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.