According to World Health Organization, worldwide, high blood pressure is estimated to cause 7.5 million deaths, about 12.8% of the total of all deaths. This accounts for 57 million disability adjusted life years (DALYS) or 3.7% of total DALYS. High blood pressure is a major risk factor for coronary heart disease and ischemic as well as hemorrhagic stroke. Blood pressure levels have been shown to be positively and continuously related to the risk for stroke and coronary heart disease. In some age groups, the risk of cardiovascular disease doubles for each increment of 20/10 milimeters of mercury (mmHg) of blood pressure, starting as low as 115/75 mmHg. In addition to coronary heart diseases and stroke, complications of high blood pressure include heart failure, peripheral vascular disease, renal impairment, retinal hemorrhage and visual impairment. Treating systolic blood pressure and diastolic blood pressure until they are less than 140/90 mmHg is associated with a reduction in cardiovascular complications.
Globally, the overall prevalence of high blood pressure in adults aged 25 and over was around 40% in 2008. The proportion of the world’s population with high blood pressure, or uncontrolled hypertension, fell modestly between 1980 and 2008. However, because of population growth and ageing, the number of people with uncontrolled hypertension rose from 600 million in 1980 to nearly 1 billion in 2008.
Across the WHO regions, the prevalence of high blood pressure was highest in Africa, where it was 46% for both sexes combined. Both men and women have high rates of high blood pressure in the Africa region, with prevalence rates over 40%. The lowest prevalence of high blood pressure was in the WHO Region of the Americas at 35% for both sexes. Men in this region had higher prevalence than women (39% for men and 32% for women). In all WHO regions, men have slightly higher prevalence of high blood pressure than women. This difference was only statistically significant in the Americas and Europe.