Cognitive health expectancies of cardiovascular risk factors for cognitive decline and dementia.

BACKGROUND: Cognitive health expectancy estimates the proportion of the lifespan that is lived in good cognitive health at the population level. A number of cardiovascular diseases have been identified to be risk factors for cognitive decline and dementia including diabetes, stroke, heart diseases and hypertension. The aim of this study was to examine how these cardiovascular conditions relate to cognitive health expectancy.

METHODS: Longitudinal data were obtained from the US Health and Retirement Study. Multistate modelling was used to estimate total life expectancy (LE), cognitive impairment free life expectancy (CIFLE) and years spent with cognitive impairment (CILE) across self-reported diabetes, hypertension, heart problems and stroke. Individual and cumulative effects of multiple cardiovascular conditions were examined.

RESULTS: The presence of cardiovascular disease was associated with a 5- to 9-year decrease in LE and 4- to 8-year decrease in CIFLE at age 55. The outcomes varied in a hierarchical fashion by cardiovascular condition. Relative to other conditions, individuals with stroke had the shortest LE and CIFLE. Analysis of multiple cardiovascular risk factors revealed that each additional cardiovascular condition was associated with an exponential decrease in LE and CIFLE.

CONCLUSIONS: Having a cardiovascular condition is associated with a lower CIFLE and higher proportion of life lived with cognitive impairment. However, the outcomes vary depending on the type of cardiovascular condition. Reducing incidence of stroke and minimising exposure to multiple cardiovascular risk factors may be beneficial in helping to improve population estimates of cognitive health expectancy.