Among all risk factors for stroke, hypertension is the main culprit. Patients with hypertension have 4-6 times the risk of developing stroke than those without hypertension. Roughly one-third of adults in the United States, or 50,000,000 people (40-70% of whom are 65 years of age or older), have hypertension. 40-90% of the stroke population has a history of hypertension prior to a stroke. Sustained blood pressure above 140/90 mmHg is diagnosed as hypertension. In the hypertensive population, the degree of effect of hypertension on stroke decreases with age, so that factors other than hypertension have a greater effect on stroke occurrence in the elderly. In people without a history of hypertension, the risk of stroke increases with age until the age of 90 years and is not comparable to that of people with hypertension until the age of 90 years. Just like stroke, there are gender differences in the occurrence of hypertension. In younger people, men have hypertension at a higher rate than women. As they get older, more women are instead more likely to develop hypertension than men. This sex-age difference in hypertension may affect the occurrence of stroke in this population. The use of antihypertensive drugs may reduce the risk of stroke in people. Recent studies have shown that antihypertensive treatment can reduce the incidence of stroke by 38% and reduce stroke mortality by 40%. Common hypertension treatment drugs include angiotensin-converting enzyme inhibitors (ACEI), angiotensin receptor blockers (ARB), calcium antagonists, beta-blockers, and diuretics.