Date Approved

2017

Degree Type

Open Access Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department or School

Psychology

Committee Member

Karen Saules

Committee Member

Renee Lajiness-O’Neill

Committee Member

Jin Bo

Committee Member

Judi Brooks

Abstract

Obesity has been associated with impairment in most cognitive domains, but the nature of this relationship is unclear. Most studies have examined the relationship between cognitive impairment and current obesity and/or history of obesity-related medical conditions. However, a number of “lower-level” obesity factors (e.g., increased adipokines, low grade inflammation, chronic mild hypoventilation) are present even among the otherwise healthy obese population, and it is possible that many of these factors have differential impact on cognition according to magnitude and duration of exposure. Knowledge of a person’s weight history, which may serve as a proxy for a number of lower-level obesity variables that cannot otherwise be measured, may provide additional utility in predicting cognitive functioning. Of the cognitive domains, processing speed is particularly important to study in this context, as its decline plays a large role in driving cognitive aging. Despite this, little is known about the impact of weight history on processing speed in old age. The present study added to the scientific body of literature by using data from the 1999–2000 and 2001–2002 NHANES cycles to examine the relationship between weight history and current processing speed among young-old adults (i.e., adults aged 65–74) using data at three timepoints: young adulthood, late mid-life, and young-old adulthood. A statistically significant relationship between persistent obesity in young adulthood and late middle-age and processing speed in young-old adulthood was identified, but it was found to be fully mediated by vascular health history. Additionally, slow processing speed was associated with the weight trajectory pattern of obesity in late middle-age coupled with the absence of obesity in both young adulthood and young-old adulthood. In regard to study implications, it may be possible that efforts toward prevention of new onset obesity during mid-life, if successful, would protect against slowed processing speed in young-old adulthood.

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