Ethnic differencesJapanese-American men with Alzheimer's disease studied by Honolulu researchers had milder cases than their Caucasian counterparts in the United States and Europe.
may affect severity
A study finds less brain
deterioration in Japanese
Americans than in Caucasians
Alzheimers IDs now available
By Helen Altonn
"We found they are much more like the Japanese (in Japan) than Caucasians," said Dr. Helen Petrovitch, University of Hawaii medical professor.
The Japanese Americans had fewer brain lesions associated with Alzheimer's than Caucasians, she said. If researchers could figure out why, she said, "We could use that to treat people, but that's way down the road."
But the recent study, indicating possible ethnic differences in Alzheimer's disease, is "a very important beginning," she added.
Petrovitch, with the Pacific Health Research Institute, is lead author of a paper published on Alzheimer's disease this month in the journal Neurology.
The research was done as part of the Honolulu-Asia Aging Study, which began in 1991.
The study stemmed from a sweeping program that started in 1965 at Kuakini Medical Center with 8,006 Japanese-American men on Oahu, identified through World War II Selective Service registration files.
Studies of the group through the years have resulted in greater understanding of heart disease, stroke, dementia and other diseases of aging.
The dementia examinations included 3,734 participants from 1991 through 1993 and 2,603 through 1996.
About 2,000 of the men, from 80 to 100 years, are still alive, Petrovitch said.
One of the reasons for the aging study, she said, was to compare dementia between Asians and Caucasians.
"The overall rates are pretty similar between the United States and Japan, but the type of dementia reported is different," she said. "In the United States, Alzheimer's is most common. In Japan, vascular dementia is most common pretty consistently."
Vascular dementia develops when blood clots block small blood vessels in the brain and destroy brain tissue.
The latest study was to determine if the reported rates of Alzheimer's and vascular dementia are accurate, Petrovitch said.
In clinical examinations of the Japanese-American volunteers, more Alzheimer's was found than in Japan, she said, but the rate was similar to what is reported for Caucasians in the United States. Vascular dementia rates were about the same as in Japan, she said.
The research included 220 postmortem examinations to confirm the cases of Alzheimer's disease diagnosed through in-depth tests before death, Petrovitch said.
Pure Alzheimer's was confirmed in 20 cases. Nineteen had Alzheimer's, plus other conditions. Findings in the other cases ranged from normal cognition to various kinds of dementia and vascular dementia.
Most of the cases initially diagnosed as Alzheimer's were confirmed, but they had fewer microscopic lesions associated with the disease than studies of Caucasians show in the United States and Europe, she said. "It's more like what they find in Japan."
Two microscopic lesions, signs of degeneration in the brain, are the hallmark of Alzheimer's disease, Petrovitch said. The major one is neuritic plaque.
She said they found the plaques in patients with Alzheimer's, "but in most cases we just didn't find very many."
She said two possibilities could explain that: genetics and environment. The Japanese Americans' environment has changed, but their genetics remain Japanese, she noted.
Since the Japanese Americans studied were more like the Japanese in Japan and have fewer neuritic plaques than Caucasians, perhaps a genetic factor results in fewer lesions or clears them out better, she speculated.
Although many environmental factors changed for the Japanese Americans, they may have maintained something in their culture that prevented the plaque from forming, she said.
The study is good news for Japanese residents, Petrovitch said.
However, she stressed, "They should really concentrate on stroke prevention, watching their blood pressure and (not) smoking."
Alzheimer's cannot be prevented, but measures can be taken to guard against vascular dementia, she said.
Vascular dementia can occur from a major stroke, but most often it is the result of many little strokes, she said, "small vessel strokes that cause trouble with thinking."
For Japanese in Hawaii, she said, "Chances of a better memory and living a long time probably are better than for Caucasians if they can avoid strokes."
Participating in the study from the Pacific Health Research Institute, University of Hawaii and Honolulu Department of Veteran Affairs were Dr. Lon White, Dr. G. Webster Ross, Sandra Steinhorn, Cliff Li, Dr. Kamal H. Masaki, Dr. Jim Nelson, Dr. John Hardman, Dr. David Curb, Dr. Patricia Blanchette and Dr. Katsuhiko Yano.
Collaborating with the Honolulu researchers were Drs. Daron Davis and William Markesbery, University of Kentucky pathologists who read the postmortem slides, and Lenore Launer, with the National Institutes of Health.
Those with loved ones suffering from Alzheimer's disease can receive identification materials this weekend at the Alzheimer's Association's Safe Return Registration Day.
Alzheimers IDs now available
The event is being held statewide and provides registrants and their families with a personalized bracelet and other forms of identification.
According to the Alzheimer's Association, those stricken with the disease are confused and sometimes unable to ask for help. Alzheimer's patients can wander off and become lost.
"People with Alzheimer's disease wander for a variety of reasons," said Janet Bender, AA executive director. "They may be searching for someone or something familiar, such as where they used to live or work."
Registration for the Safe Return program costs $40.
The Safe Return sign-up on all islands will be held from 10 a.m. to 2 p.m.
Registration on Oahu will be held at the association's offices at Ward Warehouse, 2nd Floor, Building B. Big Island registration will be at the KTA Store in Hilo, and on Maui it will be held at the Kaahumanu Shopping Center in Kahului. Residents of Kauai, Molokai and Lanai are asked to call collect at 877-43-ALOHA to request identification materials via mail.
For more information, call the Alzheimer's Association's Aloha Chapter at 591-2771.