AbstractBackgroundGiven the projected increase in the number of people with dementia and the lack of curative treatment, there is increasing attention to the contribution of modifiable risk and protective factors to dementia risk. In 2015, the “LIfestyle for BRAin health" (LIBRA) index was developed based on the results of a systematic literature review and Delphi expert study (Deckers et al., 2015). LIBRA consists of twelve modifiable risk factors for cognitive decline and dementia. Although this risk index has been well‐validated for cognitive decline and dementia risk in numerous population‐based cohorts and intervention studies, newly emerged risk factors might ask for an update (Deckers et al., 2019; Deckers et al., 2020).MethodTo update LIBRA, we conducted an umbrella review to assess all systematic reviews (SR) and meta‐analyses (MA) on modifiable dementia risk factors published between January 2015 and June 2021 in four databases (Pubmed, Embase, Web of Science, and PsychINFO). In parallel, a two‐round Delphi expert study was conducted. In the first round (May‐June 2022), eighteen dementia experts were asked to evaluate the factors currently included in LIBRA. Additionally, we asked to list new modifiable factors not previously included in LIBRA. In the second round (December 2022‐January 2023), the experts ranked the most important risk factors identified in the umbrella review and first Delphi round.ResultThe search returned 6,540 hits, of which 147 SR/MA were included in our umbrella review. Next to the existing LIBRA factors, new candidate risk factors that were consistently associated with increased risk for cognitive decline and dementia included: low social engagement, hearing impairment, vision impairment, atrial fibrillation, and anxiety. After triangulation of the results of the umbrella review and the first Delphi round, the experts identified hearing impairment, lifecourse inequalities, social contact, atrial fibrillation, and sleep as the most important new modifiable risk factors in the second Delphi round.ConclusionSeveral new modifiable risk factors for cognitive decline and dementia have been identified in this umbrella review and Delphi consensus study. These factors will be used for updating the existing LIBRA index, which will subsequently be externally validated in population‐based cohort studies.