No abstract

Background:Indigenous populations may be at increased risk, compared with majority populations, for the development of dementia due to lower education levels and socio-economic status, higher rates of diabetes, hypertension, cardiovascular disease and alcohol abuse, an aging population structure, and poorer overall health. This is the first systematic review investigating the prevalence and incidence of dementia in indigenous populations worldwide.Methods:This systematic review was conducted in accordance with PRISMA guidelines. We searched MEDLINE, Embase, and PsycInfo for relevant papers published up to April 2015. Studies were included if they reported prevalence or incidence, the disease typically occurred after the age of 45, the study population included indigenous people, and the study was conducted in the general population.Results:Fifteen studies representing five countries (Canada, Australia, the USA, Guam, Brazil) met the inclusion criteria. Dementia prevalence ranged from 0.5% to 20%. Retrospective studies relying on medical records for diagnoses had much lower prevalence rates and a higher risk of bias than population-based prospective studies performing their own diagnoses with culturally appropriate cognitive assessment methods.Conclusions:The prevalence of dementia among indigenous populations appears to be higher than it is for non-indigenous populations. Despite a building body of evidence supporting the need for dementia research among indigenous populations, there is a paucity of epidemiological research, none of which is of high quality.

The ATP cassette-binding (ABC) gene superfamily contains more than 40 members, many of which are involved in cellular lipid transport. The most prominent example is ABCA1, mutations in which affect plasma high-density lipoprotein (HDL) cholesterol concentration. ABCC6 is another member of the ABC gene family, and mutations in ABCC6 were recently shown to cause pseudoxanthoma elasticum (PXE). A Canadian patient with PXE was referred for assessment of moderately severe type IV hyperlipoproteinemia with hypoalphalipoproteinemia, which was refractory to pharmacological treatment. We identified intron-exon boundaries of ABCC6 to sequence genomic DNA from this patient to find the disease mutation. We report (1) identification of a set of amplification primers for the 31 exons of ABCC6; (2) identification of the ABCC6 RϾX1164 nonsense mutation in the PXE subject with dyslipidemia; (3) identification of common amino acid variants and silent nucleotide variants in ABCC6, with a range of allele frequencies across ethnic groups; (4) evidence consistent with a possible pseudogene encoding 9 exons with sequence homology to ABCC6; and (5) association of the ABCC6 RϾQ1268 variant with plasma triglyceride and HDL cholesterol. The results suggest that ABCC6 may be a determinant of plasma lipoproteins.