Blood pressure is a quantitative trait with a continuous distribution, and hypertension is defined as the upper part of this curve.
INTRODUCTION Blood pressure (BP) is a quantitative trait with a normal, continuous, bell-shaped (Gaussian) distribution pattern, skewed to the upper end in any general population (Figure 1.1), and hypertension represents a clinical definition of the upper part of the distribution curve. Figure 1.1 shows a distribution curve for diastolic BP plotted using BP measurements in 158,906 individuals aged 30-69 years screened for the Hypertension Detection and Follow-up Program in the United States (1).
A 1968 study studied this question.