Secular stroke trends: early life factors and future prospects

Abstract

Stroke mortality rates have declined during the second half of the 20th century in developed countries. Possible reasons for this include preventive measures, recent environmental changes impacting on adult health risks, and more distant environmental influences on childhood health. Data from a number of populations in Europe and the USA suggest that a decrease in early life blood pressure, occurring since the beginning of the 20th century, may have been an important determinant of declining stroke incidence rates and cardiovascular disease mortality in general. Advances in stroke epidemiology are increasing the accuracy of case ascertainment, and neuroimaging refinements (particularly MRI) are improving the accuracy of stroke type and subtype diagnoses. Although some risk factors are common to ischaemic and haemorrhagic stroke, there is accumulating evidence of differing aetiology. There is also an increasing recognition that early life factors may influence stroke risk. Despite the encouraging decline in stroke incidence, there is evidence of a recent increase in mean blood pressure in young people observed in the USA and UK, prompting concern that favourable trends in stroke risk may not be maintained. Reducing early life blood pressure in a population and delaying the onset of hypertension, along with effective measures to combat obesity, are required to avoid a reversal in stroke incidence trends in developed countries, and to prevent the anticipated increase in the burden of stroke in developing countries.