Session Title: Alzheimer's Disease (AD) including Non-Cognitive Aspects
THE RELATIONSHIP BETWEEN LEAN BODY MASS, COGNITION AND BLOOD BIOMARKERS IN A HEALTHY ELDERLY POPULATION
J.J. Peiffer1, B.M. Brown2, K.M. Taddei2, J. Lui1, T. Taddei2, V.K. Ward2, M.A. Rodrigues2, M. Rimajova2, J.K. Foster2, K. Ellis3, C. Masters3, D. Ames3, P. Hudson4, C. Rowe5, R.N. Martins2
In obese individuals, high insulin levels are linked to the positive correlation between obesity and the occurrence of Alzheimer's disease (AD). Increasing muscle mass can decrease insulin levels and may protect against AD. This study compared body composition indices with cognitive markers and AD-associated blood biomarkers. Sixty-eight cognitively-healthy male and female volunteers (age: 71±7 y) completed a dual x-ray absorptiometry (DEXA) scan during which lean mass (LM), fat mass (FM) and relative lean mass (%LM) were recorded. Fasting blood samples were analysed for glucose, insulin, β-amyloid 42 (Aβ42), Aβ40. The Aβ42/Aβ40 ratio was also calculated. Cognitive functioning was measured using the Mini-Mental State Examination (MMSE) and the California Verbal Language Test-Second Edition (CVLT-II). Differences in body composition across gender were examined using independent t-tests. Spearman ranked-order correlations were used to determine relationships between DEXA variables, cognition scores and blood biomarkers for the total cohort, as well as gender specific sub-groups. LM was significantly greater and FM was significantly lower in males (54.9±7.8 Kg and 20.7±6.2 Kg, respectively) compared with females (34.5±8.6 Kg and 31.2±8.2 Kg, respectively). In the total cohort, LM was negatively correlated with performance on the learning trials of the CVLT-II (r=-0.23; p< 0.05). %LM was negatively correlated with insulin in males (r=-0.46; p< 0.05) and females (r=-0.35; p< 0.05). In males, %LM was positively correlated with MMSE (r=0.48; p< 0.05). In conclusion, increases in LM may provide health benefits that could protect individuals from AD; however, increases in LM must be accompanied by a reduction in FM.