.5 per 100,000 in 1983, the increase being most marked in women. The average annual incidence seems to have been stable over the past 20-30 years. None of the patients had a pure Lapp background (having a Lapp mother and father).