Total cerebral blood flow and mortality in old age

Abstract

To examine the association of total cerebral blood flow (CBF) with all-cause, noncardiovascular, and cardiovascular mortality in older subjects at risk of cardiovascular disease. We included 411 subjects with a mean age of 74.5 years from the MRI substudy of the Prospective Study of Pravastatin in the Elderly at Risk. Total CBF was measured at baseline, and occurrence of death was recorded in an average follow-up period of 11.8 years. For each participant, total CBF was standardized for brain parenchymal volume. Cox regression models were used to estimate risk of all-cause, noncardiovascular, and cardiovascular mortality in relation to CBF. Mortality rates among participants in low, middle, and high thirds of total CBF were 52.1, 41.5, and 28.7 per 1,000 person-years, respectively. Compared with participants in the high third of CBF, participants in the low third had 1.88-fold (95% confidence interval [CI]: 1.30-2.72) higher risk of all-cause mortality, 1.66-fold (95% CI: 1.06-2.59) higher risk of noncardiovascular mortality, and 2.50-fold (95% CI: 1.28-4.91) higher risk of cardiovascular mortality. Likewise, compared with participants in the high third of CBF, participants in the middle third had 1.44-fold (95% CI: 0.98-2.11) higher risk of all-cause mortality, 1.29-fold (95% CI: 0.82-2.04) higher risk of noncardiovascular mortality, and 1.86-fold (95% CI: 0.93-3.74) higher risk of cardiovascular mortality. These associations were independent of prevalent vascular status and risk factors. Low total CBF is linked with higher risk of all-cause, noncardiovascular, and cardiovascular mortality in older people independent of clinical cardiovascular status.