Search tips
Search criteria

Results 1-14 (14)

Clipboard (0)

Select a Filter Below

more »
Year of Publication
Document Types
Mayo Clinic proceedings  2013;88(11):10.1016/j.mayocp.2013.08.012.
To investigate the association of chronic obstructive pulmonary disease (COPD) with mild cognitive impairment (MCI) and MCI sub-types, amnestic MCI (a-MCI) and non-amnestic MCI (na-MCI), in a population-based study of elderly.
Patients and Methods
Participants included 1,927 individuals, aged 70 to 89 years, enrolled in the population-based, Mayo Clinic Study of Aging. Participants were evaluated with a nurse assessment, neurological evaluation, and neuropsychological testing and the diagnosis of MCI was made according to the standardized criteria by a consensus panel. COPD was identified by the review of medical records. The study was conducted from October 1, 2004, through July 31, 2007. The associations of COPD, and disease duration with MCI, and its subtypes were evaluated using logistic regression models adjusted for potential covariates.
Of 1,927 subjects, 288 had COPD (men vs women 17.9% vs 11.8%, p<0.001). As compared to subjects without COPD, the subjects with COPD had higher prevalence of MCI (27.1% vs 14.6%, p<0.001). The odds ratio (OR) of MCI was almost two times higher in subjects with COPD (OR =1.90, 95 %CI =1.35 – 2.65), with a similar effect in men and women. The OR for MCI increased from 1.67 (97% CI, 1.00 – 2.69) in subjects with COPD duration of ≤ 5 years to 2.08 (95% CI, 1.36 – 3.14) in subjects > 5 years.
This population-based study suggests that COPD is associated with increased odds of having MCI and its sub-types. There was a dose-response association with duration of COPD, after controlling for the potential covariates.
PMCID: PMC3875365  PMID: 24182702
3.  A Prospective Study of Chronic Obstructive Pulmonary Disease and Risk of Mild Cognitive Impairment 
JAMA neurology  2014;71(5):581-588.
Previous studies suggest cross-sectional associations between a diagnosis of chronic obstructive pulmonary disease (COPD) and mild cognitive impairment (MCI). However, few studies have assessed whether COPD, a potentially modifiable factor, is associated with an increased risk of MCI and if the relation is specific to type of MCI.
To investigate whether a diagnosis of COPD, and COPD duration, is associated with an increased risk of incident MCI, and MCI subtypes (amnestic MCI (a-MCI) and non-amnestic MCI (na-MCI)).
Mayo Clinic Study on Aging, a prospective population-based cohort study.
Olmsted County, Minnesota.
The study included 1425 cognitively normal individuals aged 70–89 years, who were randomly selected from Olmsted County, MN, on October 1, 2004, using the medical records linkage system.
At baseline and every 15 months thereafter, participants were assessed with a nurse interview, neurological examination, and neuropsychological testing. A diagnosis of COPD was confirmed via medical record chart review. A baseline diagnosis of COPD and disease duration were examined as risk factors for MCI and MCI-subtypes using Cox proportional hazards models and adjusting for demographic variables and medical comorbidities, using age as the time scale.
Incident MCI, amnestic MCI, non-amnestic MCI
Of 1425 cognitively normal subjects at baseline, 370 developed incident MCI. The median duration of follow-up was 5.1 years (Interquartile Range [IQR], 3.8–5.4 years). COPD significantly increased the risk of na-MCI by 83% (HR 1.83; 95% CI, 1.04–3.23), but not any MCI or a-MCI in multivariate analyses. There was a dose-response relationship such that individuals with COPD duration of 5 years or longer at baseline had the greatest risk of both MCI (HR 1.58, 95% CI:1.04, 2.40) and na-MCI (HR 2.58, 95% CI:1.32–5.06).
COPD was associated with an increased risk of MCI, particularly na-MCI. There was a dose-response relationship between COPD duration and risk of MCI. These findings highlight the importance of COPD as a risk factor for MCI and may provide a substrate for early intervention to prevent or delay the onset and progression of MCI, particularly na-MCI.
PMCID: PMC4020948  PMID: 24637951
4.  Sputum PGP is reduced by azithromycin treatment in patients with COPD and correlates with exacerbations 
BMJ Open  2013;3(12):e004140.
Proline–glycine–proline (PGP), a neutrophil chemoattractant derived from the enzymatic breakdown of collagen, is elevated in sputum of patients with chronic obstructive pulmonary disease (COPD) and may contribute to disease progression. Whether sputum levels of PGP respond to therapy for COPD or predict outcomes is unknown.
We conducted a study ancillary to a multicenter trial of the efficacy of azithromycin treatment for 1 year in preventing COPD exacerbations to test whether sputum levels of PGP were altered by treatment or associated with exacerbation frequency.
We collected remnant sputa from trial participants and assayed them in a blinded fashion for PGP, myeloperoxidase and matrix metalloproteinase (MMP)-9 and for the ability to generate PGP from collagen ex vivo. Once the parent trial was unblinded, the results were correlated with use of azithromycin or placebo and exacerbations in participants.
Azithromycin treatment significantly reduced sputum levels of PGP and myeloperoxidase in patients with COPD, particularly with increased duration of therapy. We found no difference in sputum MMP-9 or PGP generation between participants taking azithromycin or placebo. Sputum PGP levels were highest around the time of an exacerbation and declined with successful treatment.
These data support a role for PGP in the airway and parenchymal neutrophilic inflammation that drives COPD progression and exacerbations, and provide new information on the anti-inflammatory properties of macrolides. PGP may have potential as a target for novel anti-inflammatory therapies in COPD and as a biomarker for clinical trials.
PMCID: PMC3884851  PMID: 24366582
5.  Genetic Variants Associated with the Risk of Chronic Obstructive Pulmonary Disease with and without Lung Cancer 
Chronic Obstructive Pulmonary Disease (COPD) is a strong risk factor for lung cancer. Published studies regarding variations of genes encoding glutathione metabolism, DNA repair, and inflammatory response pathways in susceptibility to COPD were inconclusive.
We evaluated 470 single nucleotide polymorphisms (SNPs) from 56 genes of these 3 pathways in 620 cases and 893 controls to identify susceptibility markers for COPD risk, using existing resources. We assessed SNP- and gene-level effects adjusting for sex, age, and smoking status. Differential genetic effects on disease risk with and without lung cancer were also assessed; cumulative risk models were established.
Twenty-one SNPs were found to be significantly associated with risk of COPD (P<0.01); gene-based analyses confirmed 2 genes (GCLC and GSS) and identified 3 additional (GSTO2, ERCC1, and RRM1). Carrying 12 high-risk alleles may increase risk by 2.7-fold; 8 SNPs altered COPD risk with lung cancer 3.1-fold, and 4 SNPs altered the risk without lung cancer 2.3-fold.
Our findings indicate that multiple genetic variations in the 3 selected pathways contribute to COPD risk through GCLC, GSS, GSTO2, ERCC1, and RRM1 genes. Functional studies are needed to elucidate the mechanisms of these genes in the development of COPD, lung cancer, or both.
PMCID: PMC3414259  PMID: 22044695
Chronic Obstructive Pulmonary Disease; Glutathione Metabolism Pathway; DNA Repair Pathway; Inflammatory Response Pathway
6.  Randomized Trial of Zileuton for Treatment of COPD Exacerbations Requiring Hospitalization 
COPD  2011;8(1):21-29.
Leukotrienes have been implicated in the pathogenesis of acute exacerbations of COPD, but leukotriene modifiers have not been studied as a possible therapy for exacerbations.
We sought to test the safety and efficacy of adding oral zileuton (a 5-lipoxygenase inhibitor) to usual treatment for acute exacerbations of COPD requiring hospitalization.
Randomized double-blind, placebo-controlled, parallel group study of zileuton 600 mg orally, 4 times daily versus placebo for 14 days starting within 12 hours of hospital admission for COPD exacerbation. Primary outcome measure was hospital length of stay; secondary outcomes included treatment failure and biomarkers of leukotriene production.
Main Findings
Sixty subjects were randomized to zileuton and 59 to placebo (the study was stopped short of enrollment goals because of slow recruitment). There was no difference in hospital length of stay (3.75±2.19 vs. 3.86±3.06 days for zileuton vs. placebo, p=0.39) or treatment failure (23% vs. 27% for zileuton vs. placebo, p=0.63) despite a decline in urinary LTE4 levels in the zileuton-treated group as compared to placebo at 24 hours (change in natural log-transformed ng/mg creatinine −1.38± 1.19 vs. 0.14±1.51, p<0.0001) and 72 hours (−1.32±2.08 vs. 0.26±1.93, p<0.006). Adverse events were similar in both groups.
Principal Conclusions
While oral zileuton during COPD exacerbations that require hospital admission is safe and reduces urinary LTE4 levels, we found no evidence suggesting that this intervention shortened hospital stay, with the limitation that our sample size may have been insufficient to detect a modest but potentially meaningful clinical improvement.
PMCID: PMC3775706  PMID: 21299475
Chronic Obstructive Pulmonary Disease (COPD); Acute exacerbation of COPD (AECOPD); Leukotrienes; Zileuton; Clinical trial
7.  Long-term Comparative Immunogenicity of Protein Conjugate and Free Polysaccharide Pneumococcal Vaccines in Chronic Obstructive Pulmonary Disease 
The Food and Drug Adminstration recently approved a diphtheria-conjugated pneumococcal polysaccharide vaccine for adults, although its long-term immunogenicity is unknown. We report that, in patients with moderate to severe chronic obstructive pulmonary disease, conjugate vaccination elicits a superior immune response to free-polysaccharide vaccine that persists for >2 years.
Background. Although the 23-valent pneumococcal polysaccharide vaccine (PPSV23) protects against invasive disease in young healthy persons, randomized controlled trials in chronic obstructive pulmonary disease (COPD) have demonstrated no benefit in the intention-to-treat population. We previously reported that the 7-valent diphtheria-conjugated pneumococcal polysaccharide vaccine (PCV7) is safe and induced greater serotype-specific immunoglobulin G (IgG) and functional antibody than did PPSV23 1 month after vaccination. We hypothesized that these advantages would persist at 1 and 2 years.
Methods. One hundred eighty-one patients with moderate to severe COPD were randomized to receive PPSV23 (n = 90) or PCV7 (1.0 mL; n = 91). We measured IgG by enzyme-linked immunosorbent assay and assessed functional antibody activity by a standardized opsonophagocytosis assay, reported as a killing index (OPK). We determined differences in IgG and OPK between vaccine groups at 1 and 2 years.
Results. Relative to PPSV23, PCV7 induced greater OPK at both 1 and 2 years for 6 of 7 serotypes (not 19F). This response was statistically greater for 5 of 7 serotypes at 1 year and 4 of 7 at 2 years. Comparable differences in IgG were observed but were less often statistically significant. Despite meeting Centers for Disease Control and Prevention criteria for PPSV23 administration, almost 50% of individuals had never been vaccinated. No differences in the frequency of acute exacerbations, pneumonia, or hospitalization were observed.
Conclusions. PCV7 induces a greater functional antibody response than PPSV23 in patients with COPD that persists for 2 years after vaccination. This superior functional response supports testing of conjugate vaccination in studies examining clinical end points.
Clinical Trials Registration: NCT00457977.
PMCID: PMC3491850  PMID: 22652582
8.  Estimates of restrictive ventilatory defect in the mining industry. Considerations for epidemiological investigations: a cross-sectional study 
BMJ Open  2013;3(7):e002561.
(1) To assess the impact of American Thoracic Society and European Respiratory Society (ATS/ERS) ‘acceptability’ and ‘usability’ criteria for spirometry on the estimates of restrictive ventilatory defect in a population of taconite miners. (2) To compare estimates of restrictive ventilatory defect with three different pulmonary function tests (spirometry, alveolar volume (VA) and diffusing capacity (DL,CO)). (3) To assess the role of population characteristics on these estimates.
Cross-sectional study.
Current and former workers in six current taconite mining operations of northeastern Minnesota were surveyed.
We attempted to enrol 3313 participants. Of these, 1353 responded while 1188 current and former workers fully participated in the survey and 1084 performed complete pulmonary function testing and were assessed.
Primary and secondary outcome measures
We applied ATS/ERS acceptability criteria for all tests and categorised participants into groups according to whether they fully met, partially met or did not meet acceptability criteria for spirometry. Obstruction and restriction were defined utilising the lower limit of normal for all tests. When using VA, restriction was identified after excluding obstruction.
Only 519 (47.9%) tests fully met ATS/ERS spirometry acceptability criteria. Within this group, 5% had obstruction and 6%, restriction on spirometry. In contrast, among all participants (N=1084), 16.8% had obstruction, while 4.5% had restriction. VA showed similar results in all groups after obstruction was excluded. Impaired gas transfer (reduced DL,CO) was identified in less than 50% of restriction identified by either spirometry or VA. Body mass index (BMI) was significantly related to spirometric restriction in all groups.
Population estimates of restriction using spirometry or VA varied by spirometric acceptability criteria. Other factors identified as important considerations in the estimation of restrictive ventilatory defect included increased BMI and gas transfer impairment in a relatively smaller proportion of those with spirometric restriction. These insights are important when interpreting population-based physiological data in occupational settings.
PMCID: PMC3717471  PMID: 23869101
Public Health; Epidemiology; Occupational & Industrial Medicine; Respiratory Medicine (see Thoracic Medicine); Statistics & Research Methods
9.  Azithromycin for Prevention of Exacerbations of COPD 
The New England journal of medicine  2011;365(8):689-698.
Acute exacerbations adversely affect patients with chronic obstructive pulmonary disease (COPD). Macrolide antibiotics benefit patients with a variety of inflammatory airway diseases.
We performed a randomized trial to determine whether azithromycin decreased the frequency of exacerbations in participants with COPD who had an increased risk of exacerbations but no hearing impairment, resting tachycardia, or apparent risk of prolongation of the corrected QT interval.
A total of 1577 subjects were screened; 1142 (72%) were randomly assigned to receive azithromycin, at a dose of 250 mg daily (570 participants), or placebo (572 participants) for 1 year in addition to their usual care. The rate of 1-year follow-up was 89% in the azithromycin group and 90% in the placebo group. The median time to the first exacerbation was 266 days (95% confidence interval [CI], 227 to 313) among participants receiving azithromycin, as compared with 174 days (95% CI, 143 to 215) among participants receiving placebo (P<0.001). The frequency of exacerbations was 1.48 exacerbations per patient-year in the azithromycin group, as compared with 1.83 per patient-year in the placebo group (P=0.01), and the hazard ratio for having an acute exacerbation of COPD per patient-year in the azithromycin group was 0.73 (95% CI, 0.63 to 0.84; P<0.001). The scores on the St. George’s Respiratory Questionnaire (on a scale of 0 to 100, with lower scores indicating better functioning) improved more in the azithromycin group than in the placebo group (a mean [±SD] decrease of 2.8±12.8 vs. 0.6±11.4, P=0.004); the percentage of participants with more than the minimal clinically important difference of −4 units was 43% in the azithromycin group, as compared with 36% in the placebo group (P=0.03). Hearing decrements were more common in the azithromycin group than in the placebo group (25% vs. 20%, P=0.04).
Among selected subjects with COPD, azithromycin taken daily for 1 year, when added to usual treatment, decreased the frequency of exacerbations and improved quality of life but caused hearing decrements in a small percentage of subjects. Although this intervention could change microbial resistance patterns, the effect of this change is not known. (Funded by the National Institutes of Health; number, NCT00325897.)
PMCID: PMC3220999  PMID: 21864166
10.  Regional Distribution of Diffusible Tracers and Carbonized Microspheres in the Left Ventricle of Isolated Dog Hearts 
Circulation research  1973;33(5):573-587.
Microspheres of different sizes, 125I-labeled antipyrine (I-Ap), and 42KCl or 86RbCl were injected into the aortic inflow of isolated, Langendorff, perfused, nonworking dogs hearts at blood flows of 1.3–4.8 ml/min g−1. After 15 seconds to 5 minutes, the left ventricle was sectioned into about 300 ordered pieces, and the amount of each tracer was determined. For all tracers, the relative density of deposition was generally higher in the endocardial region, except in one heart in which the aortic pressure and the total coronary flow were low. The deposition of 42K and that of I-Ap were essentially similar in three hearts over a large range of regional variation. This finding suggests either that both tracers were distributed in proportion to flow or that a small diminution in relative density of deposition of 42K in high-flow regions due to lower transcapillary extraction was quantitatively similar to a decrease in the residual fraction of I-Ap in these same regions due to faster washout in the first 15–30 seconds after injection. Large microspheres were deposited preferentially in regions of high flow, exaggerating the apparent heterogeneity of regional flows. The distribution of the smaller microspheres was closer to that for I-Ap or 42K.
PMCID: PMC3008666  PMID: 4752857
myocardial blood flow; tracer exchanges; capillary permeability; iodoantipyrine; radioactive microspheres; 42-potassium; 86-rubidium; indicator-dilution curves; tissue residue functions; flow-limited washout
12.  Superior Immune Response to Protein-Conjugate versus Free Pneumococcal Polysaccharide Vaccine in Chronic Obstructive Pulmonary Disease 
Rationale: Debate exists about the immunogenicity and protective efficacy of antibodies produced by the 23-valent pneumococcal polysaccharide vaccine (PPSV23) in chronic obstructive pulmonary disease (COPD). The 7-valent diphtheria-conjugated pneumococcal polysaccharide vaccine (PCV7) induces a more robust immune response than PPSV23 in healthy elderly adults.
Objectives: We hypothesized that serotype-specific IgG antibody concentration and functional antibody activity would be superior after PCV7 vaccination compared with PPSV23 in moderate to severe COPD. We also posited that older age and prior PPSV23 vaccination would be associated with reduced vaccine responsiveness.
Methods: One hundred twenty patients with COPD were randomized to PPSV23 (63 subjects) or PCV7 (57 subjects). IgG concentrations were determined by ELISA; functional antibody activity was assayed with a standardized opsonophagocytosis assay and reported as an opsonization killing index (OPK). Increases in serotype-specific IgG and OPK at 1 month post vaccination were compared within and between vaccine groups.
Measurements and Main Results: Both vaccines were well tolerated. Within each study group, postvaccination IgG and OPK were higher than baseline (P < 0.01) for all serotypes. Adjusted for baseline levels, postvaccination IgG was higher in the PCV7 group than the PPSV23 group for all seven serotypes, reaching statistical significance for five (P < 0.05). PCV7 resulted in a higher OPK for six of seven serotypes (statistically greater for four) compared with PPSV23. In multivariate analyses, younger age, vaccine naivety, and receipt of PCV7 were associated with increased OPK responses.
Conclusions: PCV7 induces a superior immune response at 1 month post vaccination compared with PPSV23 in COPD. Older age and prior PPSV23 reduce vaccine responsiveness.
Clinical trial registered with (NCT00457977).
PMCID: PMC2742743  PMID: 19556517
pneumococcal vaccines; vaccination, COPD; immune responses; immunization
13.  Genetic Determinants of Emphysema Distribution in the National Emphysema Treatment Trial 
Rationale: Computed tomography (CT) scanning of the lung may reduce phenotypic heterogeneity in defining subjects with chronic obstructive pulmonary disease (COPD), and allow identification of genetic determinants of emphysema severity and distribution.
Objectives: We sought to identify genes associated with CT scan distribution of emphysema in individuals without α1-antitrypsin deficiency but with severe COPD.
Methods: We evaluated baseline CT densitometry phenotypes in 282 individuals with emphysema enrolled in the Genetics Ancillary Study of the National Emphysema Treatment Trial, and used regression models to identify genetic variants associated with emphysema distribution.
Measurements and Main Results: Emphysema distribution was assessed by two methods—assessment by radiologists and by computerized density mask quantitation, using a threshold of −950 Hounsfield units. A total of 77 polymorphisms in 20 candidate genes were analyzed for association with distribution of emphysema. GSTP1, EPHX1, and MMP1 polymorphisms were associated with the densitometric, apical-predominant distribution of emphysema (p value range = 0.001–0.050). When an apical-predominant phenotype was defined by the radiologist scoring method, GSTP1 and EPHX1 single-nucleotide polymorphisms were found to be significantly associated. In a case–control analysis of COPD susceptibility limited to cases with densitometric upper-lobe–predominant cases, the EPHX1 His139Arg single-nucleotide polymorphism was associated with COPD (p = 0.005).
Conclusions: Apical and basal emphysematous destruction appears to be influenced by different genes. Polymorphisms in the xenobiotic enzymes, GSTP1 and EPHX1, are associated with apical-predominant emphysema. Altered detoxification of cigarette smoke metabolites may contribute to emphysema distribution, and these findings may lead to further insight into genetic determinants of emphysema.
PMCID: PMC2049064  PMID: 17363767
COPD; genetics; association analysis; computed tomography; emphysema
14.  Genetic Association Analysis of Functional Impairment in Chronic Obstructive Pulmonary Disease 
Rationale: Patients with severe chronic obstructive pulmonary disease (COPD) may have varying levels of disability despite similar levels of lung function. This variation may reflect different COPD subtypes, which may have different genetic predispositions.
Objectives: To identify genetic associations for COPD-related phenotypes, including measures of exercise capacity, pulmonary function, and respiratory symptoms.
Methods: In 304 subjects from the National Emphysema Treatment Trial, we genotyped 80 markers in 22 positional and/or biologically plausible candidate genes. Regression models were used to test for association, using a test–replication approach to guard against false-positive results. For significant associations, effect estimates were recalculated using the entire cohort. Positive associations with dyspnea were confirmed in families from the Boston Early-Onset COPD Study.
Results: The test–replication approach identified four genes—microsomal epoxide hydrolase (EPHX1), latent transforming growth factor-β binding protein-4 (LTBP4), surfactant protein B (SFTPB), and transforming growth factor-β1 (TGFB1)—that were associated with COPD-related phenotypes. In all subjects, single-nucleotide polymorphisms (SNPs) in EPHX1 (p ⩽ 0.03) and in LTBP4 (p ⩽ 0.03) were associated with maximal output on cardiopulmonary exercise testing. Markers in LTBP4 (p ⩽ 0.05) and SFTPB (p = 0.005) were associated with 6-min walk test distance. SNPs in EPHX1 were associated with carbon monoxide diffusing capacity (p ⩽ 0.04). Three SNPs in TGFB1 were associated with dyspnea (p ⩽ 0.002), one of which replicated in the family study (p = 0.02).
Conclusions: Polymorphisms in several genes seem to be associated with COPD-related traits other than FEV1. These associations may identify genes in pathways important for COPD pathogenesis.
PMCID: PMC2662917  PMID: 16456143
dyspnea; emphysema; exercise tolerance; genetic association; pulmonary function tests

Results 1-14 (14)