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1.  Systemic Inflammation in Young Adults Is Associated with Abnormal Lung Function in Middle Age 
PLoS ONE  2010;5(7):e11431.
Background
Systemic inflammation is associated with reduced lung function in both healthy individuals and those with chronic obstructive pulmonary disease (COPD). Whether systemic inflammation in healthy young adults is associated with future impairment in lung health is uncertain.
Methodology/Principal Findings
We evaluated the association between plasma fibrinogen and C-reactive protein (CRP) in young adults and lung function in the Coronary Artery Risk Development in Young Adults cohort study. Higher year 7 fibrinogen was associated with greater loss of forced vital capacity (FVC) between years 5 and 20 (439 mL in quartile 4 vs. 398 mL in quartile 1, P<0.001) and forced expiratory volume in 1 second (FEV1) (487 mL in quartile 4 vs. 446 mL in quartile 1, P<0.001) independent of cigarette smoking, body habitus, baseline lung function and demographic factors. Higher year 7 CRP was also associated with both greater loss of FVC (455 mL in quartile 4 vs. 390 mL in quartile 1, P<0.001) and FEV1 (491 mL in quartile 4 vs. 442 mL in quartile 1, P = 0.001). Higher year 7 fibrinogen and CRP were associated with abnormal FVC at year 20 (odds ratio (OR) per standard deviation 1.51 (95% confidence interval (CI): 1.30–1.75) for fibrinogen and 1.35 (95% CI: 1.14–1.59) for CRP). Higher year 5 fibrinogen was additionally associated with abnormal FEV1. A positive interaction was observed between pack-years cigarette smoking and year 7 CRP for the COPD endpoint, and among participants with greater than 10 pack-years of cigarette exposure, year 7 CRP was associated with greater odds of COPD at year 20 (OR per standard deviation 1.53 (95% CI: 1.08–2.16).
Conclusion/Significance
Systemic inflammation in young adults is associated with abnormal lung function in middle age. In particular, elevated CRP may identify vulnerability to COPD among individuals who smoke.
Trial Registration
ClinicalTrials.gov NCT00005130
doi:10.1371/journal.pone.0011431
PMCID: PMC2896391  PMID: 20625390
2.  Association of bronchial hyperresponsiveness and lung function with C-reactive protein (CRP): a population based study 
Thorax  2004;59(10):892-896.
Background: C-reactive protein (CRP), a marker of systemic inflammation, is a powerful predictor of adverse cardiovascular events. Respiratory impairment is also associated with cardiovascular risk. Although some studies have found an inverse relationship between lung function and markers of systemic inflammation, only one study has reported a relationship between lung function and CRP levels. In contrast, little is known about the relationship between bronchial hyperresponsiveness (BHR) and systemic inflammation. The association between lung function and CRP and between BHR and CRP has been investigated.
Methods: As part of the European Community Respiratory Health Survey follow up study serum CRP levels, forced expiratory volume in 1 second (FEV1), and BHR to methacholine (⩾20% decrease in FEV1 to <4 mg methacholine) were measured in 259 adults aged 28–56 years free of cardiovascular disease or respiratory infection.
Results: Mean (SD) FEV1 (adjusted for age, sex, height, and smoking status) was lower in subjects with a high CRP level (high tertile) (3.29 (0.44) l/s v 3.50 (0.44) l/s; p<0.001) and BHR was more frequent (41.9% v 24.9%; p = 0.005) than in subjects with lower CRP levels (low+middle tertiles). Similar results were obtained when the potential confounding factors were taken into account. Similar patterns of results were found in non-smokers and in non-asthmatic subjects.
Conclusions: Increased CRP levels are strongly and independently associated with respiratory impairment and more frequent BHR. These results suggest that both respiratory impairment and BHR are associated with a systemic inflammatory process.
doi:10.1136/thx.2003.015768
PMCID: PMC1746828  PMID: 15454657
3.  Systemic inflammation and decline in lung function in a general population: a prospective study 
Thorax  2007;62(6):515-520.
Background
An increase in levels of C‐reactive protein (CRP), a marker of systemic inflammation, is associated with reduced forced expiratory volume in 1 s (FEV1), supporting the hypothesis that the pathophysiology of chronic obstructive pulmonary disease has a systemic inflammatory component. However, few large studies have assessed the relationship between systemic inflammation as measured by CRP and decline in lung function prospectively in a randomly selected population.
Methods
In 1991, data were collected on FEV1 and forced vital capacity (FVC) and a blood sample was taken from 2442 randomly selected adults in a community‐based cohort. In 2000 these measures were repeated in 1301 individuals. The level of serum CRP was analysed in these samples from 1991 and 2000.
Results
In cross‐sectional analyses of data from 1991 and 2000, serum CRP levels were inversely related to FEV1 and FVC. After adjustment for smoking and other confounders, the difference in FEV1 was reduced by −9 ml (95% CI –13 to –5) and –7 ml (95% CI –13 to –2) for each mg/l increment in serum CRP in 1991 and 2000, respectively. There was no significant association between baseline serum CRP levels and decline in FEV1 and FVC over 9 years.
Conclusions
Although serum CRP levels are inversely associated with lung function in cross‐sectional studies, there was no effect of a marker of systemic inflammation on decline in lung function over 9 years.
doi:10.1136/thx.2006.066969
PMCID: PMC2117221  PMID: 17251312
4.  Chronic airflow obstruction and markers of systemic inflammation: Results from the BOLD study in Iceland 
Respiratory medicine  2009;103(10):1548-1553.
Summary
Background
Chronic obstructive pulmonary disease (COPD) is characterized by an irreversible chronic airflow obstruction and by an accelerated decline in lung function. Elevated circulating levels of C-reactive protein (CRP) and interleukin-6 (IL-6), both markers of systemic inflammation, have been found in COPD. Their possible associations with chronic airflow obstruction have mostly been evaluated in highly selected patient samples. Our objective was to evaluate the association between postbronchodilator lung function CRP and IL-6 in a randomly selected sample of the Icelandic population, 40 years and older, while adjusting for gender, age, smoking, and body weight.
Methods
Serum CRP and IL-6 values were measured among participants in the Burden of Obstructive Lung Disease (BOLD) study.
Results
Of the 938 subjects invited a total of 403 men and 355 women participated (response rate 81%) in the study. Their mean age (±SD) was 57.7 (±12.7) years. Both CRP and IL-6 were independently related to lower FEV1 and FVC values. Individuals in the highest quartiles of CRP and IL-6 had a 7.5% and 3.9%, respectively, lower FEV1% than predicted after adjustment for smoking, age, and body weight. High CRP levels were more strongly related to lower FEV1 levels in men (−11.4%) than in women ( −0.4%).
Conclusions
In a random population-based sample both CRP and IL-6 were significantly related to lower spirometric values. The association with CRP was stronger in men than in women. This finding underscores the possible importance of systemic inflammation in irreversible airflow limitation.
doi:10.1016/j.rmed.2009.04.005
PMCID: PMC3334275  PMID: 19427181
Airflow obstruction; Systemic inflammation; Cytokines; C-reactive protein; IL-6
5.  Longitudinal Association of C-Reactive Protein and Lung Function Over 13 Years 
American Journal of Epidemiology  2013;179(1):48-56.
Chronic obstructive pulmonary disease is known to be associated with systemic inflammation. We examined the longitudinal association of C-reactive protein (CRP) and lung function in a cohort of 18,110 men and women from the European Prospective Investigation Into Cancer in Norfolk who were 40–79 years of age at baseline (recruited in 1993–1997) and followed-up through 2011. We assessed lung function by measuring forced vital capacity (FVC) and forced expiratory volume in 1 second (FEV1) at baseline, 4 years, and 13 years. Serum CRP levels were measured using a high-sensitivity assay at baseline and the 13-year follow up. Cross-sectional and longitudinal associations of loge-CRP and lung function were examined using multivariable linear mixed models. In the cross-sectional analysis, 1-standard-deviation increase in baseline loge-CRP (about 3-fold higher CRP on the original milligrams per liter scale) was associated with a −86.3 mL (95% confidence interval: −93.9, −78.6) reduction in FEV1. In longitudinal analysis, a 1-standard-deviation increase in loge-CRP over 13 years was also associated with a −64.0 mL (95% confidence interval: −72.1, −55.8) decline in FEV1 over the same period. The associations were similar for FVC and persisted among lifetime never-smokers. Baseline CRP levels were not predictive of the rate of change in FEV1 or FVC over time. In the present study, we found longitudinal observational evidence that suggested that increases in systemic inflammation are associated with declines in lung function.
doi:10.1093/aje/kwt208
PMCID: PMC3864708  PMID: 24064740
aging; chronic obstructive pulmonary disease; C-reactive protein; inflammation; longitudinal study; lung function
6.  Ventilatory function and cardiovascular disease risk factors: a cross-sectional study in young adults 
BMC Pulmonary Medicine  2014;14(1):206.
Background
The association between impaired lung function and cardiovascular disease (CVD) risk factors has been shown in adults. However, there is little evidence of such an association in young adults, particularly from South America, where the burden of CVD and chronic obstructive pulmonary disease (COPD) is as high as that observed in more developed countries. We therefore investigated the relation between CVD risk factors including metabolic syndrome (MS), and lung function status in young adults from Chile.
Methods
970 subjects from a sample of 998 adults born between 1974 and 1978 in Limache, Chile, were studied. A Spanish translation of the European Community Respiratory Health Survey (ECRHS) questionnaire was used. Forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC) were measured. Weight, height, waist circumference (WC), blood pressure, Homeostatic model assessment (HOMA-IR), triglycerides, high density lipoprotein (HDL), glycaemia, and metabolic syndrome (MS) were also assessed.
Results
The prevalence of MS was 11.8%. A lower FEV1 and lower FVC were associated with having MS (β-coefficient -0.13; 95% Confidence Interval [CI] -0.21 to -0.05, and β-coefficient -0.18; 95% CI -0.27 to -0.09, respectively). Both spirometric measures were also negatively associated with having an elevated HOMA-IR (β-coefficient for FEV1 -0.08; 95% CI -0.13 to -0.03, and β-coefficient for FVC -0.11; 95% CI -0.17 to -0.05). In males only, a lower FEV1 and FVC were associated with having elevated triglycerides (β-coefficient highest vs. lowest tertile -0.13, 95% CI -0.24 to -0.03, and β-coefficient -0.13, 95% CI -0.25 to -0.01, respectively). In women, a higher FEV1 and FVC were statistically significantly related to having higher levels of HDL. Ventilatory function was unrelated to hypertension or WC in this population.
Conclusion
In this population-based study of young adults, a poorer ventilatory function was associated with many CVD risk factors. Endeavours to understand better causality issues of such associations are warranted.
doi:10.1186/1471-2466-14-206
PMCID: PMC4320557  PMID: 25524286
7.  Gender differences in the association between C-reactive protein, lung function impairment, and COPD 
Individuals with COPD have systemic inflammation that can be assessed by measuring C-reactive protein (CRP). In this paper we evaluated whether CRP is related to COPD, lung function and rate of lung function decline.
We included 1237 randomly selected subjects (mean age 42, range 28–56 years) from three centers in the European Community Respiratory Health Survey: Reykjavik, Uppsala and Tartu. CRP was measured at the end of the follow-up (mean 8.3 years) and the values were divided into 4 quartiles.
Fifty-three non-asthmatic subjects fulfilled spirometric criteria for COPD (FEV1/FVC < 70%). COPD occurred more often in the 4th CRP quartile (OR (95% CI) 3.21 (1.13–9.08)) after adjustment for age, gender, body weight and smoking. High CRP levels were related to lower FEV1 values in both men (−437 (−596, −279) mL) and women (−144 (−243, −44) mL). The negative association between CRP and FEV1 was significantly larger in men than women (p = 0.04). The decline in FEV1 was larger (16 (5, 27) mL) in men with high CRP levels whereas no significant association between CRP and FEV1 decline was found in women.
Higher CRP values are significantly associated with COPD and lower lung function in men and women. In men higher CRP values are related to a larger decline in FEV1.
PMCID: PMC2699969  PMID: 18268938
C-reactive protein; COPD; body mass index; spirometry; ECRHS
8.  High sensitive C-reactive protein as a systemic inflammatory marker and LDH-3 isoenzyme in chronic obstructive pulmonary disease 
Background and Objectives:
Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory disease, mainly due to tobacco smoke. Pulmonary function tests (PFTs) are mandatory to diagnose COPD which shows irreversible airway obstruction. This study was aimed at understanding the behavior of biochemical parameters such as high sensitive C-reactive protein (hs-CRP) and lactate dehydrogenase (LDH) isoenzymes in COPD. Cytoplasmic cellular enzymes, such as LDH in the extracellular space, although of no further metabolic function in this space, are of benefit because they serve as indicators suggestive of disturbances of the cellular integrity induced by pathological conditions. The lung pattern is characterized by proportional increases in isoenzymes 3, 4, and 5. Hs-CRP indicates low grade of systemic inflammation.
Materials and Methods:
Total (n = 45) patients of COPD (diagnosed on PFTs) were included. We followed the guidelines laid by the institute ethical committee. Investigations performed on the serum were the serum for hs-CRP, LDH isoenzymes on agarose gel electrophoresis.
Results:
The results obtained showed that the value of hs-CRP was 4.6 ± 0.42 mg/L. The isoenzymes pattern was characterized by an increase in LDH-3 and LDH-4 fractions. This is evident even in those patients with normal LDH (n = 13) levels.
Interpretation and Conclusion:
This study states that there is a moderate positive correlation in between CRP and LDH-3 (r = 0.33; P = 0.01). Raised LDH-3 levels do not correlate with FEV1 % (forced expiratory volume in first second) predicted. Moreover, it associates positively with hs-CRP and smoking status and negatively with body mass index. This underlines the potential of these parameters to complement the present system of staging which is solely based upon FEV1 % predicted.
doi:10.4103/0970-2113.92358
PMCID: PMC3276029  PMID: 22345910
COPD; hs-CRP; LDH-3 isoenzyme
9.  Angry breathing: a prospective study of hostility and lung function in the Normative Aging Study 
Thorax  2006;61(10):863-868.
Background
Hostility and anger are risk factors for, or co‐occur with, many health problems of older adults such as cardiovascular diseases, all‐cause mortality, and asthma. Evidence that negative emotions are associated with chronic airways obstruction suggests a possible role for hostility in the maintenance and decline of pulmonary function. This study tests the hypothesis that hostility contributes to a faster rate of decline in lung function in older adults.
Methods
A prospective examination was undertaken of the effect of hostility on change in lung function over time. Data are from the VA Normative Aging Study, an ongoing cohort of older men. Hostility was measured in 1986 in 670 men who also had an average of three pulmonary function examinations obtained over an average of 8.2 years of follow up. Hostility was ascertained using the 50‐item MMPI based Cook‐Medley Hostility Scale. Pulmonary function was assessed using spirometric tests to obtain measures of forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC).
Results
Baseline pulmonary function differed between high and medium/low hostility groups (mean (SE) percent predicted FEV1 88.9 (18.5) v 95.3 (16.9) and FVC 92.5 (16.5) v 98.9 (15.9), respectively; p<0.01 for both). This overall association between higher hostility and reduced lung function remained significant after adjusting for smoking and education, although the effect size was attenuated for both FEV1 and FVC. Higher hostility was associated with a more rapid decline in lung function, and this effect was unchanged and remained significant for FEV1 in multivariate models but was attenuated for FVC. Each standard deviation increase in hostility was associated with a loss in FEV1 of approximately 9 ml/year.
Conclusions
This study is one of the first to show prospectively that hostility is associated with poorer pulmonary function and more rapid rates of decline among older men.
doi:10.1136/thx.2005.050971
PMCID: PMC2104760  PMID: 16950835
psychological factors; hostility; anger; pulmonary function; risk factor
10.  Airflow obstruction, lung function, and risk of incident heart failure: the Atherosclerosis Risk in Communities (ARIC) study 
European Journal of Heart Failure  2012;14(4):414-422.
Aims
We examined the relationship between forced expiratory volume in 1 s (FEV1), airflow obstruction, and incident heart failure (HF) in black and white, middle-aged men and women in four US communities.
Methods and results
Lung volumes by standardized spirometry and information on covariates were collected on 15 792 Atherosclerosis Risk in Communities (ARIC) cohort participants in 1987–89. Incident HF was ascertained from hospital records and death certificates up to 2005 in 13 660 eligible participants. Over an average follow-up of 14.9 years, 1369 (10%) participants developed new-onset HF. The age- and height-adjusted hazard ratios (HRs) for HF increased monotonically over descending quartiles of FEV1 for both genders, race groups, and smoking status. After multivariable adjustment for traditional cardiovascular risk factors and height, the HRs [95% confidence intervals (CIs)] of HF comparing the lowest with the highest quartile of FEV1 were 3.91 (2.40–6.35) for white women, 3.03 (2.12–4.33) for white men, 2.11 (1.33–3.34) for black women, and 2.23 (1.37–3.59) for black men. The association weakened but remained statistically significant after additional adjustment for systemic markers of inflammation. The multivariable adjusted incidence of HF was higher in those with FEV1/forced vital capacity <70% vs. ≥70%: HR 1.44 (95% CI 1.20–1.74) among men and 1.40 (1.13–1.72) among women. A consistent and positive association with HF was seen for self-reported diagnosis of emphysema and chronic obstructive pulmonary disease, but not for asthma.
Conclusions
In this large population-based cohort with long-term follow-up, low FEV1 and an obstructive respiratory disease were strongly and independently associated with the risk of incident HF.
doi:10.1093/eurjhf/hfs016
PMCID: PMC3530346  PMID: 22366234
Lung function; COPD; Heart failure; Risk factors; Cohort study
11.  A Genetic Association Study of Serum Acute-Phase C-Reactive Protein Levels in Rheumatoid Arthritis: Implications for Clinical Interpretation 
PLoS Medicine  2010;7(9):e1000341.
A genetic association study by Timothy Vyse and colleagues suggests that there is a significant association between CRP variants and acute-phase serum CRP concentrations in patients with rheumatoid arthritis, including those with chronic inflammation.
Background
The acute-phase increase in serum C-reactive protein (CRP) is used to diagnose and monitor infectious and inflammatory diseases. Little is known about the influence of genetics on acute-phase CRP, particularly in patients with chronic inflammation.
Methods and Findings
We studied two independent sets of patients with chronic inflammation due to rheumatoid arthritis (total 695 patients). A tagSNP approach captured common variation at the CRP locus and the relationship between genotype and serum CRP was explored by linear modelling. Erythrocyte sedimentation rate (ESR) was incorporated as an independent marker of inflammation to adjust for the varying levels of inflammatory disease activity between patients. Common genetic variants at the CRP locus were associated with acute-phase serum CRP (for the most associated haplotype: p = 0.002, p<0.0005, p<0.0005 in patient sets 1, 2, and the combined sets, respectively), translating into an approximately 3.5-fold change in expected serum CRP concentrations between carriers of two common CRP haplotypes. For example, when ESR = 50 mm/h the expected geometric mean CRP (95% confidence interval) concentration was 43.1 mg/l (32.1–50.0) for haplotype 1 and 14.2 mg/l (9.5–23.2) for haplotype 4.
Conclusions
Our findings raise questions about the interpretation of acute-phase serum CRP. In particular, failure to take into account the potential for genetic effects may result in the inappropriate reassurance or suboptimal treatment of patients simply because they carry low-CRP–associated genetic variants. CRP is increasingly being incorporated into clinical algorithms to compare disease activity between patients and to predict future clinical events: our findings impact on the use of these algorithms. For example, where access to effective, but expensive, biological therapies in rheumatoid arthritis is rationed on the basis of a DAS28-CRP clinical activity score, then two patients with identical underlying disease severity could be given, or denied, treatment on the basis of CRP genotype alone. The accuracy and utility of these algorithms might be improved by using a genetically adjusted CRP measurement.
Please see later in the article for the Editors' Summary
Editors' Summary
C-reactive protein (CRP) is a serum marker for inflammation or infection and acts by binding to a chemical (phosphocholine) found on the surface of dead or dying cells (and some types of bacteria) in order to activate the immune system (via the complement system). Fat cells release factors that stimulate the liver to produce CRP, and serum levels greater than 10 mg/l are generally considered indicative of an infectious or inflammatory process. After an inflammatory stimulus, serum CRP levels may exceed 500 times baseline, so CRP is used in all medical specialities to help diagnose inflammation and infection. Although patients with chronic inflammatory diseases, such as rheumatoid arthritis, have raised levels of CRP, levels of CRP are still highly variable. Some studies have suggested that there may be genetic variations of CRP (CRP variants) that determine the magnitude of the acute-phase CRP response, a finding that has important clinical implications: CRP thresholds are used as a diagnostic component of formal clinical algorithms and play an important role in a clinician's decision-making process when diagnosing inflammatory disease and choosing treatment options. Therefore, it is possible that false reassurance could be given to a patient with disease, or optimal treatment withheld, because some patients are genetically predisposed to have only a modest increase in acute-phase CRP.
Why Was This Study Done?
Although some studies have looked at the CRP gene variant response, few, if any, studies have examined the CRP gene variant response in the context of chronic inflammation, such as in rheumatoid arthritis. Therefore, this study aimed to determine whether CRP gene variants could also influence CRP serum levels in rheumatoid arthritis.
What Did the Researchers Do and Find?
The authors studied two independent sets of patients with chronic inflammation due to rheumatoid arthritis (total 695 patients): one patient set used a cohort of 281 patients in the UK, and the other patient set (used for replication) consisted of 414 patients from New Zealand and Australia. A genetic technique (a tagSNP approach) was used to capture common variations at the CRP locus (haplotype association analysis) at both the population and the individual level. The relationship between genotype and serum CRP was explored by linear modeling. The researchers found that common genetic variants at the CRP locus were associated with acute-phase serum CRP in both patient sets translating into an approximate 3.5-fold change in expected serum CRP between carriers of two common CRP variants. For example, when ESR = 50 mm/h the expected CRP serum level for one common CRP variant was 43.1 mg/l and for another CRP variant was 14.2 mg/l.
What Do These Findings Mean?
The findings of this study raise questions about the interpretation of acute-phase serum CRP, as they suggest that there is a significant association between CRP variants and acute-phase serum CRP concentrations in a group of patients with rheumatoid arthritis, including those with chronic active inflammation. The size of the genetic effect may be large enough to have a clinically relevant impact on the assessment of inflammatory disease activity, which in turn may influence therapeutic decision making. Failure to take into account the potential for genetic effects may result in the inappropriate reassurance or undertreatment of patients simply because they carry low-CRP–associated genetic variants. CRP is increasingly being incorporated into clinical algorithms to compare disease activity between patients and to predict future clinical events, so these findings impact on the use of such algorithms. The accuracy and utility of these algorithms might be improved by using a genetically adjusted CRP measurement.
Additional Information
Please access these Web sites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1000341
Lab Test Online provides information on CRP
The Wellcome Trust provides a glossary of genetic terms
Learn.Genetics provides access to the Genetic Science Learning Center, which is part of the human genome project
doi:10.1371/journal.pmed.1000341
PMCID: PMC2943443  PMID: 20877716
12.  Occupation and three-year incidence of respiratory symptoms and lung function decline: the ARIC Study 
Respiratory Research  2012;13(1):24.
Background
Specific occupations are associated with adverse respiratory health. Inhalation exposures encountered in these jobs may place workers at risk of new-onset respiratory disease.
Methods
We analyzed data from 8,967 participants from the Atherosclerosis Risk in Communities (ARIC) study, a longitudinal cohort study. Participants included in this analysis were free of chronic cough and phlegm, wheezing, asthma, chronic bronchitis, emphysema, and other chronic lung conditions at the baseline examination, when they were aged 45-64 years. Using data collected in the baseline and first follow-up examination, we evaluated associations between occupation and the three-year incidence of cough, phlegm, wheezing, and airway obstruction and changes in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) measured by spirometry. All associations were adjusted for age, cigarettes per day, race, smoking status, and study center.
Results
During the approximately three-year follow-up, the percentage of participants developing chronic cough was 3%; chronic phlegm, 3%; wheezing, 3%; and airway obstruction, defined as FEV1 < lower limit of normal (LLN) and FEV1/FVC < LLN, 2%. The average annual declines in FEV1 and FVC were 56 mL and 66 mL, respectively, among men and 40 mL and 52 mL, respectively, among women. Relative to a referent category of managerial and administrative support occupations, elevated risks of new-onset chronic cough and chronic phlegm were observed for mechanics and repairers (chronic cough: RR: 1.81, 95% CI: 1.02, 3.21; chronic phlegm: RR: 2.10, 95% CI: 1.23, 3.57) and cleaning and building service workers (chronic cough: RR: 1.85, 95% CI: 1.01, 3.37; chronic phlegm: RR: 2.28, 95% CI: 1.27, 4.08). Despite the elevated risk of new-onset symptoms, employment in cleaning and building services was associated with attenuated lung function decline, particularly among men, who averaged annual declines in FEV1 and FVC of 14 mL and 23 mL, respectively, less than the declines observed in the referent population.
Conclusions
Employment in mechanic and repair jobs and cleaning and building service occupations are associated with increased incidence of respiratory symptoms. Specific occupations affect the respiratory health of adults without pre-existing respiratory health symptoms and conditions, though long-term health consequences of inhalation exposures in these jobs remain largely unexplored.
doi:10.1186/1465-9921-13-24
PMCID: PMC3352304  PMID: 22433119
ARIC study; epidemiology; occupation; respiratory tract disease
13.  Systemic Inflammation and Reduced Pulmonary Function in Chronic Spinal Cord Injury 
Objective
To evaluate the relationship between systemic inflammation and pulmonary function in persons with chronic spinal cord injury (SCI).
Design
Cross-sectional study.
Setting
Veterans Affairs Medical Center.
Participants
Fifty-nine men with chronic SCI participating in a prior epidemiologic study.
Methods
Standardized assessment of pulmonary function and measurement of plasma C-reactive protein (CRP) and interleukin-6 (IL-6).
Main Outcome Measurements
Forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC).
Results
Persons with the highest values of IL-6 had the lowest %-predicted FEV1 and FVC. There was a significant inverse linear trend between quartile of IL-6 and %-predicted FEV1 (P < .001) and FVC (P < .006), unadjusted and adjusted for SCI level and completeness of injury, obstructive lung disease history, smoking, and body mass index (P = .010-.039). Although not as strong as for IL-6, there also were similar trends for %-predicted FEV1 and FVC with CRP.
Conclusions
In chronic SCI, higher levels of IL-6 and CRP were associated with a lower FEV1 and FVC, independent of level and completeness of injury. These results suggest that the reduction of pulmonary function after SCI is related not only to neuromuscular impairment but also to factors that promote systemic inflammation.
doi:10.1016/j.pmrj.2011.02.003
PMCID: PMC3141080  PMID: 21570031
14.  Genome-wide association study of lung function decline in adults with and without asthma 
Background
Genome-wide association studies (GWAS) have identified determinants of chronic obstructive pulmonary disease, asthma and lung function level, however none addressed decline in lung function.
Aim
We conducted the first GWAS on age-related decline in forced expiratory volume in the first second (FEV1) and in its ratio to forced vital capacity (FVC) stratified a priori by asthma status.
Methods
Discovery cohorts included adults of European ancestry (1441 asthmatics, 2677 non-asthmatics; Epidemiological Study on the Genetics and Environment of Asthma (EGEA); Swiss Cohort Study on Air Pollution And Lung And Heart Disease In Adults (SAPALDIA); European Community Respiratory Health Survey (ECRHS)). The associations of FEV1 and FEV1/FVC decline with 2.5 million single nucleotide polymorphisms (SNPs) were estimated. Thirty loci were followed-up by in silico replication (1160 asthmatics, 10858 non-asthmatics: Atherosclerosis Risk in Communities (ARIC); Framingham Heart Study (FHS); British 1958 Birth Cohort (B58C); Dutch asthma study).
Results
Main signals identified differed between asthmatics and non-asthmatics. None of the SNPs reached genome-wide significance. The association between the height related gene DLEU7 and FEV1 decline suggested for non-asthmatics in the discovery phase was replicated (discovery P=4.8×10−6; replication P=0.03) and additional sensitivity analyses point to a relation to growth. The top ranking signal, TUSC3, associated with FEV1/FVC decline in asthmatics (P=5.3×10−8) did not replicate. SNPs previously associated with cross-sectional lung function were not prominently associated with decline.
Conclusions
Genetic heterogeneity of lung function may be extensive. Our results suggest that genetic determinants of longitudinal and cross-sectional lung function differ and vary by asthma status.
doi:10.1016/j.jaci.2012.01.074
PMCID: PMC3340499  PMID: 22424883
Asthma; cohort studies; genome-wide association; lung function decline; heterogeneity
15.  Lung Function and Incidence of Chronic Obstructive Pulmonary Disease after Improved Cooking Fuels and Kitchen Ventilation: A 9-Year Prospective Cohort Study 
PLoS Medicine  2014;11(3):e1001621.
Pixin Ran, Nanshan Zhong, and colleagues report that cleaner cooking fuels and improved ventilation were associated with better lung function and reduced COPD among a cohort of villagers in Southern China.
Please see later in the article for the Editors' Summary
Background
Biomass smoke is associated with the risk of chronic obstructive pulmonary disease (COPD), but few studies have elaborated approaches to reduce the risk of COPD from biomass burning. The purpose of this study was to determine whether improved cooking fuels and ventilation have effects on pulmonary function and the incidence of COPD.
Methods and Findings
A 9-y prospective cohort study was conducted among 996 eligible participants aged at least 40 y from November 1, 2002, through November 30, 2011, in 12 villages in southern China. Interventions were implemented starting in 2002 to improve kitchen ventilation (by providing support and instruction for improving biomass stoves or installing exhaust fans) and to promote the use of clean fuels (i.e., biogas) instead of biomass for cooking (by providing support and instruction for installing household biogas digesters); questionnaire interviews and spirometry tests were performed in 2005, 2008, and 2011. That the interventions improved air quality was confirmed via measurements of indoor air pollutants (i.e., SO2, CO, CO2, NO2, and particulate matter with an aerodynamic diameter of 10 µm or less) in a randomly selected subset of the participants' homes. Annual declines in lung function and COPD incidence were compared between those who took up one, both, or neither of the interventions.
Use of clean fuels and improved ventilation were associated with a reduced decline in forced expiratory volume in 1 s (FEV1): decline in FEV1 was reduced by 12 ml/y (95% CI, 4 to 20 ml/y) and 13 ml/y (95% CI, 4 to 23 ml/y) in those who used clean fuels and improved ventilation, respectively, compared to those who took up neither intervention, after adjustment for confounders. The combined improvements of use of clean fuels and improved ventilation had the greatest favorable effects on the decline in FEV1, with a slowing of 16 ml/y (95% CI, 9 to 23 ml/y). The longer the duration of improved fuel use and ventilation, the greater the benefits in slowing the decline of FEV1 (p<0.05). The reduction in the risk of COPD was unequivocal after the fuel and ventilation improvements, with an odds ratio of 0.28 (95% CI, 0.11 to 0.73) for both improvements.
Conclusions
Replacing biomass with biogas for cooking and improving kitchen ventilation are associated with a reduced decline in FEV1 and risk of COPD.
Trial Registration
Chinese Clinical Trial Register ChiCTR-OCH-12002398
Please see later in the article for the Editors' Summary
Editors' Summary
Background
Nearly 3 billion people in developing countries heat their homes and cook by burning biomass—wood, crop waste, and animal dung—in open fires and leaky stoves. Burning biomass this way releases pollutants into the home that impair lung function and that are responsible for more than a million deaths from chronic obstructive pulmonary disease (COPD) every year. COPD is a group of diseases that interfere with breathing. Normally, air is breathed in through the nose or mouth and travels down the windpipe into two bronchial tubes (airways) in the lungs. These tubes branch into smaller tubes (bronchioles) that end in bunches of tiny air sacs (alveoli). Oxygen in the air passes through the thin walls of these sacs into small blood vessels and is taken to the heart for circulation round the body. The two main types of COPD—chronic bronchitis (long-term irritation and swelling of the bronchial tubes) and emphysema (damage to the walls of the alveoli)—make it hard for people to breathe. Most people with COPD have both chronic bronchitis and emphysema, both of which are caused by long-term exposure to cigarette smoke, indoor air pollution, and other lung irritants. Symptoms of COPD include breathlessness during exercise and a persistent cough that produces large amounts of phlegm (mucus). There is no cure for COPD, but drugs and oxygen therapy can relieve its symptoms, and avoiding lung irritants can slow disease progression.
Why Was This Study Done?
Exposure to indoor air pollution has been associated with impaired lung function and COPD in several studies. However, few studies have assessed the long-term effects on lung function and on the incidence of COPD (the proportion of a population that develops COPD each year) of replacing biomass with biogas (a clean fuel produced by bacterial digestion of biodegradable materials) for cooking and heating, or of improving kitchen ventilation during cooking. Here, the researchers undertook a nine-year prospective cohort study in rural southern China to investigate whether these interventions are associated with any effects on lung function and on the incidence of COPD. A prospective cohort study enrolls a group of people, determines their characteristics at baseline, and follows them over time to see whether specific characteristic are associated with specific outcomes.
What Did the Researchers Do and Find?
The researchers offered nearly 1,000 people living in 12 villages in southern China access to biogas and to improved kitchen ventilation. All the participants, who adopted these interventions according to personal preferences, completed a questionnaire about their smoking habits and occupational exposure to pollutants and had their lung function measured using a spirometry test at the start and end of the study. Some participants also completed a questionnaire and had their lung function measured three and six years into the study. Finally, the researchers measured levels of indoor air pollution in a randomly selected subset of homes at the end of the study to confirm that the interventions had reduced indoor air pollution. Compared with non-use, the use of clean fuels and of improved ventilation were both associated with a reduction in the decline in lung function over time after adjusting for known characteristics that affect lung function, such as smoking. The use of both interventions reduced the decline in lung function more markedly than either intervention alone, and the benefits of using the interventions increased with length of use. Notably, the combined use of both interventions reduced the risk of COPD occurrence among the study participants.
What Do These Findings Mean?
These findings suggest that, among people living in rural southern China, the combined interventions of use of biogas instead of biomass and improved kitchen ventilation were associated with a reduced decline in lung function over time and with a reduced risk of COPD. Because participants were not randomly allocated to intervention groups, the people who adopted the interventions may have shared other unknown characteristics (confounders) that affected their lung function (for example, having a healthier lifestyle). Thus, it is not possible to conclude that either intervention actually caused a reduction in the decline in lung function. Nevertheless, these findings suggest that the use of biogas as a substitute for biomass for cooking and heating and improvements in kitchen ventilation might lead to a reduction in the global burden of COPD associated with biomass smoke.
Additional Information
Please access these websites via the online version of this summary at http://dx.doi.org/10.1371/journal.pmed.1001621.
The US National Heart, Lung, and Blood Institute provides detailed information for the public about COPD
The US Centers for Disease Control and Prevention provides information about COPD and links to other resources (in English and Spanish)
The UK National Health Service Choices website provides information for patients and carers about COPD, personal stories, and links to other resources
The British Lung Foundation, a not-for-profit organization, provides information about COPD in several languages
The Global Initiative for Chronic Obstructive Lung Disease works to improve prevention and treatment of COPD around the world
The World Health Organization provides information about all aspects of indoor air pollution and health (in English, French, and Spanish)
MedlinePlus provides links to other information about COPD (in English and Spanish)
doi:10.1371/journal.pmed.1001621
PMCID: PMC3965383  PMID: 24667834
16.  Impact of active and passive smoking as risk factors for asthma and COPD in women presenting to primary care in Syria: first report by the WHO-GARD survey group 
Background
The burden of chronic respiratory disease (CRD) is alarming. International studies suggest that women with CRD are undersurveyed and underdiagnosed by physicians worldwide. It is unclear what the prevalence of CRD is in the general population of Syria, particularly among women, since there has never been a survey on CRD in this nation. The purpose of this study was to investigate the impact of different patterns of smoking on CRD in women.
Materials and methods
We extracted data on smoking patterns and outcome in women from the Global Alliance Against Chronic Respiratory Diseases survey. Using spirometric measurements before and after the use of inhaled bronchodilators, we tracked the frequency of CRD in females active and passive narghile or cigarette smokers presenting to primary care. We administered the questionnaire to 788 randomly selected females seen during 1 week in the fiscal year 2009–2010 in 22 primary care centers in six different regions of Syria. Inclusion criteria were age >6 years, presenting for any medical complaint. In this cross-sectional study, three groups of female subjects were evaluated: active smokers of cigarettes, active smokers of narghiles, and passive smokers of either cigarettes or narghiles. These three groups were compared to a control group of female subjects not exposed to active or passive smoking.
Results
Exposure to active cigarette smoke but not narghile smoke was associated with doctor-diagnosed chronic obstructive pulmonary disease (COPD). However, neither cigarette nor narghile active smoking was associated with increased incidence of spirometrically diagnosed COPD. Paradoxically, exposure to passive smoking of either cigarettes or narghiles resulted in association with airway obstruction, defined as forced expiratory volume in 1 second (FEV1)/forced vital capacity (FVC) < 70% according to the Global initiative for chronic Obstructive Lung Disease criteria; association with FEV1 < 80% predicted, evidencing moderate to severe GOLD spirometric grade, and doctor-diagnosed COPD. Physicians tend to underdiagnose COPD in women who present to primary care clinics. Whereas around 15% of enrolled women had evidence of COPD with FEV1/FVC < 70% after bronchodilators, only 4.8% were physician-diagnosed. Asthma did not appear to be a significant spirometric finding in these female subjects, although around 11% had physician-diagnosed asthma. One limitation is FEV1/FVC < 70% could have also resulted from uncontrolled asthma. The same limitation has been reported by the Proyecto Latinoamericano de Investigacion en Obstruccion Pulmonar (PLATINO) study.
Conclusion
Contrary to popular belief in developing countries, women exposed to tobacco smoke, whether active or passive, and whether by cigarettes or narghiles, like men are at increased risk for the development of COPD, although cultural habits and taboos may decrease the risk of active smoking in some women.
Recommendations
These findings will be considered for country and region strategy for noncommunicable diseases, to overcome underdiagnosis of CRD in women, fight widespread female cigarette and narghile smoking, and promote behavioral research in this field.
doi:10.2147/COPD.S50551
PMCID: PMC3794890  PMID: 24124359
passive smoking; women; COPD; asthma; narghile; water pipe; behavior
17.  Systemic inflammation, depression and obstructive pulmonary function: a population-based study 
Respiratory Research  2013;14(1):53.
Background
Levels of Interleukin-6 (IL-6) and C-creative protein (CRP) indicating systemic inflammation are known to be elevated in chronic diseases including chronic obstructive pulmonary disease (COPD) and depression. Comorbid depression is common in patients with COPD, but no studies have investigated whether proinflammatory cytokines mediate the association between pulmonary function and depressive symptoms in healthy individuals with no known history of obstructive pulmonary diseases.
Methods
In a population-based sample (n = 2077) of individuals aged 55 and above with no known history of obstructive pulmonary disease in the Singapore Longitudinal Ageing Study (SLAS), we analyzed the relationships between IL-6 and CRP, depressive symptoms (GDS-15 ≥5) and obstructive pulmonary function (FEV1% predicted and FEV1/FVC% predicted).
Results
High serum levels of IL-6 and CRP were associated with greater prevalence of depressive symptoms (p < 0.05). High IL-6, high CRP and depressive symptoms were independently associated with decreased FEV1% predicted and FEV1/FVC% predicted after adjusting for smoking status, BMI and number of chronic inflammatory diseases. Increasing grades of combination of inflammatory markers and/or depressive symptoms was associated with progressive increases in pulmonary obstruction. In hierarchical models, the significant association of depressive symptoms with pulmonary obstruction was reduced by the presence of IL-6 and CRP.
Conclusions
This study found for the first time an association of depressive symptoms and pulmonary function in older adults which appeared to be partly mediated by proinflammatory cytokines. Further studies should be conducted to investigate proinflammatory immune markers and depressive symptoms as potential phenotypic indicators for chronic obstructive airway disorders in older adults.
doi:10.1186/1465-9921-14-53
PMCID: PMC3656806  PMID: 23676005
Depressive symptoms; Pulmonary function; Healthy individuals; Common neurobiological process; Inverse association
18.  Association Between Combined Interleukin-6 and C-Reactive Protein Levels and Pulmonary Function in Older Women: Results from the Women’s Health and Aging Studies I and II 
OBJECTIVES
To determine whether combined higher interleukin-6 (IL-6) and C-reactive protein (CRP) levels are associated with lower pulmonary function levels in older women, accounting for chronic inflammatory diseases, physical function, and other factors associated with inflammation.
DESIGN
Cross-sectional study using data from two prospective cohorts.
SETTING
Baltimore, Maryland.
PARTICIPANTS
Eight hundred forty disabled and 332 higher-functioning community-dwelling women aged 65 and older from the Women’s Health and Aging Studies (WHAS) I and II, respectively.
MEASUREMENTS
IL-6 and CRP, combined according to their tertile concentrations, and pulmonary function measures, assessed according to forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC).
RESULTS
In WHAS I and II, similar dose-response trends were observed between combined higher IL-6 and CRP levels and lower pulmonary function levels. In WHAS I (disabled women), the combined highest IL-6 and CRP levels were associated with the lowest levels of FEV1 (mean 137.0 mL, 95% confidence interval (CI) = 128.4–145.7 mL) and FVC (mean 191.7 mL, 95% CI = 180.4–202.9 mL). Similarly, in WHAS II (higher-functioning women), the combined highest IL-6 and CRP levels were associated with the lowest levels of FEV1 (mean 158.3 mL, 95% CI = 146.3–170.4 mL) and FVC (mean 224.2 mL, 95% CI = 209.9–238.5 mL).
CONCLUSION
Combined elevations in IL-6 and CRP were associated with the lowest pulmonary function levels in older women. These findings suggest that high IL-6 and CRP levels may be an indication of prevalent impaired pulmonary function. Future studies should determine whether measurement of IL-6 and CRP could enhance current methods of monitoring respiratory diseases beyond that provided by pulmonary function measures.
doi:10.1111/j.1532-5415.2010.03203.x
PMCID: PMC4050638  PMID: 21226682
pulmonary function; inflammation; older women
19.  Association of biomarkers of inflammation and cell adhesion with lung function in the elderly: a population-based study 
BMC Geriatrics  2013;13:82.
Background
Low lung function is associated with increased morbidity and mortality. It is therefore of interest to identify biomarkers that are associated with impaired lung function. The aim of the study was to analyse associations of biomarkers and combinations of biomarkers with lung function in an elderly general population.
Methods
Lung function (FEV1 and FVC) and a panel of 15 inflammatory markers from blood samples were analysed in 888 subjects aged 70 years. Biomarkers included cytokines, chemokines, adhesion molecules, C-reactive protein (CRP) and leukocyte count.
Results
Leukocyte count and CRP were independently associated with FEV1 after adjustments for other inflammatory markers, sex, BMI, current smoking and pack-years of smoking. In a similar model, leukocyte count and vascular cell adhesion protein 1 (VCAM-1) were the biomarkers that were significantly associated with FVC. Subjects that had both leukocyte count and CRP in the lowest tertile had a FEV1 that was 9% of predicted higher than subjects with leukocyte count and CRP in the highest tertile (103±16 vs. 94±21% of predicted, p=0.0002) (mean±SD). A difference of 8% of predicted in FVC was found between subjects with leukocyte count and VCAM-1 in the lowest and highest tertiles, respectively (106±18 vs. 98±19% of predicted, p=0.002).
Conclusion
Leucocyte count, CRP and VCAM-1 were found to relate to poorer lung function. A dose related association was found for the combination leukocyte count and CRP towards FEV1 and leukocyte and VCAM-1 towards FVC. This indicates that combination of two biomarkers yielded more information than assessing them one by one when analysing the association between systemic inflammation and lung function.
doi:10.1186/1471-2318-13-82
PMCID: PMC3750696  PMID: 23924044
Lung function; FEV1; FVC; COPD; Biomarkers; Gender
20.  Relation of ventilatory impairment and of chronic mucus hypersecretion to mortality from obstructive lung disease and from all causes. 
Thorax  1990;45(8):579-585.
The relation of ventilatory impairment and chronic mucus hypersecretion to death from all causes and death from obstructive lung disease (chronic bronchitis, emphysema and asthma) was studied in 13,756 men and women randomly selected from the general population of the City of Copenhagen. During the 10 year follow up 2288 subjects died. In 164 subjects obstructive lung disease was considered to be an underlying or a contributory cause of death (obstructive lung disease related death); in 73 subjects it was considered to be the underlying cause of death (obstructive lung disease death). Forced expiratory volume in one second, expressed as a percentage of the predicted value (FEV1% pred), and the presence of chronic phlegm were used to characterise ventilatory function and chronic mucus hypersecretion respectively. For mortality analysis the proportional hazards regression model of Cox was used; it included age, sex, pack years, inhalation habit, body mass index, alcohol consumption, and the presence or absence of asthma, heart disease, and diabetes mellitus as confounding factors. By comparison with subjects with an FEV1 of 80% pred or more, subjects with an FEV1 below 40% pred had increased risk of dying from all causes (relative risk (RR) = 5.0 for women, 2.7 for men), a higher risk of obstructive lung disease related death (RR = 57 for women, 34 for men), and a higher risk of obstructive lung disease death (RR = 101 for women, 77 for men). Chronic mucus hypersecretion was associated with only a slightly higher risk of death from all causes (RR = 1.1 for women, 1.3 for men). The association between chronic mucus hypersecretion and obstructive lung disease death varied with the level of ventilatory function, being weak in subjects with normal ventilatory function (for an FEV1 of 80% pred the RR was 1.2), but more pronounced in subjects with reduced ventilatory function (for an FEV1 of 40% pred the RR was 4.2). A similar though statistically non-significant trend was observed with regard to obstructive lung disease related death. This study shows that impaired lung function is very strongly related to total mortality, obstructive lung disease related mortality, and obstructive lung disease mortality and suggests that chronic mucus hypersecretion, in those with impaired ventilatory function, is also a significant risk factor for death from obstructive lung disease.
PMCID: PMC462624  PMID: 2402719
21.  Hypertension, Systemic Inflammation and Body Weight in Relation to Lung Function Impairment—An Epidemiological Study 
COPD  2009;6(4):250-255.
Recent reports on the simultaneous occurrence of systemic inflammation and airflow obstruction are usually based on a highly selective patient population, but their importance warrants further evaluation in the general population. The objectives were to study the interrelationship between airflow obstruction, smoking, hypertension, obesity and CRP as a marker of systemic inflammation in a randomly selected sample of the general Icelandic population (n = 939). This study comprised 758 randomly selected men and women 40 years and older living in Reykjavik, Iceland, and who were participating in the Burden of Obstructive Lung Disease (BOLD) study (81% response rate). In addition to the BOLD protocol, which included post-bronchodilator spirometry, they answered questions about general health and medication. Serum samples were taken for measurement of C-reactive protein (CRP). In the sample—245 individuals (33%) reported having hypertension. Subjects with hypertension were older, had a higher BMI and higher CRP levels. Subjects with hypertension had lower values of FEV1 than predicted (89.9 ± 18.5 vs. 94.5 ± 14.4%) (p < 0.001) and FVC (92.2 ± 15.1 vs. 95.3 ± 12.3%) (p = 0.002). These differences remained significant after adjusting for age, BMI, CRP and smoking. Hypertension and CRP levels above the median were both independently and additively associated with lower FEV1 and FVC. In addition a lower FVC% was also associated with a higher BMI (> 30 mg/m2). Use of betablocking antihypertensives was not related to lung function. Hypertension, BMI and systemic inflammation affect lung function independently of each other. All three variables have a negative effect on FVC, while hypertension and high CRP were independently associated with impaired FEV1.
PMCID: PMC3334274  PMID: 19811383
Airflow obstruction; hypertension; obesity; systemic inflammation; cytokines
22.  Increase in prevalence and severity of asthma in young adults in Copenhagen 
Thorax  2000;55(10):833-836.
BACKGROUND—It is the general impression that the prevalence of asthma has increased during recent decades. A study was undertaken to investigate asthma prevalence, respiratory symptoms, and lung function in young adults in the City of Copenhagen 15 years apart.
METHODS—Men and women aged 20-35 years were sampled from the general population living in a defined area of central Copenhagen. The first examination took place in 1976-8 and comprised 1034 subjects (response rate 67.2%). A new sample comprising 1104 subjects (response rate 62.6%) from exactly the same area was examined 15 years later in 1991-4. All participants answered a questionnaire on respiratory symptoms and diseases and performed spirometric tests with measurement of forced expiratory volume in one second (FEV1) and forced vital capacity (FVC).
RESULTS—The prevalence of self-reported asthma increased from 1.5% in the first survey to 4.8% in the second survey (p<0.001). Asthmatic subjects had, on average, poorer lung function than non-asthmatic subjects in terms of FEV1 and this difference was more pronounced in the second survey than in the first (10.0% of predicted versus 2.4% of predicted). Smoking decreased significantly from 62% in 1976-8 to 45% in 1991-4 (p<0.001).
CONCLUSIONS—The prevalence of self-reported asthma has increased significantly among young adults in Copenhagen over a 15 year period. The severity of asthma, as judged by the level of FEV1, has also increased. These findings cannot be explained by changes in smoking habits.


doi:10.1136/thorax.55.10.833
PMCID: PMC1745615  PMID: 10992534
23.  Respiratory symptoms and lung function in young adults with severe α1–antitrypsin deficiency (PiZZ) 
Thorax  2002;57(8):705-708.
Background: Neonatal screening for alpha1–antitrypsin (AAT) deficiency was undertaken in Sweden between 1972 and 1974 when 129 infants with severe AAT deficiency (phenotype PiZ) were identified. The cohort has been followed up prospectively.
Methods: 124 PiZ subjects, still alive and still living in Sweden, were invited to a follow up examination at about 22 years of age. The check up included a clinical examination, spirometric tests, and a questionnaire on smoking habits and respiratory symptoms.
Results: Ninety eight subjects (97 PiZZ and 1 PiZ–) subjects attended the follow up. The mean age of the subjects was 22.5 years (range 19.8–24.8). The mean (SD) forced expiratory volume in 1 second (FEV1) was 98 (14)% predicted, vital capacity (VC) was 103 (14)% predicted, and the mean FEV1/VC ratio was 83 (7)%. Eighty six subjects had previously undergone spirometric tests. The median follow up time was 4.3 years (range 0.9–7.3). The mean annual change in FEV1 (% predicted) was –1.2% (95% CI –2.1 to –0.3), in VC (% predicted) was –1.5% (95% CI –2.0 to –0.9), and in the FEV1/VC ratio (%) was –0.3% (95% CI –0.7 to 0.2). Twenty eight individuals (29%) reported recurrent wheezing. Fifteen subjects (15%) had been diagnosed by a physician as having asthma. Eighteen subjects reported that they had smoked at some time; 10 were current smokers. The mean number of pack years among the ever smokers was 3.4 (range 0.6–10.5). Ten of 18 ever-smokers and 18 of 80 non-smokers reported recurrent wheezing (p<0.01), while exertional dyspnoea was reported by six ever smokers and 11 non-smokers (p<0.05). Lung function test results did not differ significantly between ever smokers and non-smokers.
Conclusions: Young PiZ adults have essentially normal lung function, but have a high prevalence of asthma symptoms. Smoking in these individuals is associated with an increased frequency of respiratory symptoms.
doi:10.1136/thorax.57.8.705
PMCID: PMC1746413  PMID: 12149531
24.  The Association of Pipe and Cigar Use with Cotinine Levels, Lung Function and Airflow Obstruction: a Cross-sectional Study 
Annals of internal medicine  2010;152(4):201-210.
Background
Cigarette smoking is the major cause of chronic obstructive pulmonary disease but studies on the contribution of other smoking techniques are sparse.
Objective
We hypothesized that pipe and cigar smoking was associated with elevated cotinine levels, decrements in lung function and increased odds of airflow obstruction.
Design
Cross-sectional study.
Setting
Population-based sample from six US communities.
Participants
The Multi-Ethnic Study of Atherosclerosis (MESA) recruited men and women ages 45-84 years without clinical cardiovascular disease.
Measurements
The MESA Lung Study measured spirometry following American Thoracic Society guidelines and urinary cotinine levels by immunoassay. Pipe-years and cigar-years were calculated as years from self-reported age of starting to quitting (or to current age among current users) × pipefuls or cigars per day.
Results
Of 3,528 participants, 8% reported pipe smoking (median 15 pipe-years), 11% reported cigar smoking (median 6 cigar-years), and 52% reported cigarette smoking (median 18 pack-years). Self-reported current pipe and cigar smokers had elevated urinary cotinine levels compared to never smokers. Pipe-years were associated with decrements in the forced expiratory volume in one second (FEV1) and cigar-years were associated with decrements in the FEV1 and the ratio of the FEV1 to the forced vital capacity. Participants who smoked pipes or cigars had an increased odds of airflow obstruction whether they had also smoked cigarettes (Odds ratio 3.43; 95% CI: 1.75, 6.71; P<0.001) or had never smoked cigarettes (Odds ratio 2.31; 95% CI: 1.04, 5.11; P=0.039) compared to participants with no smoking history.
Limitations
Cross-sectional design.
Conclusions
Pipe and cigar smoking increased urinary cotinine levels and was associated with decrements in lung function and increased odds of airflow obstruction, even among participants who never smoked cigarettes.
doi:10.1059/0003-4819-152-4-201002160-00004
PMCID: PMC2906916  PMID: 20157134
25.  Inverse association of plasma IL-13 and inflammatory chemokines with lung function impairment in stable COPD: a cross-sectional cohort study 
Respiratory Research  2007;8(1):64.
Background
Chronic obstructive pulmonary disease (COPD) is a heterogeneous syndrome characterized by varying degrees of airflow limitation and diffusion impairment. There is increasing evidence to suggest that COPD is also characterized by systemic inflammation. The primary goal of this study was to identify soluble proteins in plasma that associate with the severity of airflow limitation in a COPD cohort with stable disease. A secondary goal was to assess whether unique markers associate with diffusion impairment, based on diffusion capacity of carbon monoxide (DLCO), independent of the forced expiratory volume in 1 second (FEV1).
Methods
A cross sectional study of 73 COPD subjects was performed in order to examine the association of 25 different plasma proteins with the severity of lung function impairment, as defined by the baseline measurements of the % predicted FEV1 and the % predicted DLCO. Plasma protein concentrations were assayed using multiplexed immunobead-based cytokine profiling. Associations between lung function and protein concentrations were adjusted for age, gender, pack years smoking history, current smoking, inhaled corticosteroid use, systemic corticosteroid use and statin use.
Results
Plasma concentrations of CCL2/monocyte chemoattractant protein-1 (CCL2/MCP-1), CCL4/macrophage inflammatory protein-1β (CCL4/MIP -1β), CCL11/eotaxin, and interleukin-13 (IL-13) were inversely associated with the % FEV1. Plasma concentrations of soluble Fas were associated with the % DLCO, whereas CXCL9/monokine induced by interferon-γ (CXCL9/Mig), granulocyte- colony stimulating factor (G-CSF) and IL-13 showed inverse relationships with the % DLCO.
Conclusion
Systemic inflammation in a COPD cohort is characterized by cytokines implicated in inflammatory cell recruitment and airway remodeling. Plasma concentrations of IL-13 and chemoattractants for monocytes, T lymphocytes, and eosinophils show associations with increasing severity of disease. Soluble Fas, G-CSF and CXCL9/Mig may be unique markers that associate with disease characterized by disproportionate abnormalities in DLCO independent of the FEV1.
doi:10.1186/1465-9921-8-64
PMCID: PMC2064925  PMID: 17868461

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