Biomedical subjects

O Bjarnason

Publications and source records attributed to O Bjarnason.

At least 37 records · Page 2Linked to original sources

PubMed1978

Reproductive factors and risk for breast cancer in Iceland.

A previous publication has shown that there has been a great increase in the incidence of breast cancer in Iceland. The present study was undertaken to evaluate the importance of known risk factors connected with the reroductive history of the women. In a prospective investigation of a cohort of 31,453 women we confirmed previous findings of the increased risk following higher age at first pregnancy and for nulliparous women. The age at first pregnancy and the proportion of nulliparous women have decreased with time in the Icelandic population so that these factors should have tended to decrease the risk, making the found increase still more important. The effect of parity is that the risk decreases with larger number of children and this effect is independent of the effect of age at first pregnancy. Lower age at menarche increases the breast cancer risk, but the contribution of that factor to the overall risk is negligible.

Adult↗

PubMed1978

Observer variation in histologic classification of thyroid cancer.

Histologic slides of 696 cases of thyroid cancer reported to the national cancer registries of Finland, Iceland, Norway and Sweden were reviewed by 5 Nordic pathologists in order to determine the observer variation between the pathologists, as well as the reproducibility of the WHO classification of thyroid tumours. In 58% of the cases all observers agreed upon the diagnosis and in 82% at least three of them agreed. The observer disagreement was lowest for papillary carcinoma (7%) and highest for follicular carcinoma (27%). The corresponding figures for anaplastic and medullary carcinomas were 18% and 23%, respectively. The most common diverging diagnosis for cases finally interpreted as papillary carcinoma was follicular carcinoma, and for cases finally interpreted as follicular carcinoma, a benign thyroid lesion. The results of the present study clearly indicate the necessity of having all cases reviewed by the same pathologist or group of pathologists in order to obtain reliable results for comparative studies.

Adenocarcinoma↗

PubMed1978

A prospective comparative study of clinical and pathological characteristics in Icelandic and Danish patients with gastric ulcer, duodenal ulcer, and X-ray negative dyspepsia. II. Histological results.

The occurrence of gastritis in antral and body mucosa is compared in an Icelandic and a Danish group of patients with gastric ulcer, duodenal ulcer, and X-ray negative dyspepsia. In all 93 Icelandic and 88 Danish patients were examined. All signs of antral gastritis were more frequent in Icelandic than in Danish patients, but only the incidence of superficial inflammation and decreased mucus content in surface and crypt epithelium differed significantly. In body mucosa pseudopyloric metaplasia was more frequent in Iceland and occurred equally freqeuntly in all three diseases. A statistically significant correlation was found between macroscopic gastritis and occurrence of antral superficial inflammation and between smoking and superficial inflammation and decreased mucus content in the pyloric biopsy specimen. The presence of histological gastritis was not correlated to the intake of alcohol and salicylic acid, nor to the presence of pain at the time of investigation.

Adult↗

PubMed1977

Thyroid cancer in an iodide rich area: a histopathological study.

A comparison of the incidence of the different histological types of thyroid carcinoma in an area of high dietary iodide and an area of normal iodide intake has been made. The areas chosen were Iceland and the region of Northeast Scotland centred on Aberdeen; both areas have clearly defined populations served by a single pathology laboratory. All definite and dubious thyroid carcinomas from both regions were examined and classified by the same two pathologists. The age-specific incidence rates for papillary carcinoma in surgical specimens in both areas rose with age; they were five times higher in Iceland (high iodide area) than in Northeast Scotland. The numbers of follicular carcinomas were small, and this tumor was relatively less frequent in Iceland than Aberdeen. These findings, together with the known high relative frequency of follicular carcinoma and low frequency of papillary carcinoma in areas of endemic goitre, lead to the suggestion that the incidence of papillary carcinoma and follicular carcinoma are separately influenced by dietary iodide, papillary carcinoma being high in areas of high iodide intake and low in areas with low dietary iodide. No evidence to implicate lymphocytic thyroiditis, radiation or genetic factors in the genesis of thyroid carcinoma in Iceland or Northeast Scotland was found in this study. Undifferentiated carcinoma was about three times as common in Iceland as in Northeast Scotland. Malignant lymphoma of the thyroid was suprisingly common in Northeast Scotland, possibly related to the high frequency of thyroiditis found in this region. These studies suggest that the incidence of different histological types of thyroid malignancy is influenced by different etiological factors. They also provide support for the subdivision of thyroid malignancy into these different types, and for the general importance of accurate histological typing in cancer epidemiology.

Adenocarcinoma↗

PubMed1977

A prospective comparative study of clinical and histological characteristics in Icelandic and Danish patients with gastric ulcer, duodenal ulcer, and X-ray negative dyspepsia. I. Design and clinical features.

Iceland (IS) and Denmark (DK) are ethnically, culturally, and economically closely related Nordic countries, but gastric cancer is much more frequent in Iceland, and other differences in the occurrence rates of gastric diseases are also suspected. Therefore a cooperative study was initiated comparing Icelandic and Danish patients with gastric ulcer (GU), duodenal ulcer (DU), and X-ray negative dyspepsia (XND) as regards clinical features, external factors of possible importance for gastritis and cancer, gastroscopic appearance, and histological gastric mucosal changes. The project lasted one year and comprised 93 Icelandic and 88 Danish patients. A large number of comparisons showed a high degree of similarity between Icelandic and Danish patients. Significant differences were found in tobacco consumption (DK greater than IS), duration of symptoms in XND (IS greater than DK), whereas the positon ratio of GU (IS less than DK) and acetylsalicylic acid consumption (DK greater than IS) showed non-significant trends. Significant difference was found between the occurrence of diffuse macroscopic changes of the gastric mucosa (IS greater than DK), which corresponds to the histological differences to be described in a subsequent article.

Adolescent↗

PubMed1974