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T Jónsson

Publications and source records attributed to T Jónsson.

At least 19 recordsLinked to original sources
PubMed2005

Childhood levels of immunoglobulins and mannan-binding lectin in relation to infections and allergy.

Respiratory tract infections, allergies and otitis media are common problems in early childhood. Our aim was to evaluate in a longitudinal community-based cohort study the association between maturation of immunoglobulin (Ig) and mannan-binding lectin (MBL) responses and disease manifestations in the first 4 years of life. Sustained low levels of IgA proved the strongest single indicator of susceptibility for recurrent otitis media (P = 0.008) and respiratory tract infections (P = 0.02), and this condition was also associated with low production of IgG subclasses. About 7% of the cohort had sustained low levels of MBL (<0.4 mg/l). Low MBL did not predispose to any ailments studied, but children with low IgA and recurrent otitis media had relatively low MBL at birth, which failed to increase during the study period and was significantly reduced at the age of 4 years (P = 0.04). MBL levels increased from birth to 2 years (P < 0.0001) and were higher in children than in adults (P = 0.001). The increase was 1.9-fold in children with no recorded clinical events and 1.7-fold in children with asthma or infections, but significantly lower, 1.2-fold, in children with recurrent otitis media. Low levels of IgA within the normal range may reveal disease susceptibility not detected by conventional criteria. Slow maturation of Ig appears to be the main factor of susceptibility during childhood, but a strong corollary role for MBL is indicated by the high levels produced during childhood as well as the precipitation of disease in children with low levels of MBL and Ig.

Adult↗
PubMed2004

The impact of an early truncating founder ATM mutation on immunoglobulins, specific antibodies and lymphocyte populations in ataxia-telangiectasia patients and their parents.

Eleven Norwegian patients (aged 2-33 years, seven males and four females) with Ataxia-telangiectasia (A-T) and their parents were investigated. Five of the patients were homozygous for the same ATM mutation, 3245delATCinsTGAT, a Norwegian founder mutation. They had the lowest IgG2 levels; mean (95% confidence interval) 0.23 (0.05-0.41) g/l versus 0.91 (0.58-1.26) g/l in the other patients (P = 0.002). Among the 11 A-T patients, six had IgG2 deficiency, six had IgA deficiency (three in combination with IgG2 deficiency) and seven had low/undetectable IgE values. All patients had very low levels of antibodies to Streptococcus pneumoniae 0.9 (0.4-1.4) U/ml, while normal levels were found in their parents 11.1 (8.7-13.4) U/ml (P < 0.001). A positive linear relationship between pneumococcal antibodies and IgG2 (r = 0.85, P = 0.001) was found in the patients. Six of 11 had diphtheria antibodies and 7 of 11 tetanus antibodies after childhood vaccinations, while 4 of 7 Hemophilus influenzae type b (Hib) vaccinated patients had protective antibodies. Ten patients had low B cell (CD19+) counts, while six had low T cell (CD3+) counts. Of the T cell subpopulations, 11 had low CD4+ cell counts, six had reduced CD8+ cell counts, and four had an increased portion of double negative (CD3+/CD4-/CD8-) gamma delta T cells. Of the 22 parents (aged 23-64 years) 12 were heterozygous for the ATM founder mutation. Abnormalities in immunoglobulin levels and/or lymphocyte subpopulations were also observed in these carriers, with no correlation to a special ATM genotype.

Adolescent↗
PubMed2001

Dupuytren's disease, alcohol consumption and alcoholism.

OBJECTIVE: To assess the relation between alcohol consumption and Dupuytren's disease. DESIGN: The participants were recruited from a previous study on Dupuytren's disease carried out in 1981-82 as part of a cohort study. Men with Dupuytren's disease in the former study and a control group were invited. The groups were matched for age and smoking habits. SETTINGS: The study took place at the Heart Preventive Clinic in Reykjavik. PATIENTS: Of 244 invited participants, 193 (79.1%) responded to the invitation; 137 had Dupuytren's disease and 56 were disease-free. Participants were examined for the presence of Dupuytren's disease and answered a questionnaire about alcohol habits. MAIN OUTCOME MEASURES: Alcoholism, alcohol consumption and signs of Dupuytren's disease. RESULTS: Of the Dupuytren's group, 19 (13.9%) had been treated for alcoholism or were heavy drinkers compared to 8 (14.3%) of those without Dupuytren's disease (NS). Little or moderate alcohol consumption was reported in 78.1% of the Dupuytren's patients compared to 73.2% of the controls (NS). Total abstainers from alcohol were 11 (8.0%) in the Dupuytren's group compared to 7 (12.5%) in the control group (NS). CONCLUSION: Our findings do not support a positive association between the use of alcohol and Dupuytren's disease.

Aged↗
PubMed2001

Eighteen years follow-up study of the clinical manifestations and progression of Dupuytren's disease.

OBJECTIVE: To evaluate the clinical manifestations and progression of Dupuytren's disease. METHODS: In 1981-82 a total of 1297 men were examined for Dupuytren's disease, and of these 19.2% had the disease. In 1999 those with signs of the disease in 1981-82 were invited for a follow-up study. As controls symptom free individuals from the study in 1981-82 were invited. RESULTS: A total of 53 individuals from the control group had developed Dupuytren's disease in 1999. Men with palmar nodules/fibrous cord in 1981-82 were more likely to develop contracted fingers than those without Dupuytren's disease. Patients with young age at disease onset more often required operations than those with later onset. Of the men who had been operated 70% still had finger contractures in 1999. CONCLUSION: The incidence of Dupuytren's disease is high in elderly men. Dupuytren's disease is progressive in nature and most operated patients have recurrent finger contractures.

Adult↗
PubMed2001

[Carcinoma of the colon in Iceland 1955-1989. A study on pathology.].

OBJECTIVE: The objective of this study was to investigate various pathological parameters of colon carcinoma in Iceland in the 35 year time period from 1955-1989, and changes in these parameters during the study period. MATERIAL AND METHODS: Information on all patients diagnosed with colon carcinoma in the study period was obtained from the Icelandic Cancer Registry. All pathology reports and autopsy reports were checked. All pathology samples were reviewed and the tumours reevaluated, reclassified, tumour location determined, the tumours graded and Dukes staged and age standardized incidence was calculated according to revised diagnosis. Cancers in polyps are included in the study. The study period was separated into seven five year periods and changes in pathological parameters investigated according to time periods. RESULTS: After reevaluation of the tumours 1205 fulfilled the criteria for the diagnosis of colon carcinoma, 572 in men and 633 in women. The incidence increased in the study period for men from 8.2 to 21.5/105 and for women from 7.9 to 15.8/105. The pathological parameters were determined for 1109 tumours. Adenocarcinoma NOS was the most common diagnosis or 90.1% of the tumours and mucinous carcinomas came second. Most of the tumours were located in the sigmoid colon (38.6%), 19.1% in the coecum and 14.5% in the ascending colon. No significant observed changes occurred in tumour location in the study period. The mucinous histological type and signet ring tumour type were more common in the right colon. In Dukes staging of the tumours 9.1% were in stage A, 32.1% in stage B, 24.6% in stage C and 22.7% in stage D, whereas 11.5% proved indeterminate. A minimal trend to increase in Dukes A tumours was observed in the latter half of the study period, overall no significant changes in Dukes classification could be pinpointed in the time period. Most of the tumours were of intermediate tumour grade or 70.1%, but 16.5% were well differentiated and 13.4% were poorly differentiated. A much higher percentage of poorly differentiated tumours were present in the right colon in comparison to the left colon. A poorer differentiation of the tumours went hand in hand with worse Dukes stage of tumours. CONCLUSIONS: We conclude that: 1. the incidence of colon carcinoma has much increased during the study period for both sexes, 2. observed changes in studied pathological parameters over the study period were minimal. Of interest is the minimal change in Dukes stages of colon cancer in the study period.

English Abstract↗
PubMed2000

Epidemiology of Dupuytren's disease: clinical, serological, and social assessment. The Reykjavik Study.

Dupuytren's disease or palmar fibromatosis is a common disabling hand disorder, mainly confined to Caucasians of northwestern European origin. The prevalence of Dupuytren's disease and possible risk factors related to the disease were evaluated in a random sample of 1297 males and 868 females, aged 46 to 74 years. Blood samples were collected and biochemical parameters were evaluated. The possible relation between the disease and clinical, social, and biochemical parameters were estimated with age-adjusted univariate logistic regression analysis. Altogether 19.2% of the males and 4.4% of the female participants had clinical signs of Dupuytren's disease. The prevalence increased with age, from 7.2% among males in the age group 45-49 years up to 39.5% in those 70-74 years old. The more severe form of the disease, finger contractures, was found in 5.0% of the men and 1.4% had required operation, while this was rarely seen among women. In men elevated fasting blood glucose (P < 0.04), low body weight, and body mass index were significantly correlated with the presence of the disease (P < 0.001). Dupuytren's disease was common among heavy smokers (P = 0.02) and those having manual labor as occupation (P = 0.018). These results show that Dupuytren's disease is common in the Icelandic population and occupation and lifestyle seem to be related to the disease.

Aged↗
PubMed2000

Elevation of only one rheumatoid factor isotype is not associated with increased prevalence of rheumatoid arthritis--a population based study.

OBJECTIVE: To analyse the relationship between different rheumatoid factor (RF) isotype patterns and the prevalence of RA. METHODS: Serum samples, collected between 1973 and 1983 from nearly 14,000 randomly selected individuals, were screened for elevation of RF. In 1987, 173 RF positive and 156 matched RF negative participants were evaluated clinically. RESULTS: Participants with elevation of only one RF isotype, most commonly IgM, did not have significantly higher prevalence of RA than the RF negative controls. Of the 17 RF positive individuals who were diagnosed with RA, 14 (82%) had a combined elevation of IgM and IgA RF. CONCLUSION: In contrast to a combined elevation of IgM and IgA RF, elevation of only one RF isotype may not be a significant risk factor for the development of RA.

Adult↗
PubMed2000

Smoking, rheumatoid factor isotypes and severity of rheumatoid arthritis.

OBJECTIVES: Smokers have an increased incidence of rheumatoid factor (RF) and rheumatoid arthritis (RA) and one report has also indicated that smoking may also adversely influence the severity of RA. METHODS: Sixty-three women with advanced RA answered a structured questionnaire that included detailed information about their smoking history. The women were also evaluated clinically and radiologically. RESULTS: Heavy smoking (>/= 20 pack-yr) was associated with rheumatoid nodules (P: = 0.01), a higher HAQ score (P: = 0.002) and a lower grip strength (P: = 0.01). Smoking was also associated with more radiological joint damage (P: = 0.02). A positive correlation was observed between smoking and RF levels, in particular IgA RF and a combined elevation of IgM and IgA RF. CONCLUSIONS: Smoking has an adverse effect on disease progression in patients with RA. An association was also observed between smoking and those RF types that predispose to RA and have the highest diagnostic specificity for this disease.

Adult↗
PubMed2000

A prospective study on the incidence of rheumatoid arthritis among people with persistent increase of rheumatoid factor.

OBJECTIVES: To study the stability of rheumatoid factor (RF) increases and to compare the incidence of rheumatoid arthritis (RA) in people with transient or persistent increase of one or more RF isotypes. METHODS: From an original cohort of nearly 14 000 participants in a population study, 135 previously RF positive persons were recruited in 1996 and evaluated according to the 1987 ACR criteria. The observation time ranged from 9-22 years (mean 16. 5). Blood samples were obtained from all participants at entry and again in 1996. RESULTS: About 40% of the participants who had only one raised RF isotype in the original sample had become RF negative in 1996 compared with only 15% of those with increase of two or three RF isotypes (p=0.002). The seven participants who developed RA during the study period all had persistently raised RF. Six of the 54 participants with more than one RF isotype raised in 1996 developed RA, corresponding to an annual incidence of 0.67%, which was 7.5 times higher than observed in the other participants (p=0. 045). CONCLUSION: Symptom free persons with persistently raised RF have greatly increased risk of developing RA. This suggests that dysregulation of RF production is a predisposing factor in RA.

Arthritis, Rheumatoid↗
PubMed1999

Prevalence of joint complaints amongst individuals with Dupuytren's disease--from the Reykjavík study.

It has been reported that Dupuytren's disease is very uncommon amongst patients with rheumatoid arthritis (RA). We investigated the prevalence of different joint complaints in a cohort of 1297 males, aged 46-74 years, participating in a prospective longitudinal health survey. Joint complaints were less frequently observed in men with Dupuytren's disease than in those who did not have any signs of this disease. When adjusted for age the Dupuytren's patients had less frequently history of morning stiffness (odds ratio (OR)=0.65; 95% confidence interval (CI)=0.44-0.98, P=0.04), joint swelling (OR=0.52; 95% CI=0.27-1.00, P=0.05), and attendance to doctors due to rheumatic disorders (OR=0.44; 95% CI=0.15-0.86, P=0.02) than those who did not have clinical signs of Dupuytren's disease. Furthermore, these associations were even stronger after adjustment for other potential confounding factors, such as smoking, lipids, diabetes, education, and occupation. The reason for a negative association between Dupuytren's disease and joint complaints is not clear but genetic and immunological factors may be important.

Age Factors↗
PubMed1999

A genome-wide scan reveals a maternal susceptibility locus for pre-eclampsia on chromosome 2p13.

Pre-eclampsia is a common and serious disease and a major cause of maternal and infant mortality. Antenatal care systems world-wide screen for signs of the disease such as hypertension and proteinuria. Unlike most other human disorders it impacts two individuals, the mother and the child, both of whom can be severely affected. The pathophysiology of the disorder is incompletely understood, but familial clustering of the disease is apparent. Here we report the results of a genome-wide screen of Icelandic families representing 343 affected women. Including those patients with non-proteinuric pre-eclampsia (gestational hypertension), proteinuric pre-eclampsia and eclampsia, we detected a significant locus on 2p13 with a lod score of 4.70 (single point P < 3.49 x 10(-6)). This is the first reported locus for pre-eclampsia meeting the criteria for genome-wide significance.

Chromosome Mapping↗
PubMed1998

Combined elevation of IgM and IgA rheumatoid factor has high diagnostic specificity for rheumatoid arthritis.

The diagnostic value of measuring rheumatoid factor (RF) by agglutination or isotype-specific enzyme-linked immunosorbent assay (ELISA) was compared. The study included 70 patients with rheumatoid arthritis (RA) and 205 patients with various other rheumatic conditions. Of the RA patients, 74% were RF-positive by agglutination and 90% had one or more RF isotypes elevated by ELISA compared to 14% and 22%, respectively, of the other patients. Strikingly, 70% of the RF-positive RA patients had an elevation of two or more RF isotypes compared to only 16% of the other RF-positive patients (P < 0.0001). Furthermore, a combined elevation of IgM and IgA RF was found in 52% of the RF-positive RA patients, but only in two (4%) of the other RF-positive patients (P < 0.0001). It is concluded that a combined elevation of IgM and IgA RF is highly specific for RA and is very rarely found in rheumatic diseases other than RA. Isotype-specific RF assays are therefore diagnostically superior to agglutination tests. The detection of the RA-specific RF isotype pattern may be particularly helpful early in the course of RA even before the disease is fully differentiated.

Adult↗
PubMed1998

Seroepidemiology of Mycoplasma pneumoniae infections in Iceland 1987-96.

Mycoplasma pneumoniae is a common cause of respiratory tract infections in humans. The aim of the present study was to analyse the seroepidemiology of M. pneumoniae infections in Iceland during a 10-y period. A retrospective analysis of all serological diagnosis of M. pneumoniae infections at the Department of Medical Virology, National University Hospital in Reykjavík was performed. A total of 13,201 test results from 1987 to 1996 were reviewed and altogether 762 patients were found to have raised M. pneumoniae antibody titres, using a conventional complement fixation assay. Infections were most common amongst young people (< or=16 y) but a second peak in incidence was observed around the age of 35 y. Significant annual (p < 0.0001) and seasonal variations (p=0.0003) were observed; M. pneumoniae infections were most common during the winter period. Three major outbreaks with intervals of three to five years were observed during the observation period. Patients diagnosed during these outbreaks had higher M. pneumoniae titres than those found when infections were less frequent (p=0.0017). Furthermore, the middle aged and elderly patients (> 50 y) had significantly lower M. pneumoniae titres than younger patients (p=0.0014). The findings of this study show that M. pneumoniae infections have definite annual and seasonal variations and also confirm previous studies showing community outbreaks of M. pneumoniae infections every 3-5 y.

Adolescent↗
PubMed1998

Rheumatoid factor isotypes, disease activity and the outcome of rheumatoid arthritis: comparative effects of different antigens.

The value of rheumatoid factor (RF) isotypes for assessing rheumatoid arthritis (RA) remains debatable. We investigated whether using different antigens to measure RF alters the relationships between RF isotypes and clinical variables. The association between IgA and IgM RF, disease activity, and cumulative anatomical joint damage in RA was studied in 140 patients. The RF isotypes were measured using both rabbit IgG and horse IgG as antigens. Cumulative anatomical damage was assessed radiologically using Larsen's score and disease activity was determined by C-reactive protein (CRP), the health assessment questionnaire (HAQ), and a combined disease activity score (DAS). Patients positive for IgA RF and IgM RF against rabbit IgG had significantly higher disease activity and more radiological damage than negative patients. With horse IgG as antigen these differences were smaller or absent. Patients positive for only IgM RF had milder disease than patients positive for IgA RF with or without IgM RF. The clinical relationships of RF isotypes are related to the antigen used. Measuring IgA RF against rabbit IgG provides most information about disease activity, functional impairment and joint damage.

Adult↗
PubMed1998

Does smoking stimulate rheumatoid factor production in non-rheumatic individuals?

Smoking has been associated with increased incidence of rheumatoid arthritis (RA), joint damage and positive rheumatoid factor (RF). Here we report an analysis of the association between smoking and IgM, IgG and IgA RF in a cohort of non-rheumatic individuals participating in a prospective longitudinal study of the incidence and significance of elevated RF. From the initial cohort of nearly 14,000 randomly selected individuals aged 52-80 years, 109 RF-positive and 187 RF-negative non-rheumatic participants were recruited. All participants were tested for RF at least twice at an interval ranging from 4 to 13 years. Of the RF-negative participants 21.9% were active smokers compared to 34.1% of IgM RF-positive (p=0.035), 20.8% of IgG RF-positive (N.S.) and 34.4% of IgA RF-positive participants (p=0.047). Smoking was most prevalent (44.8%) amongst participants with elevation of both IgM and IgA RF (p=0.008), and smokers were also significantly more likely to have a persistent elevation of RF than non-smokers (p=0.024). These findings indicate that smoking may influence the immune system, leading to increased production of IgM and IgA RF.

Aged↗