Biomedical subjects
Publications and source records attributed to M Grønning.
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.
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.
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.
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.
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.
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).
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.