Community-based prevention of hypertension in North Karelia, Finland.

A model programme for hypertension control in the community has been implemented in North Karelia, Finland, since 1972. The treatment status of the patients was improved and blood pressure levels were reduced during 1972 to 1977. This improvement started to level off during 1977 to 1982, although more than 10% of the population aged 35-64 years were treated with antihypertensive drugs. Several analyses were done to find out which dietary factors contributed to the blood pressure level and to its change in the community. The study material consisted of random samples of the population aged 30-59 years in two counties in Eastern Finland, who participated in the surveys in 1972, 1977 and 1982. The analyses confirmed that high BMI, high fat intake, alcohol drinking and high Na intake were associated significantly with blood pressure and also with its change both in the general population and in hypertensive persons. The high levels of these nutritional factors were also associated with unsatisfactory outcome of drug treatment in the hypertensive patients. Thus, it is likely that nutritional changes that can reduce the levels of BMI, the intake of fat, alcohol, and Na would contribute significantly both to primary prevention and to the effective treatment of elevated blood pressure in the community. In Eastern Finland the levels of alcohol intake have increased both in men and women, BMI increased in men and decreased in women and serum cholesterol levels dropped both in men and women between 1972 to 1982. The results of a community-based programme to reduce salt intake in North Karelia from 1979 to 1982 confirmed that Na intake level is high in Finland. The North Karelia Salt Project showed that it is difficult to reduce salt intake at the community level during a three-year period. A slight reduction in Na intake was seen only in women both in North Karelia and in the reference area. In men Na intake did not decrease. In conclusion our results suggest that primary prevention of hypertension at the community level is not easy and that a well conceived programme for a relatively long time period is needed.