While hypertension can, in some cases, be caused by an underlying disease like kidney disease, most people have what is known as primary hypertension, which develops over many years. The most common sign of high blood pressure is atherosclerosis or hardening of the arteries. In this condition, sticky plaques cling to the interior walls of vessels, making it more difficult for blood to circulate and narrowing the vessel opening. Atherosclerosis is associated with high cholesterol, and it occurs much more commonly with age.