INTERSALT in Italy: findings and community health implications

In INTERSALT, an international cooperative study on electrolytes and blood pressure, significant associations were found, in the pooled data for 52 centres, between systolic BP and sodium (Na) excretion, body mass index (BMI), high alcohol intake and low potassium (K) excretion. We have assessed the status of the four Italian centres (Mirano, Gubbio, Bassiano, Naples) on these variables. The four centres examined a total of 794 men and women aged 20-59 years. Combined values were similar to overall INTERSALT levels for daily Na excretion (170 mmol) and BMI (25 kg/m2). The Italian centres had slightly higher potassium excretions (57 vs. 55 mmol/day), a higher prevalence of drinkers and a greater average alcohol consumption. Participants were divided into those below or above median levels of Na, K, BMI, and by alcohol intake (below or above 300 ml/week). Both systolic BP and diastolic BP were found to be lower in the more favourable stratum, for each variable. When all four factors were combined, those below median Na excretion and BMI, above median K, and with alcohol intake less than 300 ml/week had age-adjusted systolic BP 7.5 mmHg lower than those with less favourable levels of all four variables. The difference in adjusted diastolic BP was 4.3 mmHg. The data indicate the potential for lower population average BP with improved lifestyles.