SeriesPreventing stroke: saving lives around the world
Introduction
Heart disease and stroke are the two leading causes of mortality in adults age 15 years and over, and the third and fourth leading causes of disease burden (as measured in disability-adjusted life years [DALYs]) after HIV/AIDS and unipolar depressive disorders.1 An estimated 5·7 million people died from stroke in 2005. Among adults age 45–69 years, heart disease and stroke are the leading causes of DALYs lost and deaths worldwide.
The burden of chronic, non-communicable diseases, including stroke, has remained stable, at about 85% of the total disease burden, in high-income countries over the past 10 years. However, demographic and epidemiological shifts have resulted in stroke becoming a major health problem in low-income and middle-income countries. Indeed, these countries have experienced a rise in the burden of chronic diseases, to almost 50% of total disease burden over the past decade. This increase can be attributed to population ageing and changes in the distribution of known, modifiable risk factors of cardiovascular diseases. These modifiable risk factors and the ways in which they contribute to premature deaths are known and well documented. They include tobacco use, poor diet leading to people being overweight or obese, raised blood pressure, raised cholesterol, and physical inactivity. A global goal for reducing deaths and burden of disease by an additional 2% annually on projected declines from chronic diseases worldwide has been proposed to inspire increased international effort to prevent chronic diseases.2 If reached, this goal would avert 36 million chronic disease deaths—including those from stroke, heart disease, diabetes, cancers, and chronic respiratory diseases—by 2015. As part of this global goal, about a sixth of the deaths averted would be deaths from stroke.
We propose a specific global goal for reduction of deaths from and burden of stroke as an advocacy tool to communicate the size and scope of the burden of disease that stroke represents worldwide. We quantify the health gains from achieving this goal with global and regional projections of stroke mortality and burden (in DALYs) from 2005 to 2030. We compare the results of the global goal for reducing chronic disease deaths with the outcome that an additional reduction of 2% a year in stroke deaths alone would have on worldwide chronic disease death rates.
In this paper, we first present current and projected stroke mortality and burden of disease for the world, World Bank income groups, and for selected countries, for the period 2005 to 2030. We then assess the mortality reductions and years of life saved from meeting the global goal of an additional 2% reduction each year in stroke death rates, and discuss the feasibility and challenges of meeting this bold goal by 2015.
Section snippets
Global epidemiology and burden of stroke
In recent years, WHO has undertaken a progressive reassessment of the Global Burden of Disease (GBD) for the years 2002–30, with consecutive revisions and updates published annually in WHO World Health Reports.3 These updates draw on a wide range of data sources to develop internally consistent estimates of incidence, severity, duration, and mortality for over 130 major causes, for 14 subregions of the world. The methods used here are generally similar to those of the original GBD study, albeit
Results
We estimate that there were 16 million first-ever strokes and 5·7 million stroke deaths in 2005. In the absence of additional population-wide interventions, these numbers are expected to rise to 18 million first-ever strokes and 6·5 million deaths in 2015, and to 23 million first-ever strokes and 7·8 million deaths by 2030 (table). Although the age-specific death rates are projected to decline slightly between 2005 and 2030, population ageing worldwide will result in an overall increase in
Discussion
We present the mortality and burden of disease projections for stroke using the WHO 2002 mortality estimates as a baseline. These are based on an expanded empirical database compared with the original 1990 GBD study, with the incorporation of much new data and a greater understanding of the limitations of routinely available datasets. Even so, there is substantial uncertainty about the comparative burden of diseases and injuries in many parts of the world. In particular, for regions with
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