@article {6000, title = {Do changes in circulating biomarkers track with each other and with functional changes in older adults?}, journal = {J Gerontol A Biol Sci Med Sci}, volume = {69}, year = {2014}, month = {2014 Feb}, pages = {174-81}, abstract = {

BACKGROUND: It is unclear if changes in proposed circulating biomarkers of aging are strongly correlated to each other or functional change. We tested if biomarker changes track with each other and with functional measures over 9 years in older adults.

METHODS: Dehydroepiandrosterone sulfate (DHEAS), adiponectin, insulin-like growth factor 1 (IGF-1), IGF binding proteins 1 (IGFBP-1) and 3 (IGFBP-3), interleukin-6 (IL-6), cholesterol, and function (gait speed, grip strength, Modified Mini Mental Status Exam [3MSE] and Digit Symbol Substitution Test [DSST] scores) were measured in 1996-1997 and 2005-2006 in the Cardiovascular Health Study All Stars study (N = 901, mean [standard deviation, SD] age 85.3 [3.6] years in 2005-2006). Adjusted Pearson correlations illustrated if biomarkers tracked together. Multivariable linear regression demonstrated if biomarker changes tracked with functional changes.

RESULTS: Correlations among biomarker changes were mostly <0.2. In models with each biomarker entered separately, a 1-SD increase biomarker change was associated with change in function as follows: grip strength (DHEAS β = 0.61kg, p = .001; IL-6 β = -0.46kg, p = .012; cholesterol men β = 0.79kg, p = .016); gait speed (DHEAS β = 0.02 meters per second, p = .039; IL-6 β = -0.018 meters per second, p = .049); and DSST score (DHEAS women β = 1.46, p = .004; IL-6 β = -0.83, p = .027). When biomarkers were entered in the same model, significant associations remaining were as follows: grip strength (DHEAS β = 0.54kg, p = .005; IL-6 β = -0.43kg, p = .022); 3MSE score (IGF-1 β = 0.96, p = .04; IGFBP-3 β = -1.07, p = .024); and DSST score (DHEAS women β = 1.27, p = .012; IL-6 β = -0.80, p = .04).

CONCLUSION: Changes in biomarkers were poorly correlated, supporting a model of stochastic, independent change across systems. DHEAS and IL-6 tracked most closely with function, illustrating that changes in inflammation and sex steroids may play dominant roles in changes of these functional outcomes.

}, keywords = {Adiponectin, Aged, Aged, 80 and over, Aging, Biomarkers, Cholesterol, Cognition, Cohort Studies, Dehydroepiandrosterone Sulfate, Female, Gait, Hand Strength, Humans, Insulin-Like Growth Factor Binding Protein 1, Insulin-Like Growth Factor Binding Protein 3, Insulin-Like Growth Factor I, Interleukin-6, Male, Neuropsychological Tests, Psychomotor Performance, Time Factors}, issn = {1758-535X}, doi = {10.1093/gerona/glt088}, author = {Sanders, Jason L and Ding, Victoria and Arnold, Alice M and Kaplan, Robert C and Cappola, Anne R and Kizer, Jorge R and Boudreau, Robert M and Cushman, Mary and Newman, Anne B} } @article {6737, title = {Changes in insulin-like growth factor-I and its binding proteins are associated with diabetes mellitus in older adults.}, journal = {J Am Geriatr Soc}, volume = {63}, year = {2015}, month = {2015 May}, pages = {902-9}, abstract = {

OBJECTIVES: To determine whether changes in insulin-like growth factor (IGF) protein levels are greater in participants with type 2 diabetes mellitus or worsening glycemia than in normoglycemic individuals over a 9-year follow-up period.

DESIGN: Retrospective analysis of a cohort study.

SETTING: Participants were recruited from North Carolina, California, Maryland, and Pennsylvania.

PARTICIPANTS: Cardiovascular Health Study All Stars participants, a cohort study of community-dwelling adults aged 65 and older (N=897).

MEASUREMENTS: Plasma IGF-I, IGF binding protein (IGFBP)-1, and IGFBP-3 levels were assessed and American Diabetes Association cut-points for impaired glucose tolerance (IGT), impaired fasting glucose (IFG), and diabetes mellitus were used to classify participants at baseline (1996-97) and follow-up (2005-06).

RESULTS: At baseline, mean age was 76.3{\textpm}3.6, and 18.5\% had diabetes mellitus. Participants with IFG alone and IGT plus IFG had higher IGF-I levels and lower IGFBP-1 levels than those with normoglycemia or diabetes mellitus. The greatest percentage change in IGF levels occurred in those who had diabetes mellitus at baseline (9-year changes: -9.3\% for IGF-I, 59.7\% for IGFBP-1, -13.4\% for IGFBP-3), the smallest in individuals who remained normoglycemic at follow-up (9-year changes: -3.7\% for IGF-I, 25.6\% for IGFBP-1, -6.4\% for IGFBP-3), and intermediate in those who were normoglycemic but developed IFG at follow-up.

CONCLUSION: Degrees of glycemic impairment are associated with varying degrees of change in IGF protein levels. The changes observed in the diabetes mellitus group have been previously shown to be associated with heart failure, cancer, and noncancer mortality.

}, keywords = {Aged, Blood Glucose, Cohort Studies, Diabetes Mellitus, Type 2, Female, Humans, Insulin-Like Growth Factor Binding Protein 1, Insulin-Like Growth Factor Binding Protein 3, Insulin-Like Growth Factor I, Male, Retrospective Studies}, issn = {1532-5415}, doi = {10.1111/jgs.13390}, author = {Aneke-Nash, Chino S and Parrinello, Christina M and Rajpathak, Swapnil N and Rohan, Thomas E and Strotmeyer, Elsa S and Kritchevsky, Stephen B and Psaty, Bruce M and B{\r u}zkov{\'a}, Petra and Kizer, Jorge R and Newman, Anne B and Strickler, Howard D and Kaplan, Robert C} }