Greater BMI across the lifespan is associated with better midlife cognition: The Bogalusa Heart Study

Studies of adiposity and cognition's relationship have been highly mixed, depending on points in the lifespan when adiposity and cognition were measured, primarily with low Black American representation. Therefore, we examined the association between adiposity (from early to mid-life) and mid-life cognition in an Black American (BA) and White American longitudinal cohort to address these literature gaps. The Bogalusa Heart Study has followed participants from childhood to adulthood since 1973. Adiposity was measured via body mass index (BMI) at roughly biannual visits from 1973-2016 and cognition was measured in 1295 participants between 2013- 2016. Cognition included Logical Memory I, II and II Recognition, Digit Spans Forward and Backward, Trail Making Tests A and B, and a global composite. BMI was averaged within age epochs (childhood/adolescence; early adulthood (EA); midlife (M)) with childhood/adolescence BMI as percentiles. Separate linear regression models were run for each cognitive measure (outcome), BMI within one epoch, and sex, race, and education (predictors). All analyses included the 1292 individuals who provided complete data across all epochs. Greater BMI within EA and M was associated with better global cognition (EA: Est. 0.139 S.D./BMI p = 0.000; M: Est. 0.094 S.D./BMI p = 0.022), and Logical Memory I (EA: Est. 0.036 S.D./BMI p = 0.000; M: Est. 0.022 S.D./BMI p = 0.000), II (EA: Est. 0.036 S.D./BMI p = 0.000; M: Est. 0.020 S.D./BMI p = 0.022) and II Recognition (EA: Est. 0.029 S.D./BMI p = 0.000; M: Est. 0.022 S.D./BMI p = 0.000) among men. Among BA, greater BMI within EA and M was associated with better Logical Memory I (EA: Est. 0.022 S.D./BMI p = 0.000; M: Est. 0.019 S.D./BMI p = 0.000) and II (EA: Est. 0.018 S.D./BMI p = 0.042; M: Est. 0.017 S.D./BMI p = 0.000). Greater adiposity from early adulthood to midlife was associated with better memory performance in midlife (associations strongest among men and Black Americans). More anatomically precise measurements of adiposity (e.g., subcutaneous vs. visceral fat) could help clarify the complex adiposity cognition relationship across the lifespan.