For example, The Framingham Heart Study showed that higher BMI is associated with lower cognitive performance (learning, memory, and executive function) in elderly individuals (Elias et al., 2003). Moreover, in a smaller cohort of elderly patients, Cattin et al. reported that cognitive impairment decreases with increasing BMI (Cattin et al., 1997). In contrast, Kuo et al. found that although

elderly obese (assessed by BMI) individuals did not demonstrate compelling superiority in memory compared with normal-weight individuals, they demonstrated better performance in visuospatial speed of processing (Kuo et al., 2006). Furthermore, West et al. showed an inverse association between BMI and rate of cognitive impairment (West and Haan, 2009). The reasons for the discrepancies between these studies are PLX4032 unclear, however, it is noteworthy that the battery of cognitive tests used in these studies varied considerably in terms of the breadth of domains tested and the stringency of tests employed. Thus, this may make it difficult to compare their findings. Additionally, it is well known that aging is associated with changes in body composition, including an increase in fat

mass and a decline in muscle mass (sarcopenia). Thus, the mixed findings may reflect the difficulties in defining obesity in elderly cohorts based on anthropomorphic measurements such as BMI. Indeed, using waist circumference as a OSBPL9 measure of central obesity, West et al. revealed that obesity is associated with an increased rate of cognitive impairment LY2835219 mouse in non-demented elderly individuals while BMI in the same cohort was inversely associated (West and Haan, 2009). In addition to its effect on cognitive performance, growing evidence indicates that obesity may influence brain structure. Indeed, current literature suggests

that obesity is associated with brain atrophy (Enzinger et al., 2005, Ward et al., 2005, Taki et al., 2008, Raji et al., 2010, Fotuhi et al., 2012 and Brooks et al., 2013). For example, higher BMI and waist circumference are linked with lower total brain volume in non-demented elderly patients (∼75 years) (Enzinger et al., 2005, Raji et al., 2010, Fotuhi et al., 2012 and Brooks et al., 2013). Similarly, in a cohort of younger adults (mean age 54 years) BMI was inversely associated with global brain volume, even after adjusting for age and a number of cardiovascular risk factors such as systolic blood pressure and cholesterol levels (Liang et al., 2014). A negative relationship between regional brain atrophy and obesity has also been described (Jagust et al., 2005, Pannacciulli et al., 2006, Taki et al., 2008 and Raji et al., 2010). In particular, the temporal (including the hippocampus) and frontal lobes appear to be particularly vulnerable to the effects of obesity.