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1.  Gene expression in thiazide diuretic or statin users in relation to incident type 2 diabetes 
Thiazide diuretics and statins are used to improve cardiovascular outcomes, but may also cause type 2 diabetes (T2DM), although mechanisms are unknown. Gene expression studies may facilitate understanding of these associations. Participants from ongoing population-based studies were sampled for these longitudinal studies of peripheral blood microarray gene expression, and followed to incident diabetes. All sampled subjects were statin or thiazide users. Those who developed diabetes during follow-up comprised cases (44 thiazide users; 19 statin users), and were matched to drug-using controls who did not develop diabetes on several factors. Supervised normalization, surrogate variable analyses removed technical bias and confounding. Differentially-expressed genes were those with a false discovery rate Q-value<0.05. Among thiazide users, diabetes cases had significantly different expression of CCL14 (down-regulated 6%, Q-value=0.0257), compared with controls. Among statin users, diabetes cases had marginal but insignificantly different expression of ZNF532 (up-regulated 15%, Q-value=0.0584), CXORF21 (up-regulated 11%, Q-value=0.0584), and ZNHIT3 (up-regulated 19%, Q-value=0.0959), compared with controls. These genes comprise potential targets for future expression or mechanistic research on medication-related diabetes development.
PMCID: PMC3939004  PMID: 24596594
Type 2 diabetes; statins; thiazide diuretics; whole blood; gene expression; microarray; supervised normalization; surrogate variable analysis; chemokine ligand 14; zinc finger proteins
2.  Association of Body Mass Index, Diabetes, Hypertension, and Blood Pressure Levels with Risk of Permanent Atrial Fibrillation 
After an initial episode of atrial fibrillation (AF), AF may recur and become permanent. AF progression is associated with higher morbidity and mortality. Understanding the risk factors for permanent AF could help identify people who would benefit most from interventions.
To determine whether body mass index (BMI), diabetes, hypertension, and blood pressure levels are associated with permanent AF among people whose initial AF episode terminated.
Population-based inception cohort study.
Enrollees in Group Health, an integrated health care system, aged 30–84 with newly diagnosed AF in 2001–2004, whose initial AF terminated within 6 months and who had at least 6 months of subsequent follow-up (N = 1,385).
Clinical characteristics were determined from medical records. Permanent AF was determined from medical records and ECG and administrative databases. Permanent AF was defined as AF present on two separate occasions 6–36 months apart, without any documented sinus rhythm between the two occasions. Cox proportional hazards models were used to estimate adjusted hazard ratios (HRs).
Five-year cumulative incidence of permanent AF was 24 %. Compared with normal BMI (18.5–24.9 kg/m2), BMI levels of 25.0–29.9 (overweight), 30.0–34.9 (obese 1), 35.0–39.9 (obese 2), and ≥ 40.0 kg/m2 (obese 3) were associated with HRs of permanent AF of 1.26 (95 % CI: 0.92, 1.72); 1.35 (0.96, 1.91); 1.50 (0.97, 2.33); and 1.79 (1.13, 2.84), adjusted for age, sex, diabetes, hypertension, blood pressure, coronary heart disease, valvular heart disease, heart failure, and prior stroke. Diabetes, hypertension, and blood pressure were not associated with permanent AF.
For people whose initial AF episode terminates, benefits of having lower BMI may include a lower risk of permanent AF. Risk of permanent AF was similar for people with and without diabetes or hypertension and across blood pressure levels.
Electronic supplementary material
The online version of this article (doi:10.1007/s11606-012-2220-4) contains supplementary material, which is available to authorized users.
PMCID: PMC3614136  PMID: 22972153
cohort study; anthropometry; electrocardiogram; atrial fibrillation
3.  Racial Differences in the Incidence of and Risk Factors for Atrial Fibrillation in Older Adults: The Cardiovascular Health Study 
Journal of the American Geriatrics Society  2013;61(2):10.1111/jgs.12085.
The authors examined whether differential associations of risk factors with atrial fibrillation (AF) by race could explain the lower AF incidence in blacks. Baseline risk factor information was obtained from interview, clinic examination, and echocardiography in 4774 white and 911 black Cardiovascular Health Study participants ≥65 years old without history of AF at baseline in 1989–90 or 1992–93. Incident AF was determined by hospital discharge diagnosis or annual study electrocardiogram. Cox regression was used to assess associations of risk factors and race with incident AF. During a mean 11.2 years of follow-up, 1403 whites and 182 blacks had incident AF. Associations of all examined risk factors were similar in both races, except left ventricular posterior wall thickness, which was more strongly associated with AF in blacks (per 0.2 cm, HR for blacks: 1.72, 95%CI: 1.44, 2.06; whites: 1.30, 95%CI: 1.18, 1.43). Overall, the relative risk of AF was 25% lower in blacks than whites after adjustment only for age and sex (HR: 0.75, 95%CI: 0.64, 0.87), and 45% lower after adjustment for all considered risk factors (HR: 0.55, 95%CI: 0.35, 0.88). Differential associations of the risk factors considered with incident AF by race do not explain the lower AF incidence in blacks.
PMCID: PMC3878638  PMID: 23320758
Atrial fibrillation; race; incidence; risk factors
4.  OATP1B1-related drug–drug and drug–gene interactions as potential risk factors for cerivastatin-induced rhabdomyolysis 
Pharmacogenetics and genomics  2013;23(7):355-364.
Genetic variation in drug metabolizing enzymes and membrane transporters as well as concomitant drug therapy can modulate the beneficial and the deleterious effects of drugs. We investigated whether patients exhibiting rhabdomyolysis who were taking cerivastatin possess functional genetic variants in SLCO1B1 and whether they were on concomitant medications that inhibit OATP1B1, resulting in accumulation of cerivastatin.
This study had three components: (a) resequencing the SLCO1B1 gene in 122 patients who developed rhabdomyolysis while on cerivastatin; (b) functional evaluation of the identified SLCO1B1 nonsynonymous variants and haplotypes in in-vitro HEK293/FRT cells stably transfected with pcDNA5/FRT empty vector, SLCO1B1 reference, variants, and haplotypes; and (c) in-vitro screening of 15 drugs commonly used among the rhabdomyolysis cases for inhibition of OATP1B1-mediated uptake of cerivastatin in HEK293/FRT cells stably transfected with reference SLCO1B1.
The resequencing of the SLCO1B1 gene identified 54 variants. In-vitro functional analysis of SLCO1B1 nonsynonymous variants and haplotypes showed that the V174A, R57Q, and P155T variants, a novel frameshift insertion, OATP1B1*14 and OATP1B1*15 haplotype were associated with a significant reduction (P<0.001) in cerivastatin uptake (32, 18, 72, 3.4, 2.1 and 5.7% of reference, respectively). Furthermore, clopidogrel and seven other drugs were shown to inhibit OATP1B1-mediated uptake of cerivastatin.
Reduced function of OATP1B1 related to genetic variation and drug–drug interactions likely contributed to cerivastatin-induced rhabdomyolysis. Although cerivastatin is no longer in clinical use, these findings may translate to related statins and other substrates of OATP1B1.
PMCID: PMC3894639  PMID: 23652407
cerivastatin; clopidogrel; OATP1B1; rhabdomyolysis
5.  Genome-wide study identifies two loci associated with lung function decline in mild to moderate COPD 
Human genetics  2012;132(1):79-90.
Accelerated lung function decline is a key COPD phenotype; however its genetic control remains largely unknown.
We performed a genome-wide association study using the Illumina Human660W-Quad v.1_A BeadChip. Generalized estimation equations were used to assess genetic contributions to lung function decline over a 5-year period in 4,048 European-American Lung Health Study participants with largely mild COPD. Genotype imputation was performed using reference HapMap II data. To validate regions meeting genome-wide significance, replication of top SNPs was attempted in independent cohorts. Three genes (TMEM26, ANK3 and FOXA1) within the regions of interest were selected for tissue expression studies using immunohistochemistry.
Measurements and Main Results
Two intergenic SNPs (rs10761570, rs7911302) on chromosome 10 and one SNP on chromosome 14 (rs177852) met genome-wide significance after Bonferroni. Further support for the chromosome 10 region was obtained by imputation, the most significantly associated imputed SNPs (rs10761571, rs7896712) being flanked by observed markers rs10761570 and rs7911302. Results were not replicated in four general population cohorts or a smaller cohort of subjects with moderate to severe COPD; however, we show novel expression of genes near regions of significantly associated SNPS, including TMEM26 and FOXA1 in airway epithelium and lung parenchyma, and ANK3 in alveolar macrophages. Levels of expression were associated with lung function and COPD status.
We identified two novel regions associated with lung function decline in mild COPD. Genes within these regions were expressed in relevant lung cells and their expression related to airflow limitation suggesting they may represent novel candidate genes for COPD susceptibility.
PMCID: PMC3536920  PMID: 22986903
COPD; lung function decline; GWAS; genome wide association; genes; polymorphisms
6.  Conducting comparative effectiveness research on medications: the views of a practicing epidemiologist from the other Washington 
Value in Health  2011;15(2):394-396.
PMCID: PMC3310348  PMID: 22433773
effectiveness; evidence-based; hypertension; RECORD trial
7.  Assessing Risk Prediction Models Using Individual Participant Data From Multiple Studies 
Pennells, Lisa | Kaptoge, Stephen | White, Ian R. | Thompson, Simon G. | Wood, Angela M. | Tipping, Robert W. | Folsom, Aaron R. | Couper, David J. | Ballantyne, Christie M. | Coresh, Josef | Goya Wannamethee, S. | Morris, Richard W. | Kiechl, Stefan | Willeit, Johann | Willeit, Peter | Schett, Georg | Ebrahim, Shah | Lawlor, Debbie A. | Yarnell, John W. | Gallacher, John | Cushman, Mary | Psaty, Bruce M. | Tracy, Russ | Tybjærg-Hansen, Anne | Price, Jackie F. | Lee, Amanda J. | McLachlan, Stela | Khaw, Kay-Tee | Wareham, Nicholas J. | Brenner, Hermann | Schöttker, Ben | Müller, Heiko | Jansson, Jan-Håkan | Wennberg, Patrik | Salomaa, Veikko | Harald, Kennet | Jousilahti, Pekka | Vartiainen, Erkki | Woodward, Mark | D'Agostino, Ralph B. | Bladbjerg, Else-Marie | Jørgensen, Torben | Kiyohara, Yutaka | Arima, Hisatomi | Doi, Yasufumi | Ninomiya, Toshiharu | Dekker, Jacqueline M. | Nijpels, Giel | Stehouwer, Coen D. A. | Kauhanen, Jussi | Salonen, Jukka T. | Meade, Tom W. | Cooper, Jackie A. | Cushman, Mary | Folsom, Aaron R. | Psaty, Bruce M. | Shea, Steven | Döring, Angela | Kuller, Lewis H. | Grandits, Greg | Gillum, Richard F. | Mussolino, Michael | Rimm, Eric B. | Hankinson, Sue E. | Manson, JoAnn E. | Pai, Jennifer K. | Kirkland, Susan | Shaffer, Jonathan A. | Shimbo, Daichi | Bakker, Stephan J. L. | Gansevoort, Ron T. | Hillege, Hans L. | Amouyel, Philippe | Arveiler, Dominique | Evans, Alun | Ferrières, Jean | Sattar, Naveed | Westendorp, Rudi G. | Buckley, Brendan M. | Cantin, Bernard | Lamarche, Benoît | Barrett-Connor, Elizabeth | Wingard, Deborah L. | Bettencourt, Richele | Gudnason, Vilmundur | Aspelund, Thor | Sigurdsson, Gunnar | Thorsson, Bolli | Kavousi, Maryam | Witteman, Jacqueline C. | Hofman, Albert | Franco, Oscar H. | Howard, Barbara V. | Zhang, Ying | Best, Lyle | Umans, Jason G. | Onat, Altan | Sundström, Johan | Michael Gaziano, J. | Stampfer, Meir | Ridker, Paul M. | Michael Gaziano, J. | Ridker, Paul M. | Marmot, Michael | Clarke, Robert | Collins, Rory | Fletcher, Astrid | Brunner, Eric | Shipley, Martin | Kivimäki, Mika | Ridker, Paul M. | Buring, Julie | Cook, Nancy | Ford, Ian | Shepherd, James | Cobbe, Stuart M. | Robertson, Michele | Walker, Matthew | Watson, Sarah | Alexander, Myriam | Butterworth, Adam S. | Angelantonio, Emanuele Di | Gao, Pei | Haycock, Philip | Kaptoge, Stephen | Pennells, Lisa | Thompson, Simon G. | Walker, Matthew | Watson, Sarah | White, Ian R. | Wood, Angela M. | Wormser, David | Danesh, John
American Journal of Epidemiology  2013;179(5):621-632.
Individual participant time-to-event data from multiple prospective epidemiologic studies enable detailed investigation into the predictive ability of risk models. Here we address the challenges in appropriately combining such information across studies. Methods are exemplified by analyses of log C-reactive protein and conventional risk factors for coronary heart disease in the Emerging Risk Factors Collaboration, a collation of individual data from multiple prospective studies with an average follow-up duration of 9.8 years (dates varied). We derive risk prediction models using Cox proportional hazards regression analysis stratified by study and obtain estimates of risk discrimination, Harrell's concordance index, and Royston's discrimination measure within each study; we then combine the estimates across studies using a weighted meta-analysis. Various weighting approaches are compared and lead us to recommend using the number of events in each study. We also discuss the calculation of measures of reclassification for multiple studies. We further show that comparison of differences in predictive ability across subgroups should be based only on within-study information and that combining measures of risk discrimination from case-control studies and prospective studies is problematic. The concordance index and discrimination measure gave qualitatively similar results throughout. While the concordance index was very heterogeneous between studies, principally because of differing age ranges, the increments in the concordance index from adding log C-reactive protein to conventional risk factors were more homogeneous.
PMCID: PMC3927974  PMID: 24366051
C index; coronary heart disease; D measure; individual participant data; inverse variance; meta-analysis; risk prediction; weighting
8.  A screening study of drug-drug interactions in cerivastatin users: an adverse effect of clopidogrel 
Clinical pharmacology and therapeutics  2012;91(5):10.1038/clpt.2011.295.
An analysis of a case-control study of rhabdomyolysis was conducted to screen for previously unrecognized CYP2C8 inhibitors that may cause other clinically important drug-drug interactions. Cases of rhabdomyolysis using cerivastatin (n=72) were compared with controls using atorvastatin (n=287) between 1998–2001. The use of clopidogrel (OR 29.6; 95% CI, 6.1–143) was strongly associated with rhabdomyolysis. In a replication effort that used the FDA Adverse Event Reporting System (AERS), clopidogrel was used more commonly by rhabdomyolysis cases using cerivastatin (17%) than by rhabdomyolysis cases using atorvastatin (0%, OR infinity; 95% CI = 5.2-infinity). Several medications were tested in vitro for their potential to cause drug-drug interactions. Clopidogrel, rosiglitazone and montelukast were the most potent inhibitors of cerivastatin metabolism. Clopidogrel and its metabolites also inhibited cerivastatin metabolism in human hepatocytes. These epidemiological and in-vitro findings suggest that clopidogrel may cause clinically important, dose dependent, drug-drug interactions with other medications metabolized by CYP2C8.
PMCID: PMC3830936  PMID: 22419147
rhabdomyolysis; statins; clopidogrel; adverse drug reaction; drug-drug interaction prediction; 2-oxo-clopidogrel; acyl glucuronide
9.  Occupational exposures and mortality from cardiovascular disease among women textile workers in Shanghai, China 
Exposure to textile fiber dusts, like particulate air pollution, may be associated with cardiovascular disease (CVD) mortality. Bacterial endotoxin, a potent inflammagen found in cotton dust, may be a specific risk factor.
Female textile workers (N=267,400) in Shanghai, China were followed for CVD mortality (1989-2000). Factory exposures were approximated by sector classifications based on materials and processes. Quantitative endotoxin and cotton dust measures were available for a subcohort (n=3,188). Cox proportional hazards modeling was used to estimate hazard ratios (HR) and 95% confidence interval (CI).
Slightly elevated mortality risk for the cotton sector was seen for ischemic stroke (HR=1.12, 95%CI 0.97-1.31) and hemorrhagic stroke (HR=1.12, 95%CI 1.02-1.23). Similar hemorrhagic stroke mortality risk was observed in high dust sectors (HR=1.12, 95%CI 1.02-1.24). No association was observed for ischemic heart disease.
Exposures in textile factories may have contributed to CVD mortality among this cohort. The specific components of these exposures that may be harmful are not clear and should be further investigated.
PMCID: PMC3515077  PMID: 22968969
Cardiovascular diseases; stroke; mortality; endotoxin; China
10.  Acute Respiratory Distress Syndrome after Trauma: Development and Validation of a Predictive Model 
Critical Care Medicine  2012;40(8):2295-2303.
To determine early clinical predictors of Acute Respiratory Distress Syndrome (ARDS) after major traumatic injury and characterize the performance of this ARDS prediction model, and two previously published ARDS prediction models, in an independent cohort of severely injured patients.
Prospective cohort study
University-affiliated level I trauma center in Seattle, WA, and nine hospitals participating in the Inflammation and Host Response to Injury Consortium.
Model derivation utilized data from 224 patients participating in a randomized controlled trial. All models were validated in an independent cohort of 1,762 trauma patients.
Measurements and Main Results
Variables strongly associated with ARDS in bivariate analysis (p<0.01) were entered into a multiple logistic regression equation to generate an ARDS predictive model. We evaluated the performance of all models using the area under the receiver operator characteristic (ROC) curve. ARDS occurred in 79 subjects (35%) belonging to the development cohort and in 423 subjects (24%) from the validation cohort. Multivariable predictors of ARDS after trauma included subject age, Acute Physiology and Chronic Health Evaluation (APACHE) II Score, injury severity score, and the presence of blunt traumatic injury, pulmonary contusion, massive transfusion, and flail chest injury (area under the ROC curve 0.79 [95% C.I. 0.73, 0.85]). Validation of the prediction model resulted in an area under the ROC curve of 0.71 (95% C.I. 0.68, 0.74). Our model's performance in the validation cohort was superior to that of two other published ARDS prediction models (0.65 [95% C.I. 0.63, 0.68] and 0.66 [95% C.I. 0.64, 0.69], p<0.01 for all comparisons).
Using routinely available clinical data, our prediction model identifies patients at high risk for ARDS early after severe traumatic injury. This predictive model could facilitate enrollment of subjects into future clinical trials designed to prevent this serious complication.
PMCID: PMC3400931  PMID: 22809905
Respiratory Distress Syndrome, Acute; Wounds and Injuries; Multiple Trauma, Receiver Operating Characteristic
11.  Gender Differences Between the Minnesota Code and Novacode Electrocardiographic Prognostication of Coronary Heart Disease in the Cardiovascular Health Study 
The American journal of cardiology  2011;107(6):817-820.e1.
The Minnesota Code (MC) and Novacode (Nova) are the most widely used electrocardiographic (ECG) classification systems. The comparative strengths of their classifications for Q- and ST-T–wave abnormalities in predicting coronary heart disease (CHD) events and total mortality have not been evaluated separately by gender. We studied standard 12-lead electrocardiograms at rest from 4,988 participants in the Cardiovascular Health Study. Average age at baseline was 73 years, 60% of participants were women 85% were white, and 22% had a history of cardiovascular disease or presence of ECG myocardial infarction by MC or Nova. Starting in 1989 with an average 17-year follow-up, 65% of participants died and 33% had incident CHD in a cohort free of cardiovascular disease at baseline. Of these, electrocardiograms with major Q-wave or major ST-T abnormalities by MC or Nova predicted increased risk for CHD events and total mortality with no significant differences in predictability between men and women. The study also found that women had fewer major Q-wave changes but more major ST-T abnormalities than men. However, there were no gender differences in predicting CHD events and total mortality. In conclusion, ECG classification systems for myocardial infarction/ischemia abnormalities by MC or Nova are valuable and useful for men and women in clinical trials and epidemiologic studies.
PMCID: PMC3673724  PMID: 21247534
12.  T‐Helper Type 1 Bias in Healthy People Is Associated With Cytomegalovirus Serology and Atherosclerosis: The Multi‐Ethnic Study of Atherosclerosis 
Although T‐helper type 1 (Th1) cells are considered important in atherosclerosis, the relationships between Th1 and Th2 cells and atherosclerosis have not been examined in population‐based studies.
Methods and Results
We measured Th cells as a percentage of lymphocytes by flow cytometry using CD4 staining (%CD4) in 917 participants of the Multi‐Ethnic Study of Atherosclerosis. We also measured interferon gamma–positive and interleukin‐4‐positive CD4+ cells, representing Th1 and Th2 subpopulations (%Th1 and %Th2), respectively. We found that %CD4 was 1.5% lower per 10 years of age (P<0.0001). Whites had higher %CD4 and lower %Th1 and %Th2 values than other race/ethnic groups. Body mass index (BMI) and blood pressure were associated with %CD4, but no traditional cardiovascular disease (CVD) risk factors were associated with %Th1 or %Th2. In multivariable models, the major independent variable associated with %Th1 was cytomegalovirus (CMV) antibody titer, with minor contributions from age, sex, seasonality, and interleukin‐6. In models with coronary artery calcification level as the outcome, significant independent variables included age, sex, smoking status, and %Th1 (β=0.25; P≤0.01). Both %Th1 and %Th2 were associated with common carotid intimal media thickness (β=0.02 and −0.02, respectively; both P<0.05), as were age, sex, race/ethnicity, blood pressure, and BMI.
Th1 bias is associated with subclinical atherosclerosis in a multiethnic population. The main Th1 correlate was CMV infectious burden. These findings are consistent with a role of Th1 cells in atherosclerosis and suggest the importance of prospective studies of T‐helper cell biasing in CVD.
PMCID: PMC3698770  PMID: 23688675
atherosclerosis; epidemiology; immunology; inflammation; T‐helper cell
13.  Telomere-associated polymorphisms correlate with cardiovascular disease mortality in Caucasian women: The Cardiovascular Health Study 
Leukocyte telomere length (LTL) is linked to cardiovascular disease (CVD); however, it is unclear if LTL has an etiologic role in CVD. To gain insight into the LTL and CVD relationship, a cohort study of CVD mortality and single nucleotide polymorphisms (SNPs) in OBFC1 and TERC, genes related to LTL, was conducted among 3271 Caucasian participants ages ≥65 years enrolled 1989–1990 in the Cardiovascular Health Study. Leukocyte DNA was genotyped for SNPs in OBFC1 (rs4387287 and rs9419958) and TERC (rs3772190) that were previously associated with LTL through genome-wide association studies. Cox regression was used to estimate adjusted hazard ratios (HRs) and 95% confidence intervals (CIs). The OBFC1 SNPs were in linkage disequilibrium (r2=0.99), and both SNPs were similarly associated with CVD mortality in women. For women, there was a decreased risk of CVD death associated with the minor allele (rs4387287), HR=0.7; 95% CI: 0.5–0.9 (CC vs. AC) and HR=0.5; 95% CI: 0.20–1.4 (CC vs. AA) (p-trend <0.01). For men there was no association, HR=1.0; 95% CI: 0.7–1.3 (CC vs. AC) and HR=1.7; 95% CI: 0.8–3.6 (CC vs. AA) (p-trend=0.64). These findings support the hypothesis that telomere biology and associated genes may play a role in CVD-related death, particularly among women.
PMCID: PMC3391009  PMID: 22449406
15.  Risk of Intraparenchymal Hemorrhage with MRI-Defined Leukoaraiosis and Brain Infarcts 
Annals of Neurology  2012;71(4):552-559.
To determine whether the burden of leukoaraiosis and the number of brain infarcts, defined by MRI, are prospectively and independently associated with intraparenchymal hemorrhage (IPH) incidence in a pooled population-based study.
Among 4,872 participants initially free of clinical stroke in the Atherosclerosis Risk in Communities (ARIC) Study and the Cardiovascular Health Study (CHS), we assessed white matter grade (range 0–9), reflecting increasing leukoaraiosis, and brain infarcts using MRI. Over a median of 13 years of follow-up, 71 incident, spontaneous IPH events occurred.
After adjustment for other IPH risk factors, the hazard ratios (95% confidence intervals) across white matter grades 0–1, 2, 3, and 4–9 were 1.00, 1.68 (0.86–3.30), 3.52 (1.80–6.89), and 3.96 (1.90–8.27) (p for trend <0.0001). These hazard ratios were weakened only modestly (p for trend = 0.0003) with adjustment for MRI-defined brain infarcts. The IPH hazard ratios for 0, 1, 2, or ≥3 MRI-defined brain infarcts were 1.00, 1.97 (1.10–3.54), 2.00 (0.83–4.78), and 3.12 (1.31–7.43) (p for trend = 0.002), but these were substantially attenuated when adjusted for white matter grade (p for trend = 0.049).
Greater MRI-defined burden of leukoaraiosis is a risk factor for spontaneous IPH. Spontaneous IPH should be added to the growing list of potential poor outcomes in people with leukoaraiosis.
PMCID: PMC3377969  PMID: 22522444
16.  Associations of Plasma Phospholipid and Dietary Alpha Linolenic Acid With Incident Atrial Fibrillation in Older Adults: The Cardiovascular Health Study 
Few studies have examined the relationship of α‐linolenic acid (ALA 18:3n‐3), an intermediate‐chain essential n‐3 polyunsaturated fatty acid derived from plants and vegetable oils, with incident atrial fibrillation (AF).
Methods and Results
The study population included participants from the Cardiovascular Health Study, a community‐based longitudinal cohort of adults aged 65 or older, free of prevalent coronary heart disease and atrial fibrillation. We assessed the associations of plasma phospholipid and dietary ALA with incident AF using Cox regression. The biomarker analysis comprised a total of 2899 participants, and the dietary analysis comprised 4337 participants. We found no association of plasma phospholipid ALA and incident AF. Comparing each of the second, third, and fourth quartiles to the lowest quartile, the hazard ratios for AF were 1.11 (95% CI, 0.90 to 1.37), 1.09 (95% CI, 0.88 to 1.35), and 0.92 (95% CI, 0.74 to 1.15), after adjustment for age, sex, race, clinic, education, smoking, alcohol, body mass index, waist circumference, diabetes, heart failure, stroke, treated hypertension, and physical activity (P trend=0.48). When dietary ALA was considered the exposure of interest, results were similar.
Results from this prospective cohort study of older adults indicate no association of plasma phospholipid or dietary ALA and incident AF.
PMCID: PMC3603242  PMID: 23525429
atrial fibrillation; epidemiology; fatty acids; nutrition
17.  Genetic Predictors of Medically Refractory Ulcerative Colitis 
Inflammatory bowel diseases  2010;16(11):1830-1840.
Acute severe ulcerative colitis (UC) remains a significant clinical challenge and the ability to predict, at an early stage, those individuals at risk of colectomy for medically refractory UC (MR-UC) would be a major clinical advance. The aim of this study was to use a genome-wide association study (GWAS) in a well-characterized cohort of UC patients to identify genetic variation that contributes to MR-UC.
A GWAS comparing 324 MR-UC patients with 537 Non-MR-UC patients was analyzed using logistic regression and Cox proportional hazards methods. In addition, the MR-UC patients were compared with 2601 healthy controls.
MR-UC was associated with more extensive disease (p= 2.7×10−6) and a positive family history of UC (p= 0.004). A risk score based on the combination of 46 SNPs associated with MR-UC explained 48% of the variance for colectomy risk in our cohort. Risk scores divided into quarters showed the risk of colectomy to be 0%, 17%, 74% and 100% in the four groups. Comparison of the MR-UC subjects with healthy controls confirmed the contribution of the major histocompatibility complex to severe UC (peak association: rs17207986, p= 1.4×10−16) and provided genome-wide suggestive association at the TNFSF15 (TL1A) locus (peak association: rs11554257, p= 1.4×10−6).
A SNP-based risk scoring system, identified here by GWAS analyses, may provide a useful adjunct to clinical parameters for predicting natural history in UC. Furthermore, discovery of genetic processes underlying disease severity may help to identify pathways for novel therapeutic intervention in severe UC.
PMCID: PMC2959149  PMID: 20848476
Ulcerative colitis; Natural History; Genetics
18.  Seasonal Variation in 25-Hydroxyvitamin D Concentrations in the Cardiovascular Health Study 
American Journal of Epidemiology  2011;174(12):1363-1372.
Low circulating concentrations of 25-hydroxyvitamin D (25(OH)D) are associated with adverse health outcomes in diverse populations. However, 25(OH)D concentrations vary seasonally with varying exposure to sunlight, so single measurements may poorly reflect long-term 25(OH)D exposure. The authors investigated cyclical trends in average serum 25(OH)D concentrations among 2,298 individuals enrolled in the Cardiovascular Health Study of community-based older adults (1992–1993). A sinusoidal model closely approximated observed 25(OH)D concentrations and fit the data significantly better than did a mean model (P < 0.0001). The mean annual 25(OH)D concentration was 25.1 ng/mL (95% confidence interval: 24.7, 25.5), and the mean peak-trough difference was 9.6 ng/mL (95% confidence interval: 8.5, 10.7). Male sex, higher latitude of study site, and greater physical activity levels were associated with larger peak-trough difference in 25(OH)D concentration (each P < 0.05). Serum concentrations of intact parathyroid hormone and bone-specific alkaline phosphatase also varied in a sinusoidal fashion (P < 0.0001), inversely to 25(OH)D. In conclusion, serum 25(OH)D varies in a sinusoidal manner, with large seasonal differences relative to mean concentration and laboratory evidence of biologic sequelae. Single 25(OH)D measurements might not capture overall vitamin D status, and the extent of misclassification could vary by demographic and behavioral factors. Accounting for collection time may reduce bias in research studies and improve decision-making in clinical care.
PMCID: PMC3276302  PMID: 22112344
alkaline phosphatase; parathyroid hormone; seasons; vitamin D
19.  Fasting and Post-Glucose Load Measures of Insulin Resistance and Risk of Ischemic Stroke in Older Adults 
Background and purpose
Few studies have assessed post-glucose load measures of insulin resistance and ischemic stroke risk, and data are sparse for older adults. We investigated whether fasting and post-glucose load measures of insulin resistance were related to incident ischemic stroke in non-diabetic older adults.
Participants were men and women in the Cardiovascular Health Study, aged 65+ and without prevalent diabetes or stroke at baseline, followed for 17 years for incident ischemic stroke. The Gutt insulin sensitivity index was calculated from baseline body weight and fasting and 2-hour post-load insulin and glucose; a lower Gutt index indicates higher insulin resistance.
Analyses included 3,442 participants (42% men) with a mean age of 73. Incidence of ischemic stroke was 9.8 strokes per 1,000 person years. The relative risk (RR) for lowest quartile vs. highest quartile of Gutt index was 1.64 (95% confidence interval: 1.24, 2.16), adjusted for demographics and prevalent cardiovascular and kidney disease. Similarly, the adjusted RR for highest quartile vs. lowest quartile of 2-hour glucose was 1.84 (95% CI: 1.39, 2.42). In contrast, the adjusted RR for highest quartile vs. lowest quartile of fasting insulin was 1.10 (95% CI: 0.84, 1.46).
In non-diabetic older adults, insulin resistance measured by Gutt index or 2-hour glucose, but not fasting insulin, was associated with risk of incident ischemic stroke.
PMCID: PMC3226936  PMID: 21998054
Non-diabetic older adults; Cohort study; Gutt insulin sensitivity index
20.  Reproductive history and mortality from cardiovascular disease among women textile workers in Shanghai, China 
Background Few studies have examined the possible effects of reproductive factors on cardiovascular disease (CVD) risks in Asian women.
Methods A cohort of 267 400 female textile workers in Shanghai, China, was administered a questionnaire at enrolment (1989–91) and followed for mortality through 2000. Relative risks (hazard ratios) for ischaemic heart disease (IHD), ischaemic stroke and haemorrhagic stroke were calculated using Cox proportional hazards modelling, adjusting for relevant co-variates.
Results Risks were not consistently associated with age at menopause, parity, stillbirths, miscarriages or duration of lactation. An increasing trend in IHD mortality risk, but not stroke, was observed with decreasing age at menarche. There was no evidence of increased CVD mortality risk by oral or injectable contraceptive use or induced abortions. As expected, greater mortality rates from CVD and increased CVD risks were also observed with smoking.
Conclusions Use of steroid contraceptives, induced abortions and reduced parity from China's one-child-per-family policy has not had an adverse effect on risk of CVD mortality in this cohort.
PMCID: PMC3235022  PMID: 22158661
Cohort; cardiovascular diseases; reproductive history; mortality; China
21.  Vitamin D, Parathyroid Hormone and Sudden Cardiac Death: Results from the Cardiovascular Health Study 
Hypertension  2011;58(6):1021-1028.
Recent studies have demonstrated greater risks of cardiovascular events and mortality among persons who have lower 25-hydroxyvitamin D (25-OHD) and higher parathyroid hormone (PTH) levels. We sought to evaluate the association between markers of mineral metabolism and sudden cardiac death (SCD) among the 2,312 participants from the Cardiovascular Health Study who were free of clinical cardiovascular disease at baseline. We estimated associations of baseline 25-OHD and PTH concentrations individually and in combination with SCD using Cox proportional hazards models after adjustment for demographics, cardiovascular risk factors, and kidney function. During a median follow-up of 14 years, there were 73 adjudicated SCD events. The annual incidence of SCD was greater among subjects who had lower 25-OHD concentrations: 2 events per 10,000 for 25-OHD ≥ 20 ng/ml and 4 events per 10,000 for 25-OHD < 20 ng/ml. Similarly, SCD incidence was greater among subjects who had higher PTH concentrations: 2 events per 10,000 for PTH ≤ 65 pg/ml and 4 events per 10,000 for PTH > 65 pg/ml. Multivariate adjustment attenuated associations of 25-OHD and PTH with SCD. Finally, 267 participants (11.7% of the cohort) had high PTH and low 25-OHD concentrations. This combination was associated with a more than 2-fold risk of SCD after adjustment (hazard ratio 2.19, 95% confidence interval 1.17, 4.10, p=0.017) compared to participants with normal levels of PTH and 25-OHD. The combination of lower 25-OHD and higher PTH concentrations appears to be associated independently with SCD risk among older adults without cardiovascular disease.
PMCID: PMC3337033  PMID: 22068871
Sudden cardiac death; Vitamin D; Parathyroid hormone; Elderly; Risk Factors
22.  Carotid Intima-Media Thickness, Electrocardiographic Left Ventricular Hypertrophy and Incidence of Intracerebral Hemorrhage 
Background and Purpose
Carotid intima-media thickness (IMT) and electrocardiographic left ventricular hypertrophy (ECG-LVH) are two subclinical cardiovascular disease measures associated with increased risk of total and ischemic strokes. Increased IMT and ECG-LVH also may reflect end-organ hypertensive effects. Information is scant on the associations of these subclinical measures with intracerebral hemorrhage (ICH). We hypothesized that greater carotid IMT and the presence of ECG-LVH would be independently associated with increased ICH incidence.
Among 18,155 participants initially free of stroke in the Atherosclerosis Risk in Communities Study (ARIC) and the Cardiovascular Health Study (CHS), we assessed carotid IMT, carotid plaque, and ECG-LVH. Over a median of 18 years of follow-up, 162 incident ICH events occurred.
After adjustment for other ICH risk factors, carotid IMT was associated positively with incidence of ICH in both ARIC and CHS. The risk was lowest in study-specific quartile 1, elevated 1.6 to 2.6-fold in quartiles 2–3, and elevated 2.5 to 3.7-fold in quartile 4 (p<0.05 for both studies). In CHS, having a carotid plaque was associated with a 2-fold (95% CI = 1.1–3.4) greater ICH risk than having no plaque, but only 1.2-fold (95% CI = 0.76–2.0) greater ICH risk in ARIC. ECG-LVH carried a hazard ratio of ICH of 1.7 (95% CI = 0.77–3.7) in CHS and 2.8 (95% CI = 1.2–6.4) in ARIC.
Our data suggest that people with carotid atherosclerosis and possibly LVH are at increased risk not only of ischemic stroke but also of ICH.
PMCID: PMC3202073  PMID: 21940954
atherosclerosis; left ventricular hypertrophy; intracerebral hemorrhage; prospective study; risk factors
23.  Use of administrative data to estimate the incidence of statin-related rhabdomyolysis 
PMCID: PMC3483067  PMID: 22511681
rhabdomyolysis; statins; adverse drug reaction; natural language processing
24.  Genetic variability within the cholesterol lowering pathway and the effectiveness of statins in reducing the risk of MI 
Atherosclerosis  2011;217(2):458-464.
Genetic variability has been shown to affect statin responsiveness. Participants from the Utrecht Cardiovascular Pharmacogenetics (UCP) studies were enrolled from a population-based registry of pharmacy records linked to hospital discharge records (PHARMO) to investigate tagging SNPs within candidate genes involved in the cholesterol lowering pathway for modification of the effectiveness of statins in reducing the risk of myocardial infarction (MI). Patients who received a prescription for an antihypertensive drug and/or had hypercholesterolemia were selected from the PHARMO database. We designed a nested case-control study in which cases were hospitalized for MI and controls were not. Patients were contacted through their community pharmacies. For this study, only hypercholesterolemic participants were selected. Logistic regression analysis was used to investigate pharmacogenetic interactions. The Heart and Vascular Health Study (HVH) was used to replicate findings from UCP.
The study population included 668 cases and 1217 controls. We selected 231 SNPs of which 209 SNPs in 27 genes passed quality control. Ten SNPs in eight genes were found to influence the effectiveness of statins in UCP, of which the most significant interaction was found with SCARB1 rs4765615. Other genes that reached statistical significance (p<0.05) included two SNPs in PCSK9 (rs10888896 and rs505151 (E670G)), two SNPs in ABCG5 (rs4245786 and rs1864815), LIPC rs16940379, ABCA1 rs4149264, PPARG rs2972164, LRP1 rs715948, and SOAT1 rs2493121. None of the total of 5 SNPs that were available for replication in HVH reached statistical significance.
In conclusion, ten SNPs were found to modify the effectiveness of statins in reducing the risk of MI in the UCP study. Five were also tested in the HVH study, but no interactions reached statistical significance.
PMCID: PMC3465613  PMID: 21741043
pharmacogenetics; statin; case-control study; cholesterol; myocardial infarction; PCSK9; SCARB1
25.  Drug metabolism by CYP2C8.3 is determined by substrate dependent interactions with cytochrome P450 reductase and cytochrome b5† 
Biochemical pharmacology  2011;82(6):681-691.
Genetic polymorphisms in CYP2C8 can influence the metabolism of important therapeutic agents and cause interindividual variation in drug response and toxicity. The significance of the variant CYP2C8*3 has been controversial with reports of higher in vivo but lower in vitro activity compared to CYP2C8*1. In this study, the contribution of the redox partners cytochrome P450 reductase (CPR) and cytochrome b5 to the substrate dependent activity of CYP2C8.3 (R139K, K399R) was investigated in human liver microsomes (HLMs) and E. coli expressed recombinant CYP2C8 proteins using amodiaquine, paclitaxel, rosiglitazone and cerivastatin as probe subtrates. For recombinant CYP2C8.3, clearance values were two- to five-fold higher compared to CYP2C8.1. CYP2C8.3’s higher kcat seems to be dominated by a higher, but substrate specific affinity, towards cytochrome b5 and CPR (KD and Km,red) which resulted in increased reaction coupling. A stronger binding affinity of ligands to CYP2C8.3, based on a two site binding model, in conjunction with a five fold increase in amplitude of heme spin change during binding of ligands and redox partners could potentially contribute to a higher kcat. In HLMs, carriers of the CYP2C8*1/*3 genotype were as active as CYP2C8*1/*1 towards the CYP2C8 specific reaction amodiaquine N-deethylation. Large excess of cytochrome b5 compared to CYP2C8 in recombinant systems and HLMs inhibited metabolic clearance, diminishing the difference in kcat between the two enzymes, and provides an explanation for the discrepancy to in vivo data. In silico studies illustrate the genetic differences between wild type and variant on the molecular level.
PMCID: PMC3159548  PMID: 21726541
paclitaxel; amodiaquine; rosiglitazone; cerivastatin; pharmacogenetics; ligand binding

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