The association between educational attainment and mental status examinations: Of etiologic significance for senile dementias or not?

Abstract

BOTH EDUCATIONAL level and socioeconomic status are associated with virtually every cause of morbidity and mortality. In almost all cases, for a multitude of reasons, people of lower socioeconomic groups have higher rates of disease [l-4]. For some diseases they do not have higher rates of disease incidence but still have higher rates of mortality (case-fatality) or disability [5,6]. People with few years of schooling are also known to have poorer performance scores on most kinds of intelligence and mental status exams [7-91. The question of central importance regarding the influence of education and socioeconomic status on performance of mental status exams is whether education (or some factor highly correlated with it) is of etiologic significance in the development of senile dementia (which mental status exams were designed to screen for) or whether the association reflects a stable characteristic of the individual in his or her mental performance which leads to differential misclassification and detection bias. If we are sure that educational level influences mental status scores exclusively via the latter pathway, then various adjustment procedures might well be justified. However, if there is a possibility that some part of the association between educational level and mental status score is the result of the influence of this factor on a disease process ultimately resulting in senile dementia and subsequent mental deterioration, it would clearly be a mistake to “adjust” for such a factor in the screening process for the disease. It is this latter perspective I would like to support. We have not yet arrived at such an advanced stage in our research efforts in this area that we can say with confidence that educational variability in rates of dementia are non-existent or trivial and should therefore be ignored. In fact, there are some reasons to suspect the opposite; that is, that educational level and/or socio-environmental exposures and behaviors correlated with it may be genuine risk factors for various senile dementias and are worthy of scientific exploration in their own right. The perspective I would like to present is not that the evidence indicates that such factors are risk factors, but rather that they may potentially be regarded as risk factors and ought to be investigated rather than obscured by essentially “over-adjusting”. In other words, educational level reflects many factors-social, environmental, behavioral, psychological, and biological. Many of these factors may be risk factors for dementias. Thus, education differences in mental status scores may reflect more than detection differences, although some amount of misclassification is likely to be present. What are the possible pathways by which such educational variables could influence the incidence or course and disability of dementias? Let us assume that the majority of senile