@article {1431, title = {Assessment of cerebrovascular disease in the Cardiovascular Health Study.}, journal = {Ann Epidemiol}, volume = {3}, year = {1993}, month = {1993 Sep}, pages = {504-7}, abstract = {

The Cardiovascular Health Study (CHS) is a longitudinal population-based study of coronary heart disease and stroke in men and women 65 years and older. The initial CHS cohort consisted of 5201 men and women recruited from a random sample of the Health Care Financing Administration (HCFA) Medicare eligibility lists in four communities in the United States. Extensive historical, physical, and laboratory evaluations were performed at the baseline examination in 1989 to 1990 to identify risk factors and subclinical disease. Periodic contacts are carried out to ascertain and verify incident cardiac and stroke events and their sequelae. Since only a short time has passed since entry of all the patients into the study, data are not available on time trends in the mortality rate of stroke, but we expect to contribute in this area in the years ahead. This article then is a description of the CHS, of methods of assessing stroke in the CHS cohort, and of prevalence of stroke and transient ischemic attacks at the initial examination.

}, keywords = {Aged, Aged, 80 and over, Cerebrovascular Disorders, Cohort Studies, Coronary Disease, Female, Humans, Ischemic Attack, Transient, Longitudinal Studies, Male, Prevalence}, issn = {1047-2797}, author = {Price, T R and Psaty, B and O{\textquoteright}Leary, D and Burke, G and Gardin, J} } @article {1434, title = {Prevalence of subclinical atherosclerosis and cardiovascular disease and association with risk factors in the Cardiovascular Health Study.}, journal = {Am J Epidemiol}, volume = {139}, year = {1994}, month = {1994 Jun 15}, pages = {1164-79}, abstract = {

The prevalence of subclinical atherosclerosis and cardiovascular disease was evaluated among the 5,201 adults aged > or = 65 years in four communities participating in the Cardiovascular Health Study from June 1989 through May 1990. A combined index based on electrocardiogram and echocardiogram abnormalities, carotid artery wall thickness and stenosis based on carotid ultrasound, decreased ankle-brachial blood pressure, and positive response to a Rose Questionnaire for angina or intermittent claudication defined subclinical disease. The prevalence of subclinical disease was 36\% in women and 38.7\% in men and increased with age. Among women, low-density lipoprotein cholesterol, systolic blood pressure, blood glucose, and cigarette smoking were positively associated, and high-density lipoprotein cholesterol negatively associated, with subclinical disease. In men, systolic blood pressure, blood glucose, and cigarette smoking were independent risk factors in multiple logistic regression analyses. The risk factors for subclinical disease are, therefore, similar to those for clinical disease at younger ages, especially among women. It is possible that older individuals with subclinical disease are at very high risk of developing clinical disease and that more aggressive interventions to prevent clinical disease should be oriented to individuals with subclinical disease.

}, keywords = {Aged, Aged, 80 and over, Arteriosclerosis, Cardiovascular Diseases, Female, Humans, Logistic Models, Longitudinal Studies, Male, Prevalence, Risk Factors, United States}, issn = {0002-9262}, author = {Kuller, L and Borhani, N and Furberg, C and Gardin, J and Manolio, T and O{\textquoteright}Leary, D and Psaty, B and Robbins, J} } @article {943, title = {Collaborative meta-analysis of individual participant data from observational studies of Lp-PLA2 and cardiovascular diseases.}, journal = {Eur J Cardiovasc Prev Rehabil}, volume = {14}, year = {2007}, month = {2007 Feb}, pages = {3-11}, abstract = {

BACKGROUND: A large number of observational epidemiological studies have reported generally positive associations between circulating mass and activity levels of lipoprotein-associated phospholipase A2 (Lp-PLA2) and the risk of cardiovascular diseases. Few studies have been large enough to provide reliable estimates in different circumstances, such as in different subgroups (e.g., by age group, sex, or smoking status) or at different Lp-PLA2 levels. Moreover, most published studies have related disease risk only to baseline values of Lp-PLA2 markers (which can lead to substantial underestimation of any risk relationships because of within-person variability over time) and have used different approaches to adjustment for possible confounding factors.

OBJECTIVES: By combination of data from individual participants from all relevant observational studies in a systematic {\textquoteright}meta-analysis{\textquoteright}, with correction for regression dilution (using available data on serial measurements of Lp-PLA2), the Lp-PLA2 Studies Collaboration will aim to characterize more precisely than has previously been possible the strength and shape of the age and sex-specific associations of plasma Lp-PLA2 with coronary heart disease (and, where data are sufficient, with other vascular diseases, such as ischaemic stroke). It will also help to determine to what extent such associations are independent of possible confounding factors and to explore potential sources of heterogeneity among studies, such as those related to assay methods and study design. It is anticipated that the present collaboration will serve as a framework to investigate related questions on Lp-PLA2 and cardiovascular outcomes.

METHODS: A central database is being established containing data on circulating Lp-PLA2 values, sex and other potential confounding factors, age at baseline Lp-PLA2 measurement, age at event or at last follow-up, major vascular morbidity and cause-specific mortality. Information about any repeat measurements of Lp-PLA2 and potential confounding factors has been sought to allow adjustment for possible confounding and correction for regression dilution. The analyses will involve age-specific regression models. Synthesis of the available observational studies of Lp-PLA2 will yield information on a total of about 15 000 cardiovascular disease endpoints.

}, keywords = {1-Alkyl-2-acetylglycerophosphocholine Esterase, Cardiovascular Diseases, Humans, Phospholipases A2}, issn = {1741-8267}, doi = {10.1097/01.hjr.0000239464.18509.f1}, author = {Ballantyne, C and Cushman, M and Psaty, B and Furberg, C and Khaw, K T and Sandhu, M and Oldgren, J and Rossi, G P and Maiolino, G and Cesari, M and Lenzini, L and James, S K and Rimm, E and Collins, R and Anderson, J and Koenig, W and Brenner, H and Rothenbacher, D and Berglund, G and Persson, M and Berger, P and Brilakis, E and McConnell, J P and Koenig, W and Sacco, R and Elkind, M and Talmud, P and Rimm, E and Cannon, C P and Packard, C and Barrett-Connor, E and Hofman, A and Kardys, I and Witteman, J C M and Criqui, M and Corsetti, J P and Rainwater, D L and Moss, A J and Robins, S and Bloomfield, H and Collins, D and Packard, C and Wassertheil-Smoller, S and Ridker, P and Ballantyne, C and Cannon, C P and Cushman, M and Danesh, J and Gu, D and Hofman, A and Nelson, J J and Thompson, S and Zalewski, A and Zariffa, N and Di Angelantonio, E and Kaptoge, S and Thompson, A and Thompson, S and Walker, M and Watson, S and Wood, A} } @article {1109, title = {Admixture mapping of ankle-arm index: identification of a candidate locus associated with peripheral arterial disease.}, journal = {J Med Genet}, volume = {47}, year = {2010}, month = {2010 Jan}, pages = {1-7}, abstract = {

BACKGROUND: Peripheral arterial disease (PAD) is associated with significant morbidity and mortality, and has a higher prevalence in African Americans than Caucasians. Ankle-arm index (AAI) is the ratio of systolic blood pressure in the leg to that in the arm, and, when low, is a marker of PAD.

METHODS: The authors used an admixture mapping approach to search for genetic loci associated with low AAI. Using data from 1040 African American participants in the observational, population based Health, Aging, and Body Composition Study who were genotyped at 1322 single nucleotide polymorphisms (SNPs) that are informative for African versus European ancestry and span the entire genome, we estimated genetic ancestry in each chromosomal region and then tested the association between AAI and genetic ancestry at each locus.

RESULTS: The authors found a region of chromosome 11 that reaches its peak between 80 and 82 Mb associated with low AAI (p<0.001 for rs12289502 and rs9665943, both within this region). 753 African American participants in the observational, population based Cardiovascular Health Study were genotyped at rs9665943 to test the reproducibility of this association, and this association was also statistically significant (odds ratio (OR) for homozygous African genotype 1.59, 95\% confidence interval (CI) 1.12 to 2.27). Another candidate SNP (rs1042602) in the same genomic region was tested in both populations, and was also found to be significantly associated with low AAI in both populations (OR for homozygous African genotype 1.89, 95\% CI 1.29 to 2.76).

CONCLUSION: This study identifies a novel region of chromosome 11 representing an area with a potential candidate gene associated with PAD in African Americans.

}, keywords = {African Americans, Aged, Ankle Brachial Index, Chromosome Mapping, Chromosomes, Human, Pair 11, Female, Genetic Loci, Genotype, Humans, Male, Odds Ratio, Peripheral Vascular Diseases, Polymorphism, Single Nucleotide}, issn = {1468-6244}, doi = {10.1136/jmg.2008.064808}, author = {Scherer, M L and Nalls, M A and Pawlikowska, L and Ziv, E and Mitchell, G and Huntsman, S and Hu, D and Sutton-Tyrrell, K and Lakatta, E G and Hsueh, W-C and Newman, A B and Tandon, A and Kim, L and Kwok, P-Y and Sung, A and Li, R and Psaty, B and Reiner, A P and Harris, T} } @article {1171, title = {Bayesian methods for meta-analysis of causal relationships estimated using genetic instrumental variables.}, journal = {Stat Med}, volume = {29}, year = {2010}, month = {2010 May 30}, pages = {1298-311}, abstract = {

Genetic markers can be used as instrumental variables, in an analogous way to randomization in a clinical trial, to estimate the causal relationship between a phenotype and an outcome variable. Our purpose is to extend the existing methods for such Mendelian randomization studies to the context of multiple genetic markers measured in multiple studies, based on the analysis of individual participant data. First, for a single genetic marker in one study, we show that the usual ratio of coefficients approach can be reformulated as a regression with heterogeneous error in the explanatory variable. This can be implemented using a Bayesian approach, which is next extended to include multiple genetic markers. We then propose a hierarchical model for undertaking a meta-analysis of multiple studies, in which it is not necessary that the same genetic markers are measured in each study. This provides an overall estimate of the causal relationship between the phenotype and the outcome, and an assessment of its heterogeneity across studies. As an example, we estimate the causal relationship of blood concentrations of C-reactive protein on fibrinogen levels using data from 11 studies. These methods provide a flexible framework for efficient estimation of causal relationships derived from multiple studies. Issues discussed include weak instrument bias, analysis of binary outcome data such as disease risk, missing genetic data, and the use of haplotypes.

}, keywords = {Bayes Theorem, Biostatistics, C-Reactive Protein, Fibrinogen, Genetic Markers, Humans, Meta-Analysis as Topic, Models, Statistical, Phenotype, Polymorphism, Single Nucleotide}, issn = {1097-0258}, doi = {10.1002/sim.3843}, author = {Burgess, Stephen and Thompson, Simon G and Burgess, S and Thompson, S G and Andrews, G and Samani, N J and Hall, A and Whincup, P and Morris, R and Lawlor, D A and Davey Smith, G and Timpson, N and Ebrahim, S and Ben-Shlomo, Y and Davey Smith, G and Timpson, N and Brown, M and Ricketts, S and Sandhu, M and Reiner, A and Psaty, B and Lange, L and Cushman, M and Hung, J and Thompson, P and Beilby, J and Warrington, N and Palmer, L J and Nordestgaard, B G and Tybjaerg-Hansen, A and Zacho, J and Wu, C and Lowe, G and Tzoulaki, I and Kumari, M and Sandhu, M and Yamamoto, J F and Chiodini, B and Franzosi, M and Hankey, G J and Jamrozik, K and Palmer, L and Rimm, E and Pai, J and Psaty, B and Heckbert, S and Bis, J and Anand, S and Engert, J and Collins, R and Clarke, R and Melander, O and Berglund, G and Ladenvall, P and Johansson, L and Jansson, J-H and Hallmans, G and Hingorani, A and Humphries, S and Rimm, E and Manson, J and Pai, J and Watkins, H and Clarke, R and Hopewell, J and Saleheen, D and Frossard, R and Danesh, J and Sattar, N and Robertson, M and Shepherd, J and Schaefer, E and Hofman, A and Witteman, J C M and Kardys, I and Ben-Shlomo, Y and Davey Smith, G and Timpson, N and de Faire, U and Bennet, A and Sattar, N and Ford, I and Packard, C and Kumari, M and Manson, J and Lawlor, Debbie A and Davey Smith, George and Anand, S and Collins, R and Casas, J P and Danesh, J and Davey Smith, G and Franzosi, M and Hingorani, A and Lawlor, D A and Manson, J and Nordestgaard, B G and Samani, N J and Sandhu, M and Smeeth, L and Wensley, F and Anand, S and Bowden, J and Burgess, S and Casas, J P and Di Angelantonio, E and Engert, J and Gao, P and Shah, T and Smeeth, L and Thompson, S G and Verzilli, C and Walker, M and Whittaker, J and Hingorani, A and Danesh, J} } @article {1250, title = {Lipoprotein-associated phospholipase A(2) and future risk of subclinical disease and cardiovascular events in individuals with type 2 diabetes: the Cardiovascular Health Study.}, journal = {Diabetologia}, volume = {54}, year = {2011}, month = {2011 Feb}, pages = {329-33}, abstract = {

AIMS/HYPOTHESIS: Type 2 diabetes is an established risk factor for cardiovascular disease (CVD). This increased risk may be due in part to the increased levels of inflammatory factors associated with diabetes. Lipoprotein-associated phospholipase A(2) (Lp-PLA(2)) is a risk marker for CVD and has pro-inflammatory effects in atherosclerotic plaques. We therefore sought to determine whether Lp-PLA(2) levels partially explain the greater prevalence of subclinical CVD and greater incidence of CVD outcomes associated with type 2 diabetes in the Cardiovascular Health Study.

METHODS: We conducted a cross-sectional and prospective study of 4,062 men and women without previous CVD from the Cardiovascular Health Study (1989 to 2007). Lp-PLA(2) mass and activity were measured in baseline plasma. Subclinical disease was determined at baseline and incident CVD was ascertained annually. We used logistic regression for cross-sectional analyses and Cox proportional hazards models for incident analyses.

RESULTS: At baseline, Lp-PLA(2) mass did not differ significantly by type 2 diabetes status; however, Lp-PLA(2) activity was significantly higher among type 2 diabetic individuals. Baseline subclinical disease was significantly associated with baseline diabetes and this association was similar in models unadjusted or adjusted for Lp-PLA(2) (OR 1.68 [95\% CI 1.31-2.15] vs OR 1.67 [95\% CI 1.30-2.13]). Baseline type 2 diabetes was also significantly associated with incident CVD events, including fatal CHD, fatal myocardial infarction (MI) and non-fatal MI in multivariable analyses. There were no differences in these estimates after further adjustment for Lp-PLA(2) activity.

CONCLUSIONS/INTERPRETATION: In this older cohort, differences in Lp-PLA(2) activity did not explain any of the excess risk for subclinical disease or CVD outcomes related to diabetes.

}, keywords = {1-Alkyl-2-acetylglycerophosphocholine Esterase, Aged, Cardiovascular Diseases, Cross-Sectional Studies, Diabetes Mellitus, Type 2, Female, Humans, Male, Proportional Hazards Models, Prospective Studies, Risk Factors}, issn = {1432-0428}, doi = {10.1007/s00125-010-1969-4}, author = {Nelson, T L and Kamineni, A and Psaty, B and Cushman, M and Jenny, N S and Hokanson, J and Furberg, C and Mukamal, K J} }