Ischemic heart disease in Kiruna risk factors and sequelae

Abstract: Kiruna, a Swedish community situated 300 km north of the Arctic Circle, has a very high mortality in ischemic heart disease (IHD). Acase-control study was undertaken to find out if the risk factors for IHD or their impact differed from those in other populations. The survey methods comprised questionnaires, physical examinations, laboratory tests, a food diary, ecological studies, and a register study. The study group consisted of 219 men who had suffered an acute myocardial infarction (cases) and 438 men without known ischemic heart disease (controls).The main risk factors were: a family history of IHD, hypertension, hyperlipidemia, diabetes mellitus, and smoking. Also psycho-social risk factors like lack of job support constituted a risk factor.Cholesterol ester and adipose tissue triglyceride fatty acids have a slower turn-over rate than other routinely analysed lipids and lipoproteins and thus reflect dietary habits over a longer period of time. They were measured in a subset of our cohort, showing that the cases, judged from lipid and fatty acid composition, lived on a diet comparable to that of the controls. A prospective diet diary showed few differences between cases and controls and between the whole cohort and a reference cohort in Uppsala in the central part of Sweden. Most notable differences were a low level of y-tocopherol, a low proportion of linoleic acid, and a high proportion of palmitic acid in serum cholesterol esters and adipose tissue triglycerides in the Kiruna cohort.The expected reduced morbidity in ischemic heart disease related to alcohol consumption was not seen in our material. This finding was further examined in an ecological study on a national Swedish level, longitudinally, cross-sectionally, and with time-series methodology. There was an inverse correlation between wine consumption and mortality in IHD for women but no correlation between the consumption of beer and distilled spirits, and mortality in IHD.Heart failure, a common sequela of IHD, has an increasing incidence in a hospital-based population. In spite of improved treatments the prognosis has not improved during the last seven years and is still as bad as or worse than that of many malignant diseases. Male sex and high age implied a worse prognosis.Consumption of acetylsalicylic acid (ASA) for pain relief resulted in a greater risk of developing an acute myocardial infarction in our cohort. This was further examined in an ecological study on anational Swedish level also showing a correlation between ASA consumption and mortality in IHD both in the geographical and the longitudinal analysis for the surveyed years, but not in the time series analysis.