14 Dec 2001

A study of the elderly in Sweden provides more evidence that people with a higher level of education are less likely to be diagnosed with Alzheimer's disease or other dementias. The article, by Chengxuan Qui and collegues at the Karolinska Institute in Stockholm and at Uppsala University in Uppsala, Sweden, appears in the December Archives of Neurology.

In this prospective study, the researchers followed the development of dementia in all 1,296 initially dementia-free elderly persons in a single community and adjusted for confounders such as socioeconomic status or vascular disease. In addition, the study incorporated mortality data, which may help to tease out whether higher education actually slows or prevents the progression of disease pathology, or whether it simply masks the clinical diagnosis of the AD.

During the five-year follow-up period, subjects with less than during years of schooling were 2.6 times more likely to develop AD than those with more education. (There was no difference between subjects with high school versus college educations.) On the other hand, a low level of education was not statistically related to the mortality of patients with AD or other dementias. This contradicts the "brain battering" hypothesis (that lower education and attendant socioeconomic status burden the brain through unhealthier lifestyles and more toxin exposure) and instead appears to support the "cognitive reserve" hypothesis (that people with higher education status can compensate for the disease process longer.) Alternatively, regardless of whether the underlying pathology differs between more and less educated people, the current clinical methods of detecting Alzheimer's may simply favor finding the disease in people with less education, write the authors.—Hakon Heimer