Blood pressure and sodium-lithium countertransport: findings in population-based surveys.

A total of 448 individuals ranging in age from 11 to 72 years were studied in a series of seven population-based surveys. Although the relationship was positive in all surveys, a significant correlation was noted between sodium-lithium countertransport and blood pressure in only three of the seven. Hypertensives as a group had significantly higher levels of countertransport than did those with a normal blood pressure. In stepwise regression analysis, however, entering weight into the equation eliminated a significant predictive effect of countertransport. Red cell sodium concentration and membrane leak did not bear any significant relationship to blood pressure. The association between countertransport and blood pressure appears to be weaker in the general population than previously reported for case-control studies.