Cerebrovascular disease in the form of white matter hyperintensities (WMH) increases with age and is associated separately with sedentary time and reduced kidney function. A better understanding of the relationships among these variables would help clarify whether sedentary time should be considered more closely in older adults at particular levels of kidney function to reduce the risk of WMH.
We analyzed information from 94 healthy community-dwelling older adults to determine the association of sedentary time and WMH in nondemented, nondepressed older adults, and whether level of kidney function was an effect modifier of the relationship between sedentary time and WMH. Sedentary behavior was measured using the Sedentary Behavior Questionnaire. White matter hyperintensity was assessed using whole-brain 3T magnetic resonance imaging T1- and T2-weighted images. Kidney function was calculated by the epi-chronic kidney disease formula for estimated glomerular filtration rate (eGFR). Exposures or predictors were sedentary time, age, sex, education in years, Framingham stroke risk 10-yr prediction score, and eGFR. The analytical approach was multiple linear regression.
Adjusting for age, sex, education in years, Framingham stroke risk 10-yr prediction score, greater sedentary time was associated with greater WMH but this effect was dependent on level of eGFR (sedentary time–eGFR interaction b = −0.0005, P = 0.022). At eGFR values of 69, 81, and 93 mL·min−1 per 1.73 m2 (the 25th, 50th, and 75th percentiles), sedentary time b coefficients were b = 0.021 (95% confidence interval [CI], 0.011–0.031), b = 0.015 (95% CI, 0.008–0.022), and b = 0.009 (95% CI, 0.003–0.016). The effect weakened linearly as eGFR increased, with no significant association at eGFR ≥97 mL·min−1 per 1.73 m2.
Findings suggest that sedentary time is associated with WMH in persons with an eGFR ≤96 mL·min−1 per 1.73 m2 and that this association is stronger with lower levels of kidney function.
1Department of Biobehavioral Health Science, College of Nursing, University of Illinois at Chicago, Chicago, IL;
2 Department of Health Systems Science, University of Illinois at Chicago, College of Nursing, Chicago, IL;
3Department of Clinical and Health Psychology, University of Florida, Gainesville, FL;
4Department of Psychology, University of Illinois at Chicago, Chicago, IL;
5Department of Biomedical Engineering, Illinois Institute of Technology, Chicago, IL;
6Rush Alzheimer’s Disease Center, Rush University Medical Center, Chicago, IL;
7Department of Kinesiology and Nutrition, University of Illinois at Chicago, Chicago, IL;
8Department of Medicine, University of Illinois at Chicago, Chicago, IL; and
9Department of Behavioral Sciences, Rush University Medical Center, Chicago, IL
Address for correspondence: Ulf G. Bronas, Ph.D., A.T.C., F.S.V.M., F.A.H.A., Department of Biobehavioral Health Science, College of Nursing, University of Illinois at Chicago, (M/C 802), 845 S. Damen Ave. Chicago, IL 60612-7350; E-mail: email@example.com.
Submitted for publication November 2018.
Accepted for publication February 2019.
Online date: February 21, 2019