Cross-sectional study on exhaled nitric oxide in relation to upper airway inflammatory disorders with regard to asthma and perennial sensitization.

BACKGROUND: Fractional exhaled nitric oxide (FeNO) is a well-known marker of type-2 inflammation. FeNO is elevated in asthma and allergic rhinitis, with IgE sensitization as a major determinant. OBJECTIVE: We aimed to see whether there was an independent association between upper airway inflammatory disorders (UAID) and FeNO, after adjustment for asthma and sensitization, in a multi-centre population-based study. METHODS: A total of 741 subjects with current asthma and 4155 non-asthmatic subjects participating in the second follow-up of the European Community Respiratory Health Survey (ECRHS III) underwent FeNO measurements. Sensitization status was based on measurement of IgE against airborne allergens; information on asthma, UAID and medication was collected through interview-led questionnaires. Independent associations between UAID and FeNO were assessed in adjusted multivariate regression models and test for interaction with perennial sensitization and asthma on the relation between UAID and FeNO were made. RESULTS: UAID were associated with higher FeNO after adjusting for perennial sensitization, asthma and other confounders: with 4.4 (0.9-7.9) % higher FeNO in relation to current rhinitis and 4.8 (0.7-9.2) % higher FeNO in relation to rhinoconjunctivitis. A significant interaction with perennial sensitization was found in the relationship between current rhinitis and FeNO (p = .03) and between rhinoconjunctivitis and FeNO (p = .03). After stratification by asthma and perennial sensitization, the association between current rhinitis and FeNO remained in non-asthmatic subjects with perennial sensitization, with 12.1 (0.2-25.5) % higher FeNO in subjects with current rhinitis than in those without. CONCLUSIONS & CLINICAL RELEVANCE: Current rhinitis and rhinoconjunctivitis was associated with higher FeNO, with an interaction with perennial sensitization. This further highlights the concept of united airway disease, with correlations between symptoms and inflammation in the upper and lower airways and that sensitization needs to be accounted for in the relation between FeNO and rhinitis.

Bronchodilator response and lung function decline: Associations with exhaled nitric oxide with regard to sex and smoking status.

BACKGROUND: Fractional exhaled nitric oxide (FeNO) is a marker of type-2 inflammation used both to support diagnosis of asthma and follow up asthma patients. The associations of FeNO with lung function decline and bronchodilator (BD) response have been studied only scarcely in large populations. OBJECTIVES: To study the association between FeNO and a) retrospective lung function decline over 20 years, and b) lung function response to BD among asthmatic subjects compared with non-asthmatic subjects and with regards to current smoking and sex. METHODS: Longitudinal analyses of previous lung function decline and FeNO level at follow-up and cross-sectional analyses of BD response and FeNO levels in 4257 participants (651 asthmatics) from the European Community Respiratory Health Survey. RESULTS: Among asthmatic subjects, higher percentage declines of FEV1 and FEV1/FVC were associated with higher FeNO levels (p = 0.001 for both) at follow-up. These correlations were found mainly among non-smoking individuals (p = 0.001) and females (p = 0.001) in stratified analyses.Percentage increase in FEV1 after BD was positively associated with FeNO levels in non-asthmatic subjects. Further, after stratified for sex and smoking separately, a positive association was seen between FEV1 and FeNO levels in non-smokers and women, regardless of asthma status. CONCLUSIONS: We found a relationship between elevated FeNO and larger FEV1 decline over 20 years among subjects with asthma who were non-smokers or women. The association between elevated FeNO levels and larger BD response was found in both non-asthmatic and asthmatic subjects, mainly in women and non-smoking subjects.

Determinants of fractional exhaled nitric oxide in healthy men and women from the European Community Respiratory Health Survey III.

INTRODUCTION: The fractional exhaled nitric oxide (FE NO) is a marker for type 2 inflammation used in diagnostics and management of asthma. In order to use FE NO as a reliable biomarker, it is important to investigate factors that influence FE NO in healthy individuals. Men have higher levels of FE NO than women, but it is unclear whether determinants of FE NO differ by sex. OBJECTIVE: To identify determinants of FE NO in men and women without lung diseases. METHOD: Fractional exhaled nitric oxide was validly measured in 3881 healthy subjects that had answered the main questionnaire of the European Community Respiratory Health Survey III without airways or lung disease. RESULTS: Exhaled NO levels were 21.3% higher in men compared with women P < 0.001. Being in the upper age quartile (60.3-67.6 years), men had 19.2 ppb (95% CI: 18.3, 20.2) higher FE NO than subjects in the lowest age quartile (39.7-48.3 years) P = 0.02. Women in the two highest age quartiles (54.6-60.2 and 60.3-67.6 years) had 15.4 ppb (14.7, 16.2), P = 0.03 and 16.4 ppb (15.6, 17.1), P = <0.001 higher FE NO, compared with the lowest age quartile. Height was related to 8% higher FE NO level in men (P < 0.001) and 5% higher FE NO levels in women (P = 0.008). Men who smoked had 37% lower FE NO levels and women had 30% lower levels compared with never-smokers (P < 0.001 for both). Men and women sensitized to both grass and perennial allergens had higher FE NO levels compared with non-sensitized subjects 26% and 29%, P < 0.001 for both. CONCLUSION AND CLINICAL RELEVANCE: Fractional exhaled nitric oxide levels were higher in men than women. Similar effects of current smoking, height, and IgE sensitization were found in both sexes. FE NO started increasing at lower age in women than in men, suggesting that interpretation of FE NO levels in adults aged over 50 years should take into account age and sex.

Influence of a prudent diet on circulating cathepsin S in humans.

BACKGROUND: Increased circulating cathepsin S levels have been linked to increased risk of cardiometabolic diseases and cancer. However, whether cathepsin S is a modifiable risk factor is unclear. We aimed to investigate the effects of a prudent diet on plasma cathepsin S levels in healthy individuals. FINDINGS: Explorative analyses of a randomized study were performed in 88 normal to slightly overweight and hyperlipidemic men and women (aged 25 to 65) that were randomly assigned to ad libitum prudent diet, i.e. healthy Nordic diet (ND) or a control group (habitual Western diet) for 6 weeks. Whereas all foods in the ND were provided, the control group was advised to consume their habitual diet throughout the study. The ND was in line with dietary recommendations, e.g. low in saturated fats, sugars and salt, but high in plant-based foods rich in fibre and unsaturated fats.The ND significantly decreased cathepsin S levels (from 20.1 (+/-4.0 SD) to 19.7 µg/L (+/-4.3 SD)) compared with control group (from 18.2 (+/-2.9 SD) to 19.1 µg/L (+/-3.8 SD)). This difference remained after adjusting for sex and change in insulin sensitivity (P = 0.03), and near significant after adjusting for baseline cathepsin S levels (P = 0.06), but not for change in weight or LDL-C. Changes in cathepsin S levels were directly correlated with change in LDL-C. CONCLUSIONS: Compared with a habitual control diet, a provided ad libitum healthy Nordic diet decreased cathepsin S levels in healthy individuals, possibly mediated by weight loss or lowered LDL-C. These differences between groups in cathepsin S were however not robust and therefore need further investigation.

The association between glomerular filtration rate and left ventricular function in two independent community-based cohorts of elderly.

BACKGROUND: The cardiorenal syndrome, the detrimental bi-directional interplay between symptomatic heart failure and chronic kidney disease, is a major clinical challenge. Nonetheless, it is unknown if this interplay begins already at an asymptomatic stage. Therefore we investigated whether the glomerular filtration rate (GFR) is associated with left ventricular function in participants free from clinical heart failure and with a left ventricular ejection fraction (LVEF) >40% and with pre-specified sub-group analyses in individuals with a GFR >60 mL/min/m(2). METHODS: Two independent community-based cohorts were used; the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS; n = 911; 50% women; mean age: 70 years) and the Uppsala Longitudinal Study of Adult Men (ULSAM; n = 538; mean age: 71 years). We investigated cross-sectional association between cystatin C-based GFR (estimated glomerular function [eGFR]) and systolic (LVEF), diastolic- (isovolumic relaxation time [IVRT]) and global left ventricular function (myocardial performance index [MPI]) determined by echocardiography. RESULTS: In both PIVUS and ULSAM, higher eGFR was significantly associated with higher LVEF (P = 0.004 [PIVUS] and P = 0.005 [ULSAM]). In PIVUS, higher eGFR was significantly associated with lower IVRT (P = 0.001) and MPI (P = 0.006), in age- and sex-adjusted models. After further adjustment for cardiovascular risk factors, the association between higher eGFR and higher LVEF was still statistically significant (P = 0.008 [PIVUS] and P = 0.02 [ULSAM]). In PIVUS, the age- and sex-adjusted association between eGFR and left ventricular function was similar in participants with eGFR >60 mL/min/m(2). CONCLUSIONS: Our data suggest that the interplay between kidney and heart function begins prior to the development of symptomatic heart failure and kidney disease.

Inflammation, oxidative stress, glomerular filtration rate, and albuminuria in elderly men: a cross-sectional study.

BACKGROUND: The role of inflammation and oxidative stress in mild renal impairment in the elderly is not well studied. Accordingly, we aimed at investigating the associations between estimated glomerular filtration rate (eGFR), albumin/creatinine ratio (ACR), and markers of different inflammatory pathways and oxidative stress in a community based cohort of elderly men. FINDINGS: Cystatin C-based GFR, ACR, and biomarkers of cytokine-mediated inflammation (interleukin-6, high-sensitivity C-reactive protein[CRP], serum amyloid A[SAA]), cyclooxygenase-mediated inflammation (urinary prostaglandin F2α [PGF2α]), and oxidative stress (urinary F2 isoprostanes) were assessed in the Uppsala Longitudinal Study of Adult Men(n = 647, mean age 77 years). RESULTS: In linear regression models adjusting for age, BMI, smoking, blood pressure, LDL-cholesterol, HDL-cholesterol, triglycerides, and treatment with statins, ACE-inhibitors, ASA, and anti-inflammatory agents, eGFR was inversely associated with CRP, interleukin-6, and SAA (ß-coefficient -0.13 to -0.19, p < 0.001 for all), and positively associated with urinary F2-isoprostanes (ß-coefficient 0.09, p = 0.02). In line with this, ACR was positively associated with CRP, interleukin-6, and SAA (ß- coefficient 0.09-0.12, p < 0.02 for all), and negatively associated with urinary F2-isoprostanes (ß-coefficient -0.12, p = 0.002). The associations were similar but with lower regression coefficients in a sub-sample with normal eGFR (>60 ml/min/1.73 m2, n = 514), with the exception that F2-isoprostane and SAA were no longer associated with eGFR. CONCLUSION: Our data indicate that cytokine-mediated inflammation is involved in the early stages of impaired kidney function in the elderly, but that cyclooxygenase-mediated inflammation does not play a role at this stage. The unexpected association between higher eGFR/lower albuminuria and increased F2-isoprostanes in urine merits further studies.

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.

Association between serum cathepsin S and mortality in older adults.

CONTEXT: Experimental data suggest that cathepsin S, a cysteine protease, is involved in the complex pathways leading to cardiovascular disease and cancer. However, prospective data concerning a potential association between circulating cathepsin S levels and mortality are lacking. OBJECTIVE: To investigate associations between circulating cathepsin S levels and mortality in 2 independent cohorts of elderly men and women. DESIGN, SETTING, AND PARTICIPANTS: Prospective study using 2 community-based cohorts, the Uppsala Longitudinal Study of Adult Men (ULSAM; n = 1009; mean age: 71 years; baseline period: 1991-1995; median follow-up: 12.6 years; end of follow-up: 2006) and the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS; n = 987; 50% women; mean age: 70 years; baseline period: 2001-2004; median follow-up: 7.9 years; end of follow-up: 2010). Serum samples were used to measure cathepsin S. MAIN OUTCOME MEASURE: Total mortality. RESULTS: During follow-up, 413 participants died in the ULSAM cohort (incidence rate: 3.59/100 person-years at risk) and 100 participants died in the PIVUS cohort (incidence rate: 1.32/100 person-years at risk). In multivariable Cox regression models adjusted for age, systolic blood pressure, diabetes, smoking status, body mass index, total cholesterol, high-density lipoprotein cholesterol, antihypertensive treatment, lipid-lowering treatment, and history of cardiovascular disease, higher serum cathepsin S was associated with an increased risk for mortality (ULSAM cohort: hazard ratio [HR] for 1-unit increase of cathepsin S, 1.04 [95% CI, 1.01-1.06], P = .009; PIVUS cohort: HR for 1-unit increase of cathepsin S, 1.03 [95% CI, 1.00-1.07], P = .04). In the ULSAM cohort, serum cathepsin S also was associated with cardiovascular mortality (131 deaths; HR for quintile 5 vs quintiles 1-4, 1.62 [95% CI, 1.11-2.37]; P = .01) and cancer mortality (148 deaths; HR for 1-unit increase of cathepsin S, 1.05 [95% CI, 1.01-1.10]; P = .01). CONCLUSIONS: Among elderly individuals in 2 independent cohorts, higher serum cathepsin S levels were associated with increased mortality risk. Additional research is needed to delineate the role of cathepsin S and whether its measurement might have clinical utility.

The combined contribution of albuminuria and glomerular filtration rate to the prediction of cardiovascular mortality in elderly men.

BACKGROUND: Cardiovascular risk prediction is particularly important in the primary prevention of cardiovascular disease (CVD). Yet, data on whether the combined addition of albuminuria and estimated glomerular filtration rate (eGFR) improves cardiovascular risk prediction in individuals without CVD in the community is scarce. METHODS: We investigated associations between urinary albumin excretion rate (UAER), cystatin C-based eGFR and cardiovascular mortality in a community-based cohort of elderly men (ULSAM study; n = 1113, mean age 71 years, 208 cardiovascular deaths, median follow-up 12.9 years) with prespecified analyses in participants without CVD (n = 649, 86 cardiovascular deaths). RESULTS: Using multivariable Cox regression, higher UAER and lower eGFR were associated with increased risk for cardiovascular mortality independently of established cardiovascular risk factors in the whole sample and in men without CVD at baseline [subsample without CVD: UAER; hazard ratio (HR) per 1 SD 1.26, 95% confidence interval (CI) 1.05-1.51, P = 0.01; eGFR: HR per 1 SD 0.74, 95% CI 0.59-0.92, P = 0.007]. Analyses of model discrimination, calibration, reclassification and global fit suggested that UAER and eGFR also add relevant prognostic information beyond established cardiovascular risk factors in participants without prevalent CVD. Interestingly, established cutoffs used to diagnose microalbuminuria (UAER > 20 µg/min) and chronic kidney disease Stage 3 (eGFR < 60 mL/min/1.73 m(2)), appeared less suitable for cardiovascular risk prediction [integrated discrimination improvement (IDI) 0.006, P = 0.11], while cutoffs UAER > 6 µg/min and eGFR < 45 mL/min/1.73 m(2) significantly improved IDI (0.047, P < 0.001). CONCLUSIONS: UAER and eGFR improved cardiovascular risk prediction beyond established cardiovascular risk factors, suggesting that these kidney biomarkers may be useful in predicting cardiovascular death in elderly men.

Insulin sensitivity measured with euglycemic clamp is independently associated with glomerular filtration rate in a community-based cohort.

OBJECTIVE: To investigate the association between insulin sensitivity and glomerular filtration rate (GFR) in the community, with prespecified subgroup analyses in normoglycemic individuals with normal GFR. RESEARCH DESIGN AND METHODS: We investigated the cross-sectional association between insulin sensitivity (M/I, assessed using euglycemic clamp) and cystatin C-based GFR in a community-based cohort of elderly men (Uppsala Longitudinal Study of Adult Men [ULSAM], n = 1,070). We also investigated whether insulin sensitivity predicted the incidence of renal dysfunction at a follow-up examination after 7 years. RESULTS: Insulin sensitivity was directly related to GFR (multivariable-adjusted regression coefficient for 1-unit higher M/I 1.19 [95% CI 0.69-1.68]; P < 0.001) after adjusting for age, glucometabolic variables (fasting plasma glucose, fasting plasma insulin, and 2-h glucose after an oral glucose tolerance test), cardiovascular risk factors (hypertension, dyslipidemia, and smoking), and lifestyle factors (BMI, physical activity, and consumption of tea, coffee, and alcohol). The positive multivariable-adjusted association between insulin sensitivity and GFR also remained statistically significant in participants with normal fasting plasma glucose, normal glucose tolerance, and normal GFR (n = 443; P < 0.02). In longitudinal analyses, higher insulin sensitivity at baseline was associated with lower risk of impaired renal function (GFR <50 ml/min per 1.73 m(2)) during follow-up independently of glucometabolic variables (multivariable-adjusted odds ratio for 1-unit higher of M/I 0.58 [95% CI 0.40-0.84]; P < 0.004). CONCLUSIONS: Our data suggest that impaired insulin sensitivity may be involved in the development of renal dysfunction at an early stage, before the onset of diabetes or prediabetic glucose elevations. Further studies are needed in order to establish causality.