Household-level lifestyle interventions for the prevention of cognitive decline; A Systematic review

Background: Lifestyle interventions targeting households may be an effective means of promoting healthier cognitive function in later life, with extended benefit to other household members. In this systematic review and meta-analysis, we sought to assess the effect of targeting lifestyle behaviours of households on cognitive outcomes Methods: An electronic search strategy was designed to identify randomised controlled trials (RCTs) where households were randomised to receive a lifestyle intervention for the prevention of cognitive decline, from database inception until April 2020. Our initial search identified no eligible studies, so we revised our search strategy to include trials enroling dyads. We reported the cognitive outcomes, functional outcomes, caregiver outcomes and long-term care (LTC) admissions for eligible studies. Findings: We identified no RCTs which randomised households to receive a lifestyle intervention for preventing cognitive decline. We identified five RCTs (n = 1721, with mean follow-up of 9.6 months) which randomised dyads, which evaluated diet (two trials) and physical activity (three trials). Conclusion: Trials evaluating dietary and exercise interventions in dyads were identified. No trial demonstrated a significant association of interventions with change in cognitive testing, functional outcomes or long-term care admissions, although trials were small with short-term follow-up. Future studies should consider targeting lifestyle behaviours of households for prevention of dementia.