In a study presented here at the American Stroke Association (ASA) International Stroke Conference 2008, investigators from the Erasmus Medical Center, in Rotterdam, the Netherlands, found that American men had 61% higher odds of having a stroke than European men.
Furthermore, women in the United States had a 2-fold increased stroke risk compared with European women.
According to principal investigator Mauricio Avendano, PhD, much of the gap in stroke prevalence between the United States and European populations is accounted for by poor Americans, who were much more likely to have a stroke than poor Europeans.
"African Americans have a higher prevalence of stroke than [individuals] in any of the Western Europeans and within the United States. But Americans, even those in the highest socioeconomic group, have a higher prevalence of stroke overall, so there seems to be a generalized pattern of higher prevalence among Americans vs Europeans," he said.
Survival Effect Unlikely
It is not clear from the study whether the difference in stroke prevalence rates are a reflection of better stroke prevention in Europe or better stroke treatment in the United States. However, Dr. Avendano said, the difference is unlikely to be driven by a survival effect.
"You would not expect poor Americans, many of whom do not have access to healthcare, to have better survival than poor Europeans, who have universal health coverage," he told Medscape Neurology & Neurosurgery.
The researchers also found regional variations in stroke prevalence within Europe. Populations in Northern European countries such as Denmark and Sweden had relatively high rates that were lower than, but more comparable to, stroke prevalence rates in American whites. Central Europeans, such as the Dutch, Germans, and Austrians, had middling stroke rates; and Southern Europeans — Italians, Greeks, and Spaniards — had the lowest stroke prevalence.
While stroke mortality between countries has been well studied, said Dr. Avendano, there has been no research examining cross-national variations in stroke prevalence.
"There are many differences between Europe and the United States in terms of the prevalence of preventable risk factors for stroke but also in the approach to disease prevention and treatment, and we wanted to look at these differences and their potential impact on stroke," said Dr. Avendano.
Prevention vs Treatment
Using demographic data from the 2004 US Health and Retirement Survey (HRS), the Survey of Health Aging and Retirement in Europe (SHARE), and the English Longitudinal Study of Aging (ELSA), the study included information on 43,787 individuals aged 50 years or older from the United States and 11 Western European countries.
The analysis included stroke occurrence, socioeconomic status, and major risk factors for stroke, including obesity, diabetes, smoking, physical activity, and alcohol consumption.
Adjusted analyses for these risk factors narrowed the gap in prevalence rates between Europe and the United States but did not fully explain the difference, said Dr. Avendano.
However, he added, the risk-factor analysis is not quite complete, and there is a possibility that there are other risk factors that may explain these differences.
The other possibility, he said, is that differences in stroke prevalence rates between the United States and Europe are being driven by policies, including healthcare access, which is universal in Europe but not in the United States. Furthermore, the preventive orientation of someEuropean systems vs the treatment focus of the US healthcare system may also play a role.
Something Is Wrong
Commenting on the study, Philip Gorelick, MD, from the University of Illinois College of Medicine, in Chicago, and spokesperson for the ASA, said that differences in the European and American approaches to provision of healthcare are a likely explanation.
"This gets back to an old issue that in the United States we spend an extraordinary amount of money per capita on healthcare, yet we rank very poorly with respect to our stroke rates. Our system is great at taking care of emergencies, but if you look at health indices and rates of major illnesses, they are still very high, so there's got to be something wrong," Dr. Gorelick told Medscape Neurology & Neurosurgery.
Dr. Gorelick added that this study highlights the need to intensify risk-factor control and address the issue of providing healthcare to the estimated 48 to 60 million Americans who are uninsured and have little, if any, access to health services.
The study was funded by the European Commission, the National Institute on Aging, and the UK government. The authors have no disclosures related to the study.
American Stroke Association International Stroke Conference 2008: Abstract 120. Presented February 21, 2008.
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Cite this: Caroline Cassels . Stroke Prevalence Higher in the United States Than in Europe - Medscape - Feb 28, 2008.