Hypertension as a Cardiovascular Risk Factor
It has long been recognized that elevated blood pressure is a risk factor for future cardiovascular events and that lowering it may save lives.
The relationship is strong, continuous and graded without any distinct threshold level; it is present, in both men and women, in younger and older adults and in those with and without known coronary heart disease; it is present in different countries and in different ethnic and racial groups.
Hypertension is also a risk marker for other cardiovascular risk factors (dyslipidemia, diabetes, obesity etc), which generally tend to cluster with hypertension.
In the presence of these other risk factors, there is a steeper relation between levels of blood pressure elevation and cardiovascular morbidity and mortality.
There is evidence of the age-related increase in blood pressure throughout adulthood, so that even persons who are normotensive at age 55 have a 90% lifetime risk from developing hypertension.
However, the rate of age-related rise in blood pressure varies greatly between individuals.
Age related tracking of increased blood pressure over time in an individual in relation to his or her peer.
There is evidence of disparate rather than parallel tracking of blood pressure, whereby an individual in the upper percentile of blood pressure will have a much steeper age-related increase in blood pressure than one in the lower percentile of blood pressure.
This is referred to as the “horse racing effect,” there being a close correlation between the speed of the horse and its position on the race.
Labiltiy of blood pressure, defined as large random variations of blood pressure measurements from one visits to the next, is directly related to aging and to the severity of blood pressure, suggesting that labile blood pressure is associated with increased risk.
However, when other risk factors are accounted for by multivariate analysis, risk is largely unaffected by lability of blood pressure.
It is the average blood pressure over the day and night cycle, no lability that determines cardiovascular risk.
Hypertension as a Cardiovascular Risk Factor
