Good Physical Function Halves Stroke Risk
MONDAY Dec. 10, 2007 -- Being in good physical form appears to protect middle-aged and older men and women from stroke, a new British study suggests.
The finding highlights an apparent association -- rather than a direct cause-and-effect -- between the physical ability to function well and a reduced risk for stroke.
After sifting through thousands of quality-of-life reports provided by patients themselves, the research team found that those functioning at the higher end of the physical capacity spectrum appear to have half the risk for stroke as their poorest functioning compatriots, independent of other risk factors.
"We were surprised at the magnitude of the relationship, as this is comparable to established stroke risk factors such as smoking," noted study author Dr. Phyo Kyaw Myint, who works with the Clinical Gerontology Unit at Addenbrooke's University Hospital in Cambridge.
The findings are published in the Dec. 11 issue of Neurology.
Myint and his colleagues uncovered an apparent stroke-physical function connection by analyzing data concerning more than 13,600 British men and women between the ages of 40 and 79.
All the participants first completed a health examination and questionnaire between 1993 and 1997. At that time, patient blood pressure, body-mass index, respiratory capacity, and cholesterol levels were assessed. Researchers also noted any history of diabetes, smoking and alcohol consumption.
None of the patients had experienced any incidence of cancer, stroke or heart attack before their initial exam.
Eighteen months after the initial exam, patients completed a follow-up questionnaire by mail, in which patients were asked to indicate their degree of physical and social functioning; their mental health status; any physical and/or emotional limitations on carrying out routines; energy levels; experiences of pain; and self-perceptions regarding their overall health.
All participants were followed until 2005, by which point 244 strokes were recorded.
The researchers found that those men and women who reported better physical function had a considerably lower risk for stroke.
After adjusting for all other observed characteristics -- including gender and age -- Myint and his team found that patients in the top quarter of physical function capacity had half the risk of stroke when compared with patients in the lowest quarter of physical function.
The authors concluded that poor physical function could indicate a high risk for stroke, thereby highlighting a specific segment of the general population that could derive particular benefit from some form of intervention.
Myint stressed, however, that to date his team has simply conducted a hands-off review of patient self-reports regarding their physical capacity and lined those reports up against stroke incidence records. At no time were patients assessed for their ability to follow a prescribed physical activity routine of varying intensities and durations.
He cautioned against leaping to the notion that greater physical function or activity directly causes a drop in the risk for stroke.
"We don't know whether physical function per se is causally related to stroke or simply a good marker for other factors that influence stroke risk," Myint noted. "These findings need confirmation from other studies. However, there is already a substantial body of evidence for public health recommendations to increase physical activity."
In the meantime, Alice H. Lichtenstein, director of the Cardiovascular Nutrition Lab at Tufts University in Boston, said that people should not sit idly by while investigators continue to unravel the complex web of factors related to stroke risk.
"This study does not show causation, but clearly, individuals who follow current guidelines for decreasing risk for stroke and general cardiovascular risk -- including keeping physically active -- have better outcomes," she said. "So, in terms of both physical function and activity, what people need to try to do is go from where they are to more."
"For some people, doing more may literally mean just walking around the block once, or picking up the pace, or adding extra time moving," said Lichtenstein. "For others, it can even be something like doing the housecleaning. And it can be cumulative: 10 minutes at one point, 10 minutes at another. Because although we'd like everyone to set aside special time just for physical activity every day, we know that for a lot of people, it's just not going to happen. So, any increase is going in the right direction, and that should be the goal."
This week, the American Society for Nutrition is poised to issue a new set of national recommendations regarding both physical activity and nutrition.
The recommendations are described as "comprehensive, scientific guidelines on physical activity for all Americans." According to the U.S. Department of Health and Human Services, the guidelines will gather together the latest knowledge on both healthy eating and regular physical activity.
To learn about stroke risk, visit the American Heart Association.
Posted: December 2007