A rise in blood pressure is not an inevitable consequence of aging. In some societies blood pressure remains at about 110/70 mm Hg throughout life.1 2 Dietary salt, low dietary potassium, alcohol, and body weight contribute to the increase in blood pressure with age in Western countries. The Intersalt study quantifies the effect of each of these factors while allowing for the others.1

The new Intersalt paper is a valuable addition to the evidence on salt and blood pressure.3 In the original Intersalt paper the different analyses on sodium and blood pressure varied, some suggesting a strong association, others a weaker one.1 Now the position has been clarified; all the Intersalt analyses confirm salt as an important determinant of blood pressure. The average increase in blood pressure with age (from 25 to 55 years) was greater in centres with higher sodium intake, by 10 mm Hg systolic for a 100 mmol/day higher …