PREDICTORS OF LONGITUDINAL CHANGE IN WHITE MATTER HYPERINTENSITIES
Laura Barrera-Martinez1, Sherry Willis1, Paul Robinson1, Warner Schaie1, Kristen Kennedy2.
1University of Washington, Seattle, WA, 2Center for Vital Longevity, The University of Texas at Dallas, Dallas, TX.
White matter (WM) integrity has been shown to be important both in speed of processing and in cognitively complex domains such as executive functioning. White matter hyperintensities (WMH), as an indicator of WM integrity, have also been related to vascular risk and its impact on cognitive functioning. While concurrent associations between WMH volume, cognition, and vascular risk have been studied, there is relatively limited examination of factors associated with short-term longitudinal change in WMH volume in cognitively healthy subjects. We hypothesize steeper increase in WMH with age and for ε4 carriers. In this study, we examine 4 occasions of change in WMH volume over a 6-year interval in 87 cognitively normal adults in a MANCOVA design. Approximately half the sample had been diagnosed with hypertension, although ε4 carriers did not differ in percent with hypertension. Predictor variables included age (midlife/old age) and APOE ε4 status with education as a covariate. Mean WMH volume doubled over the 4 occasions of measurement with older subjects having significantly higher WMH volume across occasions. Older subjects showed a steeper rate of increase across time, with older ε4 carriers showing the steepest increase in WMH volume, compared to ε4 noncarriers. Carriers and noncarriers did not differ at baseline. This study extends prior findings in examining rate of increase in WMH volume over 4 occasions in healthy, cognitively normal adults, examining change in midlife versus old age. Both age and APOE ε4 status were shown to contribute to rate of increase in WMH volume over time.