To examine whether self-reported functional status modified the association between blood pressure (BP) and cognitive decline among older adults.
The study included 2097 US adults aged 75 years and older from the Cardiovascular Health Study, followed for up to 6 years. Functional status was ascertained by self-reported limitation in activities of daily living (ADL; none vs. any). Cognitive function was assessed by the Modified Mini Mental State Exam (3MSE). We used linear mixed models to examine whether the presence of at least one ADL limitation modified the association between BP and cognitive decline. Potential confounders included demographics, physiologic measures, antihypertensive medication use and apolipoprotein E ε4 allele. We conducted stratified analyses for significant interactions between BP and ADL.
The association between BP and change in 3MSE differed by baseline ADL limitation. Among participants without ADL limitation, elevated systolic BP (≥140 mmHg) was associated with a 0.15 decrease (95% CI −0.24 to −0.07); P value for interaction less than 0.001, whereas in those with an ADL limitation, elevated systolic BP was independently associated with a 0.30 increase in 3MSE scores per year (95% CI 0.06–0.55). Elevated diastolic BP (≥80 mmHg) was associated with an increase in cognitive function in both groups, although the increase was greater in those with ADL limitation (0.47 points per year vs. 0.18 points per year, P value for interaction = 0.01).
Elevated BP appears to be associated with a decrease in cognitive scores among functioning older adults, and modest improvements in cognitive function among poorly functioning elders.
aSchool of Biological and Population Health Sciences, Oregon State University, Corvallis, Oregon
bKidney Health Research Collaborative at University of California San Francisco, and San Francisco VA Medical Center, San Francisco, California
cDepartment of Family Medicine, Epidemiology, and Global Health, University of Washington, Seattle, Washington, USA
dGlobal Health Research Center, Duke Kunshan University, Kunshan, Jiangsu, China
eCardiovascular Health Research Unit, Departments of Medicine, Epidemiology, and Health Services, University of Washington
fKaiser Permanente Washington Health Research Institute, Seattle, Washington
gGraduate School of Public Health, University of Pittsburgh, Pittsburgh, Pennsylvania
hDepartment of Health Research and Policy, Stanford University, Stanford, California, USA
Correspondence to Lindsay M. Miller, MPH, School of Biological and Population Health Sciences, Oregon State University, 103 Milam Hall, 2520 SW Campus Way, Corvallis, OR 97330, USA. E-mail: firstname.lastname@example.org
Abbreviations: ADL, activities of daily living; APOE, apolipoprotein E e4 allele; BP, blood pressure; CHS, Cardiovascular Health Study; CVD, cardiovascular disease; DSST, Digit Symbol Substitution Test; 3MSE, Modified Mini Mental State Exam; MMSE, Mini Mental State Exam
Received 10 October, 2018
Revised 18 February, 2019
Accepted 5 March, 2019
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