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Biomedical subjects

N Sigfússon

Publications and source records attributed to N Sigfússon.

At least 19 recordsLinked to original sources
PubMed2001

The relationship between educational level and mortality. The Reykjavík Study.

OBJECTIVE: Epidemiological studies have indicated an association between socioeconomic factors and health. It has not been clearly established whether this association is wholly or partly independent of classical risk factors. Our objective was to estimate the relationship between educational level and coronary artery disease (CAD), mortality and all-cause mortality. The Reykjavík Study involving 18 912 participants followed-up 4-30 years provides an ideal opportunity to address this question. DESIGN AND SUBJECTS: The participants were aged 33-81 years and living in the Reykjavík area. They were divided into four groups according to education. The standard risk factors were assessed on entry and mortality, and cause of death registered during follow-up. Multiple Cox regression analysis was applied to assess the relationship between age at examination, year of examination, educational level and mortality. RESULTS: The all-cause mortality and CAD mortality was significantly related to education, even after adjustment for classical risk factors. For men, 14% (95% CI: 2-24) reduction was found in CAD mortality for those having high school education relative to elementary school. The figures for junior college and university education were 17% (95% CI: 1-31) and 38% (95% CI: 21-32), respectively. These figures were only slightly lower when major CAD risk factors were controlled for and still significant. Similar figures were found for all-cause mortality. For women 34% (95% CI: 18-48) reduction was found in CAD mortality for high school education and 55% (95% CI: 22-74) for junior college, but too few had university education for reliable results. The figures were lower for all-cause mortality, but significant. The figures were reduced when major CAD risk factors were controlled for, but still significant. CONCLUSION: Education is a strong protective factor both for all-cause and CAD mortality. Only a small part of this effect can be explained through conventional risk factors.

Adult↗
PubMed2001

[Changes in myocardial infarction incidence and mortality in Iceland.].

INTRODUCTION: According to public health reports ischaemic heart disease was an uncommon cause of death in Iceland at the beginning of the last century. This death rate increased steadily until the ninety-eighties whereafter it leveled off and started to decline. The objective of the present study is to assess in detail the changes in myocardial infarction attack, incidence and death rate as well as case fatality. MATERIAL AND METHODS: Crude death rate from ischaemic heart disease is available from the Statistical Bureau of Iceland from 1911 to 1996 and age and sex standardized death rate from 1951. In this paper, however, the material is mainly from the MONICA Project, a multinational study of myocardial infarction under the auspices of the World Health Organization. The study, in which Iceland has participated since 1981, registers all myocardial infarctions in people aged 25-74 years in the whole country. The registration is performed according to standardized criteria and external quality control was applied throughout by WHO designated quality control centers. The registration now covers the period 1981-1998. RESULTS: The crude death rate in ischaemic heart disease in both sexes combined increased steadily until about 1980 when it accounted for about 30% of deaths. Age and sex specific death rate from these diseases increased from 1951 to about 1970, leveled off for the next 10 years and has since decreased. The MONICA data show a decline of death rate from myocardial infarction of 57% in men aged 25-74 during 1981-1998 and a 51% decline in women. Incidence rate has declined by 40% and 34% in men and women respectively and attack rate by 49% and 44%. Incidence, death rate and case fatality in myocardial infarction in Iceland compares favorably with other European countries. CONCLUSIONS: Myocardial infarction incidence and death rates have been declining in Iceland during the last two decades. Case fatality is now among the lowest compared to other countries. Preventive measures are most likely to further reduce incidence and death rates in myocardial infarction in Iceland.

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

Association between trans fatty acid intake and cardiovascular risk factors in Europe: the TRANSFAIR study.

BACKGROUND: High intakes of trans fatty acids (TFA) have been found to exert an undesirable effect on serum lipid profiles, and thus may increase the risk for cardiovascular disease. OBJECTIVES: Investigation of the association between TFA intake and serum lipids. DESIGN: Cross-sectional study in eight European countries (Finland, France, Greece, Iceland, The Netherlands, Portugal, Spain, Sweden) among 327 men and 299 women (50-65 y). Using a dietary history method, food consumption was assessed and TFA intake was calculated with recent figures on TFA levels of foods, collected in the TRANSFAIR study. RESULTS: Mean (+/-s.d.) TFA intake was 2.40+/-1.53 g/day for men and 1.98+/-1.49 g/day for women (0.87+/-0.48% and 0. 95+/-0.55% of energy, respectively), with the highest consumption in Iceland and the lowest in the Mediterranean countries. No associations were found between total TFA intake and LDL, HDL or LDL/HDL ratio after adjustment for cardiovascular risk factors. Additional adjustment for other fatty acid clusters resulted in a significant inverse trend between total TFA intake and total cholesterol (Ptrend<0.03). The most abundantly occurring TFA isomer, C18:1 t, contributed substantially to this inverse association. The TFA isomers C14:1 t9, C16:1 t9 and C22:1 t were not associated or were positively associated with LDL or total cholesterol. CONCLUSIONS: From this study we conclude that at the current European intake levels of trans fatty acids they are not associated with an unfavourable serum lipid profile. SPONSORSHIP: Unilever Research Laboratorium, the Dutch Dairy Foundation on Nutrition and Health, Cargill BV, the Institute of Food Research Norwich Laboratory, the Nutrition Branch of the Ministry of Agriculture, Fisheries and Food, the International Fishmeal and Oil Manufacturers' Association, Kraft Foods, NV Vandemoortele Coordination Center, Danone Group, McDonalds Deutschland Inc, Danish Veterinary and Food Administration, Valio Ltd, Raisio Group. European Journal of Clinical Nutrition (2000) 54, 126-135

Adipose Tissue↗
PubMed2000

[In search for explanatory factors in the relationship between educational level and mortality.].

OBJECTIVE: The connection between socioeconomic status and mortality is well known in Western countries. Educational level has frequently been used as a socioeconomic indicator. In a recent Icelandic prospective study, an inverse relationship between educational level and mortality was shown. The objective of the present study is to consider possible explanatory factors. MATERIAL AND METHODS: This study was a part of the Reykjavík Study. A stratified sample of 400 people was taken from one of six study groups. The sample was equally divided between the sexes and four educational levels. Mean age of the sample was 72.7 years. Participants completed a questionnaire concerning knowledge of risk factors for coronary heart disease, expected response to symptoms of cardiac infarction, social network and use of health care. Response rate was 78.5%. The relationship between answers and educational level was assessed with logistic regression. RESULTS: People with higher education were more likely to be in personal contact with nurses and doctors and receive advice concerning health and treatment from them. Participants were generally satisfied with the Icelandic health care system and seemed generally to have good access to it. A relationship with educational level was not shown. A larger proportion of those with lower education had regular communication with their general practician. CONCLUSIONS: Our results suggest that certain health care services are integrated into the social network of those with higher education. This may lower their morbidity and mortality. Other hypotheses concerning possible explanatory factors for differences in health were not supported.

English Abstract↗
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↗
PubMed1997

[Relationship between education and risk factors for coronary artery disease].

Recent epidemiological studies in the western countries show an association between the incidence of coronary artery disease and its risk factors and socioeconomic status. Education is the single factor most frequently used as to base classification of social status. The purpose of this study was to estimate the association between education level and coronary artery disease risk factors in Iceland. The study population was 18919 individuals aged 33 to 8l who were living in Reykjavik and its neighbourhood. They were divided into four groups according to their educational level. A model of the relationship was constructed using linear regression analysis and the groups compared. Risk factors such as cholesterol, triglycerides, diastolic and systolic blood pressure, height, fasting blood sugar, 90 minute blood sugar, BMI and smoking were studied. In most cases and for both sexes there was an increased risk for those in the lowest educational group compared with the other groups.

Adult↗
PubMed1997

Risk factors for malignant diseases: a cohort study on a population of 22,946 Icelanders.

The records of a cohort of 11,580 females and 11,366 males participating in an Icelandic cardiovascular risk factor study were linked with the Icelandic Cancer Registry, identifying 1,785 males and 1,490 females who had been registered with neoplastic diseases from 1968 to 1995. The interval between the time of measurement of the variables and the diagnosis of the malignancy ranged from 4 to 27 years. The variables consisted of answers from a questionnaire on smoking and the use of hypertensive drugs and anthropometric and biochemical measurements. Cox's regression was applied to analyze the predictive power of the variables on the risk of cancer after the first examination at the Heart Preventive Clinic, Reykjavík. Univariate analyses, adjusted for age, were performed for each variable and each major site. Within each major site, multivariate regression analysis was applied for variables that were found significantly (10% level in univariate analysis) positive or negative as risk factors. The results show that smoking is the most important risk factor, negative only for endometrium. For lung cancer, the risk is twice as strong for females as it is for males, whereas for pancreas, males have a relative risk ratio of 4.5, compared with 2.4 for females. Height is a risk factor for all sites for each sex, for breast in females, and for kidney in males. Several anthropometric risk factors were studied. Some of these can describe positive or negative relative risk ratios for cancer, and their use may shed light on cancer pathogenesis. Serum cholesterol is a negative risk factor for breast cancer in females, but triglycerides are a positive risk factor for cervix cancer in females and for colon or rectum and thyroid cancer in males. Serum glucose is a positive risk factor for prostate cancer and a negative risk factor for lymphomas and leukemias.

Adolescent↗
PubMed1996

Predominance of aortic calcification as an atherosclerotic manifestation in women: the Reykjavik study.

Since 1967 the Reykjavík study has monitored coronary artery disease and its risk factors in randomly selected cohorts. From 1979 to 1984, 3246 men and 3545 women aged 45-74 years were studied. Routine biplane chest X rays were assessed by a radiologist who noted the presence or absence of aortic calcification (AC), but had no detailed knowledge of the subjects. Overall, AC was diagnosed in 283 (8%) women, but in only 54 of the men (1.7%). In the women, the prevalence of AC increased from 2.0% at age 45-49 years to 17.1% at the age of 70-74 years, while in men it was 0 and 8.3%, respectively. In women, multivariate analysis of risk factors showed AC to be positively related to systolic and negatively related to diastolic blood pressure, indicating a potential relation to pulse pressure. Furthermore, AC was independently associated with age, drug treatment for hypertension, nonfasting blood sugar, use of antidiabetic drugs, total serum cholesterol levels, and the amount of smoking. Too few men had AC for multivariate assessment of risk factors. In addition, in women AC was also related to a previous myocardial infarction (p < 0.05), mortality from coronary artery disease (p < 0.01), and the presence of intermittent claudication (p < 0.01). In men, however, AC was related only to total mortality (p < 0.05). Thus, these data show AC to be more prevalent in women, independently associated with recognized atherosclerotic risk factors, and a potential marker for coronary and peripheral artery disease.

Aged↗
PubMed1995

Plasma fatty acids and lipids in two separate, but genetically comparable, Icelandic populations.

Levels of serum lipids and lipoproteins, and the fatty acid composition of plasma phospholipids, were measured in two genetically comparable, but widely separated, populations. The 1975 mortality rates for ischemic heart disease were significantly higher in one of these populations, the Manitoban residents of pure Icelandic descent, than in the other, a rural population from Northeastern Iceland. Two study populations, Icelanders and Icelandic-Canadians, were drawn from these larger populations. The study populations were matched for age and sex and divided into three age groups, 20-39, 40-59, and 60-69 years. In comparison to the Icelandic-Canadians, the Icelanders exhibited significantly higher levels of total cholesterol, low-density lipoprotein cholesterol, and high-density lipoprotein cholesterol, but lower triglyceride levels. Their plasma phospholipids contained significantly lower levels of saturated fatty acids (SFA), monounsaturated fatty acids, and n-6 polyunsaturated fatty acids (PUFA); but their n-3 PUFA levels were three times as high. It was additionally found that fatty acid composition of plasma phospholipids differed among Icelanders of different ages. SFA levels were significantly lower, and n-6 PUFA levels significantly higher, in the 20-39 year group than in the 60-69 year group, possibly due to different dietary fat consumption patterns between generations. No corresponding age-related difference in the fatty acid composition of plasma phospholipids was found in the Icelandic-Canadian study population. As the Icelandic and Icelandic-Canadian groups are assumed to be genetically similar, the biochemical differences between them are evidently due to environmental, probably dietary, differences. The findings indicate that n-3 PUFA may be cardioprotective in the context of an otherwise atherogenic diet.

Adult↗
PubMed1995

Death rates from ischemic heart disease in women with a history of hypertension in pregnancy.

BACKGROUND: Evidence about the influence of hypertension in pregnancy on later health and in particular the risk of cardiovascular disorders is conflicting, although a link has been suggested. In a population-based study with a long follow-up time the potential association between hypertension in pregnancy, preeclampsia and eclampsia with increased death rates from ischemic heart disease (IHD) was investigated. METHODS: All 7543 case records at the main maternity hospital in Iceland during 1931-1947 were reviewed to identify women with hypertension in pregnancy, subdivided by parity and severity of disease into those with eclampsia, preeclampsia and hypertension alone. Information on those who had died was obtained from death certificates, supplemented by autopsy reports and hospital records. Death rates from IHD were compared to population data from public health and census reports during corresponding periods and between study groups. RESULTS: Of 374 hypertensive women 177 had died. The death rate was slightly higher among women with any hypertension in pregnancy than in the reference population (RR = 1.20; 95% CI 1.01-1.42). About half of the increase was attributed to excess mortality from IHD with a relative risk of dying of 1.47 (95% CI 1.05-2.02). The relative risk of dying from IHD was significantly higher among eclamptic women (RR = 2.61; 95% CI 1.11-6.12) and those with preeclampsia (RR = 1.90; 95% CI 1.02-3.52) than those with hypertension alone. Parous women at the index pregnancy had a twofold higher risk of dying from IHD than primigravid women (RR = 2.05; 95% CI 1.19-3.55; p = 0.01). CONCLUSION: There is an indication of increased death rates among women with a history of hypertension in pregnancy, where ischemic heart disease may be more common than in the general population.

Adult↗
PubMed1995

[[Hypertension treatment of elderly men in Iceland].

Until recently neither the extent of antihypertensive drug usage in Iceland nor its distribution among drug classes was known. Of the 1,145 men aged 70-84 years alive in 1991, 834 participated in a study carried out by Hjartnavernd, the Heart Association. A history of hypertension or the presence of high blood pressure when measured at the Associations institute were found in 429 men, of whom 157 were on medication for hypertension alone: 95 on single drug treatment, 49 on two drugs, and five on three drugs, no information being available for the remaining eight. The most widely used drugs were diuretics or beta-blockers, of which diuretics apparently yielded better results. Of combined regiments, that of beta-blockers and diuretics was by far the most common, followed by ACE- (angiotensin converting enzyme) inhibitors and diuretics, and beta-blockers and calcium channel blockers. Thus, both medical and economic factors suggest that diuretics should be used in this age group.

Adrenergic beta-Antagonists↗
PubMed1992

Population study of the importance of rheumatoid factor isotypes in adults.

Blood samples collected from 13,858 randomly selected subjects participating in a health survey in Iceland from 1974 to 1983 were tested for rheumatoid factor. Samples that were positive in a sensitive RF screening test were analysed further by the Rose-Waaler technique and an isotype specific enzyme linked immunosorbent assay (ELISA). In 1987 the 173 available participants who were RF positive and 156 matched RF negative controls were evaluated clinically for rheumatoid diseases. RF levels and isotype patterns were more persistent in the patients with rheumatoid arthritis (RA) than in RF positive subjects who did not have overt RA. The prevalence of RA was only 19% in the participants who were RF positive in 1987. Forty per cent of the participants who had a persistent (four to 13 years) increase of IgA RF combined with either IgM or IgG RF were diagnosed as having RA. A positive correlation was found between RF levels and various manifestations of RA. This association was stronger for the IgA and IgG RF isotypes than for IgM RF. Excluding RF positivity as a diagnostic parameter, RA was diagnosed in 33 of the participants and 20 (61%) of these patients had increased levels of IgM and IgA RF. Patients with RA with bone erosions in their hands had higher levels of IgA RF than patients without erosions, but an association was not found between bone erosions and other RF isotypes. None of the RF negative participants who were symptom free when the original blood sample was taken developed RA during the four to 13 year follow up period. In contrast, five symptom free RF positive participants developed RA during this period. These five patients had all had increased levels of at least two RF isotypes before the onset of their symptoms. It is concluded that the IgA and IgG RF isotypes have a closer association with the clinical parameters of RA than IgM RF. Furthermore, increases in RF can precede clinical manifestations of RA and this applies in particular to the IgA and IgG RF isotypes.

Adult↗
PubMed1987

Left bundle branch block: prevalence, incidence, follow-up and outcome.

In a randomly selected population screening study of 8450 men and 9039 women 33 to 71 years of age conducted in Iceland in 1967-1977, 27 men and 17 women were found to have left bundle branch bock (LBBB). The prevalence of LBBB at that time was 0.43% for men and 0.28% for women. The incidence of LBBB was 3.2 per 10,000 per year for men and 3.7 per 10,000 per year for women. All except one of 37 alive patients with LBBB were examined in 1984 including chest X-ray, echocardiography and exercise testing (Bruce protocol). Eight men had had myocardial infarction (P less than 0.05), 12 had angina pectoris, 15 had hypertension, 7 had cardiomyopathy, 13 had primary conduction disease, and 3 had pacemakers. Five men and two women had died in comparison with 18 men and 1 woman in an age-matched control group of 176 people (P : ns). Three of 5 decreased LBBB men had cardiomyopathy at autopsy. Three men died suddenly. The two women died of noncardiac causes. Only one patient in the control group had cardiomyopathy (P less than 0.01). There was no significant difference in other cardiac diagnoses between the groups. Eleven LBBB women out of thirteen had a normal exercise duration (greater than or equal to 6 min) and 11/17 men exercised normally (less than or equal to 7 min). In comparison with the control group, the LBBB patients had an increased LV diameter 2.85 +/- 0.38 vs 2.58 +/- 0.38 cm m-2 body surface area (P less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Hypertension in middle-aged men. The effect of repeated screening and referral to community physicians on hypertension control.

The purpose of this study was to find the prevalence and incidence of hypertension in middle-aged Icelandic men, their awareness of this condition and treatment status and to what extent the control of hypertension was changed by regular follow-up and referral to community physicians. The study was a part of the Health Survey in the Reykjavik area, a prospective cardiovascular health survey. Participants in the study were 10,741 men aged 34-61 at the onset, that were allotted to a study group of 2,955 men (Group B) examined by standardized methods in 1967-'68 (Stage I), 1970-'71 (Stage II), 1974-'76 (Stage III) and 1979-'81 (Stage IV) and three control groups, Group C (2,744 men), Group A (2,755 men) and Group D (2,287 men) examined in Stage II, III and IV respectively. Hypertension was defined as blood pressure greater than or equal to 160 systolic and/or greater than or equal to 95 diastolic on two occasions and/or current treatment for hypertension. All hypertensives were referred to community physicians for control and/or treatment. The main findings and conclusions were as follows: The prevalence of hypertension was age dependent, increasing from about 5% in men in the mid-thirties to about 35% in the mid-seventies. In comparable age groups there was no significant change in prevalence during the 12-year study period. The annual incidence was age-dependent, lowest in the youngest around 2% and highest in the oldest, around 5%. Awareness of hypertension was low at the start of the study only 24% of hypertensives knowing about their condition but increased in the study group to 68% at the end of the study. In the control groups there was also an increase from 20% in Stage II to 63% in Stage IV. In the study group 16% of hypertensives were under treatment in 1967-'68 but 64% in 1980-'81 or 94% of known hypertensives.(ABSTRACT TRUNCATED AT 400 WORDS)

Adult↗
PubMed1984

Distribution of haematological, serum and urine values in a general population of middle-aged men. The Reykjavik Study.

In the first stage of a prospective cardiovascular health survey, 2955 males aged 34-61 years were invited for examination during a 12-month period. The response was 75%. Appointments were arranged in such a way that all age groups would be equivalent with respect to time of day, weekday and time of year on which appointments were given. In fasting blood and urine samples the following quantities were estimated: s-alkaline phosphatase (AP), s-bilirubin (Bil), s-creatinine (Cre), s-uric acid (UA), haemoglobin (Hb), haematocrit (Hct), mean cell haemoglobin content (MCHC), erythrocyte sedimentation rate (ESR) and urine specific gravity (USG). The approximate 5% and 95% centiles were as follows: (table; see text) No indication of seasonal variation was found in these results.

Adult↗