Feb. 22, 2008 (New Orleans) -- Stroke is more prevalent in the United States than in Europe -- and higher rates of obesity, diabetes, and lifetime smoking in the U.S. play a major role, researchers report.
Barriers to care in the U.S. -- chiefly a lack of universal health care coverage and minimal focus on prevention -- also contribute to its higher prevalence of stroke, says study head Mauricio Avendano, PhD, a research fellow in public health at the Erasmus Medical Center in Rotterdam, Netherlands.
The researchers looked at what is known as stroke prevalence -- the number of people who have a disease at any given point in time.
Compared with European men, American men had a 61% higher chance of having had a stroke in their lifetime, Avendano says. U.S. women had almost twice the odds of having had a stroke as European women.
"Most of this gap is among relatively poor Americans who were, in our data, much more likely to have a stroke than poor Europeans, whereas the gap in stroke prevalence is less marked between rich Americans and rich Europeans," Avendano says.
The study was presented at the American Stroke Association's (ASA) International Stroke Conference 2008.
Stroke Deaths Down in U.S.
ASA spokesman Larry Goldstein, MD, a stroke expert at Duke University in Durham, N.C., says looking at stroke prevalence may give a blurred snapshot of what's going on the U.S.
That's because prevalence goes up as the chance of dying of a disease goes down. "If everyone has a disease and everyone survives, then prevalence is 100%," he tells WebMD.
The fact that the U.S. has made great strides in reducing deaths due to stroke -- there's been a 25% drop in recent years -- may play a role in its higher prevalence, Goldstein says.
That said, "there are a lot of data linking lower socioeconomic status and lack of access of care to a variety of ill health effects, including stroke," he says.
African-Americans Have Highest Stroke Odds
The researchers analyzed 2004 data from the U.S. Health and Retirement Survey (HRS); the Survey of Health, Aging and Retirement in Europe (SHARE); and the English Longitudinal Study of Aging (ELSA). These surveys include twice-yearly interviews among people age 50 and older.
Altogether, there were data on 13,667 people in the U.S. and 30,120 individuals in 11 European countries.
Among the findings:
- Overall, women were about 25% less likely to have had a stroke, on average, than men.
- When age was taken into account, stroke was most prevalent in the U.S. and least prevalent in the southern Mediterranean European countries of Spain, Italy and Greece, as well as Switzerland.
- African-Americans had the highest odds of having a stroke of any group studied -- they were nearly three times more likely to have had a stroke in their lifetime than "other Americans," the dubious winner of the second-place prize.
- In the U.S., stroke prevalence is higher in the southern and western states.
Within Europe, "there was a north-south gradient, with the northern countries, especially Denmark and Sweden, having the highest prevalence of stroke," Avendano says.
Avendano says that while rates of lifetime smoking are higher in the U.S. than in Europe, "the proportion of current smokers is lower in the U.S. So going forward we could see a positive effect of that trend."