Papers by Helgi Sigvaldason
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[A health survey of elderly people in Reykjavik.]
Laeknabladid, 1994
In 1982 a multifactorial population health survey of people aged 80 years and older and living in... more In 1982 a multifactorial population health survey of people aged 80 years and older and living in the community, was carried out. The mortality registry was examined up to the end of year 1988. By this time 67% had died and the mortality was assessed by Cox's regression analysis on serum cholesterol as one of the main variables included in the survey. The original sample contained 170 persons and 148 were alive at the time of examination. Participation rate of sample is 72%. By end of 1988, 35 persons were alive and 71 dead. Excluded were 22 dead before entry. Serum cholesterol was found to be negatively predictive of mortality in both univariate (p < 0.01) and multivariate analysis when triglycerides, age and smoking were also included (p < 0.01). There was a 0.9% decrease in relative risk for each mg/dl increase of serum cholesterol. Ten persons had serum cholesterol of 160 mg/dl or less and they all died within 10 years from the examination, one of disseminated carcinom...
Prediction of cancer incidence in the Nordic countries up to the years 2000 and 2010. A collaborative study of the five Nordic Cancer Registries
PubMed, 1993
[Survival and trends of ocurrence of left ventricular hypertrophy, gender differences during 1967-1992. The Reykjavík Study.]
Laeknabladid, Jul 1, 2000
Objective: We estimated the prevalence and incidence of left ventricular hypertrophy (LVH) in thi... more Objective: We estimated the prevalence and incidence of left ventricular hypertrophy (LVH) in this large prospective cohort study of almost 20,000 participants and identified risk factors in them. Predictive factors of its appearance were evaluated along with morbidity and mortality calculations. Material and methods: LVH was defined as Minnesota Code 310 on ECG. Everyone with this code at first visit was defined as a prevalence case and those who developed it between subsequent visits were incidence cases. Risk factors at the time of the diagnosis of LVH were determined with logistic regression. Predictive factors for acquiring this ECG abnormality were determined by Poisson regression. The comparison cohort were all other participants in the Reykjavík Study stages I-V. Results: Two hundred ninety-seven men and 49 women were found to have LVH or 3.2% and 0.5%, respectively. The incidence was 25/1000/year among men and 6/1000/ year among women. Prevalence in both genders increased with increasing age. Risk factors at the time of diagnosis were systolic blood pressure (odds ratio pr. mmHg (OR) 1.02; 95% confidence interval (CI): 1.01-1.03), age (OR pr. year: 1.04; 95% CI: 1.02-1.05), silent myocardial infarction (MI) (OR: 3.18; 95% CI: 1.39-7.27) and ST-T changes (OR: 3.06; 95% CI: 2.14-4.38) among men and systolic blood pressure and age for women with similar odds ratio. Predictive factors for acquiring LVH were systolic blood pressure (incidence ratio (IR): 1.01; 95% CI: 1.01-1.02) and angina with ECG changes (IR: 2.33; 95% CI: 1.08-5.02) among men and systolic blood pressure among women (IR: 1.03; 95% CI: 1.01-1.04). In men severe smoking seemed to have a protective effect against developing LVH (IR: 0.36; 95% CI: 0.18-0.71). The risk for coronary mortality was significantly increased among women with hypertrophy (hazard ratio (HR): 3.07; 95% CI: 1.5-6.31) and their total survival was poorer with increasing time from diagnosis of LVH (HR: 2.17; 95% CI: 1.36-3.48). Conclusions: We conclude that the presence of LVH and its appearance is associated with age and increased blood pressure among both genders. Women with LVH have poorer survival than other women and they are at threefold risk of dying of ischemic heart disease. This could indicate that criteria for detecting LVH on ECG detect both mild and severe hypertrophy among men but only the severe hypertrophy cases among women. More sensitive ECG methods may have to be used to detect mild, moderate and severe LVH among both genders in order to differentiate the severity of LVH based on the ECG diagnosis.
The epidemiology of right bundle branch block and its association with cardiovascular morbidity -- The Reykjavik Study
European Heart Journal, Dec 2, 1993
This study is based on the Reykjavik Study, a long-term prospective cardiovascular survey, which ... more This study is based on the Reykjavik Study, a long-term prospective cardiovascular survey, which included a representative population of 9135 men and 9627 women, 33-79 years old, who were invited to participate during the years 1967-91. Right bundle branch block (RBBB) was found in 126 men and 67 women. The prevalence increased with age, from 0% among men and women 30-39 years of age to 4.1% and 1.6% in men and women, respectively, who where 75-79 years old. The incidence increased with age. In men younger than 60 years RBBB had a significant relationship with hypertension (P &lt; 0.05), elevated fasting blood glucose (P = 0.05), and increased heart size (P &lt; 0.05). In men with RBBB regardless of age, an association was found with cardiomegaly (P &lt; 0.05), ischaemic heart disease (P &lt; 0.05), arrhythmias (P &lt; 0.001) and bradycardia (P &lt; 0.01). A higher mortality from heart disease (P &lt; 0.01) was found in men with RBBB compared to the control population. This was not significant when risk factors of heart disease were taken into account by multivariate Cox analysis. There was a relationship (P &lt; 0.05) between hypertension and RBBB in women younger than 60 years. RBBB in women younger than 60 years is often associated with hypertension and in men younger than 60 it is often associated with an underlying cardiovascular disease, hypertension, cardiomegaly and elevated blood glucose.
International journal of gynaecology and obstetrics, May 1, 1993
Objective-To investigate the risk of prostate, ovarian, and endometrial cancer among relatives of... more Objective-To investigate the risk of prostate, ovarian, and endometrial cancer among relatives of patients with breast cancer. Design-Cohort study of 947 pedigrees in which the proband had breast cancer, linked with the Icelandic cancer registry. Setting-Iceland. Subjects-The 947 pedigrees included 29725 people, of whom 1539 had breast cancer, 467 had prostate cancer, 135 ovarian cancer,-and 105 endometrial cancer. Main outcome measures-Risk of prostate, ovarian, and endometrial cancer among blood relatives of women with breast cancer compared with risk in spouses. Results-The risk of prostate cancer was significandy raised for all relatives (1.5), first degree relatives (14), and second degree relatives (1-3) of women with breast cancer. Risk of ovarian cancer was raised for all relatives (1.9) and first degree relatives (1.9) and risk of endometrial cancer was raised for all relatives only (1 9). The risk of prostate cancer was raised if the proband with breast cancer had a first degree relative with prostate cancer. Conclusions-Coaggregation exists between breast cancer and cancers of the prostate, ovaries, and endometrium. This risk relation is probably based on genes which act by increasing the risk for cancer at these sites. Environmental factors that are common among relatives may also play a part. Continued research is required into pathophysiological mechanisms that could explain these observations.
Circulation, 1994
Background In a recent Finnish study, ferritin was suggested to be an independent risk factor for... more Background In a recent Finnish study, ferritin was suggested to be an independent risk factor for acute myocardial infarction. This study suggested that high levels of iron stores might thus be atherogenic and possibly explain partly the sex difference in the incidence of ischemic heart disease. Methods and Results A randomly selected group (n=2036), men and women aged 25 to 74 years, were examined between June and September 1983. All classic risk factors for coronary artery disease were measured as well as basic hematologic parameters and the parameters of iron metabolism, ie, iron, total iron-binding capacity (TIBC), and ferritin. During the follow-up for 8.5 years, 81 subjects experienced acute myocardial infarction (63 men and 18 women). The differences in the
Do Lipids, blood pressure, diabetes and smoking confer equal risk of myocardial infarction in women as in men? The Reykjavik study
Atherosclerosis Supplements, May 1, 2001
Studies on coronary risk factors in men and women are mainly based on mortality data and few comp... more Studies on coronary risk factors in men and women are mainly based on mortality data and few compare results of both sexes with consistent study design and diagnostic criteria. This study assesses the major risk factors for coronary events in men and women from the Reykjavik Study. Within a prospective, population-based cohort study individuals without history of myocardial infarction were identified and the relative risk of baseline variables was assessed in relation to verified myocardial infarction or coronary death during follow-up. Of the 9681 women and 8888 men who attended risk assessment from 1967-1991, with follow-up period of up to 28 years, 706 women and 1700 men suffered a non-fatal myocardial infarction or coronary death. Serum cholesterol was a significant risk factor for both sexes, with hazard ratios (HR) decreasing with age. Systolic blood pressure was a stronger risk factor for women as was ECG-confirmed left ventricular hypertrophy (women HR 2.89, 95% confidence interval [CI] 1.67-5.01; men HR 1.11 [CI 0.86-1.43]). Fasting blood glucose &amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; or =6.7 mmol/L identified significantly higher risk for women (HR 2.65) than men (HR 2.08) as did self-reported diabetes. Triglyceride risk was significantly higher for women and decreased significantly with age. Smoking increased risk two- to five-fold, increasing with dose, for women, which was significantly higher than the doubling in risk for men. This large study of the major risk factors compared between the sexes demonstrates similar relative risk of myocardial infarction associated with cholesterol for both sexes, however, the relative risk is higher in women for many other risk factors such as smoking, diabetes, elevated triglycerides and left ventricular hypertrophy.
Death Rates From Ischemic Heart Disease in Women With a History of Hypertension in Pregnancy
Obstetrical & Gynecological Survey, Jul 1, 1996
Evidence about the influence of hypertension in pregnancy on later health and in particular the r... more 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. 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. 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). 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.
Prevalence of coronary heart disease in Icelandic Men 1968-1986: The Reykjavik Study
European Heart Journal, May 1, 1993
The prevalence of coronary heart disease (CHD) was determined in a general population sample of 9... more The prevalence of coronary heart disease (CHD) was determined in a general population sample of 9141 Icelandic men aged 34-79 years, and the prevalence of four different forms of CHD was estimated separately: symptomatic infarction fulfilling WHO-MONICA criteria for definite myocardial infarction; myocardial infarction detected by ECG changes only (unrecognized, silent infarction); angina pectoris detected by the Rose questionnaire and associated with ECG manifestations of myocardial ischaemia, either at rest or during exercise, but no manifestations of myocardial infarction; angina pectoris without ECG changes indicative of myocardial ischaemia. The study was conducted in five stages allowing evaluation of trends from 1968-1986. Age was a major determinant of the prevalence of all forms of CHD. Thus, the prevalence of myocardial infarction (symptomatic or silent) rose from undetectable levels in the youngest age group (30-34 years) to around 12% (7% symptomatic and 5% silent) in the oldest group (75-79 years) and the prevalence of all forms of CHD rose from 4% in the youngest age group to 23% in the age group 70-74 years. Age-standardized comparison was carried out on the prevalence of the different forms of CHD at different stages of the study in 50-64-year-old men who were represented in all stages of the study. There was a gradual increase in the prevalence of myocardial infarction from 3% (symptomatic and silent combined, CI 1.9-4.8) in 1968 to 4.9% in 1986 (CI 3.9-6.1) (P &lt; 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)
Prediction of cancer incidence in the Nordic countries: empirical comparison of different approaches
Statistics in Medicine, Aug 19, 2003
Prediction of the future number of cancer cases is of great interest to society. The classical ap... more Prediction of the future number of cancer cases is of great interest to society. The classical approach is to use the age‐period‐cohort model for making cancer incidence predictions. We made an empirical comparison of different versions of this model, using data from cancer registries in the Nordic countries for the period 1958–1997. We have applied 15 different methods to 20 sites for each sex in Denmark, Finland, Norway and Sweden. Median absolute value of the relative difference between observed and predicted numbers of cases for these 160 combinations of site, sex and country was calculated. The medians varied between 10.4 per cent and 15.3 per cent in predictions 10 years ahead, and between 15.1 per cent and 32.0 per cent for 20 year predictions. We have four main conclusions: (i) projecting current trends worked better than assuming that future rates are equal to present rates; (ii) the method based on the multiplicative APC model often overestimated the number of cancer cases due to its exponential growth over time, but using a power function to level off this growth improved the predictions; (iii) projecting only half of the trend after the first 10 years also gave better long‐term predictions; (iv) methods that emphasize trends in the last decade seem to perform better than those that include earlier time trends. Copyright © 2003 John Wiley &amp; Sons, Ltd.
Breytingar á reykingavenjum miðaldra og eldri Íslendinga síðastliðin þrjátíu ár og ástæður þeirra : niðurstöður úr hóprannsóknum Hjartaverndar
Laeknabladid, Jun 1, 2003
1Rannsóknarstöð Hjarta-verndar, Holtasmára 1, 201 Kópavogi, 2Innkirtla-og efnaskiptasjúkdómadeild... more 1Rannsóknarstöð Hjarta-verndar, Holtasmára 1, 201 Kópavogi, 2Innkirtla-og efnaskiptasjúkdómadeild Landspítala Fossvogi, 108 Reykjavík. Fyrirspurnir og bréfaskipti: Nikulás Sigfússon, Rannsókn-arstöð Hjartaverndar, Holta-smára 1, 201 Kópavogi. Sími: 535 1800, ...
Magakrabbamein í Íslendingum 1955-1984 : afturskyggn rannsókn á meingerð og staðsetningu æxla í mögum teknum með skurðaðgerð
... bréfaskipti: Jonas Hailgrímsson, pósthólf 1465, 121 Reykjavik. ... Krabbameinsskrá Krabbamein... more ... bréfaskipti: Jonas Hailgrímsson, pósthólf 1465, 121 Reykjavik. ... Krabbameinsskrá Krabbameinsfélags Islands geymir upplysingar um 1437 karla og 766 konur sem greindust meõ illkynja aexli f maga á tímabilinu 1955-1984 (tafia I). Vefjafraõilegar greiningar eru til fyrir 1170 ...
[A health survey of elderly people in Reykjavik.]
Laeknabladid, 1994
In 1982 a multifactorial population health survey of people aged 80 years and older and living in... more In 1982 a multifactorial population health survey of people aged 80 years and older and living in the community, was carried out. The mortality registry was examined up to the end of year 1988. By this time 67% had died and the mortality was assessed by Cox's regression analysis on serum cholesterol as one of the main variables included in the survey. The original sample contained 170 persons and 148 were alive at the time of examination. Participation rate of sample is 72%. By end of 1988, 35 persons were alive and 71 dead. Excluded were 22 dead before entry. Serum cholesterol was found to be negatively predictive of mortality in both univariate (p < 0.01) and multivariate analysis when triglycerides, age and smoking were also included (p < 0.01). There was a 0.9% decrease in relative risk for each mg/dl increase of serum cholesterol. Ten persons had serum cholesterol of 160 mg/dl or less and they all died within 10 years from the examination, one of disseminated carcinom...
Tengsl hægra greinrofs við hjarta-og æðasjúkdóma og áhættuþætti þeirra
... 84 Fig. 3. The prevalence of right . bundle branch block amone (vearS) - women at 5 vears int... more ... 84 Fig. 3. The prevalence of right . bundle branch block amone (vearS) - women at 5 vears interval. Incidence/100.000/year 600 г 500 - 400 200 100 35 40 -EF Men 45 50 -Q-Women 60 65 70 75 80 85 Age (years) Fig. 4. The ...
Acta Anaesthesiologica Scandinavica, 2008
Background: Nosocomial infections are common in intensive care units (ICU). The objectives of thi... more Background: Nosocomial infections are common in intensive care units (ICU). The objectives of this study were to determine risk factors of ICU‐acquired infections, and potential mortality attributable to such infections.Methods: An observational study was performed in a 10‐bed multidisciplinary ICU. For a period of 27 months, all patients admitted for ≥48 h were included. Infections were diagnosed according to Centers for Disease Control and Prevention definitions. Airway colonization was explored by molecular typing. Risk factors for infection were determined by multivariable logistic regression. Survival was analyzed with time‐varying proportional hazards regression.Results: Of 278 patients, 81 (29%) were infected: urinary tract infections in 39 patients (14%), primary bloodstream infections in 25 (9%), surgical site infections in 22 (8%) and pneumonia in 21 (8%). Of the total of 147 episodes, Gram‐negative bacilli were isolated in 90, Gram‐positive cocci in 49 and Candida sp. in ...
Inngangur Undanfarna áratugi hafa hjartasjúkdómar verið al-gengasta dánarorsök Íslendinga. Þannig... more Inngangur Undanfarna áratugi hafa hjartasjúkdómar verið al-gengasta dánarorsök Íslendinga. Þannig má sjá í ... 1Rannsóknarstöð Hjarta-verndar, 2Landspítali Fossvogi. Fyrirspurnir, bréfaskipti: Nikulás Sigfússon, Rannsóknarstöð Hjarta-verndar, Lágmúla 9, ...
Nýgengi krabbameina og dánartíðni krabbameinssjúklinga á Íslandi síðustu 35 árin
Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenT... more Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenThe objective was to investigate the changes in incidence and mortality from malignant diseases over the period from 1955 to 1989 in Iceland. The results are presented as number of cases and incidence rates in five age groups and seven time periods, males and females. The same is presented for mortality. There was an increase in incidence rates in all age groups except the youngest (0-19 years). Overall there was a decrease in mortality rate, ten per cent for females and five per cent for males. In the youngest age group this decrease in mortality was more than fifty per cent for both sexes.Í þessari grein er lýst breytingum á nýgengihlutfalli og dánartíðni illkynja sjúkdóma á Íslandi 1955-1989. Niðurstöðurnar eru sýndar sem nýgengihlutfall í fimm aldurshópum og sjö fimm ára tímabilum fyrir karla og konur. Sömu upplýsingar eru um dánartíðni. Nýgengihlutfall hækkaði í öllum aldurshópum nema þeim yngstu (10-19 ára). Dánartíðni lækkaði um 10% hjá konum og um 5% hjá körlum. í yngsta aldurshópnum var lækkun á dánartíðni meira en 50% hjá báðum kynjum
Breytingar á tíðni kransæðastíflu og kransæðadauðsfalla á Íslandi : tengsl við áhættuþætti og mataræði
L/EKNABLADID 1991; 77: 49-58. 49 Nikulás Sigfússon 1), Helgi Sigvaldason 1), Inga Ingibjörg Guomu... more L/EKNABLADID 1991; 77: 49-58. 49 Nikulás Sigfússon 1), Helgi Sigvaldason 1), Inga Ingibjörg Guomundsdóttir 1), Ingibjörg Stefánsdóttir 1), Laufey Steingrímsdóttir 2), Porsteinn Porsteinsson 1) Gunnar Sigurösson 3) BREYTINGAR Á TÍONS KRÂNS/EDASTÍFLU OG KRÂNS/ ...
Ofbeldisáverkar : faraldsfræðileg athugun í Reykjavík 1974-1991
Algengi og nýgengi blóðþurrðarhelti meðal íslenskra karla 1968-1986 : sterk tengsl við reykingar og kolesteról í blóði
Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenT... more Neðst á síðunni er hægt að nálgast greinina í heild sinni með því að smella á hlekkinn View/OpenThe prospective Reykjavik study gave an opportunity to monitor secular trends from 1968-1986 of clinical intermittent claudication amongst Icelandic males, age 34-80 (n=9.141), and to assess the importance of possible risk factors. Both prevalence and incidence of intermittent claudication decreased sharply after 1970 in all age groups, and this decline (more than 50%) occurred a few years earlier than the decline of coronary heart disease in Iceland. The only significant risk factors for intermittent claudication, in addition to age, were smoking which increased the risk 8-10-fold and serum cholesterol level. This decline in prevalence and incidence of intermittent claudication can largely be explained by decreased smoking and cholesterol levels amongst Icelandic' men. A follow-up study verified that patients with intermittent claudication stood twice the risk of cardiovascular and total mortality as non-intermittent claudication patients, indicating that this is a high risk group which should receive all possible preventive measures.Í hóprannsókn Hjartaverndar mætti 9141 karl á aldrinum 34-80 ára einu sinni eða oftar 1968-1986. Gögn sem þar hefur verið aflað um blóðþurrðarhelti gefa gott tækifæri til að kanna algengi og nýgengi sjúkdómsins og tengsl við áhættuþætti. Lækkun algengis frá 1968-1986 var 55%. Meðal sjötugra karlmanna lækkaði algengið úr 6,7% í 3,1% og meðal sextugra karla úr 3,2% í 1,4%. Algengið óx mjög hratt frá fimmtugsaldri fram undir sjötugt en þá dró úr aukningunni. Nýgengið lækkaði enn meira á tímabilinu (66%). Af samtímaþáttum var marktæk fylgni við aldur, ártal, reykingar, kólesteról, slagbilsþrýsting og hlébilsþrýsting. En aðeins aldur, reykingar og kólesteról höfðu marktækt forspárgildi um blóðþurrðarhelti á rannsóknartímabilinu. Áhættan á blóðþurrðarhelti var átt- til tíföld meðal þeirra sem reyktu 15 sígarettur eða meira á dag. Aldur, reykingar, slagbilsþrýstingur og kólesteról í blóði höfðu sterkari fylgni við blóðþurrðarhelti en kransæðasjúkdóma. Hlutfallslega fleiri voru með blóðþurrðarhelti eftir því sem kransæðasjúkdómurinn varð verri. Blóðþurrðarhelti hafði marktækt forspárgildi um heildardánartíðni og dánartíðni af völdum kransæðasjúkdóma og heilablóðfalls eftir að búið var að leiðrétta fyrir mörgum þekktum áhættuþáttum. Minnkandi reykingar og lækkandi meðalgildi kólesteróls í blóði skýra mestan hluta þeirrar lækkunar sem varð á algengi og um helminginn af lækkuðu nýgengi
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Papers by Helgi Sigvaldason