Household-level Lifestyle Interventions for the Prevention of Cognitive Decline; A Systematic Review.

•We identified no RCT where the household was the unit of randomisation. However, we identified 5 clinical trials that randomised the adjacent construct of dyads.•Amongst these trials (n = 1721), lifestyle-based interventions (diet and physical activity) were not significantly associated with change in cognitive or functional outcomes.•Our findings suggest a deficit in household-level lifestyle interventions for prevention of cognitive decline and related outcomes.•Given the importance of lifestyle factors in risk of dementia, simple lifestyle interventions which target households may have group-level health benefits for all members.