BACKGROUND

Cardiovascular disease and dementia often coexist at advanced stages. Yet, longitudinal studies examining the interplay between atherosclerosis and its risk factors on brain health in midlife are scarce. We aimed to characterise the longitudinal associations between cerebral glucose metabolism, subclinical atherosclerosis, and cardiovascular risk factors in middle-aged asymptomatic individuals.

METHODS

The Progression of Early Subclinical Atherosclerosis (PESA) study is a Spanish longitudinal observational cohort study of 4184 asymptomatic individuals aged 40-54 years (NCT01410318). Participants with subclinical atherosclerosis underwent longitudinal cerebral [F]fluorodeoxyglucose ([F]FDG)-PET, and annual percentage change in [F]FDG uptake was assessed (primary outcome). Cardiovascular risk was quantified with SCORE2 and subclinical atherosclerosis with three-dimensional vascular ultrasound (exposures). Multivariate regression and linear mixed effects models were used to assess associations between outcomes and exposures. Additionally, blood-based biomarkers of neuropathology were quantified and mediation analyses were performed. Secondary analyses were corrected for multiple comparisons using the false discovery rate (FDR) approach.

FINDINGS

This longitudinal study included a PESA subcohort of 370 participants (median age at baseline 49·8 years [IQR 46·1-52·2]; 309 [84%] men, 61 [16%] women; median follow-up 4·7 years [IQR 4·2-5·2]). Baseline scans took place between March 6, 2013, and Jan 21, 2015, and follow-up scans between Nov 24, 2017, and Aug 7, 2019. Persistent high risk of cardiovascular disease was associated with an accelerated decline of cortical [F]FDG uptake compared with low risk (β=-0·008 [95% CI -0·013 to -0·002]; p=0·040), with plasma neurofilament light chain, a marker of neurodegeneration, mediating this association by 20% (β=0·198 [0·008 to 0·740]; p=0·050). Moreover, progression of subclinical carotid atherosclerosis was associated with an additional decline in [F]FDG uptake in Alzheimer's disease brain regions, not explained by cardiovascular risk (β=-0·269 [95% CI -0·509 to -0·027]; p=0·029).

INTERPRETATION

Middle-aged asymptomatic individuals with persistent high risk of cardiovascular disease and subclinical carotid atherosclerosis already present brain metabolic decline, suggesting that maintenance of cardiovascular health during midlife could contribute to reductions in neurodegenerative disease burden later in life.

FUNDING

Spanish Ministry of Science and Innovation, Instituto de Salud Carlos III, Santander Bank, Pro-CNIC Foundation, BrightFocus Foundation, BBVA Foundation, "la Caixa" Foundation.