Small vessel disease in the brain. Hypotension and hypertension as causes of cognitive decline and dementia. with focus on genetic markers and MRI.

Cerebral small vessel disease (CSVD) causes 25% of strokes and contributes to 45% of dementia cases. Prevalence increases with age, from about 5% at age 50 yr to almost 100% above 90 yrs of age. Few studies has focused on CSVD as the cause of cognitive decline and dementia.

The vascular mechanisms and pathways are unclear and almost no gene markers related to cerebral autoregulation (CA) have been identified.

Both hypotension (OH) and hypertension (HT) will be explored in relation to CSVD and cognitive decline in two longitudinal cohorts of elder (GÅS-SNAC, n=7 361) and Epihealth.

Perfusion MRI is used in a subset (n=408) to improve diagnostics for early signs of hypoperfusion especially in prefrontal areas, often affected in CSVD and related to executive functions, also assessed by a cognitive test battery in all subjects, CA is studied through transcraniell doppler of a. cerebri media during tilting combined with 24h ECG/BP and related to the cognitive test battery with 14 tests.

Genome wide association analyses is already performed in the total Epihealth cohort (2020,n=24 553) and a subset of GÅS-SNAC, n=1 457) to identify genotypes for OH and impaired CA that will be tested against cognitive tests in the 12-year follow-up of GÅS-SNAC with the same examinations at baseline and follow-up.Few studies have been done on HT among elder based on present recommendations (140/90) despite that half of elder>80 yrs are on antiHT treatment.Knowledge gap exists on specific mechanisms.