Blood pressure change and cognition in childhood and early adulthood: a systematic review

INTRODUCTION: High blood pressure in midlife is an established risk factor for cognitive decline and dementia but less is known about the impact of raised blood pressure on cognition in childhood and early adulthood. METHOD: We systematically reviewed and quantified the existing evidence base relating to blood pressure in early life and subsequent cognitive performance. Medline, Embase, PsycINFOo, Scopus, and Web of Science were searched from inception to July 2020. We included longitudinal cohort and case–control studies involving participants aged 0–40 years with a baseline and at least one follow-up blood pressure assessment alongside at least one measure of cognition, occurring at the same time as, or subsequent to blood pressure measures. Risk of bias was assessed independently by two reviewers. PROSPERO registration CRD42020214655. RESULTS: Of a total of 5638 records identified, three cohort and two case–control studies were included with ages ranging from 3 to early 30s. Repeated blood pressure measurements averaged over 25 years or cumulative blood pressure in the 25–30 years prior to assessment of cognitive function were associated with poorer cognitive performance in the two largest cohort studies. The smallest cohort study reported no evidence of an association and the results from the two case–control studies were contradictory. All studies were at risk of bias. CONCLUSION: Overall, the evidence in this area is lacking and study quality is mixed. Our review highlights an urgent need for studies evaluating the potential for a relationship between raised blood pressure and poorer cognition in early life given the potential for possible risk reduction if such a relationship exists.