Studies Find Increasing Prevalence of Alzheimer's Disease in Beijing, China

Marlene Busko

March 28, 2008

March 28, 2008 (Orlando, Florida) — The prevalence and incidence of Alzheimer's disease in Beijing, China has increased over a recent 10-year period, according to data from 2 studies. This was a time of large changes in lifestyle, according to Ge (Gail) Li, MD, from the University of Washington, in Seattle, who reported these findings in a talk on Innovative Research in Cross-Cultural Geropsychiatry here at the American Association for Geriatric Psychiatry 21st Annual Meeting.

Alzheimer's disease, which increases dramatically with age, is becoming more common worldwide and has become more of a problem for developing countries, said Dr. Li. Census data from China from 1990 to 2000 revealed an aging population with, during this decade, a 27% increase in the number of people who are age 65 years and older, she noted.

Dr. Li presented data from 2 studies done 10 years apart (1986 to 1989 and 1997 to 1999) using identical methods and looking at the same residential area of Beijing. The first study (study 1) was part of her PhD thesis, before she left China to go to the United States, and the second study (study 2) was carried out by colleagues in China.

The studies looked at individuals who were living in the community who were age 60 years and older. "In China, 60 is [considered to be] old age," she said. The researchers went to people's homes and performed a Mini-Mental State Exam (MMSE). If the person screened positive for dementia, a psychiatrist went to the person's home and performed a clinical examination to confirm the diagnosis.

The researchers used Diagnostic and Statistical Manual of Mental Disorders, 3rd ed (DSM-III) criteria for dementia in study 1 (1331 people) and used DSM-IV and International Statistical Classification of Diseases and Related Health Problems, 10th Revision (ICD-10) criteria for dementia in study 2 (1703 people).

They found that the population is aging; the number of people who fell into the "oldest-old" category (age 80 years or older) grew from 6.9% of the population in study 1 to 12.1% of the population in study 2.

The prevalence of moderate and severe dementia grew from 1.74 per 100 people screened in study 1 to 2.51 per 100 in study 2.

Similarly, the incidence of new dementia grew from 0.56 per 100 people in study 1 to 0.90 per 100 people in study 2.

"In Beijing, there are still a lot of 'young old,' and the incidence of dementia is not dramatically different from Seattle or across multiple Europe countries," Dr. Li said.

There are 3 likely reasons that Alzheimer's disease has become more common than vascular dementia in Beijing over this time period, she noted. First, the population is aging. Second, cerebrovascular disease has been decreasing over time, probably due to effective hypertension treatment and stroke prevention. Third, there has been a "dramatic" lifestyle change, Dr. Li said, explaining that the lifestyle of the elderly Chinese is catching up with the Western lifestyle. People are spending more time in front of televisions and less time walking to the next town to visit friends. They eat more meat and have a diet that is higher in cholesterol, and there is an increase in diabetes. "Diabetes, hypertension, and hypercholesterolemia have been identified as risk factors for Alzheimer's disease. This is another reason you see more Alzheimer's disease in China," she said.

In addition to looking at dementia in this population, the researchers also administered the Geriatric Depression Scale to investigate depression. They found a prevalence of depression of 25 in 1952 people. None of the 25 subjects in this Beijing community were treated for their depression with either medication or therapy, she noted.

Based on her experience in her clinical practice in Seattle, Asian patients do present with more somatic symptoms of depression such as headaches and dizziness, Dr. Li said. "In my clinical experience, you just need to ask more questions. You have to 'dig deeper,' " she added.

American Association for Geriatric Psychiatry 21st Annual Meeting: Innovative Research in Cross-Cultural Geropsychiatry. Presented March 15, 2008.

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