Blood pressure and stroke in an elderly English population.

The relation between blood pressure and subsequent stroke was examined in a four-year follow-up study of a geographically defined population sample of 2704 people aged 65 and over resident in South Tyneside in 1975. In men there was a significant relation between stroke and a history of diagnosed high blood pressure and the taking of antihypertensive medication. Stroke was not associated with either of these factors in women. Stroke incidence increased with blood pressure in men, more consistently with systolic than with diastolic pressure, but neither systolic nor diastolic pressure was related to stroke in women. In the population studied there seems little scope for the primary prevention of stroke in elderly women by detection and treatment of hypertension. Screening for the top quartile of blood pressure in men would have a sensitivity of 30% and a predictive value of 5% for stroke in the next four years. However, the extrapolation of epidemiological findings from one region or period to another may be expected to be less appropriate for the elderly than for younger people.