GDF15 and its association with cognitive performance over time in a longitudinal study of middle-aged urban adults

Serum GDF15 levels are correlated with multiple neurodegenerative diseases. Few studies have tested this marker's association with middle-aged cognitive performance over time, and whether race affects this associa-tion is unknown. We examined associations of initial serum GDF15 concentrations with longitudinal cognitive performance, spanning domains of global mental status, visual and verbal memory, attention, fluency, and ex-ecutive function in a sub-sample of adults participating in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS) study (n = 776, Agev1:30-66y, 45.6 % male, 57.0 % African American, 43.0 % below poverty). This analysis consisted of mixed-effects regression models applied to the total selected sample, while also stratifying the analyses by race in the main analyses and further stratifying by sex, age group and poverty status in an exploratory analysis. Our main findings, which passed multiple testing and covariate-adjustment, indicated that GDF15 was associated with poorer baseline performance on several cognitive tests, including animal fluency [overall sample: (Model 1: gamma 0 +/- SE:-0.664 +/- 0.208, P < 0.001; Model 2, gamma 0 +/- SE:-0.498 +/- 0.217, P < 0.05)]. Among White adults, GDF15 was linked to poorer performance on a brief test of attention (Model 1: gamma 0 +/- SE:-0.426 +/- 0.126, P < 0.001; Model 2, gamma 0 +/- SE:-0.281 +/- 0.139, P < 0.05); and Trailmaking test, part B (Model 1: gamma 0 +/- SE: +0.129 +/- 0.040, P < 0.001; Model 2, gamma 0 +/- SE: +0.089 +/- 0.041, P < 0.05), the latter being also linked to higher GDF15 among individuals living below poverty. Among women, GDF15 was associated with poor global mental status (Normalized MMSE: Model 1: gamma 0 +/- SE:-2.617 +/- 0.746, P < 0.001; Model 2: gamma 0 +/- SE:-1.729 +/- 0.709, P < 0.05). GDF15 was not associated with decline on any of the 11 cognitive test scores considered in similar to 4 years of follow-up. In sum, we detected cross-sectional associations be-tween GDF15 and cognition, although GDF15 did not predict rate of change in cognitive performance over time among a sample of middle-aged adults. More longitudinal studies are needed to address the clinical utility of this biomarker for early cognitive defects.