Participants' adiposity (fat level) was assessed by body mass index, waist circumference, sagittal diameter (distance between the back and the highest point of the abdomen), total fat mass and subcutaneous (beneath the skin) and visceral fat (fat between the internal organs) measured by computed tomography. Men whose measurements were higher were more likely to experience declines in scores on a cognitive functioning test administered at the beginning of the study and again after three, five and eight years. However, no association was observed in women.
"Women show trends toward inverse associations, with higher levels of adiposity being associated with less cognitive change," the authors write. "Traditional metabolic factors, adipocytokines [compounds produced by fat tissue] and sex hormones do not explain this sex difference. Future studies should confirm these longitudinal associations with adiposity and cognitive change and investigate why adiposity has inverse associations in men and women."
Arch Neurol. 2009;66[3]:329-335.