Obesity enhances verbal memory in postmenopausal women with Down syndrome

Several lines of evidence suggest that the loss of estrogen after menopause may play a role in cognitive declines associated with Alzheimer's disease (AD). In postmenopausal women, the principal source of estrogen is estrone, which is influenced by body mass index (BMI). Increased BMI in postmenopausal women is associated with higher levels of serum estradiol and estrone. We hypothesized that obesity could have a beneficial effect on cognition with advancing age. We compared the performance of healthy nondemented obese and non-obese women with Down syndrome (DS) on a broad spectrum of cognitive tests. Estrone levels were 66.9% higher in obese than in non-obese postmenopausal women, and 136% higher in obese than in non-obese premenopausal women. Obese postmenopausal women performed significantly better than non-obese women on measures of verbal memory and on an omnibus test of neuropsychological function, but did not differ significantly in verbal fluency, language, praxis or visuospatial functioning. Among premenopausal women, there was no difference in cognitive function between obese and non-obese women. Our results support the hypothesis that higher endogenous estrogen levels after menopause are associated with better performance on verbal memory.