As many as 18 percent of adults who have no history of stroke report having had at least one symptom of stroke, according to results of a large national study published in the October 9 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Using brain imaging to screen individuals without a history of stroke reveals that many have had an undiagnosed or silent stroke, according to background information in the article. One previous study found that 11 percent of individuals age 55 to 64, 22 percent of those ages 65 to 69 and 43 percent of those older than 85 years show evidence of stroke despite never having been diagnosed with the condition. Because awareness of stroke symptoms is low, it is possible that these individuals had symptoms but did not recognize them or that the symptoms did not reach the threshold necessary for a stroke diagnosis.

Virginia J. Howard, M.S.P.H., of the University of Alabama at Birmingham, and colleagues analyzed data from the REasons for Geographic and Racial Differences in Stroke (REGARDS) study, a random sample of 18,462 adults older than 45 years (average age 65.8) who had not been diagnosed with stroke. To ensure including many individuals at risk for stroke, the researchers included 7,567 African Americans (41 percent of the total sample, a higher ratio than in the general population) and 6,534 (35.4 percent of the sample) residents of the so-called “stroke belt,” which includes eight Southeastern states with increased rates of stroke.

In telephone interviews, participants provided information about demographics, general quality of life and medical history, including whether a physician had ever told them they had a stroke and whether they had experienced the sudden onset of any of six stroke symptoms. Brief physical examinations were conducted three to four weeks later. A stroke risk score was calculated for each individual based on demographics, behaviors and other risk factors, with higher scores indicating a greater risk for stroke.

A total of 3,292 (17.8 percent) of the participants reported having had one or more stroke symptoms. Eight and one-half percent reported sudden numbness on one side of the body; 5.8 percent sudden weakness on one side of the body; 4.6 percent sudden vision loss in one or both eyes; 2.7 percent sudden loss of the ability to understand what others were saying; and 3.8 percent suddenly could not express themselves in speech or writing.

African Americans and those with lower incomes, less education, poorer health status and higher stroke risk scores were more likely to have had stroke symptoms. “The last finding suggests that at least some of these symptoms may represent stroke events that did not reach the threshold required for clinical diagnosis,” the authors write. “These undiagnosed or unrecognized events could have a substantial impact on cognitive functioning or personality and could also be powerful harbingers of subsequent major strokes.”

It is not known whether these individuals visited a physician for their symptoms, but previous studies have shown that many people do not seek medical care for stroke symptoms and if they do, they do not seek it immediately. “Targeted education on the warning signs of stroke and risk factor reduction efforts for individuals who report stroke symptoms may be helpful in improving early recognition and in the prevention of stroke,” the authors conclude.

Source: American Medical Association (AMA)