Digitalised ECG measure of p-wave duration predicts incident heart failure

Funding Acknowledgements

Type of funding sources: Public hospital(s). Main funding source(s): Uppsala University Hospital

Background and purpose

Early identification of patients at risk of congestive heart failure (HF) may potentially alter their poor prognosis. The aim was therefore to test whether the P-wave and PR-interval, simple non-invasive ECG measures reflecting systolic and diastolic atrial function, could predict incident HF.

Methods

The PIVUS (Prospective Investigation of the Vasculature in Seniors) study including all individuals aged 70 years (1016 individuals, 50% women) was used to identify predictors of HF. Subjects with prevalent HF, QRS duration ≥ 130 msec or atrial arrhythmias on baseline ECG were excluded. Cox proportional hazard analysis was used to relate P-wave duration (Pdur), amplitude (Pamp) and PR interval in lead V1, to incident HF. Adjustment was performed for gender, RR-interval, beta-blocking agents, systolic blood pressure, body mass index and smoking.

Results

A total of 107 of 836 (12,8%) subjects at risk, developed HF during 15 years follow-up. The multivariate analysis, showed a strong U-shaped correlation between Pdur and incident HF (p=0.0001), which was significant for a Pdur< 60 msec [HR 2.75 (95% CI 1.87-4.06) at Pdur 40 msec]. There was no significant relationship between incident HF and the PR-interval, or the Pamp. A Pdur<60 msec improved discrimination by 3.7% when added to the confounders described above (p=0.048).

Conclusions

A short P-duration, a simple and easy ECG measure, may potentially be a useful predictor of developing HF, enabling early detection and treatment of HF.

CD8+ T cells in the central nervous system of mice with herpes simplex infection are highly activated and express high levels of CCR5 and CXCR3

Herpes simplex virus type 2 (HSV-2) is a neurotropic virus that can cause meningitis, an inflammation of the meninges in the central nervous system. T cells are key players in viral clearance, and these cells migrate from peripheral blood into the central nervous system upon infection. Several factors contribute to T cell migration, including the expression of chemokines in the inflamed tissue that attract T cells through their expression of chemokine receptors. Here we investigated CD8⁺ T cell profile in the spinal cord in a mouse model of herpes simplex virus type 2 neuroinflammation. Mice were infected with HSV-2 and sacrificed when showing signs of neuroinflammation. Cells and/or tissue from spinal cord, spleen, and blood were analyzed for expression of activation markers, chemokine receptors, and chemokines. High numbers of CD8⁺ T cells were present in the spinal cord following genital HSV-2-infection. CD8⁺ T cells were highly activated and HSV-2 glycoprotein B -specific effector cells, some of which showed signs of recent degranulation. They also expressed high levels of many chemokine receptors, in particular CCR2, CCR4, CCR5, and CXCR3. Investigating corresponding receptor ligands in spinal cord tissue revealed markedly increased expression of the cognate ligands CCL2, CCL5, CCL8, CCL12, and CXCL10. This study shows that during herpesvirus neuroinflammation anti-viral CD8⁺ T cells accumulate in the CNS. CD8⁺ T cells in the CNS also express chemotactic receptors cognate to the chemotactic gradients in the spinal cord. This indicates that anti-viral CD8⁺ T cells may migrate to infected areas in the spinal cord during herpesvirus neuroinflammation in response to chemotactic gradients.

Plasma perfluoroalkyls are associated with decreased levels of proteomic inflammatory markers in a cross-sectional study of an elderly population

Perfluoroalkyl substances (PFAS) have been linked to immunotoxicity in experimental studies. Although PFAS exposure is associated with altered immune response in epidemiological studies of children, it is less known whether this is observed also in elderly adults. Eight PFAS and 86 proteins were measured in plasma from 965 elderly individuals from Sweden (all aged 70, 50% women). PFAS were measured using isotope-dilution ultra-pressure liquid chromatography coupled to tandem mass spectrometry. Proteins were measured using a multiplex proximity extension assay (PEA) and covered among others inflammatory marker proteins such as monocyte chemoattractant proteins, tumor necrosis factors, and interleukins. We examined cross-sectional associations using multivariable linear regression at two levels of adjustment. We observed significant decreases in levels of 24 proteins in relation to a ln-unit increase in PFAS concentrations following adjustment for sex, sample storage time in freezer, and correction for multiple testing. Associations of PFAS and hepatocyte growth factor (HGF) and macrophage colony-stimulating factor 1 (CSF-1) remained significant (p-value <0.05) following full covariate adjustment for smoking, exercise habits, education, energy, and alcohol intake, body mass index (BMI), glomular filtration rate (GFR) as well as corticoid- and COX-inhibitor treatment. CSF-1 was inversely associated with perfluorohexane sulfonic acid (PFHxS) β: -0.08: 95% confidence interval (CI); -0.13, -0.02), perfluorooctanoic acid (PFOA) β: -0.04: 95% CI; -0.07, -0.006, perfluorononanoic acid (PFNA) β: -0.04: 95% CI; -0.08, -0.003, perfluorodecanoic acid (PFDA) β: -0.03: 95% CI; -0.06, -0.003, and perfluoroundecanoic acid (PFUnDA) β: -0.05: 95% CI; -0.08, -0.02. The magnitude and direction of PFAS vs protein relationships were similar also for HGF. Our findings implicate PFAS exposure with decreased levels of proteomic markers of inflammation in elderly humans.

Cerebrospinal fluid biomarkers of brain injury, inflammation and synaptic autoimmunity predict long-term neurocognitive outcome in herpes simplex encephalitis

OBJECTIVES

The aim was to investigate the correlation between biomarkers of brain injury and long-term neurocognitive outcome, and the interplay with intrathecal inflammation and neuronal autoimmunity, in patients with herpes simplex encephalitis (HSE).

METHODS

A total of 53 adult/adolescent HSE patients were included from a prospective cohort in a randomized placebo-controlled trial investigating the effect of a 3-month follow-up treatment with valaciclovir. Study subjects underwent repeated serum/cerebrospinal fluid (CSF) sampling and brain magnetic resonance imaging in the first 3 months along with cognitive assessment using the Mattis Dementia Rating Scale (MDRS) at 24 months. CSF samples were analysed for biomarkers of brain injury, inflammation and synaptic autoimmunity. The predefined primary analysis was the correlation between peak CSF neurofilament protein (NFL), a biomarker of neuronal damage, and MDRS at 24 months.

RESULTS

Impaired cognitive performance significantly correlated with NFL levels (rho = -0.36, p = 0.020). Development of IgG anti-N-methyl-D-aspartate receptor (NDMAR) antibodies was associated with a broad and prolonged proinflammatory CSF response. In a linear regression model, lower MDRS at 24 months was associated with previous development of IgG anti-N-methyl-D-aspartate receptor (NMDAR) (beta = -0.6249, p = 0.024) and age (z-score beta = -0.2784, p = 0.024), but not CSF NFL, which however significantly correlated with subsequent NMDAR autoimmunization (p = 0.006).

DISCUSSION

Our findings show that NFL levels are predictive of long-term neurocognitive outcome in HSE, and suggest a causative chain of events where brain tissue damage increases the risk of NMDAR autoimmunisation and subsequent prolongation of CSF inflammation. The data provides guidance for a future intervention study of immunosuppressive therapy administered in the recovery phase of HSE.

P2735Ventricular function in a large cohort of healthy, term newborns assessed by tissue doppler imaging and speckle tracking echocardiography; establishment of normal values and z-scores

Background

There is a paucity of published data presenting reference values for ventricular function in newborns.

Purpose

This study was conducted to establish echocardiographic normal data and z-scores for ventricular functional parameters in newborns assessed by Tissue Doppler Imaging (TDI) and Speckle Tracking Echocardiography (STE).

Methods

We included healthy, term newborns from a prospective, population-based study of newborns, who had a comprehensive, systematic echocardiographic (TTE) examination performed within 14 days of birth. Only newborns without any signs of structural or functional cardiac abnormalities were included. Measurements were obtained according to guidelines. Body surface area (BSA) was calculated using the Haycock formula. Z-score models according to birthweight and BSA at time of TTE were developed for TDI and STE parameters.

Results

Four hundred newborns (53% male) with gestational age of (median (IQR)) 40.3 (39.4, 41.1) weeks were included. Age, weight, and BSA at TTE were (mean±SD) 11±3 days, 3.7±0.5 kg, and 0.23±0.02m2, resp. Ejection fraction was 67±4%. TDI and STE measurements of ventricular function are presented as mean±SD (Table). Global longitudinal strain was calculated as the average of all left ventricular segmental strain values from apical 4-, 2-, and 3-chamber views. Results for selected parameters according to BSA are illustrated (Figure).

TDI and STE of ventricular function Parameter View and modality Value Unit Mitral annulus septal wall e' Apical 4-chamber Tissue Doppler 5.7±0.8 cm/s Mitral annulus septal wall a' Apical 4-chamber Tissue Doppler 5.9±1.0 cm/s Mitral annulus septal wall s' Apical 4-chamber Tissue Doppler 4.6±0.6 cm/s Mitral annulus lateral wall e' Apical 4-chamber Tissue Doppler 6.9±1.0 cm/s Mitral annulus lateral wall a' Apical 4-chamber Tissue Doppler 6.0±1.1 cm/s Mitral annulus lateral wall s' Apical 4-chamber Tissue Doppler 4.8±0.6 cm/s Left ventricular longitudinal strain, 4-chamber Apical 4-chamber 2D 19±2 % Left ventricular longitudinal strain, 2-chamber Apical 2-chamber 2D 20±2 % Left ventricular longitudinal strain, 3-chamber Apical 3-chamber 2D 19±2 % Left ventricular global strain 19±2 % Right ventricular longitudinal strain, free wall Apical 4-chamber 2D 23±4 %

Percentile charts

Conclusion

Normal data for TDI and STE assessment of ventricular function in 400 healthy, term newborns ispresented. An online z-score calculator will be available. Normal data is necessary for the evaluation of pathological changes, and these results contribute substantially to a field where available data is limited.

Acknowledgement/Funding

Danish Heart Association, Danish Children's Heart Foundation, Candy's Found., Toyota Found., Herlev-Gentofte Hospital Research Found., Gangsted Found.

Chemokines and matrix metalloproteinases in cerebrospinal fluid of patients with central nervous system complications caused by varicella-zoster virus

BACKGROUND

Varicella-zoster virus (VZV) is a common viral agent causing central nervous system (CNS) infections including encephalitis, meningitis, and Ramsay Hunt syndrome. Neurological complications occur frequently despite antiviral treatment. Matrix metalloproteinases (MMPs) and cytokines are involved in the neuroinflammatory response during CNS infection. Their role in VZV CNS infections and how they differ between different CNS entities caused by VZV are poorly investigated.

METHODS

We analyzed the levels of 30 chemokines and 9 MMPs in cerebrospinal fluid (CSF) and serum from 66 patients with VZV CNS infections diagnosed by detection of VZV DNA in CSF and concomitant neurological symptoms and compared with a control group (n = 24).

RESULTS

Levels of CCL19, CXCL8, CXCL9, and CXCL10 were significantly increased and surpassing the levels in serum when analyzing all patients with VZV CNS infections whereas CXCL11 was only increased in CSF of patients with VZV meningitis. MMP-2-levels were highly elevated in CSF of all 66 VZV patients. The patients with encephalitis had the most significantly increased levels of MMPs in CSF, and MMP-3, MMP-8, and MMP-12 were exclusively increased in this group, whereas MMP-9 in CSF was increased in the patients with VZV meningitis.

CONCLUSIONS

We show that both chemokines and MMPs are elevated in the CSF of patients with VZV CNS infections. Encephalitis and meningitis patients differed with respect to other chemokines (CXCL11) and MMPs (MMP-3, MMP-8, MMP-9, and MMP-12), indicating that different location of the virus gives rise to qualitative differences in the ensuing inflammatory response. In addition, the pronounced increase of MMPs in CSF of the patients with encephalitis suggests an association to the severity of this manifestation, compared to VZV meningitis and Ramsay Hunt syndrome. The role of MMPs in association to chemokines should be further investigated to evaluate their significance in the neuropathogenesis of VZV CNS infections and as a potential target for new treatment alternatives.

The Noncoding RNA nc886 Regulates PKR Signaling and Cytokine Production in Human Cells

Protein kinase RNA-activated (PKR) is a cytoplasmic receptor for dsRNA, and as such is involved in detection of viral infection. On binding dsRNA, PKR dimerizes, autophosphorylates, and then phosphorylates its substrate, eukaryotic translation initiation factor 2 subunit α (eIF2α), causing inhibition of mRNA translation and shutdown of viral protein production. However, active PKR has also been found to be involved in the NF-κB signaling pathway by inducing phosphorylation of IκBα. PKR is regulated by the noncoding RNA nc886, which has altered expression in cancer. We have found that expression of nc886 is highly upregulated during activation of human CD4⁺ T cells. As has been described in other cell types, nc886 bound to PKR in human T cell lysates, preventing PKR phosphorylation by polyinosinic:polycytidylic acid or HIV trans-activation response element RNA in lysates of T cell lines or primary human CD4⁺ T cells. Using clonal human T cell lines, we found that nc886 expression was strictly required for IFN-γ and IL-2 expression and secretion after T cell activation but did not affect proliferation or activation-induced cell death. In stimulated human PBMCs, nc886 expression strongly correlated with IFN-γ expression. Although nc886 inhibited PKR activation by dsRNA, it was required for PKR phosphorylation during T cell stimulation, with subsequent NF-κB signaling and CREB phosphorylation. nc886 also regulated PKR phosphorylation during human monocyte-derived macrophage activation. We have therefore identified nc886 as a noncoding RNA marker of T cell activation and regulator of PKR-dependent signaling.

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.

Extracts of Equisetum giganteum L and Copaifera reticulate Ducke show strong antiviral activity against the sexually transmitted pathogen herpes simplex virus type 2

ETHNOPHARMACOLOGICAL RELEVANCE

Equisetum giganteum L and Copaifera reticulate Ducke have been traditionally used by women of the Tacana tribe in the Bolivian Amazonas for genital hygiene and for treatment of genital infection/inflammation.

AIM OF THE STUDY

To assess the ability of extracts from Equisetum giganteum L and Copaifera reticulate Ducke to block genital viral infection by herpes simplex virus type 2.

MATERIALS AND METHODS

Equisetum giganteum L and Copaifera reticulate Ducke were collected from the Amazon region of La Paz, Bolivia. Extracts were prepared and screened for anti-viral activity against herpes simplex virus type 2 (HSV-2) using both in vitro and in in vivo models of infection.

RESULTS

Equisetum giganteum L and Copaifera reticulate Ducke efficiently blocked HSV-2 infection of cell cultures without major cell cytotoxic effects. Extracts of Equisetum giganteum L and Copaifera reticulate Ducke could prevent HSV-2 disease development when administered together with virus in a mouse model of genital HSV-2 infection. In vitro analyses revealed that both plant extracts exerted their anti-HSV-2 effects by interfering with viral cell attachment and entry, but could not block viral replication post entry.

CONCLUSIONS

These studies show that extracts of Equisetum giganteum L and Copaifera reticulate Ducke have potent antiviral activities against HSV-2 comparable to those two previously identified plants, Croton lechleri Müll. Arg. and Uncaria tomentosa (Willd. ex Schult.) DC. These studies confirm that plants used by the Tacana tribe could be explored further for the development of novel topical antiviral microbicides.

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.

Maturation-dependent expression of AIM2 in human B-cells

Intracellular DNA- and RNA-sensing receptors, such as the IFN-inducible protein Absent in Melanoma 2 (AIM2), serve as host sensors against a wide range of infections. Immune sensing and inflammasome activation by AIM2 has been implicated in innate antiviral recognition in many experimental systems using cell-lines and animal models. However, little is known about the expression and function of AIM2 in freshly isolated human cells. In this study we investigated the expression of AIM2 in different cell types derived from human cord and adult peripheral blood, in steady state and following in vitro-activation. Adult but not cord blood B-cells expressed high levels of AIM2 mRNA at steady state. In adults, AIM2 was primarily expressed in mature memory CD27⁺ B-cells. Both adult and cord blood derived B-cells could induce their transcription of AIM2 mRNA in response to type II IFN but not type I IFN or the AIM2 ligand poly dA:dT. Upon B-cell receptor stimulation, B-cells from adult blood expressed reduced levels of AIM2 mRNA. In addition, we show that adult B-cells were able to release IL-1β upon stimulation with synthetic DNA. We conclude that functional AIM2 is preferentially expressed in adult human CD27⁺ B-cells, but is absent in cord blood mononuclear cells.

Effects of a common insecticide on wetland communities with varying quality of leaf litter inputs

Chemical contamination of aquatic systems often co-occurs with dramatic changes in surrounding terrestrial vegetation. Plant leaf litter serves as a crucial resource input to many freshwater systems, and changes in litter species composition can alter the attributes of freshwater communities. However, little is known how variation in litter inputs interacts with chemical contaminants. We investigated the ecological effects resulting from changes in tree leaf litter inputs to freshwater communities, and how those changes might interact with the timing of insecticide contamination. Using the common insecticide malathion, we hypothesized that inputs of nutrient-rich and labile leaf litter (e.g., elm [Ulmus spp.] or maple [Acer spp.]) would reduce the negative effects of insecticides on wetland communities relative to inputs of recalcitrant litter (e.g., oak [Quercus spp.]). We exposed artificial wetland communities to a factorial combination of three litter species treatments (elm, maple, and oak) and four insecticide treatments (no insecticide, small weekly doses of 10 μg L^-1, and either early or late large doses of 50 μg L^-1). Communities consisted of microbes, algae, snails, amphipods, zooplankton, and two species of tadpoles. After two months, we found that maple and elm litter generally induced greater primary and secondary production. Insecticides induced a reduction in the abundance of amphipods and some zooplankton species, and increased phytoplankton. In addition, we found interactive effects of litter species and insecticide treatments on amphibian responses, although specific effects depended on application regime. Specifically, with the addition of insecticide, elm and maple litter induced a reduction in gray tree frog survival, oak and elm litter delayed tree frog metamorphosis, and oak and maple litter reduced green frog tadpole mass. Our results suggest that attention to local forest composition, as well as the timing of pesticide application might help ameliorate the harmful effects of pesticides observed in freshwater systems.

CXCL11 production in cerebrospinal fluid distinguishes herpes simplex meningitis from herpes simplex encephalitis

The closely related herpes simplex viruses 1 and 2 can cause inflammations of the central nervous system (CNS), where type 1 most often manifest as encephalitis (HSE), and type 2 as meningitis (HSM). HSE is associated with severe neurological complications, while HSM is benign in adults. We proposed that the chemokine and cytokine production in cerebrospinal fluid (CSF) and serum could indicate why two closely related viruses exhibit different severity of their accompanied CNS inflammation. Secretion patterns of 30 chemokines and 10 cytokines in CSF of adult patients with acute HSE and HSM in the initial stage of disease were analyzed and compared to control subjects without viral central nervous system infections and to levels in serum. Most measured chemokines and cytokines increased in CSF of HSE and HSM patients. Overall, the CSF chemokines levels were higher in CSF of HSM patients compared to HSE patients. However, only five chemokines reached levels in the CSF that exceeded those in serum facilitating a positive CSF-serum chemokine gradient. Of these, CXCL8, CXCL9 and CXCL10 were present at high levels both in HSE and HSM whereas CXCL11 and CCL8 were present in HSM alone. Several chemokines were also elevated in serum of HSE patients but only one in HSM patients. No chemokine in- or efflux between CSF and serum was indicated as the levels of chemokines in CSF and serum did not correlate. We show that HSM is associated with a stronger and more diverse inflammatory response in the CNS compared to HSE in the initial stage of disease. The chemokine patterns were distinguished by the exclusive local CNS production of CXCL11 and CCL8 in HSM. Inflammation in HSM appear to be restricted to the CNS whereas HSE also was associated with systemic inflammation.

Poor Response to Periodontal Treatment May Predict Future Cardiovascular Disease

Periodontal disease has been associated with cardiovascular disease (CVD), but whether the response to the treatment of periodontal disease affects this association has not been investigated in any large prospective study. Periodontal data obtained at baseline and 1 y after treatment were available in 5,297 individuals with remaining teeth who were treated at a specialized clinic for periodontal disease. Poor response to treatment was defined as having >10% sites with probing pocket depth >4 mm deep and bleeding on probing at ≥20% of the sites 1 y after active treatment. Fatal/nonfatal incidence rate of CVD (composite end point of myocardial infarction, stroke, and heart failure) was obtained from the Swedish cause-of-death and hospital discharge registers. Poisson regression analysis was performed to analyze future risk of CVD. During a median follow-up of 16.8 y (89,719 person-years at risk), those individuals who did not respond well to treatment (13.8% of the sample) had an increased incidence of CVD ( n = 870) when compared with responders (23.6 vs. 15.3%, P < 0.001). When adjusting for calendar time, age, sex, educational level, smoking, and baseline values for bleeding on probing, probing pocket depth >4 mm, and number of teeth, the incidence rate ratio for CVD among poor responders was 1.28 (95% CI, 1.07 to 1.53; P = 0.007) as opposed to good responders. The incidence rate ratio among poor responders increased to 1.39 (95% CI, 1.13 to 1.73; P = 0.002) for those with the most remaining teeth. Individuals who did not respond well to periodontal treatment had an increased risk for future CVD, indicating that successful periodontal treatment might influence progression of subclinical CVD.

A genetic risk score is significantly associated with statin therapy response in the elderly population

The ability of statins to strongly reduce low-density lipoprotein cholesterol (LDL-C) varies interindividually and is partially influenced by genetic variants. Based on a comprehensive analysis of 23 single nucleotide polymorphisms (SNPs) known to be associated with pharmacokinetics and dynamics of statins, we developed a genetic risk score to study its impact on the therapy outcome in elderly individuals under at least 5 years statin therapy. The study was performed in a population-based cohort of 1016 elderly individuals, which comprised 168 statin users investigated at age 75 and 80. Using random forest models, the major variants influencing LDL-C levels were summarized in a weighted GRS (wGRS). The wGRS was tested with lipid and glucose outcomes and validated in an independent population-based cohort including 221 statin users. Four SNPs within the APOE cluster (rs7412, rs4420638), ABCC2 (rs2002042) and CELSR/SORT1/PSRC1 (rs646776), displayed a major impact on statin efficacy. The wGRS was significantly associated with lower LDL-C at age 75 and 80. This association was replicated displaying similar results. GRS analysis is a powerful tool to evaluate the additive effects of genetic variants on statin response and to estimate the magnitude of LDL-C reduction to a considerable extent in the older population.

Lipophilic index, kidney function, and kidney function decline

BACKGROUND AND AIMS

Unhealthy dietary fats are associated with faster kidney function decline. The cell membrane composition of phospholipid fatty acids (FAs) is a determinant of membrane fluidity and rheological properties. These properties, which have been linked to kidney damage, are thought to be reflected by the lipophilic index (LI). We prospectively investigated the associations of LI with kidney function and its decline.

METHODS AND RESULTS

Observational study from the Prospective Investigation of Vasculature in Uppsala Seniors including 975 men and women with plasma phospholipid FAs composition and cystatin-C estimate glomerular filtration rate (eGFR). Of these, 780 attended re-examination after 5 years, and eGFR changes were assessed. Participants with a 5-year eGFR reduction ≥30% were considered chronic kidney disease (CKD) progressors (n = 198). LI was calculated as the sum of the products of the FA proportions with the respective FAs melting points. Blood rheology/viscosity measurements were performed in a random subsample of 559 subjects at baseline. Increased LI showed a statistically significant but overall weak association with blood, plasma viscosity (both Spearman rho = 0.16, p < 0.01), and erythrocyte deformability (rho = -0.09, p < 0.05). In cross-sectional analyses, LI associated with lower eGFR (regression coefficient 3.00 ml/min/1.73 m² 1-standard deviation (SD) increment in LI, 95% CI: -4.31, -1.69, p < 0.001). In longitudinal analyses, LI associated with a faster eGFR decline (-2.13 [95% CI -3.58, -0.69] ml/min/1.73 m², p < 0.01) and with 32% increased odds of CKD progression (adjusted OR 1.32 [95%, CI 1.05-1.65]).

CONCLUSIONS

A high LI was associated with lower kidney function, kidney function decline, and CKD progression.

Altered heart proteome in fructose-fed Fisher 344 rats exposed to bisphenol A

Bisphenol A (BPA), is an artificial estrogen initially produced for medical purposes but is today widely used in polycarbonate plastics and epoxy resins. Exposure-related reproductive disorders have been found, but recently it has also been suggested that BPA may be involved in obesity, diabetes, myocardial hypertrophy and myocardial infarction in humans. To mimic a modern lifestyle, female rats were fed with fructose or fructose plus BPA (0.25mg/L drinking water). The myocardial left ventricle proteome of water controls, fructose-fed and fructose-fed plus BPA supplemented rats was explored. The proteome was investigated using nano-liquid chromatography tandem mass spectrometry and two-dimensional gel electrophoresis followed by matrix assisted laser desorption/ionization mass spectrometry identification. In total, 41 proteins were significantly altered by BPA exposure compared to water or fructose controls. Principal component analysis and cellular process enrichment analysis of altered proteins suggested increased fatty acid transport and oxidation, increased ROS generation and altered structural integrity of the myocardial left ventricle in the fructose-fed BPA-exposed rats, indicating unfavorable effects on the myocardium. In conclusion, BPA exposure in the rats induces major alterations in the myocardial proteome.

Association between levels of pentraxin 3 and incidence of chronic kidney disease in the elderly

OBJECTIVE

Higher levels of the novel inflammatory marker pentraxin 3 (PTX3) predict cardiovascular mortality in patients with chronic kidney disease (CKD). Yet, whether PTX3 predicts worsening of kidney function has been less well studied. We therefore investigated the associations between PTX3 levels, kidney disease measures and CKD incidence.

METHODS

Cross-sectional associations between serum PTX3 levels, urinary albumin/creatinine ratio (ACR) and cystatin C-estimated glomerular filtration rate (GFR) were assessed in two independent community-based cohorts of elderly subjects: the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS, n = 768, 51% women, mean age 75 years) and the Uppsala Longitudinal Study of Adult Men (ULSAM, n = 651, mean age 77 years). The longitudinal association between PTX3 level at baseline and incident CKD (GFR <60 mL(-1) min(-1) 1.73 m(-2) was also analysed (number of events/number at risk: PIVUS 229/746, ULSAM 206/315).

RESULTS

PTX3 levels were inversely associated with GFR [PIVUS: B-coefficient per 1 SD increase -0.16, 95% confidence interval (CI) -0.23 to -0.10, P < 0.001; ULSAM: B-coefficient per 1 SD increase -0.09, 95% CI -0.16 to -0.01, P < 0.05], but not ACR, after adjusting for age, gender, C-reactive protein and prevalent cardiovascular disease in cross-sectional analyses. In longitudinal analyses, PTX3 levels predicted incident CKD after 5 years in both cohorts [PIVUS: multivariable odds ratio (OR) 1.21, 95% CI 1.01-1.45, P < 0.05; ULSAM: multivariable OR 1.37, 95% CI 1.07-1.77, P < 0.05].

CONCLUSIONS

Higher PTX3 levels are associated with lower GFR and independently predict incident CKD in elderly men and women. Our data confirm and extend previous evidence suggesting that inflammatory processes are activated in the early stages of CKD and drive impairment of kidney function. Circulating PTX3 appears to be a promising biomarker of kidney disease.

The Swedish CArdioPulmonary BioImage Study: objectives and design

Cardiopulmonary diseases are major causes of death worldwide, but currently recommended strategies for diagnosis and prevention may be outdated because of recent changes in risk factor patterns. The Swedish CArdioPulmonarybioImage Study (SCAPIS) combines the use of new imaging technologies, advances in large-scale 'omics' and epidemiological analyses to extensively characterize a Swedish cohort of 30 000 men and women aged between 50 and 64 years. The information obtained will be used to improve risk prediction of cardiopulmonary diseases and optimize the ability to study disease mechanisms. A comprehensive pilot study in 1111 individuals, which was completed in 2012, demonstrated the feasibility and financial and ethical consequences of SCAPIS. Recruitment to the national, multicentre study has recently started.

Dietary acid load, kidney function, osteoporosis, and risk of fractures in elderly men and women

SUMMARY

Because kidney dysfunction reduces the ability to excrete dietary acid excess, we hypothesized that underlying kidney function may have confounded the mixed studies linking dietary acid load with the risk of osteoporosis and fractures in the community. In a relatively large survey of elderly men and women, we report that dietary acid load did neither associate with DEXA-estimated bone mineral density nor with fracture risk. Underlying kidney function did not modify these null findings. Our results do not support the dietary acid-base hypothesis of bone loss.

INTRODUCTION

Impaired renal function reduces the ability to excrete dietary acid excess. We here investigate the association between dietary acid load and bone mineral density (BMD), osteoporosis, and fracture risk by renal function status.

METHODS

An observational study was conducted in 861 community-dwelling 70-year-old men and women (49% men) with complete dietary data from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS). The exposure was dietary acid load as estimated from 7-day food records by the net endogenous acid production (NEAP) and potential renal acid load (PRAL) algorithms. Renal function assessed by cystatin C estimated glomerular filtration rate was reduced in 21% of the individuals. Study outcomes were BMD and osteoporosis state (assessed by DEXA) and time to fracture (median follow-up of 9.2 years).

RESULTS

In cross-section, dietary acid load had no significant associations with BMD or with the diagnosis of osteoporosis. During follow-up, 131 fractures were validated. Neither NEAP (adjusted hazard ratios (HR) (95% confidence interval (CI)), 1.01 (0.85-1.21), per 1 SD increment) nor PRAL (adjusted HR (95% CI), 1.07 (0.88-1.30), per 1 SD increment) associated with fracture risk. Further multivariate adjustment for kidney function or stratification by the presence of kidney disease did not modify these null associations.

CONCLUSIONS

The hypothesis that dietary acid load associates with reduced BMD or increased fracture risk was not supported by this study in community-dwelling elderly individuals. Renal function did not influence on this null finding.

The relationship between carotid intima-media thickness and global atherosclerosis

Background

The aim of this study was to investigate the relationship between (i) carotid intima–media thickness (CIMT) at baseline as well as (ii) change in CIMT over 5 years (ΔCIMT) and atherosclerotically induced luminal narrowing in non-coronary arterial territories assessed by whole-body magnetic resonance angiography (WBMRA).

Methods and results

In subgroups of the Prospective Investigation of Vasculature in Uppsala Seniors (PIVUS) study, US measurements of CIMT in the common carotid arteries were analysed at 70 and 75 years and ΔCIMT was calculated (n = 272). WBMRA, assessing arterial stenosis in five different territories by which also a total atherosclerotic score (TAS) was calculated, was performed at 70 years (n = 306).

Results

Carotid intima–media thickness in the carotid artery at baseline was correlated with TAS (P = 0·0001) when adjusted to a set of traditional risk factors for atherosclerosis, as well as to stenosis in two of the different investigated territories (aorta and lower leg, P = 0·013 and P = 0·004), but there was no significant correlation between ΔCIMT and TAS (P = 0·41).

Conclusions

In the present study, CIMT, but not ΔCIMT over 5 years, in the carotid artery was related to overall stenoses in the body, as assessed by WBMRA. These findings support CIMT as a general marker for atherosclerosis.

Serum fatty acid patterns, insulin sensitivity and the metabolic syndrome in individuals with chronic kidney disease

OBJECTIVES

The causes of the multiple metabolic disorders of individuals with chronic kidney disease (CKD) are not fully known. We investigated the relationships between dietary fat quality, the metabolic syndrome (MetS), insulin sensitivity and inflammation in individuals with CKD.

SUBJECTS

Two population-based surveys were conducted in elderly Swedish individuals (aged 70 years) with serum cystatin C-estimated glomerular filtration rate <60 mL min(-1) /1.73 m2: the Uppsala Longitudinal Study of Adult Men (ULSAM) and the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) surveys. The present population comprised 274 men and 187 subjects (63% women) from the ULSAM and PIVUS cohorts, respectively.

DESIGN

Factor analyses of serum fatty acids were used to evaluate dietary fat quality. Insulin sensitivity was measured by homeostasis model assessment of insulin resistance (IR) and, in ULSAM, also by euglycaemic clamp.

RESULTS

Factor analyses generated two fatty acid patterns of (i) low linoleic acid (LA)/high saturated fatty acid (SFA) or (ii) high n-3 polyunsaturated fatty acid (n-3 PUFA) levels. In both surveys, the low LA/high SFA pattern increased the odds of having MetS [adjusted odds ratio 0.60 [95% confidence interval (CI) 0.44-0.81] and 0.45 (95% CI 0.30-0.67) per SD decrease in factor score in the ULSAM and PIVUS surveys, respectively] and was directly associated with both IR and C-reactive protein. The n-3 PUFA pattern was not consistently associated with these risk factors.

CONCLUSIONS

A serum fatty acid pattern reflecting low LA and high SFA was strongly associated with MetS, IR and inflammation in two independent surveys of elderly individuals with CKD. At present, there are no specific dietary guidelines for individuals with CKD; however, these findings indirectly support current recommendations to replace SFAs with PUFAs from vegetable oils.

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.

Increased age, high body mass index and low HDL-C levels are related to an echolucent carotid intima-media: the METEOR study

INTRODUCTION

Echolucent plaques are related to a higher cardiovascular risk. Studies to investigate the relationship between echolucency and cardiovascular risk in the early stages of atherosclerosis are limited. We studied the relationship between cardiovascular risk factors and echolucency of the carotid intima-media in low-risk individuals.

METHODS

Data were analysed from the Measuring Effects on Intima-Media Thickness: an Evaluation of Rosuvastatin (METEOR) study, a randomized placebo-controlled trial including 984 individuals which showed that rosuvastatin attenuated the rate of change of carotid intima-media thickness (CIMT). In this post hoc analysis, duplicate baseline ultrasound images from the far wall of the left and right common carotid arteries were used for the evaluation of the echolucency of the carotid intima-media, measured by grey-scale median (GSM) on a scale of 0-256. Low GSM values reflect echolucent, whereas high values reflect echogenic structures. The relationship between baseline GSM and cardiovascular risk factors was evaluated using linear regression models.

RESULTS

Mean baseline GSM (± SD) was 84 ± 29. Lower GSM of the carotid intima-media was associated with older age, high body mass index (BMI) and low levels of high-density lipoprotein cholesterol (HDL-C) [beta -4.49, 95% confidence interval (CI) -6.50 to -2.49; beta -4.51, 95% CI -6.43 to -2.60; beta 2.45, 95% CI 0.47 to 4.42, respectively]. Common CIMT was inversely related to GSM of the carotid intima-media (beta -3.94, 95% CI -1.98 to -5.89).

CONCLUSION

Older age, high BMI and low levels of HDL-C are related to echolucency of the carotid intima-media. Hence, echolucency of the carotid intima-media may be used as a marker of cardiovascular risk profile to provide more information than thickness alone.

Can persistent organic pollutants and plastic-associated chemicals cause cardiovascular disease?

During the last decade, associations between persistent organic pollutants (POPs), such as polychlorinated biphenyls, dioxins and pesticides, and cardiovascular (CV) risk factors and overt CV disease (CVD) have been reported in humans. Recently, associations between plastic-associated chemicals (PACs), such as bisphenol A and phthalates, and CVD have also begun to emerge. Several approaches to evaluating such associations have been used: accidents with a high level of exposure, occupational exposure studies, geographical studies of subjects living near a contaminated area and traditional case-control or cohort studies with measurements of circulating levels of different environmental contaminants in the general population. Exposure to POPs has consistently been associated with diabetes using all the approaches described above, including prospective studies. The evidence regarding associations between exposure to POPs and other CV risk factors, such as hypertension, obesity and lipids, is less strong and is mainly based on cross-sectional data. Associations between overt CVD and POPs have been reported using all the above approaches, but prospective data from population-based studies are still lacking to provide firm evidence of an important and independent role of POP exposure in the pathogenesis of CVD. Nevertheless, taken together, current evidence suggests that further longitudinal and experimental studies should be conducted to investigate the effect of exposure to both POPs and PACs, such as bisphenol A and phthalates.

Can persistent organic pollutants and plastic-associated chemicals cause cardiovascular disease?

During the last decade, associations between persistent organic pollutants (POPs), such as polychlorinated biphenyls, dioxins and pesticides, and cardiovascular (CV) risk factors and overt CV disease (CVD) have been reported in humans. Recently, associations between plastic-associated chemicals (PACs), such as bisphenol A and phthalates, and CVD have also begun to emerge. Several approaches to evaluating such associations have been used: accidents with a high level of exposure, occupational exposure studies, geographical studies of subjects living near a contaminated area and traditional case-control or cohort studies with measurements of circulating levels of different environmental contaminants in the general population. Exposure to POPs has consistently been associated with diabetes using all the approaches described above, including prospective studies. The evidence regarding associations between exposure to POPs and other CV risk factors, such as hypertension, obesity and lipids, is less strong and is mainly based on cross-sectional data. Associations between overt CVD and POPs have been reported using all the above approaches, but prospective data from population-based studies are still lacking to provide firm evidence of an important and independent role of POP exposure in the pathogenesis of CVD. Nevertheless, taken together, current evidence suggests that further longitudinal and experimental studies should be conducted to investigate the effect of exposure to both POPs and PACs, such as bisphenol A and phthalates.

Manual or semi-automated edge detection of the maximal far wall common carotid intima-media thickness: a direct comparison

BACKGROUND

Automated edge detection is thought to be superior to manual edge detection in quantification of the far wall common carotid intima-media thickness (CIMT), yet published evidence making a direct comparison is not available.

METHODS

Data were used from the METEOR study, a randomized placebo-controlled trial among 984 individuals showing that rosuvastatin attenuated the rate of change of 2 year change in CIMT among low-risk individuals with subclinical atherosclerosis. For this post hoc analysis, CIMT images of the far wall of the common carotid artery were evaluated using manual and semi-automated edge detection and reproducibility, relation to cardiovascular risk factors, rates of change over time and effects of lipid-lowering therapy were assessed.

RESULTS

Reproducibility was high for both reading methods. Direction, magnitude and statistical significance of risk factor relations were similar across methods. Rate of change in CIMT in participants assigned to placebo was 0.0066 mm per year (SE: 0.0027) for manually and 0.0072 mm per year (SE: 0.0029) for semi-automatically read images. The effect of lipid-lowering therapy on CIMT changes was -0.0103 mm per year (SE: 0.0032) for manual reading and -0.0111 mm per year (SE: 0.0034) for semi-automated reading.

CONCLUSION

Manual and semi-automated readings of the maximal far wall of the common CIMT images both result in high reproducibility, show similar risk factor relations, rates of change and treatment effects. Hence, choices between semi-automated and manual reading software for CIMT studies likely should be based on logistical and cost considerations rather than differences in expected data quality when the choice is made to use far wall common CIMT measurements.

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.

Hydrochlorothiazide compared to candesartan treatment increases adipose tissue gene expression and circulating levels of serum amyloid A in hypertensive patients

Treatment of hypertension with angiotensin receptor blockers has been shown to reduce the risk of developing type 2 diabetes in comparison to thiazide diuretics and beta adrenergic blockers. Therefore, we wanted to study the effect of antihypertensive drugs on adipose tissue with respect to insulin resistance. In the MEDICA (MEchanisms for the DIabetes preventing effects of CAndesartan) study, 22 hypertensive, nondiabetic patients with abdominal obesity (10 men, 12 women) were randomized into 12-week treatment periods with candesartan, hydrochlorothiazide, and placebo according to a 3-way cross-over design. Subcutaneous adipose tissue biopsies were taken after 8 weeks treatment to analyze gene expression, glucose uptake capacity, insulin-signaling, and adipocyte size. Adipose tissue gene expression of serum amyloid A (SAA) was higher after hydrochlorothiazide treatment compared to candesartan (p=0.036), and this was in accordance with our previous finding on circulating SAA levels. Serum levels of E selectin were increased after hydrochlorothiazide compared to candesartan treatment (p=0.002) and lower after candesartan compared to placebo (p=0.002). In adipocytes, there were no significant differences between the treatments with respect to cell size, glucose uptake capacity, or insulin-signaling. In comparison to candesartan, hydrochlorothiazide raised the adipose tissue gene expression of SAA and the serum level of SAA as well as E selectin in hypertensive patients. Less adipose and systemic inflammation may be one explanation why candesartan is favorable in comparison to thiazide diuretics with respect to development of insulin resistance and type 2 diabetes.

Plasma levels of glucagon like peptide-1 associate with diastolic function in elderly men

AIMS

Congestive heart failure is a major cause of morbidity and mortality in diabetes. Besides the glycaemic effects of glucagon-like peptide 1 (GLP-1) mimetics, their effects on the heart are of interest.

METHODS

We aimed to investigate longitudinal relationships between plasma levels of fasting GLP-1 (fGLP-1), 60-min oral glucose tolerance test-stimulated GLP-1 levels (60GLP-1), and the dynamic GLP-1 response after oral glucose tolerance test (ΔGLP-1 = 60GLP-1 - fGLP-1) and incidence of hospitalized congestive heart failure, during a follow-up time of a maximum of 9.8 years in 71-year-old men. We also investigated, cross-sectionally, the association between GLP-1 and left ventricular function as estimated by echocardiography. R: During the follow-up period, 16 of 290 participants with normal glucose tolerance experienced a congestive heart failure event (rate 0.7/100 person-years at risk), as did eight of 136 participants (rate 0.8/100 person-years at risk) with impaired glucose tolerance and nine of 72 participants (rate 1.7/100 person-years at risk) with Type 2 diabetes mellitus. Although GLP-1 concentrations did not predict congestive heart failure (fGLP-1: HR 0.98, 95% CI 0.4-2.4; 60GLP-1: HR 1.1, 95% CI 0.4-2.6; ΔGLP-1: HR 0.9, 95% CI 0.3-2.3), there was an association between left ventricular diastolic function (E/A ratio) and fGLP-1 (r = 0.19, P = 0.001), 60GLP-1 (r = 0.20, P < 0.001) and ΔGLP-1 (r = 0.18, P = 0.004). There was a lack of differences in plasma levels of GLP-1 between the groups with Type 2 diabetes and normal glucose tolerance.

CONCLUSIONS

There were no longitudinal associations between GLP-1 levels and incidence of hospitalization for congestive heart failure. However, without any causality proven, GLP-1 levels did correlate, cross-sectionally, with left ventricular diastolic function in this cohort, suggesting that pathways including GLP-1 might be involved in the regulation of cardiac diastolic function.

Multistate outbreak of Escherichia coli O157:H7 infections associated with a national fast-food chain, 2006: a study incorporating epidemiological and food source traceback results

A multistate outbreak of Escherichia coli O157:H7 infections occurred in the USA in November-December 2006 in patrons of restaurant chain A. We identified 77 cases with chain A exposure in four states - Delaware, New Jersey, New York, and Pennsylvania. Fifty-one (66%) patients were hospitalized, and seven (9%) developed haemolytic uraemic syndrome; none died. In a matched analysis controlling for age in 31 cases and 55 controls, illness was associated with consumption of shredded iceberg lettuce [matched odds ratio (mOR) 8·0, 95% confidence interval (CI) 1·1-348·1] and shredded cheddar cheese (mOR 6·2, CI 1·7-33·7). Lettuce, an uncooked ingredient, was more commonly consumed (97% of patients) than cheddar cheese (84%) and a single source supplied all affected restaurants. A single source of cheese could not explain the regional distribution of outbreak cases. The outbreak highlights challenges in conducting rapid multistate investigations and the importance of incorporating epidemiological study results with other investigative findings.