Childhood inductive reasoning, cardiovascular and cardiometabolic morbidity and dementia risk – a population representative cohort study across six decades

Abstract Background Higher cognitive ability in late adolescence and young adulthood associate with reduced risk of dementia, but such assessments are influenced by educational selection. Whether specific cognitive abilities earlier in childhood associate with later dementia risk, independent of known associations with cardiovascular disease (CVD) and diabetes, remains unclear. Methods We studied a Swedish population-representative birth cohort with cognitive testing at age 13 ( n = 10,539 born in 1948). Dementia and somatic morbidity were ascertained from nationwide inpatient and cause-of-death registers through November 2025 (> 6 decades). Cox models estimated associations between childhood inductive reasoning, verbal and spatial ability scores and dementia, somatic morbidity, CVD and diabetes, each modelled as outcomes and as time-varying covariates in dementia models. Results During follow-up, 287 individuals (2.7%) developed dementia. Higher childhood inductive reasoning associated with lower risk of dementia (HR per SD = 0.84, 95% CI 0.72–0.98), somatic morbidity, CVD (HR 0.88, 95% CI 0.83–0.92), and diabetes (HR 0.85, 95% CI 0.79–0.91). Verbal and spatial abilities were not independently associated with dementia. Somatic morbidity, CVD, and diabetes associated with dementia risk (HRs ~ 1.75–2.13), but only modestly attenuated the inductive reasoning–dementia association (HRs ~ 0.84–0.85). Findings replicated in an expanded cohort including individuals born in 1953 (total n = 19,919) and were robust to adjustment for parental and midlife education. Conclusions Higher childhood inductive reasoning was associated with lower dementia risk across six decades, and this relationship was not substantially attenuated by adjustment for education or clinically manifest cardiovascular or cardiometabolic disease. These findings are consistent with a life-course perspective in which early neurodevelopmental characteristics contribute to dementia risk alongside major vascular and metabolic risk factors.