BackgroundThe beneficial effects of higher education on healthy aging are generally accepted, but the mechanisms are less well understood. Education may influence healthy aging through improved employment opportunities that enhance feelings of personal control and reduce hazardous exposures, or through higher incomes that enable individuals to access better health care or to reside in better neighbourhoods. Income and occupation have not been explored extensively as potential mediators of the effect of education on healthy aging. This study investigates the role of income and occupation in the association between education and healthy aging including potential effect modification by gender.MethodsLogistic regression was used to explore the association of education, income (perceived income adequacy, life satisfaction with finances) and occupation (occupational prestige) with healthy aging five years later in 946 community-dwelling adults 65+ years from a population-based, prospective cohort study in Manitoba, Canada.ResultsHigher levels of education generally increased the likelihood of healthy aging. After adjusting for education, both income measures, but not occupation, predicted healthy aging among men; furthermore, the association between education and healthy aging was no longer significant. Income and occupation did not explain the significant association between education and healthy aging among women.ConclusionsPerceived income adequacy and life satisfaction with finances explained the beneficial effects of higher education on healthy aging among men, but not women. Identifying predictors of healthy aging and the mechanisms through which these factors exert their effects can inform strategies to maximize the likelihood of healthy aging.Electronic supplementary materialThe online version of this article (doi:10.1186/s12889-015-2504-9) contains supplementary material, which is available to authorized users.

Background and Objectives:Little is known about the effect of education or other indicators of cognitive reserve on the rate of reversion from mild cognitive impairment (MCI) to normal cognition (NC), or the relative rate of reversion from MCI to NC vs. progression from MCI to dementia. Our objectives were to: 1) estimate transition rates from MCI to NC and dementia, and 2) determine the effect of age, apolipoprotein E (APOE), and indicators of cognitive reserve on the relative rate (RR) of reversion vs. progression using multistate Markov modelling.Methods:We estimated instantaneous transition rates between NC, MCI and dementia after accounting for transition to death across up to 12 assessments in the Nun Study, a cohort study of religious sisters aged 75+ years. We estimated RRs of reversion vs. progression for age, APOE, and potential cognitive reserve indicators: education, academic performance (high school grades), and written language skills (idea density, grammatical complexity).Results:Of the 619 participants, 472 were assessed with MCI during the study period. Of these 472, 143 (30.3%) experienced at least one reverse transition to NC, and 120 of the 143 (83.9%) never developed dementia (mean follow-up=8.6 years). In models adjusted for age group and APOE, higher levels of education more than doubled the RR ratio of reversion vs. progression. Novel cognitive reserve indicators were significantly associated with a higher adjusted RR of reversion vs. progression (higher vs. lower levels for English grades: RR Ratio = 1.83; idea density: RR ratio=3.93; and grammatical complexity: RR ratio=5.78).Discussion:Knowledge of frequent reversion from MCI to NC may alleviate concerns of inevitable cognitive decline in those with MCI. Identification of characteristics predicting the rate of reversion from MCI to NC vs. progression from MCI to dementia may guide population-level interventions targeting these characteristics to prevent or postpone MCI and dementia. Research on cognitive trajectories would benefit from incorporating predictors of reverse transitions and competing events, such as death, into statistical modelling. Finally, these results may inform the design and interpretation of MCI clinical trials, given that a substantial proportion of participants may experience improvement without intervention.