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Biomedical subjects

H Sigvaldason

Publications and source records attributed to H Sigvaldason.

At least 37 records · Page 2Linked to original sources
PubMed1998

Survival and prognostic factors of endometrial cancer patients in Iceland 1964-1985: can attendance at population-based Pap-smear screening affect survival?

After histological review of all cases registered during the period 1964-1985 at the Cancer Registry, 260 cases with endometrial carcinoma were eligible for analyses of survival rates and prognostic factors, as well as the association of Pap-smear screening attendance with these factors and survival. The total age-adjusted 5- and 10-year relative survival rates were 76% and 75%, respectively. The prognostic factors were tested by univariate analysis and simultaneously by a multivariate analysis using the Cox proportional hazards model. Factors that independently gave a less favorable prognosis were non-attendance at screening, older age at diagnosis, deep myometrial invasion, advancing stages and tumor grading, radiotherapy only, extra-genital symptoms and histology types of serous, clear cell and undifferentiated tumors (histologic type 3). Tested simultaneously with the Cox proportional hazards model, parameters that maintained a less favourable prognosis were grade 3, stage III-IV, deep myometrial invasion, older age, radiotherapy only and extra-genital symptoms. In addition, screening attendance showed significant interaction with age. In stages III and IV only grade 3 maintained a significantly less favorable prognosis. We conclude that our results indicate that attendance at Pap-smear screening (taking Pap smears and screening for genital symptoms) has a favorable prognostic value, especially among women under the age of 62.

Aged↗
PubMed1998

Coronary heart disease mortality amongst non-insulin-dependent diabetic subjects in Iceland: the independent effect of diabetes. The Reykjavik Study 17-year follow up.

OBJECTIVES: The main aim of this study was to estimate the independent risk for coronary heart disease (CHD) death associated with non-insulin dependent (Type 2) diabetes (NIDDM) and effect on life expectancy. DESIGN AND SETTING: The Reykjavik Study is a prospective cardiovascular population study which started in 1967. A randomized selection procedure identified individuals for invitation to participate, based on their year and date of birth. Participants were examined in the years 1967-91 in one research clinic in Reykjavik. SUBJECTS AND METHODS: The population in this survey were Icelandic Caucasian males and females, born 1907-35 and therefore 34-79 years old when their examination was performed. Altogether 9139 males and 9773 females attended, and of those 267 males and 210 female were NIDDM as defined by a questionnaire or an oral glucose tolerance test. Other factors measured in the study included systolic and diastolic blood pressure, fasting total cholesterol, triglycerides, uric acid, smoking habits, height, and weight. The causes of death were determined by a review of all death certificates. Results. The relative risk of death from CHD (95% confidence limits), independently associated with NIDDM, was 2.0 (1.5-2.6) for males and 2.4 (1.6-3.6) for females. The relative risk of death from all causes was 1.9 (1.6-2.3) and 1.7 (1.3-2.1), respectively, for male and female diabetic patients. CONCLUSIONS: Non-insulin dependent diabetes mellitus carried twice the risk of CHD death in both sexes, independently of other risk factors. The diagnosis of NIDDM at the age 55 years reduced an individual's life expectancy by about five years, mostly because of increased CHD death rate.

Adult↗
PubMed1998

Incidence and prevalence of recognised and unrecognised myocardial infarction in women. The Reykjavik Study.

AIMS: The incidence and prevalence of recognised and unrecognised myocardial infarction were determined in the Icelandic cohort study of 13,000 women (the Reykjavik Study), followed for up to 29 years (mean 15 years). METHODS AND RESULTS: Women attending the Reykjavik Study, born between 1908 and 1935, were examined in five stages from 1968 to 1991. A health survey included history and ECG manifestations of coronary heart disease. Data retrieved from hospitals, autopsy records and death certificates identified 596 fatal and non-fatal myocardial infarctions to the end of 1992 (61 prior to examination, 320 non-fatal and 215 fatal). The incidence of recognised myocardial infarction ranged from 22 cases/100,000/year at 35-39 years to 1800 cases/100,000/year at 75-79 years. The incidence of unrecognised myocardial infarction ranged from 18 cases/100,000/year at 35 years to 219 cases/100,000/year at 75 years. Thirty-three percent of non-fatal myocardial infarctions were unrecognised. More occurred in the younger age groups (40%) than in the older (27%). The prevalence of recognised myocardial infarction was influenced by age and calendar year. In 1990, it was 1.3/1,000 at 35 years and 60/1000 at 75 years. Prevalence showed a time trend, tripling in all age groups from 1968-1992. Fore unrecognised myocardial infarction, prevalence rose from 0.9/1000 at 35 years to 19.2/1000 at 75 years, although there was no evident time trend. CONCLUSION: Myocardial infarction in women is very age-dependent with both incidence and prevalence increasing continuously and steeply with age. There was a significant trend for an increase in prevalence of recognised myocardial infarction from 1968 to 1992. The proportion of unrecognised non-fatal infarctions ranged from 27% in the oldest age group to 40% in the youngest. On average, this form of coronary heart disease is as common as in men.

Adult↗
PubMed1997

Prevalence and incidence of NIDDM in Iceland: evidence for stable incidence among males and females 1967-1991--the Reykjavik Study.

This is the first large survey carried out in Iceland to estimate the prevalence and incidence of known and unknown non-insulin-dependent (Type 2) diabetes (NIDDM) among males and females, aged 34-79. The population in this survey was 9128 males and 9759 females born between 1907 and 1935 and examined in the prospective Reykjavik Study 1967-1991. Participants were invited from one to five times during the 24 years. The overall age-standardized prevalence (95% confidence limits) was 2.9% (2.5 to 3.3) for males and 2.1% (1.8 to 2.5) for females, aged 30-79, according to the European standard population. The overall annual age-standardized incidence rate per 100,000 was 377 (303 to 457) for males and 266 (212 to 320) for females, aged 35-74, standardized to the European population. Our study indicates that the prevalence of NIDDM is relatively low compared to other Nordic and western countries, and has not been increasing over the past 20 years. Furthermore, the incidence of NIDDM has not been changing during the past 20 years of follow-up among Icelandic males and females aged 34-79.

Administration, Oral↗
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

Prognostic role of cardiovascular risk factors for men with cardiomegaly (the Reykjavik Study).

The Reykjavik Study is a large population-based cohort study, starting in 1967. A total of 9,139 men, born in the years 1907 to 1934, have been followed for 4 to 24 years. Heart size was determined by chest roentgenogram in 2 planes and cardiomegaly, defined as a relative heart size exceeding 550 ml/m2, was detected in 517. Multivariate Cox regression analysis was used to estimate the independent contribution of variables measured at each participant's first visit to the risk of both all-cause and coronary artery disease (CAD) mortality. Cardiomegaly was detected in 3.7% of men aged < 40 years and in 21.2% of those > 75 years. One half of these men had hypertension, one third had manifestations of CAD, and 37% had neither. Among men with cardiomegaly, the presence of CAD had marked deleterious effect on prognosis. Serum total cholesterol and systolic blood pressure were significant independent risk factors of CAD mortality with risk ratio of 1.008 per mg/dl serum cholesterol (95% confidence interval 1.00 to 1.01; p = 0.004) and 1.015/mm Hg (95% confidence interval 1.000 to 1.300; p = 0.043), respectively. Smoking > 25 cigarettes/day carried a 2.3-fold risk (95% confidence interval 1.3 to 4.4; p = 0.008) of all-cause mortality. The traditional risk factors for CAD, serum cholesterol, high blood pressure, and smoking maintain their detrimental effect on prognosis among patients with cardiomegaly. These findings have implications for secondary prevention, signifying that in the presence of cardiomegaly, complacency is not justified in controlling major risk factors for CAD.

Adult↗
PubMed1996

Silent ST-T changes in an epidemiologic cohort study--a marker of hypertension or coronary heart disease, or both: the Reykjavik study.

OBJECTIVES: We sought to evaluate the prognostic value and clinical characteristics associated with electrocardiographic (ECG) ST-T changes among men without other manifestations of coronary heart disease. BACKGROUND: Recent achievements in secondary prevention and treatment of coronary heart disease have highlighted the importance of early diagnosis of both symptomatic and silent forms of the disease. The prognostic and clinical importance of ST-T changes in men with no other manifestations of coronary heart disease is still unclear. Do they reflect silent coronary heart disease or hypertension, or both, and what is their independent contribution to prognosis? METHODS: The subjects were 9,139 men born in the years 1907 to 1934 and followed up for 4 to 24 years. On initial visit they were assigned to different categories of coronary heart disease on the basis of Rose chest pain questionnaire, hospital records, 12-lead ECG, history and physical examination. RESULTS: The prevalence of silent ST-T changes among men without overt coronary heart disease was strongly influenced by age, increasing from 2% at age 40 years to 30% at age 80 years. Men with such ST-T changes were older and had higher serum triglyceride levels and worse glucose tolerance than men without such changes or other evidence of coronary heart disease. Their blood pressure was higher, and they more often had an enlarged heart or left ventricular hypertrophy and more often took antihypertensive medication, digitalis or diuretic drugs. Serum cholesterol levels were not different between the two groups. After adjustment for other risk factors, these silent ST-T changes had a risk ratio of 2.0 for death from coronary heart disease and 1.6 for subsequent myocardial infarction or angina pectoris. CONCLUSIONS: Silent ST-T changes that are ischemic by the Minnesota code are probably both a marker of silent coronary heart disease and high blood pressure. They define a distinct group of patients with highly abnormal risk factor profile. Although not specific for coronary heart disease and often transient, they are associated with the development of every clinical manifestation of coronary heart disease and are independent predictors of reduced survival.

Age Factors↗
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

Unrecognized myocardial infarction: epidemiology, clinical characteristics, and the prognostic role of angina pectoris. The Reykjavik Study.

OBJECTIVE: To evaluate the incidence, prevalence, characteristics, and prognosis associated with clinically unrecognized myocardial infarction as diagnosed by electrocardiographic changes. DESIGN: Prospective, population-based cohort study with 4- to 20-year follow-up. SETTING: Icelandic Heart Association Preventive Clinic. PARTICIPANTS: 9141 men residing in the Reykjavik area who were born between 1907 and 1934. MEASUREMENTS: Patients were assigned to categories of coronary heart disease at first visit on the basis of hospital records, Rose chest pain questionnaire, standardized 12-lead electrocardiogram, and history and physical examination. Incidence and prevalence of unrecognized myocardial infarction were determined, survival was measured, and causes of death were determined from death certificates and autopsy records. RESULTS: Prevalence was strongly influenced by age. Nearly undetectable in the youngest age group, it increased to more than 5% in the group aged 75 to 79 years. Incidence was almost zero up to age 40, then increased steeply to more than 300 cases per year per 100,000 persons at age 60, and decreased with age after age 65. Ten- and 15-year survival probabilities were 51% and 45%, respectively, and were similar to those for patients with recognized myocardial infarction. One third of men with unrecognized and 58% of men with recognized myocardial infarction had a history of angina pectoris (P < 0.001). Angina pectoris had a greater effect on coronary heart disease mortality in the former group than in the latter. The risk ratio for unrecognized myocardial infarction was 4.6 without angina (95% CI, 2.4 to 8.6) and 16.9 with angina (CI, 9.4 to 30.3); the risk ratio for recognized myocardial infarction was 6.3 without angina (CI, 3.7 to 10.6) and 8.5 with angina (CI, 5.8 to 12.6). CONCLUSION: At least one third of all myocardial infarctions were unrecognized. Prognosis and risk factor profiles for patients with recognized and unrecognized myocardial infarction were similar. Although those with unrecognized myocardial infarction were less likely than those with recognized myocardial infarction to have a history of angina pectoris, angina in these cases was usually associated with ischemic electrocardiographic changes and a poor prognosis, suggesting severe coronary heart disease.

Adult↗
PubMed1995

Long-term prognosis of different forms of coronary heart disease: the Reykjavik Study.

BACKGROUND: While coronary heart disease (CHD) is a serious and often fatal disease the prognosis is variable and major effort has been invested in risk stratification. The purpose of this study was to examine the relation between long-term prognosis and risk factors in different clinical categories of CHD. METHODS: A general population sample of 9141 men, aged 34-79 at entry into the study was divided into six groups with respect to manifestations of CHD at entry: I. Symptomatic infarction. II. Silent or unrecognized infarction. III. Angina pectoris with ischaemic changes on ECG. IV. Angina without ischaemic changes. V. Angina by Rose questionnaire but not confirmed by a physician. VI. No manifestations of CHD. RESULTS: The risk factor profile varied considerably between the different categories and by life-table analysis marked differences in survival were demonstrated between the groups. The risk factors maintained their detrimental effects on prognosis in the presence of CHD. Thus, age, serum total cholesterol, impaired glucose tolerance and smoking were found by Cox's regression to be statistically significant independent risk factors of CHD mortality among men having manifestations of CHD (groups I-V). Furthermore, the composite risk score, a measure of the overall risk factor exposures had marked effect on the prognosis of the various CHD groups. When the comprehensive risk factor score for both CHD mortality and all-cause mortality was accounted for marked differences persisted in the long-term prognosis. Compared to those without CHD the infarct groups had about a 7.6- and 3.7-fold risk of dying from CHD and all causes respectively. Those with angina had from 2.5- to 3.2-fold risk of CHD mortality and 1.7- to 2.2-fold risk of all-cause mortality depending on the subgroup of angina, again compared to those without manifestations of CHD. CONCLUSION: Different categories of CHD had different risk factor profiles and the long-term prognosis resulted from a complex interplay between those factors and the diagnostic category of CHD. The risk factors maintained their detrimental effects on prognosis in the presence of CHD and after accounting for the comprehensive risk factor score marked differences persisted in the long-term prognosis, being worst for those having suffered a myocardial infarction, either symptomatic or silent.

Adult↗
PubMed1995

Glucose tolerance and blood pressure in a population-based cohort study of males and females: the Reykjavik Study.

OBJECTIVE: To investigate the relationship between fasting and postprandial glucose levels and the risk of hypertension, both cross-sectionally in different age and body mass index (BMI) groups, and prospectively. DESIGN: Long-term prospective health survey in the Reykjavik area, of a large representative population sample of males and females in various age groups, conducted since 1967. METHODS: Values from 8285 males and 9183 females were included in the cross-sectional analysis. The prospective analysis included 2639 males and 2346 females, with two consecutive observations for each individual, with a 3- to 8-year interval. RESULTS: After controlling for year of examination, age, BMI and various other risk factors, we found a strongly significant relationship between the blood glucose level, both fasting and 90 min after an oral glucose load, and risk for hypertension. The strength of the correlation between postprandial glucose value and blood pressure was similar in different age and BMI groups, except for in the males, in whom there was a stronger correlation with diastolic blood pressure with higher BMI. The 90-min glucose level was also predictive for development of hypertension 3-8 years later. The predictive power was somewhat stronger for females. Fasting glucose level was predictive for hypertension only for the females. Concurrent weight gain had a very strong independent explanatory power for development of hypertension. CONCLUSIONS: This study confirms the role of metabolic factors in hypertension. The correlation between impaired glucose tolerance and hypertension was found to be remarkably consistent throughout adult life, for both sexes and all values of BMI. Fasting glucose was predictive of hypertension in the females, and blood glucose at 90 min after the glucose-tolerance test was predictive of future development of hypertension in both sexes.

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↗
PubMed1994

Gastric cancer in Iceland: a retrospective study of resected gastric specimens in a high-risk country during 30 years (1960-1989).

The world-wide incidence of gastric cancer is decreasing, especially in high-risk populations such as the Icelanders. We examined retrospectively 1,040 specimens of resected gastric cancers from a 30-year period, 1960-1989. The decrease in incidence in both sexes involved mainly the largest histological group, the intestinal-type tumours. In males there was also a decrease in diffuse tumours but in females these remained relatively unchanged. Tumours of the antrum and the corpus decreased in both sexes. In males there was a significant increase in tumours of the cardia and most of these were of the intestinal type. In females there was a minor increase in tumours of the cardia, all of which were of the intestinal type. An increase in incidence of tumours of the cardia concomitant with a decrease in incidence of tumours in other parts of the stomach suggests a difference in aetiological factors. The death risk for patients with tumours of the cardia was 59% higher than that for those with tumours in other parts. The death risk following gastric resection was not significantly different when patients with intestinal-type tumours and diffuse tumours were compared.

Adolescent↗
PubMed1994

A marked decline in the prevalence and incidence of intermittent claudication in Icelandic men 1968-1986: a strong relationship to smoking and serum cholesterol--the Reykjavik Study.

The epidemiology of peripheral vascular disease has been studied much less extensively than the epidemiology of coronary heart disease (CHD). The prospective Reykjavik Study gave an opportunity to monitor secular trends from 1968 to 1986 of clinical intermittent claudication (IC) amongst Icelandic males, aged 34-80 and to assess the importance of possible risk factors. Both prevalence and incidence of IC decreased sharply after 1970 in all age groups, and this decline occurred a few years earlier than the decline of CHD in Iceland. The only significant risk factors for intermittent claudication, in addition to age, were smoking which increased the risk of IC 8- to 10-fold and serum cholesterol level. Approximately one-half of the striking decline in the incidence of IC can be explained by decreased smoking and cholesterol levels amongst Icelandic men. A follow-up study verified that IC patients stood twice the risk of cardiovascular and total mortality as non-IC patients, indicating that IC is a high risk group which should receive all possible preventive measures.

Adult↗