Blood pressure increases more swiftly above thresholds within ‘normal range’
A resting systolic blood pressure above 120 to 125 millimeters of mercury was associated with a more rapid increase toward full-on hypertension, according to an analysis of the Framingham Heart Study published in JAMA Cardiology.
The researchers noted this trend was consistent for the entire cohort, but the threshold was slightly different at various ages. Hypertension onset was defined as exceeding 140/90 mm Hg or extended use of antihypertensive medication.
People who developed hypertension in their 40s showed a rapid increase in systolic blood pressure above an average level of 123.2 mm Hg. The threshold was 122.0 mm Hg for those with hypertension onset in their 50s, 124.9 mm Hg for onset in their 60s and 120.5 mm Hg for onset in their 70s.
“Systolic BP levels are generally stable until they approach approximately 120 to 125 mm Hg, after which systolic BP rises at a relatively rapid rate toward overt hypertension,” wrote lead author Teemu J. Niiranen, MD, and colleagues. “This transitional systolic BP range was consistent whether hypertension developed in middle age or older age and could represent a critical threshold of extant vascular remodeling. Interestingly, this systolic BP range is concordant with recently published guidelines advocating use of the 130 mm Hg value for defining presence of hypertension.”
The analysis included 1,252 people—mean age 35.3 at baseline; 63.1 percent women—who were among the first generation of participants in the Framingham Heart Study. They each had their blood pressures checked approximately every two years between 1948 and 2005, allowing for precise estimates of long-term BP trajectories, the authors noted.
Niiranen and colleagues acknowledged individual blood pressure paths could vary substantially more than the group averages. But they believe these findings suggest it could be useful to treat blood pressure levels earlier—before a patient reaches the new, lower barrier for hypertension.
“Further investigations are still needed to unravel the sequence of hemodynamic and vascular changes occurring before hypertension onset,” they wrote. “In addition, investigation is needed to determine the potential benefit of interventions aimed at preventing the onset of systolic BP rise, even within the normal systolic BP range, as part of efforts to reduce the overall burden of hypertension.”
Daniel joined TriMed’s Chicago editorial team in 2017 as a Cardiovascular Business writer. He previously worked as a writer for daily newspapers in North Dakota and Indiana.