@article {1369, title = {Lipoprotein-associated phospholipase A2 (Lp-PLA2) and future risk of type 2 diabetes: results from the Cardiovascular Health Study.}, journal = {J Clin Endocrinol Metab}, volume = {97}, year = {2012}, month = {2012 May}, pages = {1695-701}, abstract = {

INTRODUCTION: Lipoprotein-associated phospholipase A2 (Lp-PLA(2)) has been consistently associated with cardiovascular disease (CVD) risk factors and predictive of CVD outcomes; furthermore, it is consistently higher among type 2 diabetics than nondiabetics. However, the relationships of circulating Lp-PLA(2) mass and activity with incident type 2 diabetes mellitus have not been examined. Therefore, the purpose of this study was to determine the association of Lp-PLA(2) mass and activity with type 2 diabetes among older adults.

METHODS: We conducted analyses of Lp-PLA(2) and prevalent and incident diabetes among 5474 men and women from the Cardiovascular Health Study (1989-2007). Lp-PLA(2) mass and activity were measured in baseline plasma. Diabetes status was ascertained annually with medication inventories and repeated blood glucose measurements. Generalized linear and Cox proportional hazards models were used to adjust for confounding factors including body mass index and inflammation.

RESULTS: At baseline, the top two quintiles of Lp-PLA(2) activity were significantly associated with prevalent type 2 diabetes with a multivariable relative risk = 1.35 [95\% confidence interval (CI) = 1.11-1.63] for quintile 4, and relative risk = 1.33 (95\% CI = 1.07-1.66) for quintile 5. Among participants free of diabetes at baseline, we found a significant positive association with both the homeostatic model assessment for insulin resistance and β-cell function per SD increase in Lp-PLA(2) activity (P values for both <0.01). In prospective analyses, the risk of incident type 2 diabetes was significantly higher among those in the highest quintile of Lp-PLA(2) activity [multivariable hazard ratio = 1.45 (95\% CI = 1.01-2.07)] compared with the lowest quintile. Lp-PLA(2) mass was not significantly associated with incident type 2 diabetes.

DISCUSSION: Lp-PLA(2) activity is positively associated with insulin resistance and predicts incident type 2 diabetes among older adults independent of multiple factors associated with diabetes pathogenesis.

}, keywords = {1-Alkyl-2-acetylglycerophosphocholine Esterase, Aged, Aged, 80 and over, Cardiovascular Diseases, Diabetes Mellitus, Type 2, Female, Humans, Incidence, Insulin Resistance, Male, Middle Aged, Predictive Value of Tests, Prevalence, Prospective Studies, Risk, Risk Factors}, issn = {1945-7197}, doi = {10.1210/jc.2011-3026}, author = {Nelson, T L and Biggs, M L and Kizer, J R and Cushman, M and Hokanson, J E and Furberg, C D and Mukamal, K J} } @article {6133, title = {Novel gene variants predict serum levels of the cytokines IL-18 and IL-1ra in older adults.}, journal = {Cytokine}, volume = {65}, year = {2014}, month = {2014 Jan}, pages = {10-6}, abstract = {

Activation of inflammatory pathways measured by serum inflammatory markers such as interleukin-18 (IL-18) and interleukin-1 receptor antagonist (IL-1ra) is strongly associated with the progression of chronic disease states in older adults. Given that these serum cytokine levels are in part a heritable trait, genetic variation may predict increased serum levels. Using the Cardiovascular Health Study and InCHIANTI cohorts, a genome-wide association study was performed to identify genetic variants that influence IL-18 and IL-1ra serum levels among older adults. Multiple linear regression models characterized the association between each SNP and log-transformed cytokine values. Tests for multiple independent signals within statistically significant loci were performed using haplotype analysis and regression models conditional on lead SNP in each region. Multiple SNPs were associated with these cytokines with genome-wide significance, including SNPs in the IL-18-BCO gene region of chromosome 2 for IL-18 (top SNP rs2250417, P=1.9{\texttimes}10(-32)) and in the IL-1 gene family region of chromosome 2 for IL-1ra (rs6743376, P=2.3{\texttimes}10(-26)). Haplotype tests and conditional linear regression models showed evidence of multiple independent signals in these regions. Serum IL-18 levels were also associated with a region on chromosome 2 containing the NLRC4 gene (rs12989936, P=2.7{\texttimes}10(-19)). These data characterize multiple robust genetic signals that influence IL-18 and IL-1ra cytokine production. In particular, the signal for serum IL-18 located on chromosome two is novel and potentially important in inflammasome triggered chronic activation of inflammation in older adults. Replication in independent cohorts is an important next step, as well as molecular studies to better understand the role of NLRC4.

}, keywords = {Aged, Aged, 80 and over, Calcium-Binding Proteins, CARD Signaling Adaptor Proteins, Chromosomes, Human, Pair 2, Female, Genetic Variation, Genome-Wide Association Study, Genotype, Haplotypes, Humans, Inflammation, Interleukin 1 Receptor Antagonist Protein, Interleukin-18, Male, Polymorphism, Single Nucleotide}, issn = {1096-0023}, doi = {10.1016/j.cyto.2013.10.002}, author = {Matteini, A M and Li, J and Lange, E M and Tanaka, T and Lange, L A and Tracy, R P and Wang, Y and Biggs, M L and Arking, D E and Fallin, M D and Chakravarti, A and Psaty, B M and Bandinelli, S and Ferrucci, L and Reiner, A P and Walston, J D} } @article {7124, title = {Brain natriuretic peptide and insulin resistance in older adults.}, journal = {Diabet Med}, year = {2016}, month = {2016 Apr 21}, abstract = {

AIMS: Higher levels of brain natriuretic peptide (BNP) have been associated with a decreased risk of diabetes in adults, but whether BNP is related to insulin resistance in older adults has not been established.

METHODS: N-Terminal (NT)-proBNP was measured among Cardiovascular Health Study participants at the 1989-1990, 1992-1993 and 1996-1997 examinations. We calculated measures of insulin resistance [homeostatic model assessment of insulin resistance (HOMA-IR), quantitative insulin sensitivity check index (QUICKI), Gutt index, Matsuda index] from fasting and 2-h concentrations of glucose and insulin among 3318 individuals with at least one measure of NT-proBNP and free of heart failure, coronary heart disease and chronic kidney disease, and not taking diabetes medication. We used generalized estimating equations to assess the cross-sectional association of NT-proBNP with measures of insulin resistance. Instrumental variable analysis with an allele score derived from nine genetic variants (single nucleotide polymorphisms) within or near the NPPA and NPPB loci was used to estimate an un-confounded association of NT-proBNP levels on insulin resistance.

RESULTS: Lower NT-proBNP levels were associated with higher insulin resistance even after adjustment for BMI, waist circumference and other risk factors (P~<~0.001 for all four indices). Although the genetic score was strongly related to measured NT-proBNP levels amongst European Americans (F statistic~=~71.08), we observed no association of genetically determined NT-proBNP with insulin resistance (P~=~0.38; P~=~0.01 for comparison with the association of measured levels of NT-proBNP).

CONCLUSIONS: In older adults, lower NT-proBNP is associated with higher insulin resistance, even after adjustment for traditional risk factors. Because related genetic variants were not associated with insulin resistance, the causal nature of this association will require future study. This article is protected by copyright. All rights reserved.

}, issn = {1464-5491}, doi = {10.1111/dme.13139}, author = {Kim, F and Biggs, M L and Kizer, J R and Brutsaert, E F and de Fillipi, C and Newman, A B and Kronmal, R A and Tracy, R P and Gottdiener, J S and Djouss{\'e}, L and de Boer, I H and Psaty, B M and Siscovick, D S and Mukamal, K J} } @article {7666, title = {Fasting and post-glucose load measures of insulin resistance and risk of incident atrial fibrillation: The Cardiovascular Health Study.}, journal = {Nutr Metab Cardiovasc Dis}, year = {2018}, month = {2018 Mar 02}, abstract = {

BACKGROUND AND AIMS: Existing literature in individuals without diabetes has not demonstrated a relationship between IR and incident AF; however, data are limited and only fasting glucose measures of IR were assessed. We evaluated the relationship of both fasting and post-glucose load IR measures with the development of atrial fibrillation in nondiabetic older adults.

METHODS AND RESULTS: Among Cardiovascular Health Study participants, a population-based cohort of 5888 adults aged 65 years or older enrolled in two waves (1989-1990 and 1992-1993), those without prevalent AF or diabetes and with IR measures at baseline were followed for the development of AF, identified by follow-up visit electrocardiograms, hospital discharge diagnosis coding, or Medicare claims data, through 2014. Fasting IR was determined by the homeostatic model of insulin resistance (HOMA-IR) and post-glucose load IR was determined by the Gutt index. Cox proportional hazards models were used to determine the association of IR with risk of AF. Analyses included 3601 participants (41\% men) with a mean age of 73 years. Over a median follow-up of 12.3 years, 1443 (40\%) developed AF. After multivariate adjustment, neither HOMA-IR nor the Gutt index was associated with risk of developing AF [hazard ratios (95\% confidence intervals): 0.96 (0.90, 1.03) for 1-SD increase in HOMA-IR and 1.03 (0.97, 1.10) for 1-SD decrease in the Gutt index].

CONCLUSIONS: We found no evidence of an association between either fasting or post-glucose load IR measures and incident AF.

}, issn = {1590-3729}, doi = {10.1016/j.numecd.2018.02.016}, author = {Garg, P K and Biggs, M L and Kaplan, R and Kizer, J R and Heckbert, S R and Mukamal, K J} } @article {8106, title = {Biochemical markers of bone turnover and risk of incident hip fracture in older women: the Cardiovascular Health Study.}, journal = {Osteoporos Int}, year = {2019}, month = {2019 Jun 21}, abstract = {

The relationships of osteocalcin (OC) and C-telopeptide of type I collagen (CTX) with long-term incidence of hip fracture were examined in 1680 post-menopausal women from a population-based study. CTX, but not OC, levels were associated with incident hip fracture in these participants, a relationship characterized by an inverted U-shape.

INTRODUCTION: We sought to investigate the relationships of OC, a marker of bone formation, and CTX, a marker of bone resorption, with long-term incidence of hip fracture in older women.

METHODS: We included 1680 women from the population-based Cardiovascular Health Study (mean [SD] age 74.5 [5.0] years). The longitudinal association of both markers with incidence of hip fracture was examined using multivariable Cox models.

RESULTS: During a median follow-up of 12.3~years, 288 incident hip fractures occurred. Linear spline analysis did not demonstrate an association between OC levels and incident hip fracture. By contrast, increasing levels of CTX up to the middle-upper range were associated with a significantly greater risk of hip fracture (HR = 1.52 per SD increment, 95\% CI = 1.10-2.09), while further increases were associated with a marginally non-significant lower risk (HR = 0.80 per SD increment, 95\% CI = 0.63-1.01), after full adjustment for potential confounders. In analyses of quartiles, CTX exhibited a similar inverted U-shaped relationship with incident fracture after adjustment, with a significant association observed only for the comparison of quartile 3 to quartile 1 (HR = 1.63, 95\% CI = 1.10-2.43). In a subset with available measures, both OC and CTX were inversely associated with bone mineral density of the hip.

CONCLUSION: CTX, but not OC, levels were associated with incident hip fracture in post-menopausal women, a relationship characterized by an inverted U-shape. These findings highlight the complex relationship of bone turnover markers with hip fracture risk.

}, issn = {1433-2965}, doi = {10.1007/s00198-019-05043-1}, author = {Massera, D and Xu, S and Walker, M D and Valderr{\'a}bano, R J and Mukamal, K J and Ix, J H and Siscovick, D S and Tracy, R P and Robbins, J A and Biggs, M L and Xue, X and Kizer, J R} }