The current systolic blood-pressure threshold for
hypertension treatment is 140 mm Hg for all adults. WHO
and the International Society of Hypertension have proposed
that normal pressure be lower than 130 mm Hg, with an
optimum pressure of less than 120 mm Hg. These
recommendations are based largely on the assumption that
cardiovascular and overall mortality depend in a strictly
increasing manner on systolic blood pressure. The
Framingham study was instrumental in establishing this
viewpoint. We reassessed data from that study to find out
whether the relation is strictly increasing or whether there is
a threshold in this relation.