Objective: In previous studies, a number of secondary aging factors, such as hypertension, low memory self-efficacy, and poor sensory functioning, have been identified. Independent of age, these factors correlate with executive functioning in older persons. Less information is known about the extent to which these factors explain age-related decline in executive functioning. This study was undertaken to quantify the contribution of these factors to the association between age and decline in executive function. An understanding of which (perhaps modifiable) factors may affect executive aging over and above primary aging processes is necessary for the development of interventions that facilitate successful aging.
Design: A group of 838 healthy individuals in the age range of 49 to 82 years were examined in a longitudinal study of cognitive aging (Maastricht Aging Study, MAAS). These participants were without medical conditions known to interfere with normal cognitive dysfunction (e.g. dementia, mental retardation, and cerebrovascular pathology). In the present longitudinal study, data from the baseline (1993-1995) and the three-year follow-up phase (1996-1998) were examined.
Materials and Methods: Twenty-one biological and non-biological factors were used to define secondary aging (i.e. hypertension, diabetes, head trauma, poor self-rated health, family history of dementia, poor intellectual ability, drug use, pesticide exposure, poor sensory functioning, high body mass index, depression, anxiety, life events, low level of education, marital status, low memory self-efficacy, smoking, alcohol consumption, disengagement). Executive functioning was based on the interference score of the Stroop Color Word Test. The relative contribution of the biological and non-biological factors to the association between age and deterioration of executive functioning was estimated by comparing, a basic ‘age-model’ with a regression model, in which the (non)biological factors were added one at a time.
Results: In the three-year follow-up interval, decline in executive performance was significantly more pronounced in older individuals. Hypertension and poor memory self-efficacy were more common among older persons and among those who showed cognitive decline. However, their contribution to the association between age and decline in executive functioning was only marginal, due to weak associations. About 19 percent of the association between age and decline in executive functioning was explained by the factors hypertension and poor memory self-efficacy. The other biological and non-biological factors did not contribute to age-related cognitive decline.
Conclusion: Our findings suggest that secondary aging factors only marginally explain why older persons have poorer executive function. This may thus support the hypothesis of primary aging, which states that changes intrinsic to the aging process are responsible for decline in functioning. However, since hypertension and memory self-efficacy have a slight effect, interventions focusing on these factors may actually have the potential of improving executive functioning in the elderly.
Back to Poster Session 2
Back to Oral and Poster Sessions
Back to The IPA European Regional Meeting (1-4 April 2003) of IPA