Are age and education independent correlates of the Mini-Mental State Exam performance of community-dwelling elderly?

We examined the effects of selected health conditions and sensory functions, socioeconomic status, age, and education on cognitive functioning in 3,974 community-dwelling individuals aged 65-84 years. Logistic regression analysis was used to examine the independent and joint effects of these variables on borderline (Mini-Mental State Exam [MMSE] of 22-25) and poor (MMSE of < or = 21) functioning relative to adequate functioning (MMSE of 26-30). The effect of age and of education on MMSE performance was relatively stable, even after adjusting for age- and education-related health conditions and sensory impairments that also influenced level of cognitive functioning. These conditions included poor vision, Parkinson's disease, diabetes, depression, stroke (in 65-74-year-olds), and low socioeconomic status (in 75-84-year-olds). Education did not modify the effect of these variables on MMSE performance. Additional studies elucidating further the mechanisms that relate these sociodemographic factors to cognitive performance are warranted, as are studies of the relationship between these factors and the incidence of cognitive impairment.