Introduction: Findings for genetic correlates of late-onset Alzheimer's disease (LOAD) in studies that rely solely on clinic visits may differ from those with capacity to follow participants unable to attend clinic visits.
Methods: We evaluated previously identified LOAD-risk single nucleotide variants in the prospective Adult Changes in Thought study, comparing hazard ratios (HRs) estimated using the full data set of both in-home and clinic visits (n = 1697) to HRs estimated using only data that were obtained from clinic visits (n = 1308). Models were adjusted for age, sex, principal components to account for ancestry, and additional health indicators.
Results: LOAD associations nominally differed for 4 of 21 variants; CR1 and APOE variants were significant after Bonferroni correction.
Discussion: Estimates of genetic associations may differ for studies limited to clinic-only designs. Home visit capacity should be explored as a possible source of heterogeneity and potential bias in genetic studies.
Keywords: Ascertainment bias; Bias; Cohort studies; Genetics; Genome-wide association studies; Genome-wide studies; Home research study visits; Inference; Late-onset Alzheimer's disease; Longitudinal studies; Missing data; Population-based studies; Prospective studies; Research clinic study visits; Selection bias.
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