The Seventh Report of the Joint National Committee on Prevention, Detection, Evaluation, and the Treatment of High Blood Pressure -- the NHLBI JNC 7 Press Conference

Linda Brookes, MSc

May 19, 2003

In This Article

New Classification of Hypertension -- Introducing "Prehypertension"

The main difference in JNC 7 compared with JNC 6 is the new classification of hypertension itself ( Table 1 ). The categories of blood pressure have been reduced to 3: normal, prehypertension, and hypertension. The definition of "normal" in JNC 7 is the same as that previously considered normal, ie, SBP < 120 mm Hg and DBP < 80 mm Hg, while "hypertension" stage 2 in JNC 7 combines stages 2 and 3 from JNC 6.

The new category, prehypertension, is the most significant change in the classification scheme and represents SBP 120-139 mm Hg or DBP 80-89 mm Hg. This class was designated for 2 reasons.

  1. Blood pressure increases steadily with age and most individuals will develop hypertension during their lifetime. For example, the Framingham Heart Study suggested that all people who are normotensive at age 55 years will have a 90% lifetime risk of developing hypertension.[6]

  2. A number of studies have indicated that the mortality rate for MIs, strokes, and other vascular disease increases progressively with a rise in blood pressure levels, starting at levels as low as 115/75 mmHg.[7] This represents a doubling of the risk for cardiovascular mortality for every 20/10-mm Hg rise in blood pressure above this level, Dr. Chobanian explained.

It is estimated that about 22% (approximately 46 million) of the adult population falls into the prehypertension category. It should be emphasized that for these individuals, JNC 7 recommends only lifestyle changes to prevent the development of hypertension. These include weight reduction, exercise, adoption of the Dietary Approaches to Stop Hypertension (DASH) eating plan, salt reduction, and limiting alcohol intake. Quitting smoking is also recommended for overall cardiovascular health.