Aging & Mental Health 2002; 6(1): 22–29 ISSN 1360–7863 print/ISSN 1364–6915 online/02/010022–08 © Taylor & Francis Ltd DOI: 10.1080/13607860120101121 ORIGINAL ARTICLE Health literacy and performance on the Mini-Mental State Examination D. W. BAKER, 1 J. A. GAZMARARIAN, 2 J. SUDANO, 1 M. PATTERSON, 3 R. M. PARKER 4 & M. V. WILLIAMS 4 1 Center for Health Care Research and Policy and the Department of Medicine, Case Western Reserve University at MetroHealth Medical Center; and the Department of Epidemiology-Biostatistics, Case Western Reserve University School of Medicine; 2 USQA Center for Health Care Research, Atlanta, Georgia; 3 Departments of Neurology and Psychiatry, Case Western Reserve University School of Medicine and the Case Western Reserve University Alzheimer Center, University Hospitals of Cleveland & 4 Department of Medicine, Emory University School of Medicine, Atlanta, Georgia, USA Abstract The objectives of the study were to determine the relationship between functional health literacy and performance on the Mini-Mental State Examination (MMSE). New Medicare managed-care enrollees aged 65 years and older, living independently in the community in four US cities (Cleveland, Houston, Tampa, and Fort Lauderdale/Miami), were eligible to participate. In-home interviews were conducted to determine demographics and health status, and interviewers then administered the Short Test of Functional Health Literacy in Adults (S-TOFHLA) and the MMSE. We then deter- mined the relationship between functional health literacy and the MMSE, including total scores, subscale scores (orientation to time, orientation to place, registration, attention and calculation, recall, language, and visual construction), and individual items. Functional health literacy was linearly related to the total MMSE score across the entire range of S- TOFHLA scores (R 2 = 0.39, p < 0.001). This relationship between health literacy and MMSE was consistent across all MMSE subscales and individual items. Adjustment for chronic conditions and self-reported overall health did not change the relationship between health literacy and MMSE score. Health literacy was related to MMSE performance even for subscales of the MMSE that were not postulated to be directly dependent on reading ability or education (e.g. delayed recall). These results suggest that the lower MMSE scores for patients with low health literacy are only partly due to ‘test bias’ and also result from true differences in cognitive functioning. ‘Adjusting’ MMSE scores for an individual’s functional health literacy may be inappropriate because it may mask true differences in cognitive functioning. Introduction The Mini Mental State Examination (MMSE; Folstein et al., 1975) is commonly used to screen for cognitive impairment. In addition, researchers are increasingly using the MMSE score as a predictor variable in models of health care use and health outcomes, including such diverse subjects as the risk of hip fracture (Guo et al., 1998), treatment of pain (Feldt et al., 1998), perception of physical symptoms (Frisoni et al., 1999), prevalence of hearing impair- ment (Naramura et al., 1999), and overall mortality (Covinsky et al., 1999). However, use of raw (unad- justed) MMSE scores with patients or for research projects is problematic because of the strong rela- tionship between performance on the MMSE and the number of years of school completed (Tombaugh & McIntyre, 1992). The prevailing viewpoint for the relationship between years of school completed and MMSE score is that ‘educa- tion introduces a psychometric bias leading to a misclassification of individuals from different educa- tional backgrounds’ (Tombaugh & McIntyre, 1992). Specifically, the use of unadjusted MMSE scores will tend to incorrectly label individuals with limited education as having cognitive impairment when they do not. To account for this ‘bias’, researchers have proposed adjusting MMSE scores to account for the number of years of school completed (Crum et al., 1993; Uhlmann & Larson, 1991; Murden et al., 1991). However, adjusting MMSE scores for the years of school completed may be sub-optimal because the number of years of school completed is an inaccurate Correspondence to: David W. Baker, MD, MPH, MetroHealth Medical Center, 2500 MetroHealth Drive, Rammelkamp 221, Cleveland, Ohio 44109-1998, USA. Tel: (216) 778 3904. Fax: (216) 778 3945. E-mail: dwb@po.cwru.edu Received for publication 27th April 2001. Accepted 5th May 2001.