Our objective was to investigate the association between hypertension and concurrent impairments in mobility, cognition and mood; the role of brain white matter hyperintensities in mediating this association; and the impact of these impairments on disability and mortality in elderly hypertensive individuals.
Methods and Results
Blood pressure, gait speed, digit symbol substitution test, and the Center for Epidemiologic Studies Depression Scale were measured yearly (1992-1999) on 4700 participants in the Cardiovascular Health Study (age: 74.7, 58% women, 17% African Americans, 68% hypertension, 3600 had brain MRI in 1992-93, survival data 1992-2005). Using latent profile analysis at baseline, we found that 498 (11%) subjects had concurrent impairments and 3086 (66%) were intact on all three measures. Between 1992 and 1999, 651 (21%) became impaired in all three domains. Hypertensive individuals were more likely to be impaired at baseline (Odds ratio 1.23, 95% CI (1.04-1.42), p=0.01) and become impaired during the follow-up (Hazard Ratio (HR)= 1.3, 95% Confidence Interval (CI): 1.02 to 1.66, p=0.037). Greater degree of white matter hyperintensities was associated with impairments in the 3 domains (p=0.007) and mediated the association with hypertension (p=0.19 for hypertension after adjusting for white matter hyperintensities in the model, 21% HR change). Impairments in the three domains increased subsequent disability with hypertension (p<0.0001). Hypertension mortality also was increased in those impaired (compared to unimpaired hypertensive individuals HR=1.10, 95% CI (1.04-1.17), p=0.004).
Hypertension increases the risk of concurrent impairments in mobility, cognition and mood, which increases disability and mortality. This association is partly mediated by microvascular brain injury.
Keywords: Hypertension, disability, white matter hyperintensities