GLP1 receptor agonist versus DPP4 inhibitor initiation was associated with a lower risk of all-cause dementia among people with BMI < 30 kg/m2 (HR [95% CI]: 0.74 [0.56–0.97]), whereas there was no association among those with BMI ≥ 30 kg/m2 (HR [95% CI]: 1.02 [0.92–1.12], and the estimates were significantly different (p = 0.029). Here, GLP1R is linked to dementia.