A Comparison of Three Different Methods to Evaluate Endothelium-Dependent Vasodilation in the Elderly

The plasma protein profile and cardiovascular risk differ between intima-media thickness of the common carotid artery and the bulb: A meta-analysis and a longitudinal evaluation

BACKGROUND AND AIMS

Genetic loci associated with CHD show different relationships with intima-media thickness in the common carotid artery (IMT-CCA) and in the bulb (IMT-bulb). We evaluated if IMT-CCA and IMT-bulb differ also with respect to circulating protein profiles and risk of incident atherosclerotic disease.

METHODS

In three Swedish cohorts (MDC, IMPROVE, PIVUS, total n > 7000), IMT-CCA and IMT-bulb were assessed by ultrasound at baseline, and 86 cardiovascular-related proteins were analyzed. In the PIVUS study only, IMT-CCA and IMT-bulb were investigated in relation to incident atherosclerotic disease over 10 years of follow-up.

RESULTS

In a meta-analysis of the analysis performed separately in the cohorts, three proteins, matrix metalloproteinase-12 (MMP-12), hepatocyte growth factor (HGF) and N-terminal pro-B-type natriuretic peptide (NT-proBNP), were associated with IMT-CCA when adjusted for traditional cardiovascular risk factors. Five proteins were associated with IMT-bulb (MMP-12, growth/differentiation factor 15 (GDF-15), osteoprotegerin, growth hormone and renin). Following adjustment for cardiovascular risk factors, IMT-bulb was significantly more closely related to incident stroke or myocardial infarction (total number of cases, 111) than IMT-CCA in the PIVUS study (HR 1.51 for 1 SD, 95%CI 1.21-1.87, p < 0.001 vs HR 1.17, 95%CI 0.93-1.47, p = 0.16). MMP-12 levels were related to this combined end-point (HR 1.30, 95%CI 1.08-1.56, p = 0.0061).

CONCLUSIONS

Elevated levels of MMP-12 were associated with both IMT-CCA and IMT-bulb, but other proteins were significantly related to IMT in only one of these locations. The finding that IMT-bulb was more closely related to incident atherosclerotic disease than IMT-CCA emphasizes a difference between these measurements of IMT.

Changes in Proteomic Profiles are Related to Changes in BMI and Fat Distribution During 10 Years of Aging

OBJECTIVE

This study investigated how changes in 84 proteins over a 10-year period of aging were related to changes in measures of body fat and distribution over the same period.

METHODS

Cardiovascular candidate proteins were measured using the proximal extension assay technique, along with BMI and waist-hip ratio (WHR), at ages 70, 75, and 80 in 1,016 participants of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort. Associations of changes in plasma protein levels, BMI, and WHR over time were analyzed using linear mixed models.

RESULTS

Changes in 19 and 16 proteins were significantly associated with changes in BMI and WHR, respectively (P < 0.00059), over the investigated 10-year period. Leptin and fatty acid-binding protein 4 were among the proteins most strongly associated with changes in both BMI and WHR. Four of the proteins significantly tracked with change in BMI (P < 0.00059) but not WHR (P > 0.05): endothelial cell-specific molecule 1, pentraxin-related protein PTX3, ST2 protein (also known as interleukin-1 receptor-like 1), and spondin-1. Five proteins tracked with change in WHR (P < 0.00059) but not BMI (P > 0.05): caspase-8, cathepsin L1, oxidized low-density lipoprotein receptor 1, interleukin-6 receptor subunit alpha, and C-C motif chemokine 20.

CONCLUSIONS

This is the first large longitudinal study of how changes in plasma protein signatures are associated with changes in measures of body fat and distribution over 10 years of aging.

A Multi-Cohort Metabolomics Analysis Discloses Sphingomyelin (32:1) Levels to be Inversely Related to Incident Ischemic Stroke

BACKGROUND AND PURPOSE

To search for novel pathophysiological pathways related to ischemic stroke using a metabolomics approach.

METHODS

We identified 204 metabolites in plasma by liquid chromatography mass spectrometry in 3 independent population-based samples (TwinGene, Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) and Uppsala Longitudinal Study of Adult Men). TwinGene was used for discovery and the other 2 samples were meta-analyzed as replication. In PIVUS, traditional cardiovascular (CV) risk factors, multiple markers of subclinical CV disease, markers of coagulation/fibrinolysis were measured and analyzed in relation to top metabolites.

RESULTS

In TwinGene (177 incident cases, median follow-up 4.3 years), levels of 28 metabolites were associated with incident ischemic stroke at a false discover rate (FDR) of 5%. In the replication (together 194 incident cases, follow-up 10 and 12 years, respectively), only sphingomyelin (32:1) was significantly associated (HR .69 per SD change, 95% CI .57-0.83, P value = .00014; FDR <5%) when adjusted for systolic blood pressure, diabetes, smoking, low density lipoportein (LDL)- and high density lipoprotein (HDL), body mass index (BMI) and atrial fibrillation. In PIVUS, sphingomyelin (32:1) levels were significantly related to both LDL- and HDL-cholesterol in a positive fashion, and to serum triglycerides, BMI and diabetes in a negative fashion. Furthermore, sphingomyelin (32:1) levels were related to vasodilation in the forearm resistance vessels, and inversely to leukocyte count (P < .0069 and .0026, respectively).

CONCLUSIONS

An inverse relationship between sphingomyelin (32:1) and incident ischemic stroke was identified, replicated, and characterized. A possible protective role for sphingomyelins in stroke development has to be further investigated in additional experimental and clinical studies.

Genetic regulation of gene expression and splicing during a 10-year period of human aging

BACKGROUND

Molecular and cellular changes are intrinsic to aging and age-related diseases. Prior cross-sectional studies have investigated the combined effects of age and genetics on gene expression and alternative splicing; however, there has been no long-term, longitudinal characterization of these molecular changes, especially in older age.

RESULTS

We perform RNA sequencing in whole blood from the same individuals at ages 70 and 80 to quantify how gene expression, alternative splicing, and their genetic regulation are altered during this 10-year period of advanced aging at a population and individual level. We observe that individuals are more similar to their own expression profiles later in life than profiles of other individuals their own age. We identify 1291 and 294 genes differentially expressed and alternatively spliced with age, as well as 529 genes with outlying individual trajectories. Further, we observe a strong correlation of genetic effects on expression and splicing between the two ages, with a small subset of tested genes showing a reduction in genetic associations with expression and splicing in older age.

CONCLUSIONS

These findings demonstrate that, although the transcriptome and its genetic regulation is mostly stable late in life, a small subset of genes is dynamic and is characterized by a reduction in genetic regulation, most likely due to increasing environmental variance with age.

A detailed lipoprotein profile in relation to intima-media thickness and echogenicity of three major arteries

OBJECTIVE

To investigate differences in risk-factor profile, with special emphasis on detailed characterization of the lipoprotein profile, for intima-media thickness (IMT) and echogenicity of the intima-media complex (IM-GSM) in three major arteries: the carotid, femoral and brachial arteries.

METHODS

IMT and IM-GSM were measured by ultrasound in the carotid, femoral and brachial arteries in 778 subjects, all aged 75 years (50% women), in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, in which a detailed lipoprotein profile was also determined by nuclear magnetic resonance spectroscopy.

RESULTS

First, IMT was considerably lower, and IM-GSM higher, in the brachial artery compared to the other two arteries. Second, IMT and IM-GSM in the arteries were related to each other. Third, significant different traditional risk-factor profiles were seen for both IMT and IM-GSM, with generally weaker relationships for IMT in the femoral and brachial arteries compared with the carotid artery. Fourth, the strength of associations between an atherogenic lipoprotein profile and IMT in the carotid artery was attenuated in the femoral artery and virtually absent in the brachial artery. Fifth, slightly different lipoprotein profiles were seen for IM-GSM in the three arteries.

CONCLUSION

Differences between the carotid, femoral and brachial artery IMT and IM-GSM were seen regarding the traditional risk factors, as well as the lipoprotein profile.

Proteomic Analysis of Longitudinal Changes in Blood Pressure

Hypertension is the leading risk factor for premature death worldwide. The identification of modifiable causes of hypertension remains an imperative task. We aimed to investigate associations between 79 proteins implicated in cardiovascular disease and longitudinal blood pressure (BP) changes in three Swedish prospective cohorts. In a discovery phase, we investigated associations between baseline circulating protein levels assessed with a proximity extension assay and BP stage progression at follow-up 5 years later among persons without BP-lowering drugs at baseline in two independent community-based cohorts from the Prospective Investigation of the Vasculature in Uppsala Seniors study (PIVUS) and the Uppsala Longitudinal Study of Adult Men (ULSAM). We used an independent cohort, the Malmö Diet and Cancer Study (MDC), for replication. The primary outcome of BP stage progression was defined as per the 2017 AHA/ACC (American Heart Association/ American College of Cardiology) Guideline BP categories. We also investigated associations of protein levels with changes in BP on a continuous scale, and meta-analyzed all three cohorts. Levels of renin were associated with BP stage progression with a 5% false discovery rate (FDR) in the ULSAM (n = 238) and PIVUS (n = 566) cohorts, but we could not replicate this association in the MDC cohort (n = 2659). The association in the discovery cohorts was modest, with an odds ratio for BP stage progression over 5 years of 1.33 (95% confidence interval 1.14 to 1.56) per standard deviation of baseline renin. In conclusion, we could not find any novel robust associations with longitudinal BP increase in a proximity extension assay-based proteomics investigation in three cohorts.

Relationship between endothelium-dependent vasodilation and fat distribution using the new "imiomics" image analysis technique

BACKGROUND AND AIMS

We investigated how vasoreactivity in the brachial artery and the forearm resistance vessels were related to fat distribution and tissue volume, using both traditional imaging analysis and a new technique, called "Imiomics", whereby vasoreactivity was related to each of the >2M 3D image elements included in the whole-body magnetic resonance imaging (MRI).

METHODS AND RESULTS

In 326 subjects in the Prospective investigation of Obesity, Energy and Metabolism (POEM) study (all aged 50 years), endothelium-dependent vasodilation was measured by acetylcholine infusion in the brachial artery (EDV) and flow-mediated vasodilation (FMD). Fat distribution was evaluated by dual-energy X-ray absorptiometry (DXA) and magnetic resonance imaging (MRI). EDV, but not FMD, was significantly related to total fat mass, liver fat, subcutaneous (SAT) and visceral (VAT) adipose tissue in a negative fashion in women, but not in men. Using Imiomics, an inverse relationship was seen between EDV and a local tissue volume of SAT in both the upper part of the body, as well as the gluteo-femoral part and the medial parts of the legs in women. Also the size of the liver, heart and VAT was inversely related to EDV. In men, less pronounced relationships were seen. FMD was also significantly related to local tissue volume of upper-body SAT and liver fat in women, but less so in men.

CONCLUSION

EDV, and to a lesser degree also FMD, were related to liver fat, SAT and VAT in women, but less so in men. Imiomics both confirmed findings from traditional methods and resulted in new, more detailed results.

Associations of Circulating Protein Levels With Lipid Fractions in the General Population

Objective- Revealing patterns of associations between circulating protein and lipid levels could improve biological understanding of cardiovascular disease (CVD). In this study, we investigated the associations between proteins related to CVD and triglyceride (TG), total cholesterol, LDL (low-density lipoprotein), and HDL (high-density lipoprotein) cholesterol levels in individuals from the general population. Approach and Results- We measured plasma protein levels using the Olink ProSeek CVD I or II+III arrays and analyzed 57 proteins available in 3 population-based cohorts: EpiHealth (n=2029; 52% women; median age, 61 years), PIVUS (Prospective Study of the Vasculature in Uppsala Seniors; n=790; 51% women; all aged 70 years), and ULSAM (Uppsala Longitudinal Study of Adult Men; n=551; all men aged 77 years). A discovery analysis was performed in EpiHealth in a regression framework (adjusted for sex, age, body mass index, smoking, glucose levels, systolic blood pressure, blood pressure medication, diabetes mellitus medication, and CVD history), and associations with false discovery rate <0.05 were further tested in PIVUS and ULSAM, where a P value of 0.05 was considered a successful replication (validation false discovery rate of 0.1%). We used summary statistics from a genome-wide association study on each protein biomarker (meta-analysis of EpiHealth, PIVUS, ULSAM, and IMPROVE [Carotid Intima-Media Thickness and IMT-Progression as Predictors of Vascular Events in a High-Risk European Population]) and publicly available data from Global Lipids Genetics Consortium to perform Mendelian randomization analyses to address possible causality of protein levels. Of 57 tested proteins, 42 demonstrated an association with at least 1 lipid fraction; 35 were associated with TG, 15 with total cholesterol, 9 with LDL cholesterol, and 24 with HDL cholesterol. Among these associations, we found KIM-1 (kidney injury molecule-1), TNFR (TNF [tumor necrosis factor] receptor) 1 and 2, TRAIL-R2 (TRAIL [TNF-related apoptosis-inducing ligand] receptor 2), and RETN (resistin) to be associated with all 4 lipid fractions. Further, 15 proteins were related to both TG and HDL cholesterol in a consistent and biologically expected manner, that is, higher TG and lower HDL cholesterol or vice versa. Another common pattern of associations was concomitantly higher TG, total cholesterol, and LDL cholesterol, which is associated with higher CVD risk. We did not find evidence of causal links for protein levels. Conclusions- Our comprehensive analysis of plasma proteins and lipid fractions of 3370 individuals from the general population provides new information about lipid metabolism.

Identification of rare-disease genes using blood transcriptome sequencing and large control cohorts

It is estimated that 350 million individuals worldwide suffer from rare diseases, which are predominantly caused by mutation in a single gene1. The current molecular diagnostic rate is estimated at 50%, with whole-exome sequencing (WES) among the most successful approaches2-5. For patients in whom WES is uninformative, RNA sequencing (RNA-seq) has shown diagnostic utility in specific tissues and diseases6-8. This includes muscle biopsies from patients with undiagnosed rare muscle disorders6,9, and cultured fibroblasts from patients with mitochondrial disorders7. However, for many individuals, biopsies are not performed for clinical care, and tissues are difficult to access. We sought to assess the utility of RNA-seq from blood as a diagnostic tool for rare diseases of different pathophysiologies. We generated whole-blood RNA-seq from 94 individuals with undiagnosed rare diseases spanning 16 diverse disease categories. We developed a robust approach to compare data from these individuals with large sets of RNA-seq data for controls (n = 1,594 unrelated controls and n = 49 family members) and demonstrated the impacts of expression, splicing, gene and variant filtering strategies on disease gene identification. Across our cohort, we observed that RNA-seq yields a 7.5% diagnostic rate, and an additional 16.7% with improved candidate gene resolution.

The metabolites urobilin and sphingomyelin (30:1) are associated with incident heart failure in the general population

Aims

We aimed to investigate whether metabolomic profiling of blood can lead to novel insights into heart failure pathogenesis or improved risk prediction.

Methods and results

Mass spectrometry‐based metabolomic profiling was performed in plasma or serum samples from three community‐based cohorts without heart failure at baseline (total n = 3924; 341 incident heart failure events; median follow‐up ranging from 4.6 to 13.9 years). Cox proportional hazard models were applied to assess the association of each of the 206 identified metabolites with incident heart failure in the discovery cohorts Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) (n = 920) and Uppsala Longitudinal Study of Adult Men (ULSAM) (n = 1121). Replication was undertaken in the independent cohort TwinGene (n = 1797). We also assessed whether metabolites could improve the prediction of heart failure beyond established risk factors (age, sex, body mass index, low‐density and high‐density lipoprotein cholesterol, triglycerides, lipid medication, diabetes, systolic and diastolic blood pressure, blood pressure medication, glomerular filtration rate, smoking status, and myocardial infarction prior to or during follow‐up). Higher circulating urobilin and lower sphingomyelin (30:1) were associated with incident heart failure in age‐adjusted and sex‐adjusted models in the discovery and replication sample. The hazard ratio for urobilin in the replication cohort was estimated to 1.29 per standard deviation unit, 95% confidence interval (CI 1.03–1.63), and for sphingomyelin (30:1) to 0.72 (95% CI 0.58–0.89). Results remained similar after further adjustment for established heart failure risk factors in meta‐analyses of all three cohorts. Urobilin concentrations were inversely associated with left ventricular ejection fraction at baseline in the PIVUS cohort (β = −0.70, 95% CI −1.03 to −0.38). No major improvement in risk prediction was observed when adding the top 2 metabolites (C‐index 0.787, 95% CI 0.752–0.823) or nine Lasso‐selected metabolites (0.790, 95% CI 0.754–0.826) to a modified Atherosclerosis Risk in Communities heart failure risk score model (0.780, 95% CI 0.745–0.816).

Conclusions

Our metabolomic profiling of three community‐based cohorts study identified associations of circulating levels of the haem breakdown product urobilin, and sphingomyelin (30:1), a cell membrane component involved in signal transduction and apoptosis, with incident heart failure.

Effects of Long-Term Storage at -80 °C on the Human Plasma Metabolome

High-quality biological samples are required for the favorable outcome of research studies, and valid data sets are crucial for successful biomarker identification. Prolonged storage of biospecimens may have an artificial effect on compound levels. In order to investigate the potential effects of long-term storage on the metabolome, human ethylenediaminetetraacetic acid (EDTA) plasma samples stored for up to 16 years were analyzed by gas and liquid chromatography-tandem mass spectrometry-based metabolomics. Only 2% of 231 tested plasma metabolites were altered in the first seven years of storage. However, upon longer storage periods of up to 16 years and more time differences of few years significantly affected up to 26% of the investigated metabolites when analyzed within subject age groups. Ontology classes that were most affected included complex lipids, fatty acids, energy metabolism molecules, and amino acids. In conclusion, the human plasma metabolome is adequately stable to long-term storage at −80 °C for up to seven years but significant changes occur upon longer storage. However, other biospecimens may display different sensitivities to long-term storage. Therefore, in retrospective studies on EDTA plasma samples, analysis is best performed within the first seven years of storage.

Microvascular capillary assessment in relation to forearm blood flow

OBJECTIVE

To study whether vascular reactivity as assessed by the methods forearm blood flow (FBF) and postocclusive reactive hyperaemia (PRH) in the nail fold was related as a measure of endothelium-dependent vasodilation in the microcirculation.

METHODS

Microvascular reactivity was assessed in forearm blood flow and in the nail fold by vital capillaroscopy of individual microvessels as postocclusive reactive hyperaemia. Vascular reactivity was assessed at baseline (n = 25) as well as after infusion of acetylcholine and of sodium nitroprusside (n = 13). We also performed a multivariate regression analysis to assess whether forearm blood flow or flow-mediated dilatation related to postocclusive reactive hyperaemia.

RESULTS

This study showed a distinct microvascular response to both acetylcholine (endothelium-dependent vasodilation) and sodium nitroprusside (endothelium-independent vasodilation) during forearm blood flow assessment and postocclusive reactive hyperaemia assessment in the nail fold (n = 13). These changes were inversely related (r- = -0·57; P<0·05).

CONCLUSIONS

Forearm blood flow was inversely correlated to postocclusive reactive hyperaemia. Postocclusive reactive hyperaemia was shortened after infusion with both acetylcholine and sodium nitroprusside. This occurred in parallel with the expected increase in forearm blood flow, conceivably reflecting that both methods can be used to assess endothelium-dependent vasodilation in the microcirculation.

On the association between body fat and left ventricular mass

OBJECTIVES

As intervention studies have shown a reduction in body weight to be paralleled with a reduction in left ventricular mass (LVM), we quantified a hypothesized causal relationship between fat mass and LVM, and how much of these effects that was mediated by blood pressure (BP), diabetes and adipokines. Also visceral and subcutaneous adipose tissue (VAT and SAT) were explored in the same fashion.

METHODS

In the Prospective Study of the Vasculature in Uppsala Seniors study (n = 1016, 50% women, all aged 70 years), LVM was measured by echocardiography (indexed for lean mass, LVMI), fat and lean mass by dual-energy X-ray. VAT and SAT were measured by abdominal MRI (in n = 275).

RESULTS

In a structural equation model adjusting for sex, the total effect of fat mass on LVMI was large (standardized coefficient 0.280, P = 3.2 × 10, 95% confidence interval 0.210-0.349). Out of the total effect of fat mass on LVMI, 29.0% was mediated by BP and glucose (P = 2.4 × 10). The BP pathway was most important, mediating 24.4% of the total effect of fat mass on LVMI (P = 4.6 × 10), while the glucose pathway accounted for 4.6% (P = 0.033). The association of VAT with LVMI (0.202, P = 2.4 × 10) was slightly weaker than that of SAT with LVMI (0.283, P = 1.0 × 10). Of several measured adipokines, leptin was a significant mediator of the effect of fat mass on LVMI (P = 3.0 × 10).

CONCLUSION

One-third of the hypothesized association between body fat and LVMI was mediated by BP and glucose in this population-based cohort. Leptin was also an important mediator. Visceral adipose tissue was not more closely related to LVMI than subcutaneous abdominal fat.

Association of Exposure to Persistent Organic Pollutants With Mortality Risk: An Analysis of Data From the Prospective Investigation of Vasculature in Uppsala Seniors (PIVUS) Study

IMPORTANCE

It has been suggested that persistent organic pollutants (POPs) are harmful to human health.

OBJECTIVE

To investigate if POP levels in plasma are associated with future mortality.

DESIGN, SETTING, AND PARTICIPANTS

Cohort study using data from the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, collected between May 2001 and June 2004 when participants reached age 70 years. Participants were followed up for 5 years after the first examination. Mortality was tracked from age 70 to 80 years. Data analysis was conducted in January and February 2018.

EXPOSURES

Eighteen POPs identified by the Stockholm Convention, including polychlorinated biphenyls (PCBs), organochlorine pesticides, and a brominated flame retardant, were measured in plasma levels by gas chromatography-mass spectrometry.

MAIN OUTCOMES AND MEASURES

All-cause mortality.

RESULTS

The study sample initially included 992 individuals (497 [50.1%] men) aged 70 years, who were examined between 2001 and 2004. At the second examination 5 years later, 814 individuals (82.1%; 412 [50.7%] women) completed follow-up. During a follow-up period of 10.0 years, 158 deaths occurred. When updated information on POP levels at ages 70 and 75 years was associated with all-cause mortality using Cox proportional hazard analyses, a significant association was found between hexa-chloro- through octa-chloro-substituted (highly chlorinated) PCBs and all-cause mortality (except PCB 194). The most significant association was observed for PCB 206 (hazard ratio [HR] for 1-SD higher natural log-transformed circulating PCB 206 levels, 1.55; 95% CI, 1.26-1.91; P < .001). Following adjustment for hypertension, diabetes, smoking, body mass index, and cardiovascular disease at baseline, most associations were no longer statistically significant, but PCBs 206, 189, 170, and 209 were still significantly associated with all-cause mortality (PCB 206: adjusted HR, 1.47; 95% CI, 1.19-1.81; PCB 189: adjusted HR, 1.29; 95% CI, 1.08-1.55; PCB 170: adjusted HR, 1.24; 95% CI, 1.02-1.52; PCB 209: adjusted HR, 1.29; 95% CI, 1.04-1.60). In a secondary analysis, these associations were mainly because of death from cardiovascular diseases rather than noncardiovascular diseases. Three organochlorine pesticides, including dichlorodiphenyldichloroethylene, and the brominated flame retardant diphenyl ether 47 were also evaluated but did not show any significant associations with all-cause mortality.

CONCLUSIONS AND RELEVANCE

Higher levels of highly chlorinated PCBs were associated with an increased mortality risk, especially from cardiovascular diseases. These results suggest that public health actions should be undertaken to minimize exposure to highly chlorinated PCBs.

Identification of metabolic profiles associated with human exposure to perfluoroalkyl substances

Recent epidemiological studies suggest that human exposure to perfluoroalkyl substances (PFASs) may be associated with type 2 diabetes and other metabolic phenotypes. To gain further insights regarding PFASs exposure in humans, we here aimed to characterize the associations between different PFASs and the metabolome. In this cross-sectional study, we investigated 965 individuals from Sweden (all aged 70 years, 50% women) sampled in 2001-2004. PFASs were analyzed in plasma using isotope-dilution ultra-pressure liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS). Non-target metabolomics profiling was performed in plasma using UPLC coupled to time-of-flight mass spectrometry (UPLC-QTOFMS) operated in positive electrospray mode. Multivariate linear regression analysis was used to investigate associations between circulating levels of PFASs and metabolites. In total, 15 metabolites, predominantly from lipid pathways, were associated with levels of PFASs following adjustment for sex, smoking, exercise habits, education, energy, and alcohol intake, after correction for multiple testing. Perfluorononanoic acid (PFNA) and perfluoroundecanoic acid (PFUnDA) were strongly associated with multiple glycerophosphocholines and fatty acids including docosapentaenoic acid (DPA) and docosahexaenoic acid (DHA). We also found that the different PFASs evaluated were associated with distinctive metabolic profiles, suggesting potentially different biochemical pathways in humans.

Longitudinal effects of aging on plasma proteins levels in older adults - associations with kidney function and hemoglobin levels

BACKGROUND

A targeted proteomics chip has been shown to be useful to discover novel associations of proteins with cardiovascular disease. We investigated how these proteins change with aging, and whether this change is related to a decline in kidney function, or to a change in hemoglobin levels.

MATERIAL AND METHODS

In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, including 1,016 participants from the general population aged 70 at baseline, 84 proteins were measured at ages 70, 75, 80. At these occasions, glomerular filtration rate (eGFR) was estimated and the hemoglobin levels were measured.

RESULTS

Sixty-one of the 84 evaluated proteins changed significantly during the 10-year follow-up (multiple testing-adjusted alpha = 0.00059), most showing an increase. The change in eGFR was inversely related to changes of protein levels for the vast majority of proteins (74%). The change in hemoglobin was significantly related to the change in 40% of the evaluated proteins, with no obvious preference of the direction of these relationships.

CONCLUSION

The majority of evaluated proteins increased with aging in adults. Therefore, normal ranges for proteins might be given in age-strata. The increase in protein levels was associated with the degree of reduction in eGFR for the majority of proteins, while no clear pattern was seen for the relationships between the proteins and the change in hemoglobin levels. Studies on changes in urinary proteins are warranted to understand the association between the reduction in eGFR and increase in plasma protein levels.

Population-based cardiovascular cohort studies in Uppsala

The first population-based cohort study in Uppsala with the aim to study cardiovascular disease was initiated in 1970 (ULSAM). This cohort of 2300 middle-aged men has since then been followed in a longitudinal fashion for almost 50 years. This study has been followed by the PIVUS study, investigating 1000 men and women at ages 70, 75, and 80. A very detailed examination has also been performed in 500 subjects aged 50 years, the POEM study. In recent years, a high-throughput study conducted in 13000 subjects has also been performed, named EpiHealth. Uppsala also collects data in 5,000 subjects in the nationwide SCAPIS study. Taken together, these cardiovascular-oriented studies constitute a very rich source for cardiovascular epidemiological research in Uppsala. This review summarizes the design of these studies and highlights some of the important results published based on data from these studies.

Genome-Wide Association Studies of Estimated Fatty Acid Desaturase Activity in Serum and Adipose Tissue in Elderly Individuals: Associations with Insulin Sensitivity

Fatty acid desaturases (FADS) catalyze the formation of unsaturated fatty acids and have been related to insulin sensitivity (IS). FADS activities differ between tissues and are influenced by genetic factors that may impact the link to IS. Genome-wide association studies of δ-5-desaturase (D5D), δ-6-desaturase (D6D) and stearoyl-CoA desaturase-1 (SCD) activities (estimated by product-to-precursor ratios of fatty acids analyzed by gas chromatography) in serum cholesterol esters (n = 1453) and adipose tissue (n = 783, all men) were performed in two Swedish population-based cohorts. Genome-wide significant associated loci were evaluated for associations with IS measured with a hyperinsulinemic euglycemic clamp (n = 554). Variants at the FADS1 were strongly associated with D5D in both cholesterol esters (p = 1.9 × 10⁻⁷⁰) and adipose tissue (p = 1.1 × 10⁻²⁷). Variants in three further loci were associated with D6D in cholesterol esters (FADS2, p = 3.0 × 10⁻⁶⁷; PDXDCI, p = 4.8 × 10⁻⁸; and near MC4R, p = 3.7 × 10⁻⁸) but no associations with D6D in adipose tissue attained genome-wide significance. One locus was associated with SCD in adipose tissue (PKDL1, p = 2.2 × 10⁻¹⁹). Genetic variants near MC4R were associated with IS (p = 3.8 × 10⁻³). The FADS cluster was the main genetic determinant of estimated FADS activity. However, fatty acid (FA) ratios in adipose tissue and cholesterol esters represent FADS activities in separate tissues and are thus influenced by different genetic factors with potential varying effects on IS.

Predictors of 10-year changes in levels of N-terminal pro B-type natriuretic peptide and cardiac troponin I in the elderly

BACKGROUND

Measurement of N-terminal pro B-type natriuretic peptide (NT-proBNP) and cardiac troponin I (cTnI) might be useful for monitoring of cardiovascular disease in the elderly. However, it is not clear whether changes in these biomarkers are associated with changes in the cardiovascular risk profile and if this pattern could be modified by changes in lifestyle habits or medications.

METHODS

We measured levels of NT-proBNP and cTnI in community-dwelling subjects (PIVUS study) upon visits scheduled at age 70 (n=1007), 75 (n=825) and 80 (n=602). The associations of these biomarkers with repeated measurements of clinical variables (risk factors, lifestyle habits, echocardiographic data and medications) were investigated using sex-adjusted linear mixed random effect models.

RESULTS

NT-proBNP and cTnI were positively associated with increasing age. NT-proBNP, but not cTnI, was affected by changes of renal function and the degree of obesity. NT-proBNP was more closely related than cTnI to changes in echocardiographic estimates of cardiac geometry and function. Biomarker levels and/or their changes were inversely associated with a physically more active lifestyle (both NT-proBNP and cTnI) and statin treatment at age 70 (only cTnI). Changes in smoking status or antihypertensive treatment had no effect on biomarker levels.

CONCLUSIONS

Changes in NT-proBNP and cTnI levels are associated with different patterns of cardiovascular disease burden when using a longitudinal approach. However, levels of both biomarkers and their changes also reflect changes in the cardiovascular risk profile that might be modifiable. This is an important aspect for the use of any cardiovascular biomarker in an elderly population.

Proteomic profiling of endothelium-dependent vasodilation

OBJECTIVE

As endothelial dysfunction is an early event in atherosclerosis formation, we investigated if proteins previously related to cardiovascular disease also were related to endothelial function using a novel targeted proteomics approach.

METHODS

In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (n = 850-970, all aged 70 years), endothelium-dependent vasodilation (EDV) in the forearm was assessed by intra-arterial infusion of acetylcholine. Flow-mediated vasodilation (FMD) was investigated in the brachial artery by ultrasound. The same investigations were carried out in the Prospective investigation of Obesity, Energy and Metabolism (POEM) study (n = 375-461, all aged 50 years). After strict quality control, 84 cardiovascular-related proteins measured by the proximity extension assay were studied in relation to EDV and FMD in PIVUS (discovery sample) and POEM (validation sample).

RESULTS

Of the 15 proteins being significantly related to EDV in PIVUS (false discovery rate <0.025), seven could be replicated in POEM at nominal significance and same effect direction when adjusted for sex and storage time. Of those, only cathepsin D remained significant following further adjustment for traditional cardiovascular risk factors (beta, -0.08; 95% confidence interval, -0.16, -0.01; P = 0.033; change in ln-transformed EDV per 1-SD increase in protein level). No protein was significantly related to FMD.

CONCLUSION

Using a discovery/validation approach in two samples, our results indicate an inverse association between plasma cathepsin D levels and endothelial-dependent vasodilation.

Epigenetic influences on aging: a longitudinal genome-wide methylation study in old Swedish twins

Age-related changes in DNA methylation were observed in cross-sectional studies, but longitudinal evidence is still limited. Here, we aimed to characterize longitudinal age-related methylation patterns using 1011 blood samples collected from 385 Swedish twins (age at entry: mean 69 and standard deviation 9.7, 73 monozygotic and 96 dizygotic pairs) up to five times (mean 2.6) over 20 years (mean 8.7). We identified 1316 age-associated methylation sites (P<1.3×10⁻⁷) using a longitudinal epigenome-wide association study design. We measured how estimated cellular compositions changed with age and how much they confounded the age effect. We validated the results in two independent longitudinal cohorts, where 118 CpGs were replicated in Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS, 390 samples) (P<3.9×10⁻⁵), 594 in Lothian Birth Cohort (LBC, 3018 samples) (P<5.1×10⁻⁵) and 63 in both. Functional annotation of age-associated CpGs showed enrichment in CCCTC-binding factor (CTCF) and other transcription factor binding sites. We further investigated genetic influences on methylation and found no interaction between age and genetic effects in the 1316 age-associated CpGs. Moreover, in the same CpGs, methylation differences within twin pairs increased with 6.4% over 10 years, where monozygotic twins had smaller intra-pair differences than dizygotic twins. In conclusion, we show that age-related methylation changes persist in a longitudinal perspective, and are fairly stable across cohorts. The changes are under genetic influence, although this effect is independent of age. Moreover, methylation variability increase over time, especially in age-associated CpGs, indicating the increase of environmental contributions on DNA methylation with age.

Design and methodology of the screening for CKD among older patients across Europe (SCOPE) study: a multicenter cohort observational study

Background

Decline of renal function is common in older persons and the prevalence of chronic kidney disease (CKD) is rising with ageing. CKD affects different outcomes relevant to older persons, additionally to morbidity and mortality which makes CKD a relevant health burden in this population. Still, accurate laboratory measurement of kidney function is under debate, since current creatinine-based equations have a certain degree of inaccuracy when used in the older population. The aims of the study are as follows: to assess kidney function in a cohort of 75+ older persons using existing methodologies for CKD screening; to investigate existing and innovative biomarkers of CKD in this cohort, and to align laboratory and biomarker results with medical and functional data obtained from this cohort. The study was registered at ClinicalTrials.gov, identifier NCT02691546, February 25th 2016.

Methods/design

An observational, multinational, multicenter, prospective cohort study in community dwelling persons aged 75 years and over, visiting the outpatient clinics of participating institutions. The study will enroll 2450 participants and is carried out in Austria, Germany, Israel, Italy, the Netherlands, Poland and Spain. Participants will undergo clinical and laboratory evaluations at baseline and after 12 and 24 months- follow-up. Clinical evaluation also includes a comprehensive geriatric assessment (CGA). Local laboratory will be used for ‘basic’ parameters (including serum creatinine and albumin-to-creatinine ratio), whereas biomarker assessment will be conducted centrally. An intermediate telephone follow-up will be carried out at 6 and 18 months.

Discussion

Combining the use of CGA and the investigation of novel and existing independent biomarkers within the SCOPE study will help to provide evidence in the development of European guidelines and recommendations in the screening and management of CKD in older people.

Trial registration

This study was registered prospectively on the 25th February 2016 at clinicaltrials.gov (NCT02691546).

Flow-mediated vasodilation assay indicates no endothelial dysfunction in hereditary angioedema patients with C1-inhibitor deficiency

BACKGROUND

Hereditary angioedema with C1 inhibitor deficiency (C1-INH-HAE) is a rare, potentially life-threatening disorder characterized by recurrent edematous attacks. The edema formation is the consequence of interaction of bradykinin and various vasoactive peptides with endothelium. Besides these agents, danazol, a modified testosterone derivative used in these patients to prevent edematous attacks, can also affect the function of the endothelium, because it shifts the blood lipid profile to a pro-atherogenic phenotype.

OBJECTIVE

To assess the endothelial function in C1-INH-HAE patients and in healthy matched controls.

METHODS

To evaluate the endothelial function, we used the flow-mediated dilation method measured in the region of the brachial artery in 33 C1-INH-HAE patients and in 30 healthy matched controls. Laboratory measurements of standard biochemical parameters were performed on computerized laboratory analyzers.

RESULTS

No difference was found in endothelial function (reactive hyperemia, RH) between patients (median, 9.0; 25%-75% percentile, 6.3-12.9) and controls (median, 7.37; 25%-75% percentile, 4.52-9.93). Although we found elevated cardiovascular risk (high body mass index and low-density lipoprotein/high-density lipoprotein ratio) in danazol-treated C1-INH-HAE patients, RH values did not differ between danazol-treated and nontreated patients. Furthermore, risk factors correlated with the endothelial function only in healthy controls and patients not treated with danazol.

CONCLUSION

In summary, our results did not indicate any signs of endothelial dysfunction in C1-INH-HAE patients. Moreover, the normal endothelial function in danazol-treated patients with pro-atherogenic lipid profile suggests that elevated bradykinin level or other factor(s) involved in the pathogenesis of edematous attacks may have a protective role against endothelial dysfunction and atherosclerosis.

The interrelation of endothelial function and microvascular reactivity in different vascular beds, and risk assessment in hypertension: results from the Doxazosin-ramipril study

There are several non-invasive methods to study endothelial function, but their interrelation and association to cardiovascular risk have not been well evaluated. We studied macrovascular and microvascular endothelial function simultaneously in different vascular beds in relation to cardiovascular mortality risk (Systematic Coronary Risk Evaluation, SCORE) and hypertension induced cardiac organ damage, and their interrelationship. The study investigated 71 hypertensive patients by forearm post-ischemic flow-mediated vasodilation, pulse wave analysis (applanation tonometry) and beta 2-adrenoceptor agonist stimulation for changes in reflection index, skin microvascular reactivity by laser Doppler fluxmetry with iontophoresis and heat-induced hyperaemia, and coronary microvascular function by subendocardial viability ratio (derived from pulse wave analysis). Flow mediated vasodilation related inversely to SCORE (r =  0.34, P = 0.011). Adding microalbuminuria and pulse wave velocity strengthened the associations. Pulse wave reflection changes did not relate to SCORE. Skin microvascular reactivity related inversely to SCORE (peak flux change to sodium nitroprusside r =  0.29, P = 0.033, and to heating r =  0.31, P = 0.018). Subendocardial viability ratio did not relate to SCORE. Endothelial function indices showed no consistent relation to cardiac target organ damage. The agreement between the different methods for evaluating indices of macrovascular and microvascular endothelial function was weak. In conclusion, indices of macrovascular and microvascular endothelial function relate to cardiovascular mortality risk. Their use may improve cardiovascular risk prediction in hypertension. However, methods representing different vascular beds show little interrelationship and are not interchangeable, which may depend on different pathogenetic mechanisms representing different aspects of future cardiovascular risk.

Trial registry: NCT02901977

Endothelial dysfunction is associated with impaired lung function in two independent community cohorts

BACKGROUND

Prior studies investigating the association between endothelial dysfunction and impaired lung function have been small and inconsistent. The primary aim was to investigate the association between endothelial function and lung function in two community-based cohorts.

METHODS

We used a discovery/replication approach to study the association between endothelial function and lung function in the Prospective investigation of Obesity, Energy and Metabolism (POEM, discovery cohort, n = 490, mean age 50.3 ± 0.2 years) and the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS, replication cohort, n = 892, mean age 70.2 ± 0.15 years). Spirometry and three different measures of endothelial function were performed including both the invasive forearm technique (endothelium-dependent and endothelium-independent vasodilation [EDV and EIDV, respectively] and noninvasive flow mediated dilation [FMD]).

RESULTS

An age and sex adjusted association between lower EDV and lower FEV₁ was found in POEM and replicated in PIVUS. After merging the two cohorts, 1 standard deviation decrease in EDV was associated with 1.57% lower FEV₁ after additional adjustment for smoking status, body mass index, exercise level, and C-reactive protein (95% confidence intervals 0.63-2.51, p = 0.001). The association was slightly lower albeit still statistically significant after excluding participants without cardiovascular disease and chronic respiratory disease and appeared stronger among previous/current smokers vs. non-smokers and in men vs. women (p for interaction = 0.2 and 0.02 respectively).

CONCLUSIONS

Our findings suggest that even individuals with sub-clinical impairments of lung function in the community have concomitant endothelial dysfunction.

Changes in markers of liver function in relation to changes in perfluoroalkyl substances - A longitudinal study

BACKGROUND

While it is known that perfluoroalkyl substances (PFASs) induce liver toxicity in experimental studies, the evidence of an association in humans is inconsistent.

OBJECTIVE

The main aim of the present study was to examine the association of PFAS concentrations and markers of liver function using panel data.

METHODS

We investigated 1002 individuals from Sweden (50% women) at ages 70, 75 and 80 in 2001-2014. Eight PFASs were measured in plasma using isotope dilution ultra-performance liquid chromatography/tandem mass spectrometry (UPLC-MS/MS). Bilirubin and hepatic enzymes alanine aminotransferase (ALT), alkaline phosphatase (ALP), and γ-glutamyltransferase (GGT) were determined in serum using an immunoassay methodology. Mixed-effects linear regression models were used to examine the relationship between the changes in markers of liver function and changes in PFAS levels.

RESULTS

The changes in majority of PFAS concentrations were positively associated with the changes in activity of ALT, ALP, and GGT and inversely associated with the changes in circulating bilirubin after adjustment for gender and the time-updated covariates LDL- and HDL-cholesterol, serum triglycerides, BMI, statin use, smoking, fasting glucose levels and correction for multiple testing. For example, changes in perfluorononanoic acid (PFNA) were associated with the changes liver function markers β_BILIRUBIN = -1.56, 95% confidence interval (CI) -1.93 to -1.19, β_ALT = 0.04, 95% CI 0.03-0.06, and β_ALP = 0.11, 95% CI 0.06-0.15.

CONCLUSION

Our longitudinal assessment established associations between changes in markers of liver function and changes in plasma PFAS concentrations. These findings suggest a relationship between low-dose background PFAS exposure and altered liver function in the general population.

Screening for Peripheral Artery Disease Using the Ankle-Brachial Index: Updated Evidence Report and Systematic Review for the US Preventive Services Task Force

IMPORTANCE

Peripheral artery disease (PAD) is associated with a high risk for cardiovascular events and poor ambulatory function, even in the absence of symptoms. Screening for PAD with the ankle-brachial index (ABI) may identify patients in need of treatment to improve health outcomes.

OBJECTIVE

To systematically review evidence for the US Preventive Services Task Force on PAD screening with the ABI, the diagnostic accuracy of the test, and the benefits and harms of treatment of screen-detected PAD.

DATA SOURCES

MEDLINE, PubMed, and the Cochrane Central Register of Controlled Trials for relevant English-language studies published between January 2012 and May 2, 2017. Surveillance continued through February 7, 2018.

STUDY SELECTION

Studies of unselected or generally asymptomatic adults with no known cardiovascular disease.

DATA EXTRACTION AND SYNTHESIS

Independent critical appraisal and data abstraction by 2 reviewers.

MAIN OUTCOMES AND MEASURES

Cardiovascular morbidity; PAD morbidity; mortality; health-related quality of life; diagnostic accuracy; and serious adverse events.

RESULTS

Five studies (N = 5864 participants) were included that examined the indirect evidence for the benefits and harms of screening and treatment of screen-detected PAD. No population-based screening trials evaluated the direct benefits or harms of PAD screening with the ABI alone. A single diagnostic accuracy study of the ABI compared with magnetic resonance angiography gold-standard imaging (n = 306) found low sensitivity (7%-34%) and high specificity (96%-100%) in a screening population. Two adequately powered trials (n = 4626) in asymptomatic populations with and without diabetes with a variably defined low ABI (≤0.95 or ≤0.99) showed no statistically significant effect of aspirin (100 mg daily) for composite CVD outcomes (adjusted hazard ratio [HR], 1.00 [95% CI, 0.81-1.23] and HR, 0.98 [95% CI, 0.76-1.26]). One trial (n = 3350) demonstrated no statistically significant increase in major bleeding events with the use of aspirin (adjusted HR, 1.71 [95% CI, 0.99- 2.97]) and no statistically significant increase in major gastrointestinal bleeding (relative risk, 1.13 [95% CI, 0.44-2.91]). Two exercise trials (n = 932) in screen-relevant populations reported no differences in quality of life, Walking Impairment Questionnaire walking distance, or symptoms at 12 and 52 weeks; no harms were reported.

CONCLUSIONS AND RELEVANCE

There was no direct evidence and limited indirect evidence on the benefits of PAD screening with the ABI in unselected or asymptomatic populations. Available studies suggest low sensitivity and lack of beneficial effect on health outcomes, but these studies have important limitations.

Changes in plasma levels of perfluoroalkyl substances (PFASs) are related to increase in carotid intima-media thickness over 10 years - a longitudinal study

BACKGROUND

It has previously been reported that the environmental contaminants perfluoroalkyl substances (PFASs) are linked to atherosclerosis in cross-sectional studies. Since cross-sectional studies could be subject to reverse causation, the purpose of this study was to analyze if the longitudinal changes in PFASs during a 10-year follow-up were related to the change in carotid artery intima-media thickness (IMT, ultrasound) during the same period.

METHODS

In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, 1016 individuals were investigated at age 70; 826 of them were reinvestigated at age 75 and 602 at age 80 years. Eight different PFASs were measured in plasma by ultra-performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), and IMT was measured at all three time points. Random-effects mixed regression models were used to examine the associations over time.

RESULTS

IMT increased 0.058 mm during the 10-year period (p < 0.0001). Following adjustment for baseline values of PFASs (age 70) and sex, the changes in plasma levels of 6 of the 8 measured PFASs were significantly related to the change in IMT over the 10-year follow-up period in a positive fashion (p < 0.0062 using Bonferroni correction for 8 tests). Further adjustment for traditional cardiovascular (CV) risk factors (HDL and LDL cholesterol, smoking, systolic blood pressure, statin use, fasting glucose and serum triglycerides) affected these relationships only marginally.

CONCLUSION

The change in plasma levels of several PFASs during 10 years was positively related to increase in IMT seen during the same period, giving prospective evidence that PFASs might interfere with the atherosclerotic process.

Circulating endostatin and the incidence of heart failure

OBJECTIVE

Circulating levels of endostatin are elevated in many underlying conditions leading to heart failure such as hypertension, diabetes, chronic kidney disease and ischemic heart disease. Yet, the association between endostatin and the incidence of heart failure has not been reported previously in the community.

DESIGN

We investigated the longitudinal association between serum endostatin levels and incident heart failure in two community-based cohorts of elderly: Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS, n = 966; mean age 70 years, 51% women, 81 events, mean follow-up 10 years) and Uppsala Longitudinal Study of Adult Men (ULSAM, n = 747 men; mean age 78 years, 98 heart failure events, mean follow-up 8 years). We also investigated the cross-sectional association between endostatin and echocardiographic left ventricular systolic function and diastolic function (ejection fraction and E/A-ratio, respectively).

RESULTS

Higher serum endostatin was associated with an increased risk for heart failure in both cohorts after adjustment for established heart failure risk factors, glomerular filtration rate and N-terminal pro-brain natriuretic peptide (NT-proBNP) (PIVUS: multivariable hazard ratio (HR) per 1-standard deviation (SD) increase, HR 1.46 (95%CI, 1.17-1.82, p < .001); ULSAM: HR 1.29 (95%CI, 1.00-1.68, p < .05). In cross-sectional analyses at baseline, higher endostatin was significantly associated with both worsened left ventricular systolic and diastolic function in both cohorts. Conclusion Higher serum endostatin was associated with left ventricular dysfunction and an increased heart failure risk in two community-based cohorts of elderly. Our findings encourage further experimental studies that investigate the role of endostatin in the development of heart failure.

A genome-wide association study of IgM antibody against phosphorylcholine: shared genetics and phenotypic relationship to chronic lymphocytic leukemia

Phosphorylcholine (PC) is an epitope on oxidized low-density lipoprotein (oxLDL), apoptotic cells and several pathogens like Streptococcus pneumoniae. Immunoglobulin M against PC (IgM anti-PC) has the ability to inhibit uptake of oxLDL by macrophages and increase clearance of apoptotic cells. From our genome-wide association studies (GWASs) in four European-ancestry cohorts, six single nucleotide polymorphisms (SNPs) in 11q24.1 were discovered (in 3002 individuals) and replicated (in 646 individuals) to be associated with serum level of IgM anti-PC (the leading SNP rs35923643-G, combined β = 0.19, 95% confidence interval 0.13-0.24, P = 4.3 × 10-11). The haplotype tagged by rs35923643-G (or its proxy SNP rs735665-A) is also known as the top risk allele for chronic lymphocytic leukemia (CLL), and a main increasing allele for general IgM. By using summary GWAS results of IgM anti-PC and CLL in the polygenic risk score (PRS) analysis, PRS on the basis of IgM anti-PC risk alleles positively associated with CLL risk (explained 0.6% of CLL variance, P = 1.2 × 10-15). Functional prediction suggested that rs35923643-G might impede the binding of Runt-related transcription factor 3, a tumor suppressor playing a central role in the immune regulation of cancers. Contrary to the expectations from the shared genetics between IgM anti-PC and CLL, an inverse relationship at the phenotypic level was found in a nested case-control study (30 CLL cases with 90 age- and sex-matched controls), potentially reflecting reverse causation. The suggested function of the top variant as well as the phenotypic association between IgM anti-PC and CLL risk needs replication and motivates further studies.

Molecular and Clinical Issues about the Risk of Venous Thromboembolism in Older Patients: A Focus on Parkinson's Disease and Parkinsonism

Venous thromboembolism (VTE) is a common and potentially life-threatening condition which includes both deep-vein thrombosis (DVT) and pulmonary embolism (PE). VTE has a significant clinical and epidemiological impact in the elderly, and its incidence increases to more than 1% per year in older patients, suggesting the presence of specific age-related risk factors in this population. Immobilization seems to predominate as the main cause in patients admitted for medical acute illness in medicine wards, and there is evidence of a high risk in older patients with immobilization resulting from advanced forms of Parkinson’s disease (PD), regardless of the presence of an acute medical condition. In this review, we would to discuss the recent evidence on clinical, molecular and epidemiological features of VTE in older frail subjects focusing on patients with PD and parkinsonism. We also discuss some therapeutic issues about the risk prevention and we suggest a thorough comprehensive geriatric assessment that can represent an optimal strategy to identify and prevent the VTE risk in these patients.

High plasma organochlorine pesticide levels are related to increased biological age as calculated by DNA methylation analysis

BACKGROUND

Organochlorine pesticides (OCPs) have been shown in the experimental setting to alter DNA methylation. Since DNA methylation changes during the life-span, formulas have been presented to calculate "DNA methylation age" as a measure of biological age.

OBJECTIVES

We aimed to investigate if circulating levels of three OCPs were related to increased DNA methylation age METHODS: 71CpG DNA methylation age (Hannum formula) was calculated based on data from the Illumina 450 k Bead Methylation chip in 1000 subjects in the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS) study (50% women, all aged 70 years at the examination). The difference between DNA methylation age and chronological age was calculated (DiffAge). 2,2-bis (4-chlorophenyl)-1,1-dichloroethene (p,p'-DDE), hexachlorobenzene (HCB), and transnonachlor (TNC) levels were measured in plasma by high-resolution gas chromatography coupled mass spectrometry (HRGC-HRMS).

RESULTS

Increased p,p'-DDE and TNC, but not HCB, levels were related to increased DiffAge both in sex and BMI-adjusted models, as well as in multiple adjusted models (sex, education level, exercise habits, smoking, energy and alcohol consumption and BMI) (p = 0.0051 and p = 0.011, respectively). No significant interactions between the OCPs and sex or BMI regarding DiffAge were found.

CONCLUSION

In this cross-sectional study, increased levels of two out of three OCPs were related to increased DNA methylation age, further suggesting negative health effects in humans of these widespread environmental contaminants.

Salbutamol-induced Decrease in Augmentation Index is Related to the Parallel Increase in Heart Rate

The change in augmentation index following salbutamol inhalation has been applied to evaluate endothelial function. We examined the contribution of salbutamol-induced increase in heart rate to the observed decrease in augmentation index. Haemodynamics were recorded using whole-body impedance cardiography and continuous pulse wave analysis from tonometric radial blood pressure. All subjects (n = 335, mean age 46, body mass index 26, 48% men) were without medications with cardiovascular influences. The effects of salbutamol inhalation (0.4 mg) versus the endothelium-independent agent nitroglycerin resoriblet (0.25 mg) were examined during passive head-up tilt, as the haemodynamic influences of these compounds depend on body position. Salbutamol decreased augmentation index by ~3-4% units in supine and upright positions. Although salbutamol moderately increased cardiac index (+4.5%) and decreased systemic vascular resistance (-8.5%), the significant haemodynamic explanatory factors for decreased augmentation index in multivariate analysis were increased supine heart rate, and increased upright heart rate and decreased ejection duration (p < 0.001 for all, r²  = 0.36-0.37). Sublingual nitroglycerin decreased supine and upright augmentation index by ~15% units and ~23% units, respectively. The haemodynamic explanatory factors for these changes in multivariate analysis were increased heart rate, reduced ejection duration and reduced systemic vascular resistance (p ≤ 0.021 for all, r²  = 0.22-0.34). In conclusion, the lowering influence of salbutamol on augmentation index may be largely explained by increased heart rate, suggesting that this effect may not predominantly reflect endothelial function.

Targeted proteomic analysis of habitual coffee consumption

BACKGROUND

Coffee drinking has been implicated in mortality and a variety of diseases but potential mechanisms underlying these associations are unclear. Large-scale systems epidemiological approaches may offer novel insights to mechanisms underlying associations of coffee with health.

OBJECTIVE

We performed an analysis of known and novel protein markers linked to cardiovascular disease and their association with habitual coffee intake in the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS, n = 816) and followed up top proteins in the Uppsala Longitudinal Study of Adult Men (ULSAM, n = 635) and EpiHealth (n = 2418).

METHODS

In PIVUS and ULSAM, coffee intake was measured by 7-day dietary records whilst a computer-based food frequency questionnaire was used in EpiHealth. Levels of up to 80 proteins were assessed in plasma by a proximity extension assay.

RESULTS

Four protein-coffee associations adjusted for age, sex, smoking and BMI, met statistical significance in PIVUS (FDR < 5%, P < 2.31 × 10^-3 ): leptin (LEP), chitinase-3-like protein 1 (CHI3L), tumour necrosis factor (TNF) receptor 6 and TNF-related apoptosis-inducing ligand. The inverse association between coffee intake and LEP replicated in ULSAM (β, -0.042 SD per cup of coffee, P = 0.028) and EpiHealth (β, -0.025 SD per time of coffee, P = 0.004). The negative coffee-CHI3L association replicated in EpiHealth (β, -0.07, P = 1.15 × 10^-7 ), but not in ULSAM (β, -0.034, P = 0.16).

CONCLUSIONS

The current study supports an inverse association between coffee intake and plasma LEP and CHI3L1 levels. The coffee-CHI3L1 association is novel and warrants further investigation given links between CHI3L1 and health conditions that are also potentially influenced by coffee.

Methylation-based estimated biological age and cardiovascular disease

BACKGROUND

DNA methylation changes over life at specific sites in the genome, which can be used to estimate "biological age." The aim of this population-based longitudinal cohort study was to investigate the association between estimated biological age and incident cardiovascular disease (CVD).

MATERIALS AND METHODS

Based on formulas published by Hannum et al and Horvath et al, "biological age" was calculated using data from the Illumina 450k Bead Methylation chip in 832 participants free from cardiovascular disease in the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS) study (50% women, all aged 70 years at the examination). The difference between estimated biological and chronological age was calculated (DiffAge).

RESULTS

During 10 years of follow-up, 153 incident cases of cardiovascular disease occurred. In the sex-adjusted analyses, the Horvath estimation of DiffAge was significantly related to incident cardiovascular disease (HR 1.040, 95% CI 1.010-1.071, P = .0079). Thus, for each year of increased biological age, a 4% increased risk of future cardiovascular disease was observed. This relationship was still significant following adjustment for the traditional risk factors sex, BMI, diabetes, HDL and LDL-cholesterol, systolic blood pressure and smoking (HR 1.033, 95% CI 1.004-1.063, P = .024). No such significant association was found using the Hannum formula.

CONCLUSIONS

DNA methylation-based estimation of "biological age" per Horvath was associated with incident cardiovascular disease.

Impact of Aging on the Strength of Cardiovascular Risk Factors: A Longitudinal Study Over 40 Years

Background

The knowledge of the impact of cardiovascular risk factors at different ages has mainly been based on different studies performed at different ages. This study aimed to investigate the change in impact of traditional cardiovascular risk factors over the aging process in subjects followed for 4 decades.

Methods and Results

In the ULSAM (Uppsala Longitudinal Study of Adult Men) study, 2322 men originally investigated in 1970 to 1974 have been followed regarding cardiovascular diseases until the end of 2013. This cohort has been investigated physically at ages 50, 60, 70, 77, and 82 years regarding body mass index, low‐density lipoprotein‐ and high‐density lipoprotein‐cholesterol, triglycerides, systolic blood pressure and diastolic blood pressure, fasting glucose, and smoking. These data were used to model the interactions between risk factors and age regarding incident myocardial infarction (n=540), ischemic stroke (n=343), or heart failure (n=397). Significant interactions were observed between age and the set of traditional risk factors regarding all 3 outcomes (P<0.05 for all). Generally, a decline in the rate ratios was seen with aging for most risk factors, being most pronounced for body mass index regarding myocardial infarction and for systolic blood pressure regarding ischemic stroke and heart failure. However, low‐density lipoprotein‐cholesterol was significantly related to incident myocardial infarction, whereas both body mass index and fasting glucose were significantly related to incident heart failure also at a high age.

Conclusions

Using a longitudinal design in middle‐aged men spanning 4 decades showed that the impact of traditional cardiovascular risk factors generally declined with aging. However, some of the risk factors remained significantly associated with incident cardiovascular disease also at old age.

The association between p,p'-DDE levels and left ventricular mass is mainly mediated by obesity

BACKGROUND AND OBJECTIVES

The pesticide metabolite p,p'-DDE has been associated with left ventricular (LV) mass and known risk factors for LV hypertrophy in humans and in experimental models. We hypothesized that the associations of p,p'-DDE with LV hypertrophy risk factors, namely elevated glucose, adiposity and hypertension, mediate the association of p,p'-DDE with LV mass.

METHODS

p,p'-DDE was measured in plasma from 70-year-old subjects (n = 988) of the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS). When these subjects were 70-, 75- and 80- years old, LV characteristics were measured by echocardiography, while fasting glucose, body mass index (BMI) and blood pressure were assessed with standard clinical techniques.

RESULTS

We found that p,p'-DDE levels were associated with increased fasting glucose, BMI, hypertension and LV mass in separate models adjusted for sex. Structural equation modeling revealed that the association between p,p'-DDE and LV mass was almost entirely mediated by BMI (70%), and also by hypertension (19%).

CONCLUSION

The obesogenic effect of p,p'-DDE is a major determinant responsible for the association of p,p'-DDE with LV mass.

Epigenetic Patterns in Blood Associated With Lipid Traits Predict Incident Coronary Heart Disease Events and Are Enriched for Results From Genome-Wide Association Studies

Supplemental Digital Content is available in the text.

Background—

Genome-wide association studies have identified loci influencing circulating lipid concentrations in humans; further information on novel contributing genes, pathways, and biology may be gained through studies of epigenetic modifications.

Methods and Results—

To identify epigenetic changes associated with lipid concentrations, we assayed genome-wide DNA methylation at cytosine–guanine dinucleotides (CpGs) in whole blood from 2306 individuals from 2 population-based cohorts, with replication of findings in 2025 additional individuals. We identified 193 CpGs associated with lipid levels in the discovery stage (P<1.08E-07) and replicated 33 (at Bonferroni-corrected P<0.05), including 25 novel CpGs not previously associated with lipids. Genes at lipid-associated CpGs were enriched in lipid and amino acid metabolism processes. A differentially methylated locus associated with triglycerides and high-density lipoprotein cholesterol (HDL-C; cg27243685; P=8.1E-26 and 9.3E-19) was associated with cis-expression of a reverse cholesterol transporter (ABCG1; P=7.2E-28) and incident cardiovascular disease events (hazard ratio per SD increment, 1.38; 95% confidence interval, 1.15–1.66; P=0.0007). We found significant cis-methylation quantitative trait loci at 64% of the 193 CpGs with an enrichment of signals from genome-wide association studies of lipid levels (P_TC=0.004, P_HDL-C=0.008 and P_{triglycerides}=0.00003) and coronary heart disease (P=0.0007). For example, genome-wide significant variants associated with low-density lipoprotein cholesterol and coronary heart disease at APOB were cis-methylation quantitative trait loci for a low-density lipoprotein cholesterol–related differentially methylated locus.

Conclusions—

We report novel associations of DNA methylation with lipid levels, describe epigenetic mechanisms related to previous genome-wide association studies discoveries, and provide evidence implicating epigenetic regulation of reverse cholesterol transport in blood in relation to occurrence of cardiovascular disease events.

Metabolomics applied to diabetes-lessons from human population studies

The 'classical' distribution of type 2 diabetes (T2D) across the globe is rapidly changing and it is no longer predominantly a disease of middle-aged/elderly adults of western countries, but it is becoming more common through Asia and the Middle East, as well as increasingly found in younger individuals. This global altered incidence of T2D is most likely associated with the spread of western diets and sedentary lifestyles, although there is still much debate as to whether the increased incidence rates are due to an overconsumption of fats, sugars or more generally high-calorie foods. In this context, understanding the interactions between genes of risk and diet and how they influence the incidence of T2D will help define the causative pathways of the disease. This review focuses on the use of metabolomics in large cohort studies to follow the incidence of type 2 diabetes in different populations. Such approaches have been used to identify new biomarkers of pre-diabetes, such as branch chain amino acids, and associate metabolomic profiles with genes of known risk in T2D from large scale GWAS studies. As the field develops, there are also examples of meta-analysis across metabolomics cohort studies and cross-comparisons with different populations to allow us to understand how genes and diet contribute to disease risk. Such approaches demonstrate that insulin resistance and T2D have far reaching metabolic effects beyond raised blood glucose and how the disease impacts systemic metabolism.

Circulating proteins as predictors of incident heart failure in the elderly

AIMS

To identify novel risk markers for incident heart failure using proteomic profiling of 80 proteins previously associated with cardiovascular pathology.

METHODS AND RESULTS

Proteomic profiling (proximity extension assay) was performed in two community-based prospective cohorts of elderly individuals without heart failure at baseline: the Prospective Investigation of the Vasculature in Uppsala Seniors [PIVUS, n = 901, median age 70.2 (interquartile range 70.0-70.3) years, 80 events]; and the Uppsala Longitudinal Study of Adult Men [ULSAM, n = 685, median age 77.8 (interquartile range 76.9-78.1) years, 90 events]. Twenty-nine proteins were associated with incident heart failure in the discovery cohort PIVUS after adjustment for age and sex, and correction for multiple testing. Eighteen associations replicated in ULSAM. In pooled analysis of both cohorts, higher levels of nine proteins were associated with incident heart failure after adjustment for established risk factors: growth differentiation factor 15 (GDF-15), T-cell immunoglobulin and mucin domain 1 (TIM-1), tumour necrosis factor-related apoptosis-inducing ligand receptor 2 (TRAIL-R2), spondin-1 (SPON1), matrix metalloproteinase-12 (MMP-12), follistatin (FS), urokinase-type plasminogen activator surface receptor (U-PAR), osteoprotegerin (OPG), and suppression of tumorigenicity 2 (ST2). Of these, GDF-15, U-PAR, MMP-12, TRAIL-R2, SPON1 and FS were associated with worsened echocardiographic left ventricular systolic function at baseline, while only TIM-1 was positively associated with worsened diastolic function (P < 0.02 for all).

CONCLUSION

Proteomic profiling identified several novel associations between proteins involved in apoptosis, inflammation, matrix remodelling, and fibrinolysis with incident heart failure in elderly individuals. Our results encourage additional studies investigating the underlying mechanisms and the clinical utility of our findings.

Relationships between serum-induced AhR bioactivity or mitochondrial inhibition and circulating polychlorinated biphenyls (PCBs)

Metabolic syndrome and mitochondrial dysfunction have been linked to elevated serum levels of persistent organic pollutants (POPs). However, it is not clear which specific POPs contribute to aryl hydrocarbon receptor (AhR)-dependent bioactivity or inhibit mitochondrial function in human subjects. Here, we measured the cumulative bioactivity of AhR ligand mixture (AhR bioactivity) and the effects on mitochondrial function (ATP concentration) in recombinant Hepa1c1c7 cells incubated with raw serum samples obtained from 911 elderly subjects in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort. Plasma concentrations of 30 POPs and plastic chemicals have previously been determined in the same PIVUS subjects. Linear regression analysis demonstrated that total toxic equivalence (TEQ) values and polychlorinated biphenyls (PCBs) were significantly correlated with AhR bioactivity (positively) and ATP concentration (negatively). Serum AhR bioactivities were positively associated with some PCBs, regardless of their dioxin-like properties, but only dioxin-like PCBs stimulated AhR bioactivity. By contrast, PCBs mediated a reduction in ATP content independently of their dioxin-like properties. This study suggests that AhR bioactivity and ATP concentrations in serum-treated cells may be valuable surrogate biomarkers of POP exposure and could be useful for the estimation of the effects of POPs on human health.

Tea and coffee consumption in relation to DNA methylation in four European cohorts

Lifestyle factors, such as food choices and exposure to chemicals, can alter DNA methylation and lead to changes in gene activity. Two such exposures with pharmacologically active components are coffee and tea consumption. Both coffee and tea have been suggested to play an important role in modulating disease-risk in humans by suppressing tumour progression, decreasing inflammation and influencing estrogen metabolism. These mechanisms may be mediated by changes in DNA methylation. To investigate if DNA methylation in blood is associated with coffee and tea consumption, we performed a genome-wide DNA methylation study for coffee and tea consumption in four European cohorts (N = 3,096). DNA methylation was measured from whole blood at 421,695 CpG sites distributed throughout the genome and analysed in men and women both separately and together in each cohort. Meta-analyses of the results and additional regional-level analyses were performed. After adjusting for multiple testing, the meta-analysis revealed that two individual CpG-sites, mapping to DNAJC16 and TTC17, were differentially methylated in relation to tea consumption in women. No individual sites were associated with men or with the sex-combined analysis for tea or coffee. The regional analysis revealed that 28 regions were differentially methylated in relation to tea consumption in women. These regions contained genes known to interact with estradiol metabolism and cancer. No significant regions were found in the sex-combined and male-only analysis for either tea or coffee consumption.

Omega-3 polyunsaturated fatty acids improve endothelial function in humans at risk for atherosclerosis: A review

Epidemiology studies and clinical trials show that omega-3 polyunsaturated fatty acids (n-3 PUFAs) can prevent atherosclerotic morbidity and evidence suggests this may be mediated by improving endothelial dysfunction. Endothelial dysfunction is characterized by reduced vasodilation and a pro-inflammatory, pro-thrombotic state, and is an early pathological event in the development of atherosclerosis. Flow-mediated dilation (FMD), a gold standard for assessing endothelial dysfunction, is a predictor of future cardiovascular events and coronary heart disease risk. Notably, risk factors for endothelial dysfunction include classic risk factors for atherosclerosis: Elevated lipids, diabetes, hypertension, elevated BMI, cigarette smoking, and metabolic syndrome. In this paper, we review the ability of n-3 PUFAs to improve endothelial dysfunction in individuals with classic risk factors for atherosclerosis, but lacking diagnosed atherosclerotic disease, with the goal of identifying those individuals that might gain the most vasoprotection from n-3 PUFA supplements. We include trials using eicosapentaenoic acid (EPA), docosahexaenoic acid (DHA), or alpha-linolenic acid (ALA) alone, or EPA+DHA; and assessing endothelial function by FMD, forearm blood flow, or peripheral arterial tonometry. We found that n-3 PUFAs improved endothelial dysfunction in 16 of 17 studies in individuals with hyperlipidemia, elevated BMI, metabolic syndrome, or that smoked cigarettes, but only in 2 of 5 studies in diabetics. Further, these trials showed that use of EPA+DHA consistently improve endothelial dysfunction; ALA-enriched diets appear promising; but use of EPA or DHA alone requires further study. We conclude that individuals with hyperlipidemia, elevated BMI, metabolic syndrome, or that smoke could derive vaosprotective benefits from EPA+DHA supplementation.

Use of Proteomics To Investigate Kidney Function Decline over 5 Years

BACKGROUND AND OBJECTIVES

Using a discovery/replication approach, we investigated associations between a multiplex panel of 80 circulating proteins associated with cardiovascular pathology or inflammation, and eGFR decline per year and CKD incidence.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

We used two cohorts, the Prospective Investigation of the Vasculature in Uppsala Seniors Study (PIVUS; n=687, mean age of 70 years, 51% women) and the Uppsala Longitudinal Study of Adult Men (ULSAM; n=360 men, mean age of 78 years), with 5-year follow-up data on eGFR. There were 231 and 206 incident cases of CKD during follow-up in the PIVUS and ULSAM studies, respectively. Proteomic profiling of 80 proteins was assessed by a multiplex assay (proximity extension assay). The assay uses two antibodies for each protein and a PCR step to achieve a high-specific binding and the possibility to measure multiple proteins in parallel, but gives no absolute concentrations.

RESULTS

In the discovery cohort from the PIVUS Study, 28 plasma proteins were significantly associated with eGFR decline per year, taking into account the multiple testing. Twenty of these proteins were significantly associated with eGFR decline per year in the replication cohort from the ULSAM Study after adjustment for age, sex, cardiovascular risk factors, medications, and urinary albumin-to-creatinine ratio (in order of significance: TNF-related apoptosis-inducing ligand receptor 2*, CD40L receptor, TNF receptor 1*, placenta growth factor*, thrombomodulin*, urokinase plasminogen activator surface receptor*, growth/differentiation factor 15*, macrophage colony-stimulating factor 1, fatty acid-binding protein*, cathepsin D, resistin, kallikrein 11*, C-C motif chemokine 3, proteinase-activated receptor 1*, cathepsin L, chitinase 3-like protein 1, TNF receptor 2*, fibroblast growth factor 23*, monocyte chemotactic protein 1, and kallikrein 6). Moreover, 11 of the proteins predicted CKD incidence (marked with * above). No protein consistently predicted eGFR decline per year independently of baseline eGFR in both cohorts.

CONCLUSIONS

Several circulating proteins involved in phosphate homeostasis, inflammation, apoptosis, extracellular matrix remodeling, angiogenesis, and endothelial dysfunction were associated with worsening kidney function. Multiplex proteomics appears to be a promising way of discovering novel aspects of kidney disease pathology.

Total atherosclerotic burden measured by magnetic resonance imaging is related to five-year decline in cognitive function

OBJECTIVE

The aim of this study was to explore whether total atherosclerotic burden is related to future decline in performance on cognitive tests.

METHODS

The total atherosclerotic burden (TAS) was assessed by whole-body magnetic resonance angiography (WBMRA) in 305 subjects at age 70 in the study Prospective Investigation of Vasculature in Uppsala Seniors (PIVUS). The mini-mental state examination (MMSE) and trail making tests (TMT) A and B were evaluated at ages 75 and 80 in 190 of those subjects. No subject with a diagnosis of dementia was included in the sample.

RESULTS

MMSE did not change during the 5 years of follow-up, while TMT A and B increased by 4 and 7 s, respectively. TAS at age 70 was significantly related to the individual change in TMT B (P<0·0001) between age 75 and 80, when adjusted for sex, education level, TMT B at age 75 and Framingham score at age 70. No such relationship was seen for the change in TMT A (P = 0·10). The relationship between TAS and the change in MMSE was of borderline significance (P = 0·025).

CONCLUSION

A relationship was found between the total atherosclerotic burden and future decline in performance on TMT B, highlighting a role of global atherosclerosis in the cognitive decline seen during ageing.

Change in Body Weight from Age 20 Years Is a Powerful Determinant of the Metabolic Syndrome

BACKGROUND

Higher body weight is a well-known determinant of the metabolic syndrome (MetS) and its components. It is however less well studied how the change in weight from age 20 years to middle age or old age affects MetS development.

METHODS

In the community-based EpiHealth (n = 19,000, age range 45 to 75 years, 56% females) and PIVUS (n = 1000, all aged 70 years, 50% females) studies, the participants were asked about their body weight at age 20 years. Data were collected to determine MetS prevalence (NCEP ATP III criteria).

RESULTS

In EpiHealth, the probability of having MetS increased fairly linearly with increasing weight from age 20 in the obese [odds ratios (OR) 1.04 per kg change in weight, 95% confidence interval (CI) 1.03-1.05, P < 0.0001], as well as in the overweight (OR 1.15, 95% CI 1.14-1.17, P < 0.0001) and normal-weight (OR 1.18, 95% CI 1.14-1.21, P < 0.0001), subjects after adjustment for age, sex, body mass index (BMI) at age 20, alcohol intake, smoking, education, and exercise habits. Also in the PIVUS study, the change in weight over 50 years was related to prevalent MetS (OR 1.08 per kg change in weight, 95% CI 1.06-1.10, P < 0.0001). In both studies, self-reported BMI at age 20 was related to prevalent MetS.

CONCLUSION

Self-reported weight gain from age 20 was strongly and independently associated with prevalent MetS both in middle age or old age. Interestingly, this relationship was not restricted only to obese subjects. Our data provide additional support for the importance of maintaining a stable weight throughout life.

Impact of physical activity on cardiovascular status in obesity

BACKGROUND

We have recently shown that being physically active (PA) counteracts, but not eliminates the increased risk of future cardiovascular disease in overweight and obese subjects. To investigate this further, we studied the impact of being normal weight, overweight and obese on multiple markers of subclinical cardiovascular disease in relation to physical activity.

MATERIALS AND METHODS

At age 70, 1016 subjects were investigated in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Being PA was defined as performing regular heavy exercise (self-reported). According to body mass index (BMI)/PA groups, the participants were categorized as PA/normal weight (BMI < 25 kg/m² , n = 104), non-PA/normal weight (n = 234), PA/overweight (BMI 25-29·9 kg/m² , n = 133), non-PA/overweight (n = 295), PA/obese (BMI ≥ 30 kg/m² , n = 54) and non-PA/obese (n = 169). Several different measurements of endothelial reactivity and arterial compliance (plethysmography and ultrasound), cartotid artery atherosclerosis and echocardiography were performed, and seven markers of coagulation/fibrinolysis were measured.

RESULTS

Physically active subjects with obesity showed impaired vasoreactivity in the forearm resistance vessels, increased left ventricular mass and impaired left ventricular systolic and diastolic functions, together with impaired coagulation/fibrinolysis when compared to PA/normal-weight subjects (P < 0·05 to <0·001). The majority of these disturbances were seen also in PA/overweight subjects when compared to PA/normal-weight subjects (P < 0·05 to <0·001).

CONCLUSIONS

Our data provide additional support for the notion that an increased level of self-reported physical activity does not fully eliminate the deleterious cardiovascular consequences associated with overweight and obesity.

Uric acid and endothelial function in elderly community-dwelling subjects

The role of serum uric acid (SUA), an inflammatory agent and potential mediator of cardiovascular diseases, in endothelial function (EF) has been tested only in middle-aged subjects affected by specific diseases. Our aim was to assess the relationship between SUA and measures of EF in a cohort of elderly community-dwellers. This study involved 424 males and 426 females aged 70years from the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS), having complete data on SUA and EF assessed by flow-mediated vasodilation (FMD) and by intra-arterial infusion of acetylcholine (endothelium-dependent vasodilation, EDV) and sodium nitroprusside (endothelium-independent vasodilation, EIDV). Univariate and multivariate regression models obtained by backward selection from initial fully-adjusted models were built to assess the relationship between SUA and measures of EF in both genders. Cardiovascular risk factors, serum hormonal and metabolic mediators, and body composition were considered as potential confounders. In the univariate model, SUA was inversely associated in both genders with log(EDV) (β±SE males -0.39±0.17, p=0.03; females -0.57±0.19, p=0.003) and log(EIDV) (males -0.23±0.12, p=0.05; females -0.49±0.15, p=0.002), but not with log(FMD). After adjustment for BMI, only the association between SUA and log(EIDV) in females persisted, though attenuated (-0.32±0.16, p=0.049), and was no longer significant in the fully-adjusted multivariate model including waist/hip ratio. In conclusion, in older subjects, especially women, SUA is associated with EF not independently of a list of confounders including BMI and trunk fat mass, suggesting a role as surrogate metabolic marker rather than an active player in EF.

Circulating levels of perfluoroalkyl substances (PFASs) and carotid artery atherosclerosis

BACKGROUND AND OBJECTIVE

During recent years, some persistent organic pollutants (POPs) have been linked to atherosclerosis. One group of POPs, the poly- and perfluoroalkyl substances (PFASs) have not been investigated with regard to atherosclerotic plaques.

METHODS

Carotid artery atherosclerosis was assessed by ultrasound in 1016 subjects aged 70 years in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. Eight PFASs were detected in >75% of participants' plasma by ultra-performance liquid chromatography coupled to tandem mass spectrometry (UPLC-MS/MS).

RESULTS

No significant linear associations were observed between the PFASs and intima-media thickness (IMT), or the echogenicity in the intima-media complex (IM-GSM, a marker of lipid infiltration in the artery) when men and women were analyzed together. Neither was occurrence of carotid plaques related to PFASs levels. However, highly significant interactions were observed between some PFASs and sex regarding both IM-GSM and plaque prevalence. Perfluorononanoic acid (PFNA), perfluorodecanoic acid (PFDA), and perfluoroundecanoic acid (PFUnDA), were all related to IM-GSM in a positive fashion in women (p=0.002-0.003), while these relationships were negative in men. The levels of PFUnDA were significantly related to carotid plaque in women (OR 1.59, 95%CI 1.03-2.43, p=0.03), but not in men (OR 0.93, 95%CI 0.62-1.42, p=0.75).

CONCLUSIONS

In this cross-sectional study, a pronounced gender difference was observed regarding associations between some PFASs, especially the long-chain PFUnDA, and markers of atherosclerosis, with more pronounced relationships found in women. These findings suggest a sex-specific role for PFASs in atherosclerosis.