Older Samoans are a unique population for gaining knowledge about cognitive resilience. Dementia has been reported as occurring at low rates among them. Further, our recent pilot data from Independent Samoa found that although there was variability in their memory scores, older Samoans had scores that did not significantly differ from younger Samoans. The proposed study will examine factors that might contribute to this cognitive resilience: (a) unique positive age beliefs that predominate in Samoan culture; and (b) the recently identified CREBRF gene variant (rs373863828) that occurs in 45% of Samoans, but in less than 1% of non- Samoans. Previous research supports our premise that these cultural and genetic factors will contribute to cognitive resilience. The Principal Investigator conducted the first studies to demonstrate that culture-based positive age beliefs predict lower stress and better aging cognitive health, including lower risk of developing Alzheimer?s- disease biomarkers and dementia. This age belief-cognition finding has been supported by three meta-analyses, but has not been studied among Samoans. Additionally, our pilot data with older persons living in Independent Samoa showed the CREBRF gene variant predicted significantly better cognitive scores, and previous studies have shown this gene variant is associated with lower levels of type 2 diabetes and fasting blood glucose, both of which are associated with lower dementia risk. Further, the gene variant is part of a larger mechanism, present in everyone, that leads to the development of brain neuroplasticity. Because favorable environmental factors can increase this neuroplasticity, positive age beliefs (which tend to be assimilated from culture) may stimulate the neuroplasticity property of the CREBRF gene variant. Thus, our Specific Aims, which will be carried out for the first time, are to examine whether aging cognitive resilience is predicted by: (a) greater adherence to the prevailing positive Samoan aging beliefs; (b) the CREBRF gene variant; (c) a synergistic interaction of positive age beliefs and the gene variant; and (d) structural- level factors (i.e., Westernization, ageism and usefulness to others) as well as individual-level factors (i.e., ethnic identity and self-relevance of age beliefs) acting as moderators of a gene-culture interaction. We will assess the CREBRF gene variant and age beliefs at baseline, and cognitive resilience across three years, among 750 Samoans, aged 60 and older. We will recruit one third from each of the following (in ascending order of Westernization): Independent Samoa, American Samoa and San Francisco, CA. The proposed research has the potential to benefit cognitive aging health because it could identify a set of modifiable age beliefs and moderators for interventions and identify a new biological pathway to cognitive resilience in all older persons.
The proposed project examines for the first time whether traditional Samoan age beliefs and a newly-identified CREBRF gene variant predict greater cognitive resilience including lower risk of dementia. To accomplish this, we will interview older Samoans because there is evidence that they tend to have a high level of cognitive resilience, traditional age beliefs are still prevalent among them, and close to half have the CREBRF gene variant, whereas less than 1% of non-Samoans have it. Our research is relevant to the National Institute on Aging?s mission of improving the cognitive health of older persons by examining novel determinants of cognitive resilience in diverse cohorts.
