Sex Differences in the Associations between Education, Neuropathology, and Cognition
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IMPORTANCE
Autopsy evidence on sex-specific associations of education with neuropathology and cognition is limited.
OBJECTIVE
To test sex differences in education associations with neuropathologic burden and cognition.
DESIGN
Cohort study of data collected from September 2005 through August 2024.
SETTING
Multicenter autopsy cohort from the National Alzheimer’s Coordinating Center.
PARTICIPANTS
Adults aged 55 years or older; cross-sectional eligibility required a final CDR-SB assessment within 2 years before death, and longitudinal eligibility additionally required at least 3 assessments.
EXPOSURES
Years of formal education.
MAIN OUTCOMES AND MEASURES
Neuropathologic measures and the Clinical Dementia Rating Scale Sum of Boxes (CDR-SB). Linear regression and mixed-effects models tested associations and interactions of education with sex, neuropathology, and linear and quadratic time. Benjamini-Hochberg correction addressed multiple comparisons.
RESULTS
Among 2592 participants (mean [SD] age at death, 81.6 [10.8] years; 1188 [45.8%] female), 1969 contributed to longitudinal analyses. In female participants, higher education was associated with lower Thal amyloid phase, diffuse plaques, neuritic plaques, and Braak stage (β range, −0.097 to −0.071; q FDR <.026); none was significant among male participants. Education-by-sex interactions supported differences in Thal amyloid phase, and diffuse and neuritic plaques (β range, −0.119 to −0.097; q FDR <.045). Education was unrelated to final CDR-SB among female (β, −0.007; 95% CI, −0.052 to 0.038; P =.767) and male participants (β, −0.026; 95% CI, −0.071 to 0.019; P =.254), with no education-by-sex interaction ( P =.660). The education-by-Braak-stage-by-sex interaction indicated that higher education was associated with a weaker Braak stage-CDR-SB association among females than males (β, −0.104; 95% CI, −0.171 to −0.038; q FDR =.022). Longitudinally, education was unrelated to linear CDR-SB change in either sex. Education-by-quadratic-time associations were observed among females (β, 0.002; 95% CI, 0.001-0.003; P <.001) and male participants (β, 0.001; 95% CI, 0-0.002; P =.037). The corresponding interaction with sex was also significant ( P =.043).
CONCLUSIONS AND RELEVANCE
Among female participants, higher education was associated with lower selected Alzheimer’s disease neuropathologic measures and weaker associations of tau pathology with cognition. Longitudinal trajectories were nonlinear, with slower earlier decline followed by later acceleration at higher education levels.
Key Points
Question
Do associations between education, neuropathologic burden and cognition differ by sex?
Findings
In this cohort study of 2592 autopsy participants, higher education was associated with lower Alzheimer’s disease neuropathologic burden among female but not male participants, and education-by-sex interactions were significant for Thal amyloid phase, diffuse and neuritic plaques. Higher education was associated with a weaker Braak stage-CDR-SB association among female than male participants and with lower CDR-SB five years before death in both sexes. The associations persisted after adjustment for neuropathologic burden.
Meaning
Education-neuropathology associations and the clinical expression of neuropathology may be sex-specific.
