Obesity has been associated with cognitive decline in longitudinal studies of older individuals. We hypothesized that the cognitive sequelae of obesity may be detectable in the reproductive years. In addition, we explored the hypothesis that these associations may be mediated by the hormonal milieu. In this study of 49 young healthy lean and overweight women aged 20–45, we investigated the association between performance on a battery of cognitive tests, body composition parameters (BMI, total fat, abdominal (visceral, subcutaneous and total) adipose tissue, and muscle), and hormone levels (insulin, adiponectin, leptin, IGF-1, estrogen, testosterone, and vitamin D). We found a significant negative association between both visceral adiposity and muscle, and performance in the domain of verbal learning and memory, after controlling for age and education. Other body composition parameters showed similar trends (0.05<p<0.10). Additionally, the degree of insulin resistance was negatively associated with executive function domain. None of the associations between the other hormones examined (adipokines, IGF-1, gonadal hormones and vitamin D) and cognitive function were significant. These preliminary findings suggest a possible association between obesity and cognitive function in healthy young women of reproductive age. More research is warranted into the potential modulatory effect of insulin resistance on this association
