Inductive Reasoning Scores at Age 13 Tied to 2% Lower Dementia Risk per Point in 60-Year Swedish Cohort

Researchers administered tests of inductive reasoning, verbal ability, and spatial ability to sixth-graders and linked results directly to hospital and death registers spanning six decades. Only inductive reasoning showed a graded, persistent inverse association with dementia; verbal and spatial scores did not. The association survived adjustment for parental and own education plus midlife cardiometabolic diagnoses, addressing a key limitation of prior studies that examined cognition after schooling had already diverged. The findings align with cognitive-reserve hypotheses but add temporal precision by capturing reasoning before major educational stratification. Still, the observational design cannot exclude residual confounding by unmeasured factors such as genetic liability or early nutrition, and absolute risk differences were modest given the low base rate of diagnosed dementia. Next steps require replication in diverse cohorts, integration of polygenic scores and midlife neuroimaging, and ideally randomized trials of reasoning-focused interventions begun in adolescence or early adulthood to test whether the observed association is modifiable.