Extract from a letter from Dr James McCormick and Dr Peter Skrabanek
NORTH KARELIA PROJECT
At the beginning of the 1970s, Finland was reputed to have the highest mortality from coronary heart disease in the world and, within Finland, the province of North Karelia had the highest mortality. The majority of the Karelians live in the countryside, have physically demanding jobs (farming and forestry), and very few are overweight. The chief risk markers in North Karelia were thought to be smoking hypercholesterolaemia and hypertension. A community-based intervention program was started in 1972 and its main emphasis was on reducing these three risk markers. The effectiveness of this program was assessed by comparing CHD mortality in North Karelia with that in the neighbouring province of Kuopio. Table III summarises the changes in CHD mortality and overall mortality between 1970/71;
immediately before the program began, and 1976/77, for both sexes, in North Karelia and in Kuopio.
Perhaps surprisingly, larger percentage reductions were observed in Kuopio—where there was no change in the average number of cigarettes smoked per day, no change in plasma cholesterol, and no change in mean blood pressure—than in North Karelia, in which it was claimed there had been a significant reduction in risk markers. Also unexplained is the observation that women in Kuopio and North Karelia had a larger relative reduction in mortality from coronary heart disease than men, although the reduction in risk markers in women was generally negligible or non-existent. At the end of 1977, North Karelians still had the highest mortality from coronary heart disease in Finland. This project, much quoted as incontrovertible evidence of the benefits of intervention, has failed to demonstrate any benefit—a reality which has lately been discussed by one of the principal investigators.