LONGITUDINAL DIFFERENCES IN THE PROGRESSION FROM MCI TO AD BETWEEN HISPANIC AND NON-HISPANIC SUBJECTS

Background: Biomarkers were analyzed to find longitudinal differences in the way Hispanic (H) and non-Hispanic (NH) subjects progress from mild cognitive impairment (MCI) to Alzheimer's disease (AD). Methods: The ADNI database was screened for H (n = 9) and NH (n = 310) subjects with MCI who developed AD. Data included information from as far as 10 years after the baseline visit, yielding 1,444 total observations (43 for H). Analyses included 32 features from neuropsychological assessments (n = 7), biospecimens (n = 9), and imaging studies (n = 21). Statistical longitudinal models fitted to class-stratified quadratic equations identified features with significant differences in longitudinal behavior between H and NH (q-value <0.5; Benjamini-Hochberg correction for multiple comparisons). The fitting was performed using a generalized least square approach with an autoregressive correlation structure of first order (position = time to event; grouping = subject ID). Results: Figure 1 shows that there is no significant difference in the rate of progression between H and NH. However, the executive function score (Figure 2) was significantly different at time of event (first visit at which AD was diagnosed) and 18 months earlier. Furthermore, hippocampal volume (Figure 3 and Figure 4) was significantly different at time of event and up to 3 years earlier, and verified using data from two studies (UCSD and UCSF). Other features showed significant differences too (Table 1). Conclusions: The amount of H subjects limited this study, but significant conclusions were yielded anyways. Additionally, there are more sources of information available in the ADNI database that could potentially show additional differences between these populations. Regardless, there was no significant difference found in the rate at which H and NH subjects progressed from MCI to AD, and neither in the rate at which any of the biomarkers evolved throughout that period of time. But, H were found to start their executive function decay before NH did, and their hippocampal atrophy after NH did, indicating that these populations do not necessarily progress to AD in the same way, incentivizing further analyses on the matter. (Table Presented).