Hypertension after Intersalt: prospects for prevention

Special methods of statistical analysis of the Intersalt data permitted a better comparison between populations and between age groups than was previously possible, but these methods led to an exclusive focus on the distribution of blood pressure (BP) rather than on the prevalence of hypertension. Big changes in prevalence that accompany small changes in mean BP were implied but not illustrated. A plot of prevalence against log Na excretion from the tabulated data suggests that a Na excretion rate greater than 100 mmol/day could not be recommended under any circumstances. However, a rate less than 40 mmol/day would be expected to prevent hypertension and to prevent the BP from rising with age. From the intersalt data, an intermediate range of Na excretion of 40-100 or 50-100 mmol/day, which are public health targets in Australia and the United States, respectively, would be expected to be protective in the presence of other aspects of a healthy lifestyle, especially if the K intake preserves the natural Na/K ratio (less than or equal to 1.0).