Search

Objective: This study sought to conduct a comprehensive search for genetic risk of cognitive decline in the context of geriatric depression. Design: A genome-wide association study (GWAS) analysis in the Neurocognitive Outcomes of Depression in the Elderly (NCODE) study. Setting: Longitudinal, naturalistic follow-up study. Participants: Older depressed adults, both outpatients and inpatients, receiving care at an academic medical center. Measurements: The Consortium to Establish a Registry for Alzheimer's Disease (CERAD) neuropsychological battery was administered to the study participants at baseline and a minimum of twice within a subsequent 3-year period in order to measure cognitive decline. A GWAS analysis was conducted to identify genetic variation that is associated with baseline and change in the CERAD Total Score (CERAD-TS) in NCODE. Results: The GWAS of baseline CERAD-TS revealed a significant association with an intergenic single-nucleotide polymorphism (SNP) on chromosome 6, rs17662598, that surpassed adjustment for multiple testing (p = 3.7 × 10−7; false discovery rate q = 0.0371). For each additional G allele, average baseline CERAD-TS decreased by 8.656 points. The most significant SNP that lies within a gene was rs11666579 in SLC27A1 (p = 1.1 × 10−5). Each additional copy of the G allele was associated with an average decrease of baseline CERAD-TS of 4.829 points. SLC27A1 is involved with processing docosahexaenoic acid (DHA), an endogenous neuroprotective compound in the brain. Decreased levels of DHA have been associated with the development of Alzheimer's disease. The most significant SNP associated with CERAD-TS decline over time was rs73240021 in GRXCR1 (p = 1.1 × 10−6), a gene previously linked with deafness. However, none of the associations within genes survived adjustment for multiple testing. Conclusions: Our GWAS of cognitive function and decline among individuals with late-life depression (LLD) has identified promising candidate genes that, upon replication in other cohorts of LLD, may be potential biomarkers for cognitive decline and suggests DHA supplementation as a possible therapy of interest. [ABSTRACT FROM AUTHOR]

The article presents information on a study conducted on mild cognitive impairment without dementia among older adults in the U.S. It is mentioned that mild cognitive impairment might affect attention, language, judgment, and memory, but it doesn't severely impair activities of daily living. In the study, many neuropsychological tests were done on 856 people above 71 years. The researchers found that about 22% of the older people had cognitive impairment that did not develop into dementia.

Aim: To estimate the prevalence of Alzheimer's disease (AD) and other dementias in the USA using a nationally representative sample., Methods: The Aging, Demographics, and Memory Study sample was composed of 856 individuals aged 71 years and older from the nationally representative Health and Retirement Study (HRS) who were evaluated for dementia using a comprehensive in-home assessment. An expert consensus panel used this information to assign a diagnosis of normal cognition, cognitive impairment but not demented, or dementia (and dementia subtype). Using sampling weights derived from the HRS, we estimated the national prevalence of dementia, AD and vascular dementia by age and gender., Results: The prevalence of dementia among individuals aged 71 and older was 13.9%, comprising about 3.4 million individuals in the USA in 2002. The corresponding values for AD were 9.7% and 2.4 million individuals. Dementia prevalence increased with age, from 5.0% of those aged 71-79 years to 37.4% of those aged 90 and older., Conclusions: Dementia prevalence estimates from this first nationally representative population-based study of dementia in the USA to include subjects from all regions of the country can provide essential information for effective planning for the impending healthcare needs of the large and increasing number of individuals at risk for dementia as our population ages., ((c) 2007 S. Karger AG, Basel.)