Parathyroid hormone (PTH) may be an important determinant of cortical bone remodeling in the elderly. Vitamin D status is one of the determining factors in this relationship. The aim of this study was to quantify the relationship between serum PTH, vitamin D and bone mineral density (BMD) in elderly women in Reykjavik (64 degrees N), where daily intake of cod liver oil is common and mean calcium intake is high. In PTH correlated inversely with 25(OH)D (r = -0.26, p
Information in the Icelandic Cancer Registry on breast cancer and its collection of breast cancer families has been used to elucidate changes in breast cancer incidence by time period and by age, and the effect of degree of relationship and age on the familial risk of breast cancer. Since 1921 the incidence rates have increased, but the increase is significantly greater (2.06% per year) for ages over 44 years than for ages 20-44 (1.20% per year). It has been shown before that when familial risk is computed, the age of the proband influences the risk for the relatives. However, this study shows that the age of the relative is also important and with increasing age the familial risk decreases.
The relationship between cholecystectomy and colorectal cancer in the Icelandic population was analyzed in a historical prospective study. A total of 3,425 individuals (857 males and 2,568 females) who underwent cholecystectomy during a 26-yr period (1955-1980) were followed for 8-33 yr. The risk of colonic cancer in Icelandic males increased significantly 11 yr or more after operation (relative risk, 2.73; 95% confidence interval, 1.25-5.19). This is the only study that shows a significantly increased risk of colonic cancer in males only. In spite of this increased risk, regular screening for colonic cancer in Icelandic males would probably not be warranted, since almost 70% of the males are 70 yr old or older at the time of diagnosis.
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.
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.
OBJECTIVE--To monitor trends in mortality and morbidity due to ischaemic heart disease and compare these with observed levels of risk factors from population surveys. DESIGN--Analysis of trends in death rates from ischaemic heart disease in Iceland compared with expected rates computed from population surveys. Risk factor levels together with beta factors obtained from Cox's regression analysis were used to compute expected death rates. Trends in morbidity due to acute myocardial infarction were assessed and secular trends in dietary consumption compared with trends in cholesterol concentrations. SETTING--Reykjavik, Iceland (total population 250,000; over half the population live in Reykjavik). SUBJECTS--12,814 randomly selected residents in the Reykjavik area aged 45-64 (6623 men, 6191 women; 72% and 80% of those invited). MAIN OUTCOME MEASURES--Age adjusted rates of myocardial infarction and deaths from ischaemic heart disease. Expected risk from risk factor levels (smoking, total serum cholesterol concentration, systolic blood pressure) at each unique survey visit. RESULTS--Mortality from ischaemic heart disease has decreased by 17-18% since 1970. During 1981-6 the myocardial infarction attack rate in men under 75 decreased by 23%. A decrease occurred in the level of all three major risk factors after 1968. The fall in the serum cholesterol concentration coincided with a reduction in consumption of dairy fat and margarine. The calculated reduction in risk for the age group 45-64 was about 35%, which was closely similar to the observed decrease in mortality due to ischaemic heart disease in that age group. CONCLUSION--The reduction in mortality from ischaemic heart disease was substantially due to a decreased incidence of myocardial infarction and could be attributed largely to the reduction in risk factors.
All individuals subjected to x-ray examination of the large bowel at Borgarspitalinn, Reykjavik, over the 5-year period 1975-1979 were matched against the files of the Icelandic Cancer Registry, 1955-1980 inclusively. The diagnostic accuracy was 84.9% and with additional proctoscopy the diagnostic accuracy was 92.5%.
OBJECTIVE: To estimate the risk of malignant diseases in families of probands with the same mutation in the BRCA2 gene. DESIGN: A cohort study using record linkage of a breast cancer family resource and the Icelandic Cancer Registry. SETTING: Iceland. SUBJECTS: Families of 995 breast cancer patients, from which 887 were tested for a single founder 999del5 mutation; 90 had the mutation and 797 did not. RESULTS: Relatives of probands with the mutation had significantly increased relative risk (RR) of breast cancer. For first degree relatives, the RR was 7.55 (95% CI 6.04 to 9.03) but was 1.72 (95% CI 1.49 to 1.96) in first degree relatives of probands without the mutation. For prostate and ovarian cancer, the first and second degree relatives of probands with the mutation had a significantly increased RR, but in families of probands without the mutation no significant familial risk was found. CONCLUSIONS: The 999del5 mutation in the BRCA2 gene explains a substantial proportion of familial risk of breast cancer in Iceland, but significant familial risk remains in relatives of probands without the mutation. For prostate and ovarian cancer, the mutation accounts for most of the familiality observed in families of breast cancer patients.
BACKGROUND: Stroke is a major cause of illness, death, and health expenditures. Leisure-time physical activity may reduce the risk for stroke. OBJECTIVE: To examine the association of leisure-time physical activity and pulmonary function with risk for stroke. DESIGN: Prospective cohort study. SETTING: Reykjavík, Iceland. PARTICIPANTS: 4484 men 45 to 80 years of age followed for a mean (+/-SD) of 10.6 +/- 3.6 years. MEASUREMENTS: Patients underwent physical examination, blood sampling, and spirometry and completed a questionnaire about health and exercise. Computerized hospital records were used to identify strokes, and the Icelandic National Registry was used to identify deaths. RESULTS: New stroke developed in 249 men (5.6%) (hemorrhagic stroke in 44 [18%] and ischemic stroke in 205 [82%]). In a multivariable hazard analysis that controlled for known risk factors for cerebrovascular disease, leisure-time physical activity maintained after 40 years of age was associated with a reduced risk for stroke (relative risk, 0.69 [CI, 0.47 to 1.01] for total stroke and 0.62 [CI, 0.40 to 0.97] for ischemic stroke). Risk for stroke increased with diminished ventilatory function (FVC or FEV1) (relative risk, 1.9 [CI, 1.06 to 3.25] for the lowest compared with the highest quintile). CONCLUSION: Middle-aged men who participate in leisure-time physical activity and have good pulmonary function seem to have a lower risk for stroke than men who are not active or have diminished pulmonary function.
The Icelandic Cancer Registry has collected 989 pedigrees of breast cancer patients since 1972. In addition to the probands, the families also include 401 other women with breast cancer, so family information exists for 1390 women with breast cancer out of a total of 2748 diagnosed with the disease from 1910 to 1988. Most of the probands have been selected with care to avoid the bias of selecting families with a known history of breast cancer. After excluding all those who did not conform to the strict selection criteria, 947 pedigrees remained for this analysis. First, second, and third degree relatives all had a significantly increased risk of breast cancer: 2.26, 1.43, and 1.49, respectively. Male relatives also had a significantly increased risk, whereas females related by marriage had not. Of the first degree relatives, sisters had the largest increase in risk. When pedigrees were classified by the age at diagnosis of breast cancer of the proband, the risk was highest in the relatives of probands who were young at diagnosis. Bilaterality of breast cancer increased the risk in relatives and the highest risk (9.04) was found in sisters of probands with bilateral disease and an age at diagnosis of first cancer of less than 45 years (95% confidence limits 4.14, 17.18). Sisters consistently have the highest risk, significantly higher than other first degree relatives. This points to an important role of shared environmental aetiological factors acting after birth and it can not yet be excluded that most of the increase in risk can be explained by this.(ABSTRACT TRUNCATED AT 250 WORDS)
Comment In: J Med Genet. 1992 Mar;29(3):152-31552555