@article {8405, title = {Incorporating sampling weights into robust estimation of Cox proportional hazards regression model, with illustration in the Multi-Ethnic Study of Atherosclerosis.}, journal = {BMC Med Res Methodol}, volume = {20}, year = {2020}, month = {2020 03 14}, pages = {62}, abstract = {

BACKGROUND: Cox proportional hazards regression models are used to evaluate associations between exposures of interest and time-to-event outcomes in observational data. When exposures are measured on only a sample of participants, as they are in a case-cohort design, the sampling weights must be incorporated into the regression model to obtain unbiased estimating equations.

METHODS: Robust Cox methods have been developed to better estimate associations when there are influential outliers in the exposure of interest, but these robust methods do not incorporate sampling weights. In this paper, we extend these robust methods, which already incorporate influence weights, so that they also accommodate sampling weights.

RESULTS: Simulations illustrate that in the presence of influential outliers, the association estimate from the weighted robust method is closer to the true value than the estimate from traditional weighted Cox regression. As expected, in the absence of outliers, the use of robust methods yields a small loss of efficiency. Using data from a case-cohort study that is nested within the Multi-Ethnic Study of Atherosclerosis (MESA) longitudinal cohort study, we illustrate differences between traditional and robust weighted Cox association estimates for the relationships between immune cell traits and risk of stroke.

CONCLUSIONS: Robust weighted Cox regression methods are a new tool to analyze time-to-event data with sampling, e.g. case-cohort data, when exposures of interest contain outliers.

}, issn = {1471-2288}, doi = {10.1186/s12874-020-00945-9}, author = {Sitlani, Colleen M and Lumley, Thomas and McKnight, Barbara and Rice, Kenneth M and Olson, Nels C and Doyle, Margaret F and Huber, Sally A and Tracy, Russell P and Psaty, Bruce M and C Delaney, Joseph A} } @article {8403, title = {Innate and adaptive immune cell subsets as risk factors for coronary heart disease in two population-based cohorts.}, journal = {Atherosclerosis}, volume = {300}, year = {2020}, month = {2020 05}, pages = {47-53}, abstract = {

BACKGROUND AND AIMS: Cell-mediated immunity is implicated in atherosclerosis. We evaluated whether innate and adaptive immune cell subsets in peripheral blood are risk factors for coronary heart disease.

METHODS: A nested case-cohort study (n~=~2155) was performed within the Multi-Ethnic Study of Atherosclerosis (MESA) and the Cardiovascular Health Study (CHS). Cases of incident myocardial infarction (MI) and incident angina (n~=~880 total cases) were compared with a cohort random sample (n~=~1275). Immune cell phenotypes (n~=~34, including CD14 monocytes, natural killer cells, γδ T cells, CD4, CD8 and CD19 lymphocyte subsets) were measured from cryopreserved cells by flow cytometry. Cox proportional hazards models with adjustment for cardiovascular disease risk factors were used to evaluate associations of cell phenotypes with incident MI and a composite phenotype of incident MI or incident angina (MI-angina) over a median 9.3 years of follow-up. Th1, Th2, Th17, T regulatory (CD4CD25CD127), naive (CD4CD45RA), memory (CD4CD45RO), and CD4CD28 cells were specified as primary hypotheses. In secondary analyses, 27 additional cell phenotypes were investigated.

RESULTS: After correction for multiple testing, there were no statistically significant associations of CD4 naive, memory, CD28, or T helper cell subsets with MI or MI-angina in MESA, CHS, or combined-cohort meta analyses. Null associations were also observed for monocyte subsets, natural killer cells, γδ T cells, CD19 B cell and differentiated CD4 and CD8 cell subsets.

CONCLUSIONS: The proportions of peripheral blood monocyte and lymphocyte subsets are not strongly related to the future occurrence of MI or angina in adults free of autoimmune disease.

}, issn = {1879-1484}, doi = {10.1016/j.atherosclerosis.2020.03.011}, author = {Olson, Nels C and Sitlani, Colleen M and Doyle, Margaret F and Huber, Sally A and Landay, Alan L and Tracy, Russell P and Psaty, Bruce M and Delaney, Joseph A} } @article {8658, title = {Natural killer cells, gamma delta T cells and classical monocytes are associated with systolic blood pressure in the multi-ethnic study of atherosclerosis (MESA).}, journal = {BMC Cardiovasc Disord}, volume = {21}, year = {2021}, month = {2021 Jan 22}, pages = {45}, abstract = {

BACKGROUND: Hypertension is a major source of cardiovascular morbidity and mortality. Recent evidence from mouse models, genetic, and cross-sectional human studies suggest increased proportions of selected immune cell subsets may be associated with levels of systolic blood pressure (SBP).

METHODS: We assayed immune cells from cryopreserved samples collected at the baseline examination (2000-2002) from 1195 participants from the multi-ethnic study of atherosclerosis (MESA). We used linear mixed models, with adjustment for age, sex, race/ethnicity, smoking, exercise, body mass index, education, diabetes, and cytomegalovirus titers, to estimate the associations between 30 immune cell subsets (4 of which were a priori hypotheses) and repeated measures of SBP (baseline and up to four follow-up measures) over 10~years. The analysis provides estimates of the association with blood pressure level.

RESULTS: The mean age of the MESA participants at baseline was 64 {\textpm} 10~years and 53\% were male. A one standard deviation (1-SD) increment in the proportion of γδ T cells was associated with 2.40~mmHg [95\% confidence interval (CI) 1.34-3.42] higher average systolic blood pressure; and for natural killer cells, a 1-SD increment was associated with 1.88~mmHg (95\% CI 0.82-2.94) higher average level of systolic blood pressure. A 1-SD increment in classical monocytes (CD14CD16) was associated with 2.01 mmHG (95\% CI 0.79-3.24) lower average systolic blood pressure. There were no associations of CD4 T helper cell subsets with average systolic blood pressure.

CONCLUSION: These findings suggest that the innate immune system plays a role in levels of SBP whereas there were no associations with adaptive immune cells.

}, issn = {1471-2261}, doi = {10.1186/s12872-021-01857-2}, author = {Delaney, Joseph A C and Olson, Nels C and Sitlani, Colleen M and Fohner, Alison E and Huber, Sally A and Landay, Alan L and Heckbert, Susan R and Tracy, Russell P and Psaty, Bruce M and Feinstein, Matt and Doyle, Margaret F} } @article {9175, title = {Association of immune cell subsets with incident heart failure in two population-based cohorts.}, journal = {ESC Heart Fail}, year = {2022}, month = {2022 Sep 12}, abstract = {

AIMS: Circulating inflammatory markers are associated with incident heart failure (HF), but prospective data on associations of immune cell subsets with incident HF are lacking. We determined the associations of immune cell subsets with incident HF as well as HF subtypes [with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF)].

METHODS AND RESULTS: Peripheral blood immune cell subsets were measured in adults from the Multi-Ethnic Study of Atherosclerosis (MESA) and Cardiovascular Health Study (CHS). Cox proportional hazard models adjusted for demographics, HF risk factors, and cytomegalovirus serostatus were used to evaluate the association of the immune cell subsets with incident HF. The average age of the MESA cohort at the time of immune cell measurements was 63.0~{\textpm}~10.4~years with 51\% women, and in the CHS cohort, it was 79.6~{\textpm}~4.4~years with 62\% women. In the meta-analysis of CHS and MESA, a higher proportion of CD4+ T helper (Th) 1 cells (per one standard deviation) was associated with a lower risk of incident HF [hazard ratio (HR) 0.91, (95\% CI 0.83-0.99), P~=~0.03]. Specifically, higher proportion of CD4+ Th1 cells was significantly associated with a lower risk of HFrEF [HR 0.73, (95\% CI 0.62-0.85), <0.001] after correction for multiple testing. No association was observed with HFpEF. No other cell subsets were associated with incident HF.

CONCLUSIONS: We observed that higher proportions of CD4+ Th1 cells were associated with a lower risk of incident HFrEF in two distinct population-based cohorts, with similar effect sizes in both cohorts demonstrating replicability. Although unexpected, the consistency of this finding across cohorts merits further investigation.

}, issn = {2055-5822}, doi = {10.1002/ehf2.14140}, author = {Sinha, Arjun and Sitlani, Colleen M and Doyle, Margaret F and Fohner, Alison E and B{\r u}zkov{\'a}, Petra and Floyd, James S and Huber, Sally A and Olson, Nels C and Njoroge, Joyce N and Kizer, Jorge R and Delaney, Joseph A and Shah, Sanjiv S and Tracy, Russell P and Psaty, Bruce and Feinstein, Matthew} } @article {9245, title = {Circulating Soluble CD163, Associations With Cardiovascular Outcomes and Mortality, and Identification of Genetic Variants in Older Individuals: The Cardiovascular Health Study.}, journal = {J Am Heart Assoc}, volume = {11}, year = {2022}, month = {2022 Nov}, pages = {e024374}, abstract = {

Background Monocytes/macrophages participate in cardiovascular disease. CD163 (cluster of differentiation 163) is a monocyte/macrophage receptor, and the shed sCD163 (soluble CD163) reflects monocyte/macrophage activation. We examined the association of sCD163 with incident cardiovascular disease events and performed a genome-wide association study to identify sCD163-associated variants. Methods and Results We measured plasma sCD163 in 5214 adults (aged >=65 years, 58.7\% women, 16.2\% Black) of the CHS (Cardiovascular Health Study). We used Cox regression models (associations of sCD163 with incident events and mortality); median follow-up was 26 years. Genome-wide association study analyses were stratified on race. Adjusted for age, sex, and race and ethnicity, sCD163 levels were associated with all-cause mortality (hazard ratio [HR], 1.08 [95\% CI, 1.04-1.12] per SD increase), cardiovascular disease mortality (HR, 1.15 [95\% CI, 1.09-1.21]), incident coronary heart disease (HR, 1.10 [95\% CI, 1.04-1.16]), and incident heart failure (HR, 1.18 [95\% CI, 1.12-1.25]). When further adjusted (eg, cardiovascular disease risk factors), only incident coronary heart disease lost significance. In European American individuals, genome-wide association studies identified 38 variants on chromosome 2 near (top result rs62165726, =3.3{\texttimes}10),19 variants near chromosome 17 gene (rs55714927, =1.5{\texttimes}10), and 18 variants near chromosome 11 gene . These regions replicated in the European ancestry ADDITION-PRO cohort, a longitudinal cohort study nested in the Danish arm of the Anglo-Danish-Dutch~study~of~Intensive~Treatment~Intensive Treatment In peOple with screeNdetcted Diabetes in Primary Care. In Black individuals, we identified 9 variants on chromosome 6 (rs3129781 =7.1{\texttimes}10) in the region, and 3 variants (rs115391969 =4.3{\texttimes}10) near the chromosome 16 gene Conclusions Monocyte function, as measured by sCD163, may be predictive of overall and cardiovascular-specific mortality and incident heart failure.

}, keywords = {Aged, Antigens, CD, Antigens, Differentiation, Myelomonocytic, Asialoglycoprotein Receptor, Biomarkers, Cardiovascular Diseases, Female, Genome-Wide Association Study, Heart Failure, Humans, Longitudinal Studies, Male}, issn = {2047-9980}, doi = {10.1161/JAHA.121.024374}, author = {Durda, Peter and Raffield, Laura M and Lange, Ethan M and Olson, Nels C and Jenny, Nancy Swords and Cushman, Mary and Deichgraeber, Pia and Grarup, Niels and Jonsson, Anna and Hansen, Torben and Mychaleckyj, Josyf C and Psaty, Bruce M and Reiner, Alex P and Tracy, Russell P and Lange, Leslie A} } @article {9247, title = {Immune cell subpopulations as risk factors for atrial fibrillation: The Cardiovascular Health Study and Multi-Ethnic Study of Atherosclerosis.}, journal = {Heart Rhythm}, year = {2022}, month = {2022 Oct 18}, issn = {1556-3871}, doi = {10.1016/j.hrthm.2022.10.012}, author = {Floyd, James S and Sitlani, Colleen M and Doyle, Margaret F and Feinstein, Matthew J and Olson, Nels C and Heckbert, Susan R and Huber, Sally A and Tracy, Russell P and Psaty, Bruce M and Delaney, Joseph A C} } @article {9090, title = {Monocyte subsets, T cell activation profiles, and stroke in men and women: The Multi-Ethnic Study of Atherosclerosis and Cardiovascular Health Study.}, journal = {Atherosclerosis}, volume = {351}, year = {2022}, month = {2022 06}, pages = {18-25}, abstract = {

BACKGROUND AND AIMS: Despite mechanistic data implicating unresolving inflammation in stroke pathogenesis, data regarding circulating immune cell phenotypes - key determinants of inflammation propagation versus resolution - and incident stroke are lacking. Therefore, we aimed to comprehensively define associations of circulating immune phenotypes and activation profiles with incident stroke.

METHODS: We investigated circulating leukocyte phenotypes and activation profiles with incident adjudicated stroke in 2104 diverse adults from the Multi-Ethnic Study of Atherosclerosis (MESA) followed over a median of 16.6 years. Cryopreserved cells from the MESA baseline examination were thawed and myeloid and lymphoid lineage cell subsets were measured using polychromatic flow cytometry and intracellular cytokine activation staining. We analyzed multivariable-adjusted associations of cell phenotypes, as a proportion of parent cell subsets, with incident stroke (overall) and ischemic stroke using Cox regression models.

RESULTS: We observed associations of intermediate monocytes, early-activated CD4 T cells, and both CD4 and CD8 T cells producing interleukin-4 after cytokine stimulation (T and T, respectively) with higher risk for incident stroke; effect sizes ranged from 35\% to 62\% relative increases in risk for stroke. Meanwhile, differentiated and memory T cell phenotypes were associated with lower risk for incident stroke. In sex-stratified analyses, positive and negative associations were especially strong among men but null among women.

CONCLUSIONS: Circulating IL-4 producing T cells and intermediate monocytes were significantly associated with incident stroke over nearly two decades of follow-up. These associations were stronger among men and not among women. Further translational studies are warranted to define more precise targets for prognosis and intervention.

}, keywords = {Atherosclerosis, CD4-Positive T-Lymphocytes, CD8-Positive T-Lymphocytes, Cytokines, Female, Follow-Up Studies, Humans, Incidence, Inflammation, Interleukin-4, Ischemic Stroke, Lymphocyte Activation, Male, Monocytes, Stroke, T-Lymphocyte Subsets}, issn = {1879-1484}, doi = {10.1016/j.atherosclerosis.2022.05.007}, author = {Feinstein, Matthew J and B{\r u}zkov{\'a}, Petra and Olson, Nels C and Doyle, Margaret F and Sitlani, Colleen M and Fohner, Alison E and Huber, Sally A and Floyd, James and Sinha, Arjun and Thorp, Edward B and Landay, Alan and Freiberg, Matthew S and Longstreth, William T and Tracy, Russell P and Psaty, Bruce M and Delaney, Joseph Ac} } @article {9478, title = {Association of Immune Cell Subsets with Incident Hip Fracture: The Cardiovascular Health Study.}, journal = {Calcif Tissue Int}, year = {2023}, month = {2023 Aug 31}, abstract = {

In this study, we aimed to evaluate the association of innate and adaptive immune cell subsets in peripheral blood mononuclear cells (PBMCs) with hip fracture. To conduct this study, we used data from the Cardiovascular Health Study (CHS), a U.S. multicenter observational cohort of community-dwelling men and women aged >= 65 years. Twenty-five immune cell phenotypes were measured by flow cytometry from cryopreserved PBMCs of CHS participants collected in 1998-1999. The natural killer (NK), γδ T, T helper 17 (Th17), and differentiated/senescent CD4CD28 T cell subsets were pre-specified as primary subsets of interest. Hip fracture incidence was assessed prospectively by review of hospitalization records. Multivariable Cox hazard models evaluated associations of immune cell phenotypes with incident hip fracture in sex-stratified and combined analyses. Among 1928 persons, 259 hip fractures occurred over a median 9.7 years of follow-up. In women, NK cells were inversely associated with hip fracture [hazard ratio (HR) 0.77, 95\% confidence interval (CI) 0.60-0.99 per one standard deviation higher value] and Th17 cells were positively associated with hip fracture [HR 1.18, 95\% CI 1.01-1.39]. In men, γδ T cells were inversely associated with hip fracture [HR 0.60, 95\% CI 0.37-0.98]. None of the measured immune cell phenotypes were significantly associated with hip fracture incidence in combined analyses. In this large prospective cohort of older adults, potentially important sex differences in the associations of immune cell phenotypes and hip fracture were identified. However, immune cell phenotypes had no association with hip fracture in analyses combining men and women.

}, issn = {1432-0827}, doi = {10.1007/s00223-023-01126-8}, author = {Elam, Rachel E and B{\r u}zkov{\'a}, Petra and Delaney, Joseph A C and Fink, Howard A and Barzilay, Joshua I and Carbone, Laura D and Saha, Rick and Robbins, John A and Mukamal, Kenneth J and Valderr{\'a}bano, Rodrigo J and Psaty, Bruce M and Tracy, Russell P and Olson, Nels C and Huber, Sally A and Doyle, Margaret F and Landay, Alan L and Cauley, Jane A} } @article {9240, title = {Circulating differentiated and senescent lymphocyte subsets and incident diabetes risk in older adults: The Cardiovascular Health Study.}, journal = {Endocrinol Diabetes Metab}, volume = {6}, year = {2023}, month = {2023 Jan}, pages = {e384}, abstract = {

INTRODUCTION: Cellular senescence is a feature of aging implicated in the pathophysiology of diabetes mellitus (DM). Whether senescent lymphocytes are associated with the future occurrence of DM is uncertain.

METHODS: We used cryopreserved peripheral blood mononuclear cells collected from 1860 Cardiovascular Health Study participants (average age 80.2 years) and flow cytometry immunophenotyping to evaluate the longitudinal relationships of naive (CD45RA ), memory (CD45RO ), senescent (CD28 ), and T effector memory RA (TEMRA) (CD28 CD57 CD45RA ) CD4 and CD8 T cells, and memory B cells (CD19 CD27 ), with the risk of incident DM. In exploratory analyses we evaluated the relationships of 13 additional innate lymphocyte and CD4 and CD8 subsets with incident DM risk.

RESULTS: Over a median follow-up time of 8.9 years, 155 cases of incident DM occurred. In Cox models adjusted for demographic variables (age, sex, race, study site and flow cytometry analytical batch) or diabetes risk factors (demographic variables plus education, body mass index, smoking status, alcohol use, systolic blood pressure, hypertension medication use and physical activity), no significant associations were observed for any CD4 , CD8 or CD19 cell phenotypes with incident DM.

CONCLUSIONS: These results suggest the frequencies of naive, memory and senescent T cells and memory B cells are not strongly associated with incident DM risk in older adults.

}, keywords = {CD28 Antigens, CD8-Positive T-Lymphocytes, Cellular Senescence, Diabetes Mellitus, Leukocytes, Mononuclear, Lymphocyte Subsets}, issn = {2398-9238}, doi = {10.1002/edm2.384}, author = {Olson, Nels C and Doyle, Margaret F and B{\r u}zkov{\'a}, Petra and Huber, Sally A and de Boer, Ian H and Sitlani, Colleen M and Tracy, Russell P and Psaty, Bruce M and Mukamal, Kenneth J and Delaney, Joseph A} } @article {9613, title = {Levels of procoagulant factors and peak thrombin generation in relation to dementia risk in older adults: The Cardiovascular Health Study.}, journal = {Thromb Res}, volume = {235}, year = {2024}, month = {2024 Mar}, pages = {148-154}, abstract = {

INTRODUCTION: Markers of hemostasis such as procoagulant factors and peak thrombin generation are associated with cardiovascular outcomes, but their associations with dementia risk are unclear. We aimed to evaluate prospective associations of selected procoagulant factors and peak thrombin generation with dementia risk.

METHODS: We measured levels of 7 hemostatic factors (fibrinogen, factor VII coagulant activity [FVIIc], activated factor VII [FVIIa], factor VIIa-antithrombin [FVIIa-AT], factor XI antigen [FXI], peak thrombin generation, and platelet count) among participants in the Cardiovascular Health Study, a cohort of older adults free of dementia in 1992/1993 (n~=~3185). Dementia was adjudicated and classified by DSM-IV criteria through 1998/1999. Cox proportional hazards models estimated hazard ratios (HRs) for any dementia associated with 1-standard deviation (SD) differences, adjusting for sociodemographic and clinical factors and APOE genotype. Secondary analyses separately evaluated the risk of vascular dementia, Alzheimer{\textquoteright}s disease, and mixed dementia.

RESULTS: At baseline, participants had a median age of 73~years. Over 5.4~years of follow-up, we identified 448 dementia cases. There was no evidence of linear associations between levels of these hemostatic factors with any dementia risk (HRs per 1-SD difference ranged from 1.0 to 1.1; 95~\% confidence intervals included 1.0). Results of secondary analyses by dementia subtype were similar.

CONCLUSIONS: In this prospective study, there was no strong evidence of linear associations between levels of fibrinogen, FVIIc, FVIIa, FVIIa-AT, FXI, peak thrombin generation, or platelet count with dementia risk. Despite their associations with cardiovascular disease, higher levels of these biomarkers measured among older adults may not reflect dementia risk.

}, keywords = {Aged, Anticoagulants, Antithrombin III, Antithrombins, Dementia, Factor VIIa, Fibrinogen, Hemostatics, Humans, Prospective Studies, Thrombin}, issn = {1879-2472}, doi = {10.1016/j.thromres.2024.01.024}, author = {Harrington, Laura B and Ehlert, Alexa N and Thacker, Evan L and Jenny, Nancy S and Lopez, Oscar and Cushman, Mary and Olson, Nels C and Fitzpatrick, Annette and Mukamal, Kenneth J and Jensen, Majken K} }