The INTERSALT study: main results, conclusions and some implications.

INTERSALT is an epidemiological study of electrolyte excretion and blood pressure in 10,079 men and women from 52 centres and 32 countries. The data were collected according to strict protocol with extensive quality control, and were analysed both in individuals and across centres. In the individual analysis, with adjustment for confounding variables, significant positive associations were observed between blood pressure and twenty-four hour sodium excretion, body mass index and alcohol intake, and significant negative associations between blood pressure and potassium excretion. For a number of reasons, it is likely that the size of these relationships was underestimated. Across centres, linear slope of blood pressure with age was positively related to median sodium excretion. These observations imply that a policy combining changes in sodium and potassium intake with reductions in obesity and alcohol consumption could bring important public health benefits.