Publications

Background: Despite their intrinsic strengths and resilience, some American Indian and Alaska Native (AI/AN) communities experience among the highest rates of suicide of any racial and ethnic group. Caring Contacts is one of the only interventions shown to reduce suicide in clinical trials, but it has not been tested in AI/AN settings.

Objective: To compare the effectiveness of Enhanced Usual Care (control) to Enhanced Usual Care augmented with a culturally adapted version of Caring Contacts (intervention) for reducing suicidal ideation, suicide attempts, and suicide-related hospitalizations.

Methods: We are implementing a single blind randomized controlled trial of Caring Contacts in five AI/AN communities across the country (South Dakota, Montana, Oklahoma, and Alaska). Eligible participants have to be (1) actively suicidal or have made a suicide attempt within the past year; (2) at least 18 years of age; (3) AI/AN; (4) able to speak and read English; (5) able to participate voluntarily; (6) willing to be contacted by text, email or postal mail; and (7) able to provide consent. Following consent and baseline assessment, participants are randomized to receive either Enhanced Usual Care alone, or Enhanced Usual Care with 12 months (25 messages) of culturally adapted Caring Contacts. Follow-up assessments are conducted at 12 and 18 months.

Conclusions: If effective, this study of Caring Contacts will inform programs to reduce suicide in the study communities as well as inform future research on Caring Contacts in other tribal settings. Modifications to continue the trial during the COVID-19 pandemic are discussed.

Clinical trials registration: NCT02825771.

Keywords: Alaska native; American Indian; Clinical trial; Suicidal ideation; Suicide attempt; Tribal.

Little is known about incidence of vascular and Alzheimer’s dementias in American Indians. METHODS We conducted a large, heterogeneous, population-based, longitudinal cohort study of brain aging in community-dwelling American Indians aged 64-95 years from 11 tribes across 3 states, with neurological examinations, 1.5T magnetic resonance imaging (MRI), and extensive cognitive testing. Visit 1 in 2010-2013 (n=817) and Visit 2 in 2017-2019 (n=403) included all willing, surviving participants. Standardized cognitive tests at both visits included Modified Mini Mental Status Examination (3MSE), Wechsler Adult Intelligence Scale digit symbol coding (WAIS), Controlled Oral Word Association fas (COWA), California Verbal Learning Test short form (CVLT). Test materials added at follow-up included Wide Range Achievement (reading) Test (WRAT) and National Alzheimer’s Coordinating Center Uniform Data Set cognitive battery (v3 form C2) , including Montreal Cognitive Assessment (MoCA). MRI neuroradiologists coded infarcts, hemorrhages, white matter hyperintensities, sulcal atrophy, and ventricle enlargement. RESULTS Mean time between exams was 6.7 years (SD 1.1, range 3.8-9.1). Years of formal education had modest correlation with WRAT reading score (r=0.45). Prevalence and incidence of infarcts were (respectively) 32% and 12.8/1000 person-years (PY); hemmorhages 6% and 4.4/1000 PY; worsening sulci 74% and 19.0/1000 PY; wosening ventricle 79% and 30.1/1000 PY; worsening leukoaraiosis 44% and 26.1/1000 PY. Linear losses per year in cognitive scores were 0.6% 3MSE, 1.2% WAIS, 0.6% COWA, 2.2% CVLT. Mean MoCA scores were 18.9 (SD 4.3). DISCUSSION These are the first data on longitudinal cognitive and imaging changes in American Indians, as well as first reports of AD related features. Mean scores in MoCA were similar or lower than standard cutoffs used to diagnose dementia in other racial/ethnic groups, suggesting that standardized cognitive tests may not perform well in this population. Test validation, adaptation, and score adjustment are warranted. Years of education was a poor proxy for premorbid function, suggesting novel methods for cognitive score contextualization is also needed in this population. Evaluation of selective survival suggests attrition from death and frailty should be accounted for in causal analyses. Overall, these data represent a unique opportunity to examine neurology topics of critical importance to an understudied population.

Introduction: Distinguishing Alzheimer’s disease (AD) patient subgroups may optimize positive clinical outcomes. Cortical atrophy is correlated with memory deficits, but these associations are understudied in American Indians.

Methods: We collected imaging and cognition data in the Strong Heart Study (SHS), a cohort of 11 tribes across three regions. We processed 1.5T MRI using FreeSurfer and iterative principal component analysis. Linear mixed models estimated volumetric associations with diabetes.

Results: Over mean 7 years follow-up (N = 818 age 65-89 years), overall volume loss was 0.5% per year. Significant losses associated with diabetes were especially strong in the right hemisphere. Annualized hippocampal, parahippocampal, entorhinal atrophy were worse for men, older age, diabetes, hypertension, stroke; and associated with both encoding and retrieval memory losses.

Discussion: Our findings suggest that diabetes is an important risk factor in American Indians for cortical atrophy and memory loss. Future research should examine opportunities for primary prevention in this underserved population.

Keywords: Alzheimer’s disease; American Indians; MRI; volumetric atrophy.