The National Israel Brain Repository: Characterizing those who sign and do not sign intent to autopsy

Abstract Background Collection of postmortem human brain and spinal cords for research is invaluable, especially in neurodegeneration, since human clinicopathologic data may lead to better understanding their pathophysiology and to new therapeutic targets. The National Israel Brain Repository was established in 2018 and began recruiting donors from two large‐scale community‐based studies of individuals at high dementia risk: older adults with type 2 diabetes (Israel Diabetes and Cognitive Decline study‐IDCD) and middle‐aged offspring of AD patients (The Israel Registry for Alzheimer’s Prevention‐ IRAP).We compared sociodemographic, cardiovascular (CVRFs)and cognitive characteristics of individuals who agreed and did not agree to sign intent to autopsy (ITA) Method In the IDCD, of the 750 active participants, we approached 636. Of them, 196 (31%) agreed to sign ITA.IRAP has 480 active participants of whom 395 were approached and of them 176 (45%) agreed to sign ITA. All participants are from the Maccabi Health Services, providing CVRF data since 1998. Using t‐test we compared the groups on sociodemographic and CVRFs. For IDCD, which averages 36‐months cognitive follow ups, mixed regression models adjusting for age, sex and education tested whether signing ITA predicted cognitive trajectories. For IRAP, whose follow‐ups have only recently begun, we used linear regressions adjusting for the same covariates, compared cognitive functioning between those the two groups Result In the IRAP sample, participants who signed ITA did not differ from those who did not sign on any of the characteristics except for HbA1c (Table 1). In the IDCD sample, those who signed ITA had higher education, creatinine, and BMI and better motor function (hand grip and 3‐meter walk). Finally, those who signed ITA had a slower rate of decline in episodic memory (Estimate = 0.002, SE = 0.001, p = 0.05) Conclusion Our results suggest that middle‐aged adults at high AD risk willing to donate their brains to science do not differ in sociodemographic or CVRFs from those who do not wish to be organ donors. In contrast, older adults at high dementia risk due to T2D who signed ITA are more educated, have better motor function and a slower rate of cognitive decline suggesting a selection bias towards better health.Development of strategies to diminish this selection bias are warranted.