Sex Difference in Effects of Low-Dose Aspirin on Prevention of Dementia in Patients With Type 2 Diabetes: A Long-term Follow-up Study of a Randomized Clinical Trial

OBJECTIVE To evaluate and compare the efficacy of long-term use of low-dose aspirin for the prevention of dementia in men and women. RESEARCH DESIGN AND METHODS This study is a follow-up cohort study of the Japanese Primary Prevention of Atherosclerosis with Aspirin for Diabetes (JPAD) trial, which was a randomized, open-label, standard care–controlled trial examining the effects of low-dose aspirin on cardiovascular events. We followed up 2,536 Japanese patients with type 2 diabetes (T2D) enrolled in the JPAD trial from 2002 to 2017. The primary outcome of this post hoc analysis was the incidence of dementia, which was defined by the prescription of antidementia drugs or admission due to dementia. RESULTS Among the originally enrolled patients, 2,121 (84%) retained their original allocation. During a median follow-up of 11.4 years, 128 patients developed dementia. The overall effect of low-dose aspirin on the prevention of dementia adjusted for age, sex, and other established risk factors was not significant (hazard ratio [HR] 0.82, 95% CI 0.58–1.16). However, a significant reduction was seen in the risk of dementia in women (HR 0.58, 95% CI 0.36–0.95), but not in men (HR 1.27, 95% CI 0.75–2.13) (Pinteraction = 0.03). CONCLUSIONS Long-term use of low-dose aspirin may reduce the risk for dementia in women with T2D.