A systematic review of prevalence and incidence studies of dementia with Lewy bodies

BACKGROUND: Substantial variation in the prevalence of Dementia with Lewy Bodies (DLB) has been reported with estimates ranging from 0 to 26.3% of all dementia cases, potentially making it the second most common dementia subtype. OBJECTIVES: The aim of this study was to review systematically and critically for the first time previous studies of the clinical prevalence and incidence of DLB in the population. METHODS: A systematic literature search was performed using PubMed. Selected articles had to describe an original study that provided a prevalence and/or incidence number for the whole population for DLB as defined by pre-set clinical criteria and findings. RESULTS: Six studies reporting the prevalence of DLB and one study reporting the incidence of DLB met the inclusion criteria. Prevalence estimates, depending on case criteria, range from 0 to 5% with regard to the general population, and from 0 to 30.5% of all dementia cases. The only estimate for DLB incidence is 0.1% a year for the general population and 3.2% a year for all new dementia cases. The number of available studies was too small to hypothesise on the potential effect of age, sex and genetic background on the results. CONCLUSIONS: Although the literature on the prevalence and incidence of DLB is limited, there is a general consensus that DLB must be considered in the range of neurodegenerative conditions in the elderly. The move towards use of consensus criteria facilitates comparison and is welcome. Their application in a more routine way towards rigorously defined and selected study populations will lead to more comparable and generalisable studies in the future.