Is there a common threshold level above which blood pressure rise tends to accelerate in progression toward hypertension?
This community-based longitudinal cohort study found that, prior to hypertension onset, individuals generally maintained a resting systolic blood pressure of less than 120 to 125 mm Hg. Above this level, resting systolic blood pressure increased at a more rapid rate over time, a consistent trend whether hypertension manifested earlier or later in life.
A resting systolic blood pressure that chronically exceeds approximately 120 to 125 mm Hg tends to signal incipient hypertension, irrespective of age.
Given that hypertension remains a leading risk factor for chronic disease globally, there are substantial ongoing efforts to define the optimal range of blood pressure (BP).
To identify a common threshold level above which BP rise tends to accelerate in progression toward hypertension.
Design, Setting, and Participants
This longitudinal, community-based epidemiological cohort study of adults enrolled in Framingham, Massachusetts, included 1252 participants (mean [SD] age, 35.3 [2.7] years) from the Framingham Original Cohort, of whom 790 (63.1%) were women. Each participant contributed up to 28 serial examinations of standardized resting BP measurements between 1948 and 2005.
Age and systolic BP.
Main Outcomes and Measures
Via a segmented mixed model, we identified significant change points in the association between advancing age and increasing systolic BP among individuals categorized by their age at hypertension onset.
Individuals maintained a relatively stable resting systolic BP level prior to hypertension onset. Systolic BP level began to rise at a more rapid rate after reaching a level of 123.2 mm Hg (95% CI, 122.7-130.1 mm Hg) in people with onset at 40 to 49 years; 122.0 mm Hg (95% CI, 120.3-123.9 mm Hg) in those with onset between 50 and 59 years, 124.9 mm Hg (95% CI, 120.2-127.9 mm Hg) in those with onset between 60 and 69 years, and 120.5 mm Hg (95% CI, 118.0-123.2 mm Hg) in those with onset between 70 and 79 years (P = .29 for between-group heterogeneity).
Conclusions and Relevance
We observed that individuals in the community generally maintained a systolic BP of less than 120 to 125 mm Hg, above which systolic BP increased at a relatively rapid rate toward overt hypertension. This trend was consistent whether the hypertension manifested earlier or later in life. Thus, a resting systolic BP that chronically exceeds the range of approximately 120 to 125 mm Hg may represent an important threshold of underlying vascular remodeling and signal incipient hypertension irrespective of age. Further investigations are needed to unravel the sequence of hemodynamic and vascular changes occurring prior to hypertension onset.
Niiranen TJ, Henglin M, Claggett B, et al. Trajectories of Blood Pressure Elevation Preceding Hypertension OnsetAn Analysis of the Framingham Heart Study Original Cohort. JAMA Cardiol. Published online March 21, 2018. doi:10.1001/jamacardio.2018.0250
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