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Biomedical subjects

Martin G Larson

Publications and source records attributed to Martin G Larson.

At least 19 recordsLinked to original sources

Prediction of Atrial Fibrillation From the ECG in the Community Using Deep Learning: A Multinational Study.

BACKGROUND: We aimed to refine and validate a deep neural network model from the ECG to predict atrial fibrillation (AF) risk, using samples from diverse backgrounds: the Framingham Heart Study (FHS), UK Biobank, and Estudo Longitudinal da Saúde do Adulto (ELSA-Brasil). We compared the model's performance to the clinical Cohorts for Heart and Aging Research in Genomic Epidemiology consortium (CHARGE-AF) risk score and evaluated the association with other cardiovascular outcomes. METHODS: The ECG-derived deep-learning prediction of AF (ECG-AF) model was refined using 60% of FHS samples free of AF. Its performance was then tested in the remaining FHS samples, UK Biobank, and ELSA-Brasil, with discrimination assessed by the area under the receiver operating characteristic curve. The association of ECG-AF with cardiovascular outcomes was assessed using Cox proportional hazards models. RESULTS: The study sample included 10 097 FHS participants (mean age 53±12 years; 54.9% women), 49 280 participants from the UK Biobank (mean age 64±8 years, 47.9% women), and 12 284 participants from ELSA-Brasil (mean age 53±8 years, 54.7% women). The ECG-AF model showed moderate discrimination for incident AF (area under the curve, 0.82 [95% CI, 0.80-0.84]) in the FHS, comparable to the CHARGE-AF score (area under the curve, 0.83 [95% CI, 0.81-0.85]), and incremental when combined (area under the curve, 0.85 [95% CI, 0.83-0.87]). In UK Biobank and ELSA-Brasil, combining ECG-AF and CHARGE also improved prediction. Higher ECG-AF scores were associated with increased risks of heart failure, myocardial infarction, stroke, and all-cause mortality in all 3 cohorts. CONCLUSIONS: In multinational cohort studies, the single-input ECG-AF deep neural network model demonstrated good performance in predicting AF and other cardiovascular outcomes, comparable to a multivariable clinical risk score, with improved performance when combined.

Humans↗

Genetic architecture and analysis practices of circulating metabolites in the NHLBI Trans-Omics for Precision Medicine Program.

Circulating metabolite levels partly reflect the state of human health and diseases and can be impacted by genetic determinants. Hundreds of loci associated with circulating metabolites have been identified; however, most findings focus on predominantly European ancestry or single-study analyses. Leveraging the rich metabolomics resources generated by the National Heart, Lung, and Blood Institute (NHLBI) Trans-Omics for Precision Medicine (TOPMed) Program, we harmonized and accessibly cataloged 1,729 circulating metabolites among 25,058 ancestrally diverse samples. From our comparison of multiple methods, we provided a set of reasonable strategies for outlier and imputation handling to process metabolite data and show that inverse normalization by study and half-minimum imputation provide mostly similar results for pooled or meta-analysis. Following the practical analysis framework, we further performed a genome-wide association analysis on 1,135 selected metabolites using whole-genome sequencing data from 16,359 individuals passing the quality-control filters and discovered 1,775 independent loci associated with 667 metabolites. Among 160 unreported locus-metabolite pairs, we identified associations with loci locating within previously implicated metabolite-associated genes, as well as associations with loci locating in genes such as GAB3 and VSIG4 (located on the X chromosome) that may play a role in metabolic regulation. In the sex-stratified analysis, we revealed 85 independent locus-metabolite pairs with evidence of sexual dimorphism, which were located in well-known metabolic genes such as FADS2, D2HGDH, SUGP1, and UGT2B17, strongly supporting the importance of exploring sex difference in the human metabolome. Taken together, our study depicted the genetic contribution to circulating metabolite levels, providing additional insight into the understanding of human health.

Humans↗

Choice of time scale and its effect on significance of predictors in longitudinal studies.

Time-to-event regression is a frequent tool in biomedical research. In clinical trials this time is usually measured from the beginning of the study. The same approach is often adopted in the analysis of longitudinal observational studies. However, in recent years there has appeared literature making a case for the use of the date of birth as a starting point, and thus utilize age as the time-to-event. In this paper, we explore different types of age-scale models and compare them with time-on-study models in terms of the estimated regression coefficients they produce. We consider six proportional hazards regression models that differ in the choice of time scale and in the method of adjusting for the years before the study. By considering the estimating equations of these models as well as numerical simulations we conclude that correct adjustment for the age at entry is crucial in reducing bias of the estimated coefficients. The unadjusted age-scale model is inferior to any of the five other models considered, regardless of their choice of time scale. Additionally, if adjustment for age at entry is made, our analyses show very little to suggest that there exists any practically meaningful difference in the estimated regression coefficients depending on the choice of time scale. These findings are supported by four practical examples from the Framingham Heart Study.

Age Factors↗

Multiple biomarkers for the prediction of first major cardiovascular events and death.

BACKGROUND: Few investigations have evaluated the incremental usefulness of multiple biomarkers from distinct biologic pathways for predicting the risk of cardiovascular events. METHODS: We measured 10 biomarkers in 3209 participants attending a routine examination cycle of the Framingham Heart Study: the levels of C-reactive protein, B-type natriuretic peptide, N-terminal pro-atrial natriuretic peptide, aldosterone, renin, fibrinogen, D-dimer, plasminogen-activator inhibitor type 1, and homocysteine; and the urinary albumin-to-creatinine ratio. RESULTS: During follow-up (median, 7.4 years), 207 participants died and 169 had a first major cardiovascular event. In Cox proportional-hazards models adjusting for conventional risk factors, the following biomarkers most strongly predicted the risk of death (each biomarker is followed by the adjusted hazard ratio per 1 SD increment in the log values): B-type natriuretic peptide level (1.40), C-reactive protein level (1.39), the urinary albumin-to-creatinine ratio (1.22), homocysteine level (1.20), and renin level (1.17). The biomarkers that most strongly predicted major cardiovascular events were B-type natriuretic peptide level (adjusted hazard ratio, 1.25 per 1 SD increment in the log values) and the urinary albumin-to-creatinine ratio (1.20). Persons with "multimarker" scores (based on regression coefficients of significant biomarkers) in the highest quintile as compared with those with scores in the lowest two quintiles had elevated risks of death (adjusted hazard ratio, 4.08; P<0.001) and major cardiovascular events (adjusted hazard ratio, 1.84; P=0.02). However, the addition of multimarker scores to conventional risk factors resulted in only small increases in the ability to classify risk, as measured by the C statistic. CONCLUSIONS: For assessing risk in individual persons, the use of the 10 contemporary biomarkers that we studied adds only moderately to standard risk factors.

Biomarkers↗

Cardiovascular disease risk factors in chronic kidney disease: overall burden and rates of treatment and control.

BACKGROUND: Mild to moderate chronic kidney disease (CKD) is associated with increased risk for cardiovascular disease. The burden of cardiovascular disease risk factors in this setting is not well described. METHODS: We compared the age- and sex-adjusted prevalence of cardiovascular disease risk factors and their treatment and control among persons with and without CKD in 3258 Framingham offspring cohort members who attended the seventh examination cycle (1998-2001). Glomerular filtration rate (GFR) was estimated using the simplified Modification of Diet in Renal Disease Study equation. We defined CKD as a GFR of less than 59 mL/min per 1.73 m(2) in women and less than 64 mL/min per 1.73 m(2) in men. RESULTS: Those with CKD were older, more likely to be obese (33.5% vs 29.3%; P=.02), and more likely to have low levels of high-density lipoprotein cholesterol (45.2% vs 29.4%; P<.001) and high triglyceride levels (39.9% vs 29.8%; P<.001). Those with CKD had a higher prevalence of hypertension (71.2% vs 42.7%; P<.001) and hypertension treatment (86.0% vs 72.5%; P<.001), but were less likely to achieve optimal blood pressure control (27.0% vs 45.5%; P<.001). Participants with CKD had a higher prevalence of elevated low-density lipoprotein cholesterol levels (60.5% vs 44.7%; P=.06) and lipid-lowering therapy (57.1% vs 42.6%; P=.09), although this was not statistically significant. A greater proportion of individuals with CKD than those without had diabetes (23.5% vs 11.9%; P=.02) and were receiving diabetes treatment (63.6% vs 46.9%; P=.05), but were less likely to achieve a hemoglobin A(1c) level of less than 7% (43.8% vs 59.4%; P=.03). CONCLUSIONS: Chronic kidney disease is associated with a significant burden of cardiovascular disease risk factors in the community. The diagnosis of CKD should alert the practitioner to look for potentially modifiable cardiovascular risk factors.

Aged↗

Matrix Gla protein is associated with risk factors for atherosclerosis but not with coronary artery calcification.

OBJECTIVE: Atherosclerotic coronary artery calcification (CAC) is associated with increased coronary heart disease (CHD) risk. Matrix Gla protein (MGP) is an inhibitor of calcification in vivo. However, little is known regarding the distribution of circulating MGP and its associations with CHD risk factors or with CAC in humans. METHODS AND RESULTS: Serum MGP concentrations were determined in 2 independent populations of men and women free of clinically apparent cardiovascular disease: study A, n=316, mean age 58 years, and study B, n=452, mean age 68 years. CAC was determined by computed tomography. Mean MGP concentrations were 98.4 and 198 ng/mL in men, and 97.4 and 201 ng/mL in women, in study A and study B, respectively. In both cohorts, MGP levels were higher with increasing age. In age-adjusted analyses, there was an association of circulating MGP with increasing Framingham CHD risk score (in study A, P=0.003 in men and P=0.016 in women, respectively; in study B, a nonsignificant increase in men and P=0.05 in women, respectively). Significant associations of circulating MGP with high-density lipoprotein and other individual CHD risk factors were also noted in both cohorts. There were no consistent associations between MGP and CAC after adjustment for CHD risk score in the 2 cohorts. CONCLUSIONS: MGP is associated with individual CHD risk factors and the Framingham CHD risk score in men and women free of clinically apparent CHD. The relation of MGP with CAC deserves further study in larger populations.

Adult↗

Association of parental heart failure with risk of heart failure in offspring.

BACKGROUND: The association between heart failure in parents and the prevalence of left ventricular systolic dysfunction and the risk of heart failure in their offspring has not been investigated in a community-based setting. METHODS: We examined the cross-sectional association of heart failure in parents with the prevalence of left ventricular systolic dysfunction, as well as left ventricular mass, internal dimensions, and wall thickness, in 1497 participants of the Framingham Offspring Study (mean age, 57 years; 819 women) who underwent routine echocardiography. We also investigated prospectively whether heart failure in parents increased the risk of heart failure in 2214 offspring (mean age, 44 years; 1150 women). RESULTS: As compared with the 1039 participants whose parents did not have heart failure, the 458 participants in the cross-sectional cohort who had at least one parent with heart failure were more likely to have increased left ventricular mass (17.0 percent vs. 26.9 percent), left ventricular internal dimensions (18.6 percent vs. 23.4 percent), and left ventricular systolic dysfunction (3.1 percent vs. 5.7 percent); the multivariable-adjusted odds ratios were 1.35 (95 percent confidence interval, 0.99 to 1.84), 1.29 (95 percent confidence interval, 0.96 to 1.72), and 2.37 (95 percent confidence interval, 1.22 to 4.61), respectively. In the longitudinal cohort, heart failure developed in 90 offspring during follow-up (mean length of follow-up, 20 years). The age- and sex-adjusted 10-year incidence rates of heart failure were 2.72 percent among offspring with a parent with heart failure, as compared with 1.62 percent among those without a parent with heart failure. This increase in risk persisted after multivariable adjustment (hazard ratio, 1.70; 95 percent confidence interval, 1.11 to 2.60). CONCLUSIONS: Heart failure in parents is associated with an increased prevalence of left ventricular systolic dysfunction cross-sectionally and an elevated risk of heart failure longitudinally. Our data emphasize the contribution of familial factors to the heart-failure burden in the community.

Adult Children↗

Single-gene mutations and increased left ventricular wall thickness in the community: the Framingham Heart Study.

BACKGROUND: Mutations in sarcomere protein, PRKAG2, LAMP2, alpha-galactosidase A (GLA), and several mitochondrial genes can cause rare familial cardiomyopathies, but their contribution to increased left ventricular wall thickness (LVWT) in the community is unknown. METHODS AND RESULTS: We studied 1862 unrelated participants (52% women; age, 59+/-9 years) from the community-based Framingham Heart Study who had echocardiograms and provided DNA samples but did not have severe hypertension, aortic prosthesis, or significant aortic stenosis. Eight sarcomere protein genes, 3 storage cardiomyopathy-causing genes, and 27 mitochondrial genes were sequenced in unrelated individuals with increased LVWT (maximum LVWT >13 mm). Fifty eligible participants (9 women) had unexplained increased LVWT. We detected 8 mutations in 9 individuals (2 women); 7 mutations in 5 sarcomere protein genes (MYH7, MYBPC3, TNNT2, TNNI3, MYL3), and 1 GLA mutation. In individuals with increased LVWT, participants with sarcomere protein and storage mutations were clinically indistinguishable from those without mutations. CONCLUSIONS: In a community-based cohort, about 3% of eligible participants had increased LVWT, of whom 18% had sarcomere protein or lipid storage gene mutations. Increased LVWT in the community is a very heterogeneous condition, which sometimes may arise from single-gene variants in one of a number of genes.

Anthropometry↗

Phenotype-genotype association grid: a convenient method for summarizing multiple association analyses.

BACKGROUND: High-throughput genotyping generates vast amounts of data for analysis; results can be difficult to summarize succinctly. A single project may involve genotyping many genes with multiple variants per gene and analyzing each variant in relation to numerous phenotypes, using several genetic models and population subgroups. Hundreds of statistical tests may be performed for a single SNP, thereby complicating interpretation of results and inhibiting identification of patterns of association. RESULTS: To facilitate visual display and summary of large numbers of association tests of genetic loci with multiple phenotypes, we developed a Phenotype-Genotype Association (PGA) grid display. A database-backed web server was used to create PGA grids from phenotypic and genotypic data (sample sizes, means and standard errors, P-value for association). HTML pages were generated using Tcl scripts on an AOLserver platform, using an Oracle database, and the ArsDigita Community System web toolkit. The grids are interactive and permit display of summary data for individual cells by a mouse click (i.e. least squares means for a given SNP and phenotype, specified genetic model and study sample). PGA grids can be used to visually summarize results of individual SNP associations, gene-environment associations, or haplotype associations. CONCLUSION: The PGA grid, which permits interactive exploration of large numbers of association test results, can serve as an easily adapted common and useful display format for large-scale genetic studies. Doing so would reduce the problem of publication bias, and would simplify the task of summarizing large-scale association studies.

Computer Graphics↗

A common genetic variant in the NOS1 regulator NOS1AP modulates cardiac repolarization.

Extremes of the electrocardiographic QT interval, a measure of cardiac repolarization, are associated with increased cardiovascular mortality. We identified a common genetic variant influencing this quantitative trait through a genome-wide association study on 200 subjects at the extremes of a population-based QT interval distribution of 3,966 subjects from the KORA cohort in Germany, with follow-up screening of selected markers in the remainder of the cohort. We validated statistically significant findings in two independent samples of 2,646 subjects from Germany and 1,805 subjects from the US Framingham Heart Study. This genome-wide study identified NOS1AP (CAPON), a regulator of neuronal nitric oxide synthase, as a new target that modulates cardiac repolarization. Approximately 60% of subjects of European ancestry carry at least one minor allele of the NOS1AP genetic variant, which explains up to 1.5% of QT interval variation.

Adaptor Proteins, Signal Transducing↗

Common genetic variation in five thrombosis genes and relations to plasma hemostatic protein level and cardiovascular disease risk.

OBJECTIVE: We undertook a linkage disequilibrium (LD)-based genetic approach to investigate the hypothesis that common sequence variants in 5 thrombosis genes influence plasma hemostatic protein levels or risk of cardiovascular disease (CVD). METHODS AND RESULTS: In a reference panel, we characterized LD structure at the fibrinogen gene cluster (fibrinogen-beta[FGB], FGA, and FGG), factor VII (F7), and tissue plasminogen activator (PLAT) loci. Forty-one tag single nucleotide polymorphisms (SNPs) were genotyped in 1811 unrelated Framingham Heart Study participants. There were significant associations of 9 FGB SNPs with fibrinogen level (minimum P=0.002) and of 7 F7 SNPs and factor VII level (minimum P<0.0001). SNPs at the PLAT locus were not associated with PLAT level. In stepwise analysis, a single FGB variant explained 1% of the residual variance in fibrinogen level, and 2 F7 SNPs together explained 10% of the residual variance in factor VII level. Two PLAT haplotypes were associated with CVD (multivariable-adjusted global P=0.0004). CONCLUSIONS: A comprehensive survey of common sequence variation demonstrates that cis-regulatory SNPs explain a modest proportion of the residual variance in circulating fibrinogen and factor VII level and PLAT haplotypes increase the risk of CVD. Additional studies are warranted to confirm the association of PLAT sequence variation and risk of CVD.

Aged↗

Electrocardiographic QRS duration and the risk of congestive heart failure: the Framingham Heart Study.

Prolonged electrocardiographic QRS duration is frequently observed in congestive heart failure (CHF) patients. We hypothesized that CHF risk increases with longer QRS interval in individuals free of CHF. We evaluated 1759 Framingham Study participants (mean age, 69 years; 63% women) without prior myocardial infarction or CHF who attended a routine examination. QRS duration was analyzed as a continuous (log-transformed) and a categorical variable [referent, <100 ms; incomplete bundle branch block (BBB), 100 to 119 ms; complete BBB, > or =120 ms]. During follow-up (mean, 12.7 years), 324 participants (205 women) developed CHF. CHF incidence increased across the 3 baseline QRS duration categories in both sexes. Each SD increment in log-QRS duration was associated with a multivariable-adjusted 23% increase in CHF risk [95% confidence interval [CI] 8% to 38%; P<0.001]. In time- dependent models with QRS category and risk factors updated every 2 years, incomplete BBB was associated with a 1.4-fold (95% CI, 1.05 to 1.96; P=0.03) and complete BBB with a 1.7-fold (95% CI, 1.28 to 2.35; P<0.001) risk of CHF. These associations were maintained on adjustment for baseline left ventricular mass. In our community-based sample, longer electrocardiographic QRS was associated with increased CHF risk, consistent with the hypothesis that depolarization delay may increase CHF risk.

Aged↗

Relations of inflammation and novel risk factors to valvular calcification.

Investigators have suggested that inflammation may play a role in the pathogenesis of valve calcium. Participants in the Framingham Heart Study's offspring cohort had systemic levels of C-reactive protein, intercellular adhesion molecule-1, interleukin-6, and monocyte chemoattractant protein-1 measured at examination cycle 7. Mitral annular calcium, aortic annular calcium, aortic sclerosis, and aortic stenosis were assessed by echocardiography at examination cycle 6. Logistic regression was used to examine the odds of valvular calcium per 1 unit increase in inflammation (ISUM), a summary statistic of all normalized deviates of the individual markers. Two thousand six hundred eighty-three participants (mean age 61 +/- 10 years; 52% women) were analyzed: 8.2% (n = 216) had > or = 1 calcified valve or annulus; 89 had mitral annular calcium, 78 had aortic annular calcium, 135 had aortic sclerosis, and 33 had aortic stenosis. Participants with valvular calcium were older and were more likely to have hypertension and diabetes mellitus. Participants with valve calcium had higher median levels of all markers. For each log unit increase in ISUM, after adjustment for age and gender, there was an associated 1.1-fold increased odds of > or = 1 calcified valve (p = 0.02); the odds ratios were no longer significant after adjustment for cardiovascular disease risk factors (odds ratio 1.0, 95% confidence interval 0.9 to 1.1). Similar results were obtained for the individual markers and the odds of > or = 1 calcified valve. In conclusion, inflammatory markers were elevated in patients with valvular calcium. Our findings suggest that much of the observed association between systemic inflammatory markers and valvular calcium may be due to shared risk factors.

Aged↗

Contribution of clinical correlates and 13 C-reactive protein gene polymorphisms to interindividual variability in serum C-reactive protein level.

BACKGROUND: Serum C-reactive protein (CRP) level is a heritable complex trait that predicts incident cardiovascular disease. We investigated the clinical and genetic sources of interindividual variability in serum CRP. METHODS AND RESULTS: We studied serum CRP in 3301 Framingham Heart Study (FHS) participants (mean age 61 years, 53% women). Twelve clinical covariates explained 26% of the variability in CRP level, with body mass index alone explaining 15% (P<0.0001) of the variance. To investigate the influence of genetic variation at the CRP gene on CRP levels, we first constructed a dense linkage disequilibrium map for common single-nucleotide polymorphisms (SNPs) spanning the CRP locus (1 SNP every 850 bases, 26 kilobase [kb] genomic region). Thirteen CRP SNPs were genotyped in 1640 unrelated FHS participants with measured CRP levels. After adjustment for clinical covariates, 9 of 13 SNPs were associated with CRP level (P<0.05). To account for correlation among SNPs, we conducted forward stepwise selection among all 13 SNPs; a triallelic SNP (rs3091244) remained associated with CRP level (stepwise P<0.0001). The triallelic SNP (C-->T-->A; allele frequencies 62%, 31%, and 7%), located in the promoter sequence, explained 1.4% of total serum CRP variation; haplotypes harboring the minor T and A alleles of this SNP were associated with higher CRP level (haplotype P=0.0002 and 0.004). CONCLUSIONS: In our community-based sample, clinical variables explained 26% of the interindividual variation in CRP, whereas a common triallelic CRP SNP contributed modestly. Studies of larger samples are warranted to assess the association of genetic variation in CRP and risk of cardiovascular disease.

Age Factors↗

Cross-sectional relations of multiple biomarkers from distinct biological pathways to brachial artery endothelial function.

BACKGROUND: Endothelial dysfunction is a critical intermediate phenotype in the pathogenesis of cardiovascular disease. We evaluated the relative contributions of distinct biological pathways to interindividual variation in endothelial function by relating prototype biomarkers (representing these pathways) to brachial artery vasodilator function. METHODS AND RESULTS: We investigated the cross-sectional relations of a panel of 7 biomarkers measured at a routine examination to brachial artery vasodilator function (flow-mediated dilation [FMD] and reactive hyperemia) assessed at a subsequent examination (mean interval, 2.9 years) in 2113 Framingham Heart Study participants (mean age, 61 years; 54% women). We selected biomarkers from 4 biological domains: neurohormonal (N-terminal pro-atrial natriuretic peptide [N-ANP], B-type natriuretic peptide [BNP], renin, aldosterone), hemostatic factors (plasminogen activator inhibitor-1 [PAI-1]), inflammation (C-reactive protein [CRP]), and target organ damage (urine albumin-creatinine ratio). In age- and sex-adjusted models, several biomarkers were related to baseline brachial artery diameter (PAI-1, CRP, urine albumin-creatinine ratio), baseline mean flow (N-ANP, BNP, PAI-1, CRP, aldosterone), FMD (N-ANP, PAI-1, CRP, renin), and reactive hyperemia (BNP, PAI-1, CRP, renin, urine albumin-creatinine ratio). In multivariable analyses relating the 7 biomarkers conjointly to each vascular function measure (adjusting for known risk factors), N-ANP and renin were positively related to FMD (P=0.001 and P=0.04, respectively), and N-ANP was inversely related to baseline mean flow velocity (P=0.01). None of the other biomarkers was significantly related to the vascular function measures studied. CONCLUSIONS: In our large community-based sample, a conservative strategy relating several biomarkers to vascular endothelial function identified plasma N-ANP as a key correlate of mean flow under basal conditions and of FMD in response to forearm cuff occlusion.

Aged↗

Prediction of lifetime risk for cardiovascular disease by risk factor burden at 50 years of age.

BACKGROUND: Lifetime risk for atherosclerotic cardiovascular disease (CVD) has not previously been estimated, and the effect of risk factor burden on lifetime risk is unknown. METHODS AND RESULTS: We included all Framingham Heart Study participants who were free of CVD (myocardial infarction, coronary insufficiency, angina, stroke, claudication) at 50 years of age. Lifetime risks to 95 years of age were estimated for men and women, with death free of CVD as a competing event. We followed up 3564 men and 4362 women for 111,777 person-years; 1757 had CVD events and 1641 died free of CVD. At 50 years of age, lifetime risks were 51.7% (95% CI, 49.3 to 54.2) for men and 39.2% (95% CI, 37.0 to 41.4) for women, with median survivals of 30 and 36 years, respectively. With more adverse levels of single risk factors, lifetime risks increased and median survivals decreased. Compared with participants with > or =2 major risk factors, those with optimal levels had substantially lower lifetime risks (5.2% versus 68.9% in men, 8.2% versus 50.2% in women) and markedly longer median survivals (>39 versus 28 years in men, >39 versus 31 years in women). CONCLUSIONS: The absence of established risk factors at 50 years of age is associated with very low lifetime risk for CVD and markedly longer survival. These results should promote efforts aimed at preventing development of risk factors in young individuals. Given the high lifetime risks and lower survival in those with intermediate or high risk factor burden at 50 years of age, these data may be useful in communicating risks and supporting intensive preventive therapy.

Age Factors↗

Social networks and inflammatory markers in the Framingham Heart Study.

Lack of social integration predicts coronary heart disease mortality in prospective studies; however, the biological pathways that may be responsible are poorly understood. The specific aims of this study were to examine whether social networks are associated with serum concentrations of the inflammatory markers interleukin-6 (IL-6), C-reactive protein (CRP), soluble intercellular adhesion molecule-1 (sICAM-1) and monocyte chemoattractant protein-1 (MCP-1). Participants in the Framingham Study attending examinations from 1998 to 2001 (n=3267) were eligible for inclusion in the study. Social networks were assessed using the Berkman-Syme Social Network Index (SNI). Concentrations of IL-6, CRP, sICAM-1 and MCP-1 were measured in fasting serum samples. Multivariable linear regression analyses were used to assess the association of social networks with inflammatory markers adjusting for potential confounders including age, smoking, blood pressure, total:HDL cholesterol ratio, body mass index, lipid-lowering and antihypertensive medication, diabetes, cardiovascular disease, depression and socioeconomic status. Results found that the SNI was significantly inversely associated with IL-6 in men (p=0.03) after adjusting for potential confounders. In age-adjusted analyses, social networks also were significantly inversely associated with IL-6 for women (p=0.03) and were marginally to modestly associated with CRP and sICAM-1 for men (p=0.08 and 0.02, respectively), but these associations were not significant in the multivariate analyses. In conclusion, social networks were found to be inversely associated with interleukin-6 levels in men. The possibility that inflammatory markers may be potential mediators between social integration and coronary heart disease merits further investigation.

Biomarkers↗