Overall and sex‐specific AT(N) biomarker prevalence in a low SES community: A population‐based study

Abstract Background Most previous studies of amyloid[A], tau[T], and/or neurodegeneration[(N)] prevalence have been completed in highly selected samples, leaving low SES older adults from medically underserved areas underrepresented in research. Furthermore, women consistently have greater T and sometimes greater A accumulation than men, but clear characterizations of AT(N) biomarker positivity overall and by sex in different populations are lacking. Methods Neuroimaging (NI) sub‐study participants in a population‐representative study of older adults from a low SES, medically underserved US Rust Belt area underwent PET and MRI. We calculated overall and sex‐specific AT(N) biomarker positivity within the NI sub‐study (Table 2) and population‐representative prevalence (Table 3) with inverse probability of selection weighting (IPSW). We calculated age and education adjusted odds ratios (ORs) for women vs men. Results The overall sample (N = 1226) was 61% female, 94% white, and 98% dementia‐free. NI study participants (N = 115) were older, likelier to be from the parent study’s original (vs. replenishment) cohort, and less likely to report diabetes than non‐NI participants (N = 1111; Table 1). IPSW based on variables associated with AT(N) biomarkers (age, cohort, sex, race, education, hypertension, diabetes, and number of medications) successfully balanced these characteristics across NI and non‐NI samples. Population‐weighted prevalence of the A‐T‐(N)‐ profile was 18.8%. Based on 2018 NIA‐AA Research Framework terminology, prevalence of AD continuum biomarkers (any A+) was 24.4%; about 2/3 of these cases were specifically due to AD (A+T+ biomarkers). Prevalence of any T+ was 34.7%, and any (N)+ was the most common at 63.0%. Prevalence of A‐ with T+ and/or (N)+ was 56.8%. Any T+ and AD continuum/AD+ biomarkers were non‐significantly more common in women than men (weighted ORs ranging from 1.20 to 1.69, Table 3). Conclusions Completely normal AD biomarkers (A‐T‐(N)‐) were comparatively rare in older participants in this community, while any N+ and A‐ with T+ and/or (N)+ were quite common. Women trended toward a greater prevalence of AD+ biomarkers than men. These results are more applicable to other primarily white, low SES, and medically underserved populations than results from highly selected samples. Characterizing brain health across varying cohorts is essential to advance precision medicine and population health.