Association between plasma beta-amyloid (Aß) levels to declines in cognitive and azheimer’s risk factor Professional Medicine

Association between plasma beta-amyloid (Aß) levels to declines in cognitive and azheimer’s risk factor

August 13, 2010, 9:23 pm

In the 880 adults samples of the study results that published in August 9, 2010 of the Archives of Neurology, the researchers found that there is linear association between the change in plasma beta-amyloid (Aß) levels and cognitive to markers of cognitive decline and Alzeimer’s disease risk factor.

This study represent 3 ethnic group included caribbean hispanic, white, and black, that free of dementia at the time of first Aß sample, were drawn from the Washington Heights and Inwood Columbia Aging Project.

At follow-up, 481 patients remained cognitively healthy, 329 were cognitively or functionally impaired but not demented at any point, and 70 patients developed Alzheimer’s disease.

The purpose of this study is to determine whether Aß levels could be linked to either specific cognitive changes that constitute conversion to Alzheimer’s disease or whether they corresponded to cognitive change independent of dementia. Cognitive change consisted of a composite score and memory, language, and visuospatial indices.

Overall, according to study authors, Stephanie Consentino, PhD, from Columbia University Medical Center, at the Taub Insitute for Research in Alzheimer’s Disease and the Aging Brain, New York City, and multicenter colleagues, found that in their overall 880 adults sample, individuals in the top 3 quartiles of Aß42 at baseline had faster declines in cognitive function during 4.5 years of follow-up than those in the lowest quartile. The same observation held largely true for individuals who remained cognitively healthy during the same study interval.

The investigators added, “Individuals in the top 3 Aß40 quartiles also declined faster than those in the lowest quartile, whereas in the healthy elderly individuals, only the highest quartile declined faster than those in the lowest.”

The investigators noted based on their observing to the rate of global cognitive change by change in Aß, both the overall cohort and the healthy elderly, individuals with relatively stable or decreasing Aß42 values had faster cognitive decline than those with increasing Aß42 values. In contrast, change in Aß40 was not associated with cognitive change in either the overall cohort or the healthy elderly.

According to Dr. Cosentino, they are trying to characterize the absence of an increase in Aß42 levels over time based on their observe in healthy elders with steady increase in Aß42 levels over the period.

She also noted that previous studies have shown that high initial plasma levels of Aß and declining levels of Aß over time are risk factors for Alzheimer’s disease. Therefore, according to her, changes in Aß levels may provide information about disease risk. In this particular study, changes in the same plasma Aß levels predicted the rate of cognitive decline in patients who eventually developed dementia.

However, Dr. Cosentino cautioned, “We need to further validate these Aß levels, and we also need to understand how plasma Aß levels relate to brain levels. But, once we have a better understanding of this, testing patients for plasma Aß levels is an expensive and noninvasive way to identify people at greater risk for cognitive decline and Alzheimer’s disease, and ultimately, this would be very important in terms of being able to provide preventive treatment when we have such a treatment.”

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