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

Variation in genes in the endothelin pathway and endothelium-dependent and endothelium-independent vasodilation in an elderly population

AIM

Indirect evidences by blockade of the endothelin receptors have suggested a role of endothelin in endothelium-dependent vasodilation. This study aimed to investigate whether circulating levels of endotehlin-1 or genetic variations in genes in the endothelin pathway were related to endothelium-dependent vasodilation.

METHODS

In 1016 seventy-year-old participants of the population-based Prospective Study of the Vasculature in Uppsala Seniors (PIVUS) study (52% women), we measured endothelium-dependent vasodilation using the invasive forearm technique with acetylcholine given in the brachial artery (EDV) and the brachial artery ultrasound technique with measurement of flow-mediated dilatation (FMD). Plasma endothelin-1 levels were measured and 60 SNPs in genes in the endothelin pathway (ECE1, EDN1, EDNRA, EDNRB) were genotyped.

RESULTS

No significant associations were found between circulating endothelin levels and EDV or FMD. No single genotype was related to EDV or FMD following adjustment for multiple testing, but a genotype score for 3 SNPs (rs11618266 in EDNRB, rs17675063 in EDNRA, rs3026868 in ECE1) was significantly related to EDV (beta coefficient 0.070, 95% CI 0.025-0.12, P = 0.002) when adjusting for gender, systolic blood pressure, HDL and LDL cholesterol, serum triglycerides, BMI, diabetes, smoking, antihypertensive medication or statins and CRP. This score was also related to nitroprusside-induced vasodilation in the forearm.

CONCLUSION

A combination of genotypes in the endothelin pathway was related to both endothelium-dependent and endothelium-independent vasodilation in forearm resistance vessels, but not in the brachial artery in an elderly population, giving evidence for a role of the endothelin system in resistance vessel reactivity independent of major cardiovascular risk factors.

An environmental wide association study (EWAS) approach to the metabolic syndrome

BACKGROUND

Environmental contaminants have previously been linked to components of the Metabolic Syndrome (MetS). However, exposure to environmental contaminants is in part determined by various lifestyle factors.

OBJECTIVE

Using an "Environmental Wide Association Study" (ELWAS) integrating environmental contaminants and lifestyle factors, we aimed to evaluate a possible additive role of both contaminants and lifestyle factors regarding MetS.

METHODS

1016 subjects aged 70years were investigated in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study. 43 environmental contaminants were measured in the circulation. Dietary records were used to evaluate 21 nutrients and the proportions of 13 fatty acids were determined in serum cholesterol esters to further quantify fat quality intake. Adding 5 other important lifestyle factors yielded together 76 environmental and lifestyle factors. MetS was defined by the NCEP/ATPIII-criteria.

RESULTS

23% had MetS. Using cross-validation within the sample, fourteen environmental contaminants or lifestyle factors consistently showed a false discovery rate <0.05. When the major variables entered a multiple model, only p, p'-DDE levels (positive), PCB209 (inverse) and exercise habits (inverse) were together with a fatty acid pattern, with high levels of palmitic acid and oleic acid and low levels of linoleic acid, related to MetS (p<0.002 for all variables).

CONCLUSION

Using a cross-sectional EWAS approach, certain environmental contaminants and lifestyle factors were found to be associated with prevalent metabolic syndrome in an additive fashion in an elderly population.

Circulating levels of persistent organic pollutants (POPs) are associated with left ventricular systolic and diastolic dysfunction in the elderly

BACKGROUND AND OBJECTIVE

Major risk factors for congestive heart failure (CHF) are myocardial infarction, hypertension, diabetes, atrial fibrillation, smoking, left ventricular hypertrophy (LVH) and obesity. However, since these risk factors only explain part of the risk of CHF, we investigated whether persistent organic pollutants (POPs) might also play a role.

METHODS

In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, left ventricular ejection fraction, (EF), E/A-ratio and isovolumic relaxation time (IVRT), were determined by echocardiography and serum samples of 21 POPs were analyzed in serum measured by high-resolution chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS) in 998 subjects all aged 70 years.

RESULTS

In this cross-sectional analysis, high levels of several of the polychlorinated biphenyls (PCB congeners 99, 118, 105, 138, 153, and 180) and octachlorodibenzo-p-dioxin (OCDD) were significantly related to a decreased EF. Some POPs were also related to a decreased E/A-ratio (PCBs 206 and 209). All the results were adjusted for gender, hypertension, diabetes, smoking, LVH and BMI, and subjects with myocardial infarction or atrial fibrillation were excluded from the analysis.

CONCLUSIONS

Circulating levels of POPs were related to impairments in both left ventricular systolic and diastolic function independently of major congestive heart failure risk factors, suggesting a possible role of POPs in heart failure.

SHBG and endothelial function in older subjects

BACKGROUND

Endothelial dysfunction is predictor of cardiovascular diseases that have different prevalence in men and women before menopause. Sex hormones and sex hormone binding globulin (SHBG), novel risk factors for diabetes and cardiovascular diseases even in older individuals, might explain this difference. However, the relationship between these hormones and endothelial function has never been addressed in the elderly.

METHODS AND RESULTS

430 men and,424 women 70 years older of Prospective Study of the Vasculature in Uppsala Seniors study, with complete data on SHBG, testosterone(T), estradiol(E2), endothelium-independent vasodilation (EIDV), endothelium-dependent vasodilation(EDV), flow-mediated vasodilation (FMD) and the pulse wave analysis (reflection index, RI) were evaluated. Multivariate regression analysis adjusted for confounders was used to assess the relationship between T, E2, SHBG and endothelial function. In men we found a positive relationship between SHBG and EDV (β ± SE 3.60 ± 0.83, p<0.0001), EIDV (2.42 ± 0.58, p<0.0001) but not with FMD. The relationship between SHBG and EDV and EIDV was maintained after adjustment for sex (1.64 ± 0.47, p<0.001 and 1.79 ± 0.35, p<0.0006, respectively). After adjustment for confounders, the relationship between SHBG and EDV and EIDV was still statistically significant (2.63 ± 0.90 and 1.86 ± 0.63, p = 0.004 for both). In women SHBG and EIDV were positively associated (1.58 ± 0.46; p = 0.0007), and this relationship was independent of sex (1.79 ± 0.35; p<0.001). No significant interaction SHBG * SEX was found for EIDV (p = 0.72). In a combined analysis in two sexes, SHBG and EIDV were positively associated (1.13 ± 0.45; p = 0.01). SHBG was not associated with EDV, FMD and RI. No significant relationship was found between T or E2 and EDV, EIDV, FMD or RI in both sexes.

CONCLUSIONS

In older men SHBG, but not T and E2, is positively and independently associated with EDV in resistance arteries. In both sexes, SHBG was positively and independently associated with EIDV.

Leptin and endothelial function in the elderly: the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study

BACKGROUND

Leptin levels are elevated in obese humans. Several studies have shown an association between hyperleptinemia and development of atherosclerosis and cardiovascular disease (CVD), but the relationship between leptin and vascular function remains unclear.

AIM

To evaluate associations between circulating plasma leptin and measures of vascular function in a large sample of elderly individuals from the community.

METHODS

This cross-sectional study included 1016 subjects aged 70 (50% women) from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS). The invasive technique forearm plethysmography with intra-arterial infusions of acetylcholine and sodium nitroprusside was used for estimation of endothelial dependent vasodilatation (EDV) and endothelial independent vasodilatation (EIDV), respectively, in resistance arteries, and the non-invasive technique ultrasound assessed flow mediated vasodilation (FMD) in conduit arteries. The aortic augmentation index (AoAI), a surrogate measure of arterial stiffness, was evaluated by pulse wave analysis. Associations of vascular function, arterial stiffness and blood pressure with leptin were explored.

RESULTS

In sex-adjusted models, high levels of leptin were inversely associated with EDV and EIDV. These associations remained after stratification for sex, traditional risk factors of CVD and insulin resistance, but were attenuated after taking a measure of obesity (body mass index) into account. In addition, leptin associated with arterial stiffness and systolic and diastolic blood pressure.

CONCLUSION

Hyperleptinemia associated inversely with vasodilatation in resistance arteries. Furthermore, hyperleptinemia associated with arterial stiffness and hypertension. These associations were attenuated after adjusting for body mass index suggesting that leptin may be the mediator between obesity and impaired vascular function.

A combined test of acetylcholine-mediated vasodilation of both the forearm resistance vessels and the radial artery

OBJECTIVE

To evaluate a new combined test of endothelium-dependent vasodilation (EDV) in the forearm resistance vessel and the radial artery.

METHODS

Acetylcholine (ACh) and sodium nitroprusside (SNP) infusion in the brachial artery were used to simultaneous evaluate EDV and endothelium-independent vasodilation (EIDV) in forearm resistance vessels (plethysmography) and in the radial artery (ultrasound) in 76 healthy subjects. Brachial artery ultrasound was used to assess flow-mediated vasodilation (FMD).

RESULTS

Acetylcholine induced a 4·5% (median value, P = 0·0010) increase in the radial artery diameter, while SNP induced a 31·2% increase in diameter (P<0·0001). While no increase in radial artery blood flow was induced by ACh (P = 0·69), an increase by 181% in radial blood flow was induced by SNP (P<0·0001). When relating the radial artery diameter data to FMD, the change in radial artery diameter induced by ACh was significantly correlated with FMD (r = 0·35, P = 0·013). No such relationship was seen for the diameter change induced by SNP (r = -0·03, P = 0·81). When relating the radial artery blood flow data to EDV and EIDV, the change in radial artery blood flow induced by ACh was significantly correlated with EDV in an inverse fashion (r = -0·42, P = 0·0032). No such relationship was seen for the blood flow change induced by SNP when related to EIDV (r = -0·07, P = 0·63).

CONCLUSION

Simultaneous measurements of blood flow in forearm vessels by plethysmography and in the radial artery by ultrasound during ACh infusion is a new way to assess EDV in both resistance and conduit arteries during one investigation.

Cardiac troponin I levels measured with a high-sensitive assay increase over time and are strong predictors of mortality in an elderly population

OBJECTIVES

This study sought to assess changes in troponin levels, underlying conditions, and the prognostic implications in elderly subjects from the community.

BACKGROUND

Cardiac troponin levels are often detectable in community dwellers when sensitive assays are applied. However, information on the course of troponin levels over time is limited.

METHODS

Cardiac troponin I (cTnI) was measured by using a novel, high-sensitive assay in community dwellers aged 70 years from the Prospective Investigation of the Vasculature in Uppsala Seniors study. Measurements were performed at baseline (n = 1,004) and after 5 years (n = 814). Total follow-up was 8.0 years.

RESULTS

cTnI levels were detectable in 968 (96.4%) subjects at baseline and independently predicted all-cause mortality (adjusted hazard ratio [HR]: 1.44 [95% confidence interval (CI): 1.18 to 1.77]) and cardiovascular mortality (adjusted HR: 1.66 [95% CI: 1.20 to 2.29]) when levels from baseline and 5-year follow-up were used as updated covariates. The integrated discrimination improvement of cTnI regarding all-cause mortality was 0.014 (p = 0.04), and the category-free net reclassification improvement was 0.231 (p = 0.02). Median cTnI levels increased by 45% between both measurements. The change in cTnI levels was significantly related to male sex (p = 0.02), body mass index (p = 0.01), high-density lipoprotein cholesterol (p = 0.005), N-terminal pro-B-type natriuretic peptide (p = 0.004), and left ventricular ejection fraction (p = 0.04), and it independently predicted all-cause mortality occurring after 5-year follow-up (adjusted HR: 1.97 [95% CI: 1.14 to 3.40]; p = 0.02).

CONCLUSIONS

Using a novel high-sensitive assay, cTnI levels could be determined in nearly all elderly study subjects. cTnI levels increased over time and were a strong marker of mortality risk. Our data suggest that cTnI might offer utility for clinical assessment of subjects in the general population.

Total atherosclerotic burden by whole body magnetic resonance angiography predicts major adverse cardiovascular events

OBJECTIVE

The purpose of the present study was to investigate the relationship between the Total Atherosclerotic Score (TAS), a measurement of the overall atherosclerotic burden of the arterial tree by whole body magnetic resonance angiography (WBMRA), and the risk of major adverse cardiovascular events (MACE), defined as cardiac death, myocardial infarction, stroke and/or coronary revascularization, assuming that TAS predicts MACE.

METHODS AND RESULTS

305 randomly selected 70 year-old subjects (47% women) underwent WBMRA. Their atherosclerotic burden was evaluated and TAS > 0, that is atherosclerotic changes, were found in 68% of subjects. During follow-up (mean 4.8 years), MACE occurred in 25 subjects (8.2%). Adjusting for multiple risk factors, TAS was associated with MACE (OR 8.86 for any degree of vessel lumen abnormality, 95%CI 1.14-69.11, p = 0.037). In addition, TAS improved discrimination and reclassification when added to the Framingham risk score (FRS), and ROC (Receiver Operator Curve) increased from 0.681 to 0.750 (p = 0.0421).

CONCLUSION

In a population-based sample of 70 year old men and women WBMRA, with TAS, predicted MACE independently of major cardiovascular risk factors.

Serum FGF23 and risk of cardiovascular events in relation to mineral metabolism and cardiovascular pathology

BACKGROUND AND OBJECTIVES

Circulating fibroblast growth factor-23 is associated with adverse cardiovascular outcomes in CKD and non-CKD individuals, but the underlying mechanism remains unclear. This study tested whether this association is independent of mineral metabolism and indices of subclinical cardiovascular pathology.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

The prospective association between fibroblast growth factor-23 and major cardiovascular events (a composite of hospital-treated myocardial infarction, hospital-treated stroke, or all-cause mortality) was investigated in the community-based Prospective Investigation of the Vasculature in Uppsala Seniors (n=973; mean age=70 years, 50% women) using multivariate logistic regression. Subjects were recruited between January of 2001 and June of 2004.

RESULTS

During follow-up (median=5.1 years), 112 participants suffered a major cardiovascular event. In logistic regression models adjusted for age, sex, and estimated GFR, higher fibroblast growth factor-23 was associated with increased risk for major cardiovascular events (odds ratio for tertiles 2 and 3 versus tertile 1=1.92, 95% confidence interval=1.19-3.09, P<0.01). After additional adjustments in the model, adding established cardiovascular risk factors, confounders of mineral metabolism (calcium, phosphate, parathyroid hormone, and 25(OH)-vitamin D), and indices of subclinical pathology (flow-mediated vasodilation, endothelial-dependent and -independent vasodilation, arterial stiffness, and atherosclerosis and left ventricular mass) attenuated this relationship, but it remained significant (odds ratio for tertiles 2 and 3 versus tertile 1=1.69, 95% confidence interval=1.01-2.82, P<0.05).

CONCLUSIONS

Fibroblast growth factor-23 is an independent predictor of cardiovascular events in the community, even after accounting for mineral metabolism abnormalities and subclinical cardiovascular damage. Circulating fibroblast growth factor-23 may reflect novel and important aspects of cardiovascular risk yet to be unraveled.

Circulating levels of persistent organic pollutants are related to retrospective assessment of life-time weight change

BACKGROUND

Persistent organic pollutants (POPs) have been suggested to be linked to obesity. We have previously shown that less-chlorinated PCBs were positively related to fat mass, while highly-chlorinated PCBs were inversely related to obesity.

OBJECTIVE

The aim of the present evaluation is to investigate the relationship between retrospective assessed life-time change in body weight (20-70 years) with circulating POP levels measured at age 70 years.

METHODS

1016 subjects aged 70 years were investigated in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUSs) study. 16 PCBs and 3 OC pesticides were analyzed using HRGC/HRMS. Current body weight was measured and participants self-reported their weight at age 20.

RESULTS

The average estimated weight change over 50 years was 14.4 kg. Both the sum of OC pesticide concentrations (4.3 kg more weight gain in quintile 5 vs. quintile 1, p<0.0001) and the sum of the less-chlorinated PCBs were positively related to the estimated weight change (3.7 kg more weight gain in quintile 2 vs. quintile 1, non-linear relationship p=0.0015). In contrast, the sum of concentrations of highly-chlorinated PCBs were inversely related to estimated weight change (8.4 kg less weight gain in quintile 5 vs. quintile 1, p<0.0001).

CONCLUSION

High levels of OC pesticides and the less-chlorinated PCBs at age 70 were associated with a pronounced estimated weight change over the previous 50 years. However, the opposite was seen for highly-chlorinated PCBs. Differences in mode of action, toxicokinetics, non-linear relationships and reverse causation might explain these discrepancies.

Prognostic usefulness of the change in N-terminal pro B-type natriuretic peptide levels to predict mortality in a single community cohort aged ≥ 70 years

The levels of N-terminal pro B-type natriuretic peptide (NT-proBNP) are closely related to cardiac abnormalities and adverse outcomes in the general population. However, little is known about the course of NT-proBNP levels over time, the underlying conditions, and the prognostic effect of changes. To investigate these issues, we measured the NT-proBNP levels (Elecsys 2010, Roche Diagnostics) in community-dwellers participating in the Prospective Investigation of the Vasculature in Uppsala Seniors study at 70 (n = 1,005) and 75 (n = 817) years of age. The total follow-up was 8.0 years. In subjects with available results from both examinations, the median NT-proBNP levels increased from 106 pg/ml (25th to 75th percentile 62 to 174) to 125 pg/ml (25th to 75th percentile 73-234; p <0.001). The change in NT-proBNP levels was positively and independently related to male gender, baseline information on ischemic electrocardiographic changes, renal dysfunction, impaired left ventricular ejection fraction, and intercurrent cardiovascular events (e.g., myocardial infarction, stroke, or coronary revascularization). The change in NT-proBNP levels independently predicted mortality after the measurements at 75 years of age (all-cause mortality, adjusted hazard ratio 2.4, 95% confidence interval 1.6 to 3.6; cardiovascular mortality, adjusted hazard ratio 2.3, 95% confidence interval 1.2 to 4.5). Compared to those without significant NT-proBNP changes (n = 606), subjects with increasing levels (n = 162) had markedly increased all-cause mortality (adjusted hazard ratio 4.3, 95% confidence interval 2.1 to 8.8). No subject with decreasing NT-proBNP levels (n = 49) died. In conclusion, repeat measurements of NT-proBNP might add useful information to the routine clinical assessment in subjects aged ≥ 70 years, because changes in their levels were associated with cardiovascular risk indicators and strongly predictive of mortality.

Elevated circulating levels of copper and nickel are found in elderly subjects with left ventricular hypertrophy

Identified risk factors for left ventricular hypertrophy (LVH) are hypertension, diabetes and obesity. However, since these risk factors only explain a part of the variation in left ventricular mass, we investigated if trace and heavy metals might also play a role in LVH. In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, left ventricular mass index (LVMI) and relative wall thickness (RWT) were determined by echocardiography together with eleven different trace and heavy metals in 993 subjects aged 70 years. Only copper levels were significantly related to LVMI following adjustment for sex, blood pressure, antihypertensive treatment, diabetes and body mass index (BMI) (p<0.0001). However, both copper (Cu) and nickel (Ni) were related to RWT following adjustment (p<0.0001). When divided into four geometric groups, both Cu and Ni were elevated in subjects with concentric remodelling and concentric LVH, but not in those with eccentric hypertrophy, when compared to subjects with a normal left ventricle. No relationships were found for zinc, aluminium, manganese, molybdenum, mercury, lead, cadmium, cobalt or chromium. Elevated levels of copper and nickel are found in elderly subjects with LVH, especially of the concentric type, following adjustment for known risk factors for LVH.

An investigation of the co-variation in circulating levels of a large number of environmental contaminants

We are daily exposed to many different environmental contaminants. Mixtures of these contaminants could act together to induce more pronounced effects than the sum of the individual contaminants. To evaluate the effects of such mixtures, it is of importance to assess the co-variance amongst the contaminants. Thirty-seven environmental contaminants representing different classes were measured in blood samples from 1016 individuals aged 70 years. Hierarchical cluster analysis and principal component analysis were used to assess the co-variation among the contaminants. Within each identified cluster, possible marker contaminants were sought for. We validated our findings using data from the National Health and Nutrition Examination Survey (NHANES) 2003-2004 study. Two large clusters could be identified, one representing low/medium chlorinated polychlorinated biphenyls (PCBs) (≤6 chlorine atoms), as well as two pesticides and one representing medium/high chlorinated PCBs (≥6 chlorine atoms). PCBs 118 and 153 could be used as markers for the low/medium chlorinated cluster and PCBs 170 and 209 could be used as markers for the medium/high chlorinated cluster. This pattern was similar to data from the NHANES study. Apart from the PCBs, little co-variation was seen among the contaminants. Thus, a large number of chemicals have to be measured to adequately identify mixtures of environmental contaminants.

Reference values of thirty-one frequently used laboratory markers for 75-year-old males and females

BACKGROUND

We have previously reported reference values for common clinical chemistry tests in healthy 70-year-old males and females. We have now repeated this study 5 years later to establish reference values also at the age of 75. It is important to have adequate reference values for elderly patients as biological markers may change over time, and adequate reference values are essential for correct clinical decisions.

METHODS

We have investigated 31 frequently used laboratory markers in 75-year-old males (n = 354) and females (n = 373) without diabetes. The 2.5 and 97.5 percentiles for these markers were calculated according to the recommendations of the International Federation of Clinical Chemistry.

RESULTS

Reference values are reported for 75-year-old males and females for 31 frequently used laboratory markers.

CONCLUSION

There were minor differences between reference intervals calculated with and without individuals with cardiovascular diseases. Several of the reference intervals differed from Scandinavian reference intervals based on younger individuals (Nordic Reference Interval Project).

Association between glomerular filtration rate and endothelial function in an elderly community cohort

BACKGROUND

Endothelial dysfunction is prevalent among individuals with chronic kidney disease. However, the association between glomerular filtration rate and endothelial function in the community is unclear and needs to be investigated in the general population.

METHODS

In the community-based Prospective Investigation of the Vasculature of Uppsala Seniors study (PIVUS, n = 952, mean age 70, women 49.3%), we investigated cross-sectional associations between estimated cystatin C-based glomerular filtration rate (eGFR), and 3 measures representing different aspects of endothelial function (endothelial-dependent vasodilation [EDV], endothelial independent vasodilatation [EIDV], and flow-mediated dilatation [FMD]). We also performed pre-specified sub-group analyses in participants with normal eGFR (>60 ml/min/1.73 m(2)).

RESULTS

In the whole cohort, 10 ml/min/1.73 m(2) higher eGFR was associated with 3% higher EDV (p = 0.001) and 2% higher EIDV (p = 0.007), adjusted for age and sex. The associations were attenuated and no longer statistically significant after adjusting for established cardiovascular risk factors. In participants with eGFR >60 ml/min/1.73 m(2), 10 ml higher eGFR was associated with 2% higher EDV (p = 0.04) after adjusting for sex and age. eGFR was not associated to FMD in any model or sub-sample.

CONCLUSION

This community-based study suggests that eGFR is associated with endothelial function also in persons with normal kidney function, but that this association is largely explained by confounding by established cardiovascular risk factors. Thus, our data do not support the notion of a direct causal interplay between renal and vascular function prior to the development of CKD.

Relations of circulating vitamin D concentrations with left ventricular geometry and function

AIMS

Vitamin D deficiency has been associated with risk of overt cardiovascular disease (CVD), but associations with subclinical disease are not well characterized. Hence, we examined associations of circulating vitamin D concentrations and left ventricular (LV) geometry and function by echocardiography at baseline and after 5 years in a community-based study.

METHODS AND RESULTS

In the PIVUS study, we measured serum 25-dihydroxyvitamin-D (25-OH D) at age 70 and performed echocardiography including LV mass, wall thickness, end-diastolic diameter, end-systolic diameter (LVESD), left atrial diameter, fractional shortening, ejection fraction, isovolumic relaxation time, and E/A ratio at both age 70 and 75. We included 870 participants (52% women) without prior myocardial infarctions, heart failure, or prevalent valvular disease. After adjusting for potential confounders, 25-OH D at baseline was found to be significantly associated with LVESD, fractional shortening, and ejection fraction (β, -0.42 mm, P = 0.03; β, 0.70%, P = 0.03; and β, 0.91% P = 0.01, respectively), per 1 SD increase in 25-OH D (SD = 20 nmol/L) at baseline. In longitudinal analyses, vitamin D levels at baseline were not significantly associated with change in LV geometry and function after 5 years.

CONCLUSION

In our community-based study among the elderly, we found higher circulating vitamin D concentrations to be associated cross-sectionally with better LV systolic function and smaller LVESD at baseline. The association persisted after adjusting for several potential confounders, including cardiovascular risk factors and calcium, phosphate, and parathyroid hormone levels. Randomized clinical trials are needed to establish firmly or refute a causal relationship between vitamin D levels and changes in LV geometry and function.

Circulating levels of secretory- and lipoprotein-associated phospholipase A2 activities: relation to atherosclerotic plaques and future all-cause mortality

AIMS

Secretory- and lipoprotein-associated phospholipases A2 (sPLA2 and Lp-PLA2) are enzymes both suggested to be of importance for atherosclerosis. We investigated relationships between the activities of these enzymes in the circulation and atherosclerosis as well as future clinical events.

METHODS AND RESULTS

The population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study included 1016 randomly selected subjects, all aged 70. The prevalence of carotid artery plaques was recorded by ultrasound (n= 954), and arterial stenosis was assessed by whole-body magnetic resonance angiography (WBMRA, n= 302). Secretory-associated phospholipase A2 [odds ratio 1.23 for 1 SD increase, 95% confidence interval (CI): 1.05-1.44, P= 0.007], but not Lp-PLA2 (P= 0.26), activity was significantly related to carotid atherosclerosis and to the amount of stenosis at WBMRA (P= 0.006) following adjustment for multiple risk factors (waist circumference, serum triglycerides, body mass index, C-reactive protein, high density lipoprotein-C, low density lipoprotein-C, triglycerides, GFR, fasting glucose, blood pressure, statin use, and exercise habits). Secretory-associated phospholipase A2 [hazard ratio (HR) 1.45 for 1 SD increase, 95% CI: 1.15-1.84, P= 0.001], but not Lp-PLA2 (HR 0.95, P= 0.55), activity was a significant risk factor for all-cause mortality (114 had died) during 7.0 years follow-up after adjustment for the risk factors described above. In a sample of 1029 post-myocardial infarction (MI) patients (French registry of Acute ST-elevation and non-ST-elevation Myocardial Infarction), sPLA2 (adjusted HR 1.32 for 1 unit increase, 95% CI: 1.02-1.71, P= 0.036), but not Lp-PLA2 (HR 1.03, P= 0.90), activity predicted death or recurrent MI during 1-year follow-up (n= 136 cases).

CONCLUSION

sPLA2 activity was related to atherosclerosis and predicted all-cause mortality in a sample of elderly subjects, as well as death or MI in post-MI patients.

Associations between circulating levels of bisphenol A and phthalate metabolites and coronary risk in the elderly

Studies have pointed out associations between various chemicals with estrogenic activity and cardiovascular disease. Being ubiquitous, the plastic additive substances bisphenol A (BPA), and phthalates have been detected in almost all types of analyzed human samples. The aim of this study was to investigate whether circulating levels of BPA and/or four selected phthalate metabolites are associated to coronary risk in an elderly population. In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, coronary risk was assessed by the Framingham Risk Score (FRS) together with circulating serum levels of BPA and the four phthalate metabolites monoisobutyl phthalate (MiBP), monomethyl phthalate (MMP), monoethyl phthalate (MEP), mono-(2-ethylhexyl) phthalate (MEHP) in 1016 subjects aged 70 years. BPA, MEHP, and MMP were associated to LDL-cholesterol and MEHP to HDL-cholesterol, MEP to diastolic blood pressure and MiBP to fasting glucose when the compounds were investigated one by one. After Bonferronni correction, only the relations for MMP to LDL-cholesterol (p<0.0001), MEP to diastolic blood pressure (p<0.0002), and MiBP to fasting glucose (p<0.0001) remained significant. MMP was associated to the FRS (p=0.02), but after Bonferronni correction, this association was not significant. In conclusion, associations were found between MMP and LDL-cholesterol, MEP and diastolic blood pressure, and MiBP and fasting glucose. We did not observe any strong associations between BPA nor any of the four phthalate metabolites and Framingham Risk Score in this elderly population.

Plasma prolylcarboxypeptidase (angiotensinase C) is increased in obesity and diabetes mellitus and related to cardiovascular dysfunction

BACKGROUND

Prolylcarboxypeptidase (PRCP) (angiotensinase C) has 3 major targets, angiotensin II, prekallikrein, and α-melanocyte stimulating hormone(1-13). The truncation of the latter leads to loss in appetite regulation and obesity in experimental animals. The objectives of this study were to purify PRCP from a native source, establish a sensitive immunoassay for PRCP, and relate plasma PRCP concentrations to signs and symptoms of obesity, diabetes mellitus, and cardiovascular dysfunction.

METHODS

Purification of PRCP from human neutrophils and establishment of a sensitive ELISA was carried out with the use of samples from study participants. Three cohorts were studied: healthy individuals (n = 40); a chest pain cohort (Fast Assessment of Thoracic Pain by Neural Networks) (n = 165); and a community-based cohort [Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS)] (n = 1004).

RESULTS

PRCP was purified to homogeneity. Mean (SD) plasma concentrations in healthy individuals were 12.9 (3.2) μg/L and were increased in patients with chest pain and in patients with obesity and/or diabetes mellitus (P < 0.0001). In the PIVUS cohort the concentrations were related to several measures of arterial plaque formation, thickness of arterial intima media and posterior wall of the heart (P = 0.04-0.000005); the Framingham score (r = 0.14, P < 0.0001); and concentrations of C-reactive protein (r = 0.16, P < 0.0001) and N-terminal pro B-type natriuretic peptide (r = -0.13, P < 0.0001).

CONCLUSIONS

Plasma concentrations of PRCP may be used to reflect metabolic conditions in individuals with obesity and diabetes mellitus. The associations of PRCP concentrations with signs of cardiovascular dysfunction and cardiovascular abnormalities suggest a pivotal role of the enzyme in disease.

Brachial artery hyperaemic blood flow velocity in relation to established indices of vascular function and global atherosclerosis: the Prospective Investigation of the Vasculature in Uppsala Seniors study

BACKGROUND

Systolic to diastolic blood flow velocity (SDFV) ratio in the brachial artery recently proved to be related to cardiovascular risk and carotid atherosclerosis. We hypothesized that the SDFV ratio was related to established markers of vascular function and global atherosclerosis.

METHODS

Established markers of endothelial function in forearm resistance vessels, flow-mediated vasodilation and arterial stiffness were assessed in the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study including 1016 individuals aged 70. Whole-body magnetic resonance angiography was performed in a random 306 of the participants. Atherosclerotic lesions were summarized in a total atherosclerotic score (TAS). Before and during hyperaemia of the brachial artery, systolic and diastolic blood flow velocities were measured by Doppler.

RESULTS

The SDFV ratio was positively related to endothelium-independent vasodilatation, while inverse relations were found to flow-mediated dilation, common carotid artery distensibility and the stroke volume to pulse pressure ratio. Endothelium-dependent vasodilatation and total peripheral resistance index were not significantly related to the SDFV ratio. The SDFV ratio (P = 0·015) and the blood flow increase (BFI) during hyperaemia (P = 0·020) were both significantly related to TAS after gender adjustment. When adjusted for the Framingham risk score, both the SDFV ratio (P = 0·057) and BFI (P = 0·078) lost somewhat in significance.

CONCLUSION

The SDFV ratio was related to established markers of both vasodilation and arterial compliance, and to global atherosclerosis. Future larger studies have to evaluate whether the SDFV ratio is related to global atherosclerosis independently of traditional risk factors.

Methods for evaluating endothelial function: a position statement from the European Society of Cardiology Working Group on Peripheral Circulation

The endothelium holds a pivotal role in cardiovascular health and disease. Assessment of its function was until recently limited to experimental designs due to its location. The advent of novel techniques has facilitated testing on a more detailed basis, with focus on distinct pathways. This review presents available in-vivo and ex-vivo methods for evaluating endothelial function with special focus on more recent ones. The diagnostic modalities covered include assessment of epicardial and microvascular coronary endothelial function, local vasodilation by venous occlusion plethysmography and flow-mediated dilatation, arterial pulse wave analysis and pulse amplitude tonometry, microvascular blood flow by laser Doppler flowmetry, biochemical markers and bioassays, measurement of endothelial-derived microparticles and progenitor cells, and glycocalyx measurements. Insights and practical information on the theoretical basis, methodological aspects, and clinical application in various disease states are discussed. The ability of these methods to detect endothelial dysfunction before overt cardiovascular disease manifests make them attractive clinical tools for prevention and rehabilitation.

Impaired insulin sensitivity as indexed by the HOMA score is associated with deficits in verbal fluency and temporal lobe gray matter volume in the elderly

OBJECTIVE

Impaired insulin sensitivity is linked to cognitive deficits and reduced brain size. However, it is not yet known whether insulin sensitivity involves regional changes in gray matter volume. Against this background, we examined the association between insulin sensitivity, cognitive performance, and regional gray matter volume in 285 cognitively healthy elderly men and women aged 75 years from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study.

RESEARCH DESIGN AND METHODS

Insulin sensitivity was calculated from fasting serum insulin and plasma glucose determinations using the homeostasis model assessment of insulin resistance (HOMA-IR) method. Cognitive performance was examined by a categorical verbal fluency. Participants also underwent a magnetic resonance imaging (MRI) brain scan. Multivariate analysis using linear regression was conducted, controlling for potential confounders (sex, education, serum LDL cholesterol, mean arterial blood pressure, and abdominal visceral fat volume).

RESULTS

The HOMA-IR was negatively correlated with verbal fluency performance, brain size, and temporal lobe gray matter volume in regions known to be involved in speech production (Brodmann areas 21 and 22, respectively). No such effects were observed when examining diabetic (n = 55) and cognitively impaired (n = 27) elderly subjects as separate analyses.

CONCLUSIONS

These cross-sectional findings suggest that both pharmacologic and lifestyle interventions improving insulin signaling may promote brain health in late life but must be confirmed in patient studies.

Circulating levels of metals are related to carotid atherosclerosis in elderly

The aim of this study was to investigate if blood levels of trace and/or heavy metals are related to atherosclerosis in a cross-sectional study in elderly. In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (1016 subjects, all aged 70), the prevalence of carotid artery plaques was recorded by ultrasound. The numbers of carotid arteries with plaques (0, 1 or 2) were recorded. Also the thickness (IMT) and gray scale (IM-GSM) of the intima-media complex were measured together with plaque echogenicity. Eleven heavy metals and trace elements were analyzed in whole blood, using inductively coupled plasma-sector field mass spectrometry. Nickel levels were related to the number of carotid arteries with plaques in an inverted U-shaped manner after multiple adjustment for gender, waist circumference, body mass index, fasting blood glucose, systolic and diastolic blood pressure, HDL and LDL cholesterol, serum triglycerides, smoking, antihypertensive treatment and statin use (p=0.026). IM-GSM and plaque echogenicity were both inversely related to chromium in a linear fashion, and to aluminum in an inverted U-shaped manner (both p<0.0001 for IM-GSM). The relationships between metals and IMT were modest. Circulating levels of some metals, like nickel, aluminum and chromium, were related to atherosclerotic plaques or the echogenicity of the IM-GSM and overt plaques independently of cardiovascular risk factors, including lipids.

Late-life obesity is associated with smaller global and regional gray matter volumes: a voxel-based morphometric study

OBJECTIVE:

Obesity adversely affects frontal lobe brain structure and function. Here we sought to show that people who are obese versus those who are of normal weight over a 5-year period have differential global and regional brain volumes.

DESIGN:

Using voxel-based morphometry, contrasts were done between those who were recorded as being either obese or of normal weight over two time points in the 5 years prior to the brain scan. In a post-hoc preliminary analysis, we compared scores for obese and normal weight people who completed the trail-making task.

SUBJECTS:

A total of 292 subjects were examined following exclusions (for example, owing to dementia, stroke and cortical infarcts) from the Prospective Investigation of the Vasculature in Uppsala Seniors cohort with a body mass index of normal weight (<25 kg m⁻²) or obese (⩾30 kg m⁻²).

RESULTS:

People who were obese had significantly smaller total brain volumes and specifically, significantly reduced total gray matter (GM) volume (GMV) (with no difference in white matter or cerebrospinal fluid). Initial exploratory whole brain uncorrected analysis revealed that people who were obese had significantly smaller GMV in the bilateral supplementary motor area, bilateral dorsolateral prefrontal cortex (DLPFC), left inferior frontal gyrus and left postcentral gyrus. Secondary more stringent corrected analyses revealed a surviving cluster of GMV difference in the left DLPFC. Finally, post-hoc contrasts of scores on the trail-making task, which is linked to DLPFC function, revealed that obese people were significantly slower than those of normal weight.

CONCLUSION:

These findings suggest that in comparison with normal weight, people who are obese have smaller GMV, particularly in the left DLPFC. Our results may provide evidence for a potential working memory mechanism for the cognitive suppression of appetite that may lower the risk of developing obesity in later life.

Circulating levels of persistent organic pollutants (POPs) and carotid atherosclerosis in the elderly

BACKGROUND AND OBJECTIVE

Increased circulating levels of persistent organic pollutants (POPs) have been associated with myocardial infarction. Because myocardial infarction is an atherosclerotic disease, we investigated, in a cross-sectional study, whether POP levels are related to atherosclerosis.

METHODS

In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (n = 1,016 participants 70 years of age), the prevalence of carotid artery plaques was determined by ultrasound. The number of carotid arteries with plaques (0, 1, or 2) was recorded. Also, the intima-media thickness (IMT) and gray scale median of the intima-media complex (IM-GSM) were measured. Twenty-three POPs, comprising 16 polychlorinated biphenyls (PCBs), 5 pesticides, 1 dioxin, and 1 brominated compound (brominated diphenyl ether congener BDE-47), were analyzed by high-resolution chromatography coupled to high-resolution mass spectrometry.

RESULTS

Seven of the POPs (PCB congeners 153, 156, 157, 170, 180, 206, and 209) were significantly associated with the number of carotid arteries with plaques even after adjusting for multiple risk factors (sex, waist circumference, body mass index, fasting blood glucose, systolic and diastolic blood pressure, high-density lipoprotein and low-density lipoprotein cholesterol, serum triglycerides, smoking, antihypertensive treatment, and statin use; p = 0.002-0.0001). Highly chlorinated PCBs (congeners 194, 206, and 209) were associated with an echolucent IM-GSM (p < 0.0001 after adjustment), whereas associations between POPs and IMT were modest.

CONCLUSIONS

Circulating levels of PCBs were associated with atherosclerotic plaques and echogenicity of the intima-media complex independent of cardiovascular risk factors, including lipids. This suggests that POPs may be a risk factor for myocardial infarction, but associations need to be confirmed in prospective studies.

Gender differences for associations between circulating levels of metals and coronary risk in the elderly

Several studies have pointed out associations between various metals and cardiovascular disease. Since cardiovascular disease prevalence is different between males and females, we investigated whether circulating levels of metals related differently to coronary risk in men and women. In the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study, coronary risk was assessed by the Framingham Risk Score together with circulating blood levels of 11 different trace and heavy metals in 1016 subjects aged 70 years. Circulating levels of cadmium, copper and manganese were significantly higher in women than in men, while mercury, zinc and lead were significantly lower following adjustment for kidney function (measured by glomerular filtration rate, GFR). No significant differences between women and men were seen regarding levels of aluminium, molybdenum, cobalt, chromium and nickel. When all 11 metals were entered as independent variables together with GFR in multiple models in the Framingham Risk Score as the dependent variable, cadmium was the major determinant of the Framingham Risk Score in women (p<0.0001, followed by zinc p=0.03), while copper was the major determinant of the Framingham Risk Score in men (p<0.0001, followed by inverse relations vs. aluminium p=0.01 and nickel p=0.01). There are gender differences in levels of metals and also regarding the association between metals and coronary risk, with cadmium levels being most important for women and copper levels for men in this elderly population.

Prevalence of unrecognized myocardial infarction detected with magnetic resonance imaging and its relationship to cerebral ischemic lesions in both sexes

OBJECTIVES

The purpose of this study was to investigate the prevalence of unrecognized myocardial infarction (UMI) detected with magnetic resonance imaging (MRI) and whether it is related to cerebral ischemic lesions on MRI in an elderly population-based cohort.

BACKGROUND

There is a correlation between stroke and recognized myocardial infarction (RMI) and between stroke and UMI detected with electrocardiography, whereas the prevalence of stroke in subjects with MRI-detected UMI is unknown.

METHODS

Cerebral MRI and cardiac late-enhancement MRI were performed on 394 randomly selected 75-year-old subjects (188 women, 206 men). Images were assessed for cerebral ischemic lesions and myocardial infarction (MI) scars. Medical records were scrutinized. Subjects with MI scars, with or without a hospital diagnosis of MI, were classified as RMI or UMI, respectively.

RESULTS

UMIs were found in 120 subjects (30%) and RMIs in 21 (5%). The prevalence of UMIs (p = 0.004) and RMIs (p = 0.02) was greater in men than in women. Men with RMI displayed an increased prevalence of cortical and lacunar cerebral infarctions, whereas women with UMI more frequently had cortical cerebral infarctions (p = 0.003).

CONCLUSIONS

MI scars are more frequent in men than in women at 75 years of age. The prevalence of RMI is related to that of cerebral infarctions.

Several sources of error in estimation of left ventricular mass with M-mode echocardiography in elderly subjects

INTRODUCTION

M-mode echocardiography estimates of the left ventricular mass (LVM) were greater than magnetic resonance imaging (MRI) estimates. There are substantial differences between the methods both in the means of measuring and the calculation formula. The aim of this study was to investigate whether any difference in estimates of LVM between M-mode echocardiography and MRI is due to the means of measuring or to the calculation formula, using MRI as the gold standard.

MATERIAL AND METHODS

M-mode echocardiography and MRI were performed on 229 randomly selected 70-year-old community-living subjects. LVM was calculated from echocardiography (LVM(echo)) and from MRI (LVM(MRI)) measurements using standard techniques. Additionally LVM was calculated with the echocardiography formula from echo-mimicking measurements made on MR images (LVM(MRI/ASE)).

RESULTS

There were significant differences between all three LVM estimates in women, in men, and in the entire population. Echocardiography estimated LVM to be larger than did MRI, and the LVM(MRI/ASE) estimate was larger than the LVM(MRI). The difference between LVM(MRI) and LVM(MRI/ASE) was larger than the difference between LVM(echo) and LVM(MRI/ASE). There was a low correlation between LVM(echo) and LVM(MRI) (R(2) = 0.46) as well as between LVM(MRI/ASE) and LVM(MRI) (R(2) = 0.65).

CONCLUSION

The means of measuring and the calculation formula both independently add to the error in LVM estimation with M-mode echocardiography. The error of the calculation formula seems to be greater than the error of the means of measuring in a population of community-living elderly men and women.

Circulating levels of persistent organic pollutants associate in divergent ways to fat mass measured by DXA in humans

BACKGROUND

Environmental contaminants have recently been implicated in the pathogenesis of obesity.

OBJECTIVE

To explore relations between persistent organic pollutants (POPs) and fat mass independently of body stature, using a cross-sectional design.

METHODS

In the Prospective Study of the Vasculature in Uppsala Seniors (PIVUS), fat mass was determined in 70-year-old subjects (n=890) by dual-energy X-ray absorptiometry (DXA). The plasma levels of 21 POPs (including 16 PCB congeners, 3 OC pesticides, 1 BDE47, and 1 dioxin) were measured by high resolution chromatography coupled with high resolution mass spectrometry (HRGC/HRMS).

RESULTS

Lipid-standardized plasma concentrations of octachlorodibenzo-p-dioxin (OCDD), the PCBs 74, 99, 105 and 118, and the pesticides HCB, TNK, and DDE were all positively related to fat mass (p=0.03-0.0001). Subjects in the fifth quintile for PCB 105 showed a mean fat mass that was 4.8 kg more than subjects in the first quintile. On the other hand, the PCBs 156, 157, 169, 170, 180, 189, 194, 206, and 209 were negatively related to fat mass (p=0.0001). For PCB 194, subjects in the fifth quintile showed a mean fat mass that was 10.8 kg less than subjects in the first quintile. Following adjustment for smoking, physical activity, education level, height, lean mass, and gender, these results remained significant (p=0.01-0.0001) except for the PCBs 74 and 99. For some PCBs, the associations vs. fat mass were more pronounced in women than in men.

CONCLUSION

Plasma concentrations of some pesticides are positively related to fat mass, while divergent associations are seen for the PCBs. These results implicate a complex role of POPs in obesity.

Number of teeth is related to atherosclerotic plaque in the carotid arteries in an elderly population

BACKGROUND

Periodontal disease has been associated with cardiovascular disorders with an atherosclerotic background, and number of teeth (NT) has been suggested as a possible risk indicator for cardiovascular disease. The objective of this study is to investigate whether NT was related to the intima-media thickness (IMT) and to atherosclerotic plaque in carotid arteries in an elderly population.

METHODS

In a population-based study including 1,016 participants aged 70 years, the NT was self-reported by 947 of the participants. Carotid artery IMT was evaluated by ultrasound. The occurrence of plaque was also measured. Logistic regression was used to analyze the associations between NT and the number of carotid arteries with plaque.

RESULTS

A significant inverse relationship was found between the NT and the number of carotid arteries with plaque after adjustment for age, sex, smoking, body mass index, waist/hip ratio, blood glucose, triglycerides, cholesterol, C-reactive protein, leukocyte count, blood pressure, and Framingham risk score, with odds ratio of 0.89, 95% confidence interval of 0.82 to 0.98, and P = 0.016. The relationship was fairly linear, suggesting a dose-response relationship. When NT was divided into quintiles using the first one as referent, the relationship persisted for all quintiles except for the second one. However, no relationship to IMT was seen.

CONCLUSION

The present study further emphasizes that tooth loss could be an easily obtained risk indicator for atherosclerosis.

Impaired endothelium-dependent vasodilatation is a novel predictor of mortality in intensive care

OBJECTIVE

Endothelial function may be impaired in critical illness. We hypothesized that impaired endothelium-dependent vasodilatation is a predictor of mortality in critically ill patients.

DESIGN

Prospective observational cohort study.

SETTING

Seventeen-bed adult intensive care unit in a tertiary referral university teaching hospital.

PATIENTS

Patients were recruited within 24 hrs of admission to the intensive care unit.

INTERVENTIONS

The SphygmoCor Mx system was used to derive the aortic augmentation index from radial artery pulse pressure waveforms. Endothelium-dependent vasodilatation was calculated as the change in augmentation index in response to an endothelium-dependent vasodilator (salbutamol).

MEASUREMENTS AND MAIN RESULTS

Demographics, severity of illness scores, and physiological parameters were collected. Statistically significant predictors of mortality identified using single regressor analysis were entered into a multiple logistic regression model. Receiver operator characteristic curves were generated. Ninety-four patients completed the study. There were 80 survivors and 14 nonsurvivors. The Simplified Acute Physiology Score II, the Sequential Organ Failure Assessment score, leukocyte count, and endothelium-dependent vasodilatation conferred an increased risk of mortality. In logistic regression analysis, endothelium-dependent vasodilatation was the only predictor of mortality with an adjusted odds ratio of 26.1 (95% confidence interval [CI], 4.3-159.5). An endothelium-dependent vasodilatation value of 0.5% or less predicted intensive care unit mortality with a sensitivity of 79% (CI, 59-88%) and specificity of 98% (CI, 94-99%).

CONCLUSIONS

In vivo bedside assessment of endothelium-dependent vasodilatation is an independent predictor of mortality in the critically ill. We have shown it to be superior to other validated severity of illness scores with high sensitivity and specificity.

Identification of cis- and trans-acting genetic variants explaining up to half the variation in circulating vascular endothelial growth factor levels

RATIONALE

Vascular endothelial growth factor (VEGF) affects angiogenesis, atherosclerosis, and cancer. Although the heritability of circulating VEGF levels is high, little is known about its genetic underpinnings.

OBJECTIVE

Our aim was to identify genetic variants associated with circulating VEGF levels, using an unbiased genome-wide approach, and to explore their functional significance with gene expression and pathway analysis.

METHODS AND RESULTS

We undertook a genome-wide association study of serum VEGF levels in 3527 participants of the Framingham Heart Study, with preplanned replication in 1727 participants from 2 independent samples, the STANISLAS Family Study and the Prospective Investigation of the Vasculature in Uppsala Seniors study. One hundred forty single nucleotide polymorphism (SNPs) reached genome-wide significance (P<5×10(-8)). We found evidence of replication for the most significant associations in both replication datasets. In a conditional genome-wide association study, 4 SNPs mapping to 3 chromosomal regions were independently associated with circulating VEGF levels: rs6921438 and rs4416670 (6p21.1, P=6.11×10(-506) and P=1.47×10(-12)), rs6993770 (8q23.1, P=2.50×10(-16)), and rs10738760 (9p24.2, P=1.96×10(-34)). A genetic score including these 4 SNPs explained 48% of the heritability of serum VEGF levels. Six of the SNPs that reached genome-wide significance in the genome-wide association study were significantly associated with VEGF messenger RNA levels in peripheral blood mononuclear cells. Ingenuity pathway analyses showed found plausible biological links between VEGF and 2 novel genes in these loci (ZFPM2 and VLDLR).

CONCLUSIONS

Genetic variants explaining up to half the heritability of serum VEGF levels were identified. These new insights provide important clues to the pathways regulating circulating VEGF levels.

Detailed analysis of variants in FTO in association with body composition in a cohort of 70-year-olds suggests a weakened effect among elderly

Background

The rs9939609 single-nucleotide polymorphism (SNP) in the fat mass and obesity (FTO) gene has previously been associated with higher BMI levels in children and young adults. In contrast, this association was not found in elderly men. BMI is a measure of overweight in relation to the individuals' height, but offers no insight into the regional body fat composition or distribution.

Objective

To examine whether the FTO gene is associated with overweight and body composition-related phenotypes rather than BMI, we measured waist circumference, total fat mass, trunk fat mass, leg fat mass, visceral and subcutaneous adipose tissue, and daily energy intake in 985 humans (493 women) at the age of 70 years. In total, 733 SNPs located in the FTO gene were genotyped in order to examine whether rs9939609 alone or the other SNPs, or their combinations, are linked to obesity-related measures in elderly humans.

Design

Cross-sectional analysis of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort.

Results

Neither a single SNP, such as rs9939609, nor a SNP combination was significantly linked to overweight, body composition-related measures, or daily energy intake in elderly humans. Of note, these observations hold both among men and women.

Conclusions

Due to the diversity of measurements included in the study, our findings strengthen the view that the effect of FTO on body composition appears to be less profound in later life compared to younger ages and that this is seemingly independent of gender.

Circulating levels of bisphenol A and phthalates are related to carotid atherosclerosis in the elderly

BACKGROUND AND OBJECTIVE

Bisphenol A (BPA) levels have previously been associated with coronary heart disease (CHD). Since CHD is an atherosclerotic disease, we investigated if circulating levels of BPA and phthalate metabolites are related to atherosclerosis in a cross-sectional study.

METHODS

In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (1016 subjects all aged 70), the prevalence of overt plaques and echogenectity (grey scale median, GSM) of carotid artery plaques were recorded by ultrasound in both of the carotid arteries. The thickness (IMT) and echogenicity (IM-GSM) of the intima-media complex were also measured. Bisphenol A (BPA) and 10 phthalate metabolites were analyzed in serum by a API 4000 liquid chromatograph/tandem mass spectrometer.

RESULTS

Mono-methyl phthalate (MMP) was related to carotid plaques in an inverted U-shaped manner. This pattern was significant after adjustment for gender, body mass index, blood glucose, blood pressure, HDL and LDL-cholesterol, serum triglycerides, smoking, antihypertensive treatment and statin use (p=0.004). High levels of BPA, mono-isobutyl phthalate (MiBP) and MMP were associated with an echogenic IM-GSM and plaque GSM, while high levels of mono-2-ethylhexyl phthalate (MEHP) were associated with an echolucent IM-GSM and plaque GSM (p<0.0001 after adjustment).

CONCLUSION

The phthalate metabolite MMP was related to atherosclerotic plaques in an inverted U-shaped manner independently of CV risk factors. Some phthalates and BPA were also related to the echogenicity of the plaques, suggesting a role for plaque-associated chemicals in atherosclerosis.

Aging and vascular endothelial function in humans

Advancing age is the major risk factor for the development of CVD (cardiovascular diseases). This is attributable, in part, to the development of vascular endothelial dysfunction, as indicated by reduced peripheral artery EDD (endothelium-dependent dilation) in response to chemical [typically ACh (acetylcholine)] or mechanical (intravascular shear) stimuli. Reduced bioavailability of the endothelium-synthesized dilating molecule NO (nitric oxide) as a result of oxidative stress is the key mechanism mediating reduced EDD with aging. Vascular oxidative stress increases with age as a consequence of greater production of reactive oxygen species (e.g. superoxide) without a compensatory increase in antioxidant defences. Sources of increased superoxide production include up-regulation of the oxidant enzyme NADPH oxidase, uncoupling of the normally NO-producing enzyme, eNOS (endothelial NO synthase) (due to reduced availability of the cofactor tetrahydrobiopterin) and increased mitochondrial synthesis during oxidative phosphorylation. Increased bioactivity of the potent endothelial-derived constricting factor ET-1 (endothelin-1), reduced endothelial production of/responsiveness to dilatory prostaglandins, the development of vascular inflammation, formation of AGEs (advanced glycation end-products), an increased rate of endothelial apoptosis and reduced expression of oestrogen receptor α (in postmenopausal females) also probably contribute to impaired EDD with aging. Several lifestyle and biological factors modulate vascular endothelial function with aging, including regular aerobic exercise, dietary factors (e.g. processed compared with non-processed foods), body weight/fatness, vitamin D status, menopause/oestrogen deficiency and a number of conventional and non-conventional risk factors for CVD. Given the number of older adults now and in the future, more information is needed on effective strategies for the prevention and treatment of vascular endothelial aging.

Endothelial function in resistance and conduit arteries and 5-year risk of cardiovascular disease

BACKGROUND

Impaired endothelial function has been implicated as a cause of cardiovascular disease. Little is known of the relations of measures of endothelial function in resistance and conduit arteries to incident cardiovascular disease in the general population, and available techniques have not been compared.

METHODS AND RESULTS

In 1016 participants (70 years of age) of the population-based Prospective Study of the Vasculature in Uppsala Seniors (PIVUS) study (52% women), we measured endothelium-dependent vasodilation using the invasive forearm technique with acetylcholine given in the brachial artery, the brachial artery ultrasound technique with measurement of flow-mediated dilatation, and the pulse-wave analysis-based method with β-2-agonist terbutaline provocation. During 5 years of follow-up, 101 participants experienced a composite end point of myocardial infarction, stroke, or death, excluding the 85 persons with a history of myocardial infarction or stroke at baseline. In logistic regression models adjusted for several established and novel cardiovascular disease risk factors and medications, endothelium-dependent vasodilation by the invasive forearm technique with acetylcholine was associated with risk of the end point (odds ratio, 0.72 per SD; 95% confidence interval, 0.56 to 0.93; P=0.01). Endothelial function by the other 2 methods was not related to risk of the end point. Addition of endothelium-dependent vasodilation to the Framingham risk score improved discrimination of risk of the end point.

CONCLUSIONS

Endothelium-dependent vasodilation in resistance arteries, but not in the brachial conduit artery (flow-mediated dilatation), was associated with 5-year risk of a composite end point of death, myocardial infarction, or stroke independently of major cardiovascular disease risk factors. This vascular measurement improved risk discrimination when added to an established risk score in an elderly population.

Relation of brachial and digital measures of vascular function in the community: the Framingham heart study

Impaired vascular function contributes to the development of clinical cardiovascular disease. The relation between vasodilator function assessed noninvasively in the brachial and digital arteries remains incompletely defined. In the Framingham Offspring, Third Generation and Omni Cohorts, we measured flow-mediated dilation (FMD; n = 7031; age 48 ± 13 years; age range, 19 to 88 years; 54% women) and peripheral arterial tonometry (PAT) ratio (n = 4352; 55 ± 16 years; age range, 19 to 90 years; 51% women). Abnormal vascular function for each measure was defined by the sex-specific fifth percentile in a reference group free of conventional cardiovascular risk factors. The prevalence of abnormal FMD but not abnormal PAT ratio was higher with advancing age. In multivariable models, higher body mass index was associated with a higher prevalence of both abnormal FMD and PAT ratio. Additional correlates of abnormal FMD included increasing age and higher systolic blood pressure. In contrast, correlates of abnormal PAT ratio included lower systolic blood pressure, increasing total/high-density lipoprotein cholesterol ratio, diabetes, smoking, and lipid-lowering medication. Whereas women had higher FMD and PAT ratios compared with men, using sex-specific reference values, women had a higher prevalence of abnormal brachial and digital vascular function. In participants who had concurrent testing (n = 1843), PAT ratio was not significantly associated with FMD in multivariable models. In this large, community-based cohort, brachial and digital measures of vascular function had differing relations with cardiovascular risk factors and were nearly uncorrelated with each other. These results suggest that FMD and PAT provide distinct information regarding vascular function in conduit versus smaller digital vessels.

Vasoreactivity is rapidly improved in obese subjects after gastric bypass surgery

BACKGROUND

Obesity is associated with increased risk of cardiovascular disease. We investigated vasoreactivity in conduit and resistance arteries in morbidly obese subjects, and the effect of weight loss after gastric bypass surgery.

METHODS

A total of 19 obese subjects (body mass index (BMI): 43.8+/-3.1 kg m(-2), 75% female, mean age 41 years) were investigated before surgery and after 1 and 12 months of surgery. Nineteen non-obese controls matched for age and gender were examined. Vasoreactivity was evaluated by ultrasound to measure flow-mediated dilation (FMD, evaluating a conduit vessel) and pulse-wave analysis with terbutaline provocation (change in reflectance index (RI), evaluating resistance vessels).

RESULTS

Before surgery, the obese showed a low change in RI (18+/-12 vs 37+/-15% in controls, P=0.0001), but not significantly regarding FMD (7.9+/-6.4 vs 8.9+/-5.4% in controls). Surgery resulted in a weight loss of 9% at 1 month and 30% at 1 year. Change in RI markedly improved to 36+/-12% at 1 month (P=0.0001 vs baseline) and further to 44+/-11% at 1 year (P=0.014 vs 1 month). FMD did not change significantly. Heart rate and brachial artery diameter were reduced, with no significant change in blood pressure. The improvement in resistance vessel vasodilation, estimated as change in RI, was not correlated to changes in weight or measures of glucose and lipid metabolism.

CONCLUSIONS

Obese patients showed impaired vasoreactivity in resistance arteries that was normalized already 1 month after gastric bypass surgery. The basis for this remarkable outcome, not significantly related to changes in body weight and metabolic variables, remains to be clarified.

Circulating fibroblast growth factor-23 is associated with fat mass and dyslipidemia in two independent cohorts of elderly individuals

OBJECTIVE

Disturbances in mineral metabolism define an increased cardiovascular risk in patients with chronic kidney disease. Fibroblast growth factor-23 (FGF23) is a circulating regulator of phosphate and vitamin D metabolism and has recently been implicated as a putative pathogenic factor in cardiovascular disease. Because other members of the FGF family play a role in lipid and glucose metabolism, we hypothesized that FGF23 would associate with metabolic factors that predispose to an increased cardiovascular risk. The goal of this study was to investigate the relationship between FGF23 and metabolic cardiovascular risk factors in the community.

METHODS AND RESULTS

Relationships between serum FGF23 and body mass index (BMI), waist circumference, waist-to-hip ratio, serum lipids, and fat mass were examined in 2 community-based, cross-sectional cohorts of elderly whites (Osteoporotic Fractures in Men Study: 964 men aged 75±3.2; Prospective Investigation of the Vasculature in Uppsala Seniors study: 946 men and women aged 70). In both cohorts, FGF23 associated negatively with high-density lipoprotein and apolipoprotein A1 (7% to 21% decrease per 1-SD increase in log FGF23; P<0.01) and positively with triglycerides (11% to 14% per 1-SD increase in log FGF23; P<0.01). A 1-SD increase in log FGF23 was associated with a 7% to 20% increase in BMI, waist circumference, and waist-to-hip ratio and a 7% to 18% increase in trunk and total body fat mass (P<0.01) as determined by whole-body dual x-ray absorptiometry. FGF23 levels were higher in subjects with the metabolic syndrome compared with those without (46.4 versus 41.2 pg/mL; P<0.05) and associated with an increased risk of having the metabolic syndrome (OR per 1-SD increase in log FGF23, 1.21; 95% CI, 1.04 to 1.40; P<0.05).

CONCLUSIONS

We report for the first time on associations between circulating FGF23, fat mass, and adverse lipid metabolism resembling the metabolic syndrome, potentially representing a novel pathway(s) linking high FGF23 to an increased cardiovascular risk.

Circulating soluble CTLA-4 is related to inflammatory markers in the 70 year old population

OBJECTIVE

Measurement of inflammatory mediators is an important tool to assess inflammation. We have, therefore, conducted a survey within the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study to evaluate the inter-relationship between soluble CTLA-4 (sCTLA-4) and other inflammatory markers.

MATERIALS AND METHODS

This is a population-based study, designed to quantify the circulating serum levels of sCTLA-4 and other inflammatory markers such as CRP and pro-inflammatory cytokines and chemokines by in-house ELISA, Immuno-turbidimetry and multiplex ELISA, respectively. A total of 1016 Swedish Caucasians aged 70 years old were recruited. The statistical analysis was performed by ANOVA.

RESULTS

The levels of sCTLA-4 were directly related to the levels of pro-inflammatory cytokines such as IL-6, IL-1alpha, IL-1beta, TNF-alpha, IFN-gamma and chemokines such as IL-8. However, the levels of sCTLA-4 were inversely related to the levels of MCP-1. Also, we could not demonstrate any relation between the levels of sCTLA-4 and CRP or soluble adhesion molecules.

CONCLUSIONS

Circulating sCTLA-4 could be used as a biomarker for inflammation, potentially reflecting dysregulated T lymphocytes.

Associations of circulating adiponectin with measures of vascular function and morphology

CONTEXT

Some previous studies have reported an association between circulating adiponectin and selected measures of vascular function and morphology, but most of these studies have been performed in small samples of patients with preexisting disease.

OBJECTIVE

We aimed to evaluate associations between circulating adiponectin and comprehensive measures of vascular function and morphology in a large sample of individuals from the community.

DESIGN, SETTINGS, AND PARTICIPANTS

We conducted a cross-sectional investigation of 981 70-yr-old participants (50% women) of the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS).

MAIN OUTCOME MEASURES

Measures of outcome included vascular function [common carotid artery (CCA) distensibility, flow-mediated dilation, endothelium-dependent and endothelium-independent vasodilation using invasive methods] and vascular morphology [intima-media (IM) thickness, plaque presence, gray scale median (GSM) in the IM and plaques].

RESULTS

In age- and sex-adjusted models, adiponectin was positively associated with IM-GSM, plaque GSM, CCA distensibility, endothelium-dependent and endothelium-independent vasodilation. In multivariable models (with additional adjustment for body mass index; systolic blood pressure; antihypertensive, antidiabetic, and lipid-lowering medication; fasting blood glucose; total cholesterol; high-density lipoprotein cholesterol; creatinine; and smoking), adiponectin remained positively associated with IM-GSM [beta = 2.06; 95% confidence interval (CI), 0.54, 3.58], plaque GSM (beta = 3.11; 95% CI, 0.36, 5.86), and CCA distensibility (beta = 0.04; 95% CI, 0.00, 0.07).

CONCLUSIONS

Serum levels of adiponectin were positively associated with IM-GSM and plaque GSM (indicating lower fat content in the IM and plaques) and CCA distensibility (indicating higher wall elasticity), independent of potential confounders. Our results imply that adiponectin is associated with less arterial pathology.