TUESDAY, Jan. 15, 2002 (HealthDayNews) -- A new study finds that close relatives of black people with Alzheimer's disease are almost twice as likely to develop the mind-robbing condition as are family members of white people with the disease.
The researchers also found that's true even if the relative is not blood-related, such as a spouse.
Thanks to the large scale of the study, people who are worried about developing Alzheimer's disease because a close relative has it now have a clearer sense of their risk, the researchers say.
"For the first time, we have some accurate risk curves for groups of people who are family members of people with Alzheimer's disease," says Dr. Robert C. Green, lead author and associate professor of neurology at Boston University School of Medicine. "If you go to a doctor and say, 'What are the chances of my developing memory problems?' until now the doctor could only give you vague answers. Now, if the doctor chooses to use them, he or she can say, 'Here are some risk curves that can help you understand your risk.'"
The findings, which appear in tomorrow's issue of the Journal of the American Medical Association, come from a study that gathered information on more than 23,000 close relatives and spouses of Alzheimer's patients at 17 medical centers between 1991 and 2001.
One of the notable discoveries was that the risk is higher for black Americans than for white Americans. The cumulative risk that close relatives (parents, brothers, sisters and children) of white Alzheimer's patients would develop the condition was 26.9 percent, but it was 43.7 percent for relatives of black patients, the report says. Similarly, spouses of black patients were 1.8 times more likely to develop the condition than spouses of white patients were.
"This fits in with a group of papers published recently saying that Alzheimer's disease is more common in the African-American community," says Bill Thies, vice president for medical and scientific affairs for the Alzheimer's Association. "The reasons for that are not clear. Even whether the finding is real is not clear. It is a matter for research."
The reason for doubt is that "the examinations we use for diagnosing Alzheimer's disease are sensitive to cultural differences," Thies explains. "Most have been validated in white, middle-class populations. If you take them into a population that will miss some of the questions because they don't understand what they mean, or have different answers, the results could have nothing to do with cognitive differences."
The new study gives some support to that proposition. In both black and white people, the risk of developing Alzheimer's disease was the same for all carriers of a specific gene that has been linked to the condition.
However, unpublished data from the study showed the educational level of the individuals didn't change the results, indicating that cultural factors were not responsible for the differences, Green says. More research is needed to determine why the differences exist, he says.
Whatever the reason, "the biggest importance of the study is in terms of trying to distribute services," Thies says. "Eventually, we will have more services related to the black community."
What To Do
A close relative or spouse of an Alzheimer's disease patient can ask a doctor to apply the information from the study to give a risk estimate and take whatever action is appropriate.
The immediate value of knowing a person's risk is not great, Thies and Green say, because there is no way now of stopping the progression of Alzheimer's disease. However, Green says that will change.
"On the horizon are treatments to slow the progression or prevent the disease," he says. "So it will be very important to evaluate who is at high risk."
Basic information about Alzheimer's disease is available from the Alzheimer's Association or the National Institute on Aging's Alzheimer's Disease Education and Referral Center.
