Knowing blood pressure patterns from middle age onward could help doctors better assess health risks and develop interventions to prevent stroke and other diseases, according to new research in the American Heart Association journal Hypertension.

“We already know that high blood pressure is the biggest risk factor for stroke, and that in people 50 to 75 it can change in a couple years’ time,” said M. Arfan Ikram, M.D., Ph.D, senior study author and associate professor of neuroepidemiology at Erasmus University Medical Center in Rotterdam, the Netherlands. “Yet, most studies looking at the relationship between high blood pressure and stroke have relied on a blood pressure measurement at a single point in time, rather than looking at the course of blood pressure and stroke risk.”

For the study, Dutch researchers tracked the systolic (top number) blood pressure of 6,745 people 55 to 106 years old living in a suburb of Rotterdam, the Netherlands for more than two decades and identified four blood pressure trajectories:

  • Class 1 experienced gradually increasing blood pressure from normal systolic blood pressure (120 mm Hg) in middle age to high systolic blood pressure (160 mm Hg) at age 95. Class 1 was the most common trajectory.
  • Class 2 began with normal blood pressure in middle age, but experienced a steep increase to very high systolic blood pressure (200 mm Hg) over the same time period.
  • Class 3 had moderate high systolic blood pressure (140 mm Hg) in middle age that didn’t change much over time.
  • Class 4 had high systolic blood pressure (160 mm Hg) in middle age, but their blood pressure decreased after age 65. Class 4 were more frequently men who more often used medication.

The study accounted for blood pressure-lowering medications, smoking, alcohol use, body weight and other factors that might affect results. After adjustments, researchers found:

  • Those whose blood pressure climbed steeply with time (Class 2) and those with high blood pressure that decreased after age 65 (Class 4) had the highest risk of stroke and dying from non-stroke diseases up to age 80.
  • People with moderately high blood pressure at mid-life and throughout (Class 3) had the highest risk of stroke, but their risk of dying from non-stroke events, along with those in Class 1, was the lowest.
  • Those with normal baseline and gradually increasing blood pressure from borderline-high to high (Class 1) had the lowest risk of stroke and a low risk of death for non-stroke events.

“Blood pressure should be measured regularly because it can change markedly over a couple years and put you at high risk for an adverse event, Ikram said. “Since the risk of stroke and death differ across these trajectory paths, they are potentially important for preventive strategies.”