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1.  Determinants of Forced Expiratory Volume in 1 Second (FEV1), Forced Vital Capacity (FVC), and FEV1/FVC in Chronic Spinal Cord Injury 
Objective
To assess factors that influence pulmonary function, because respiratory system dysfunction is common in chronic spinal cord injury (SCI).
Design
Cross-sectional cohort study.
Setting
Veterans Affairs Boston SCI service and the community.
Participants
Between 1994 and 2003, 339 white men with chronic SCI completed a respiratory questionnaire and underwent spirometry.
Interventions
Not applicable.
Main Outcome Measures
Forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and FEV1/FVC.
Results
Adjusting for SCI level and completeness, FEV1 (−21.0mL/y; 95% confidence interval [CI], −26.3 to −15.7 mL/y) and FVC (−17.2mL/y; 95% CI, −23.7 to −10.8mL/y) declined with age. Lifetime cigarette use was also associated with a decrease in FEV1 (−3.8mL/pack-year; 95% CI, −6.5 to −1.1mL/pack-year), and persistent wheeze and elevated body mass index were associated with a lower FEV1/FVC. A greater maximal inspiratory pressure (MIP) was associated with a greater FEV1 and FVC. FEV1 significantly decreased with injury duration (−6.1mL/y; 95% CI, −11.7 to −0.6mL/y), with the greatest decrement in the most neurologically impaired. The most neurologically impaired also had a greater FEV1/FVC, and their FEV1 and FVC were less affected by age and smoking.
Conclusions
Smoking, persistent wheeze, obesity, and MIP, in addition to SCI level and completeness, were significant determinants of pulmonary function. In SCI, FEV1, FVC, and FEV1/FVC may be less sensitive to factors associated with change in airway size and not reliably detect the severity of airflow obstruction.
doi:10.1016/j.apmr.2006.06.015
PMCID: PMC1896316  PMID: 17023241
Pulmonary disease; chronic obstruction; Pulmonary function tests; Quadriplegia; Rehabilitation; Spinal cord injuries
2.  Repetitive element hypomethylation in blood leukocyte DNA and cancer incidence, prevalence and mortality in elderly individuals: the Normative Aging Study 
Cancer causes & control : CCC  2010;22(3):437-447.
Background
Global genomic hypomethylation is a common epigenetic event in cancer that mostly results from hypomethylation of repetitive DNA elements. Case-control studies have associated blood leukocyte DNA hypomethylation with several cancers. Because samples in case-control studies are collected after disease development, whether DNA hypomethylation is causal or just associated with cancer development is still unclear.
Methods
In 722 elderly subjects from the Normative Aging Study cohort, we examined whether DNA methylation in repetitive elements (Alu, LINE-1) was associated with cancer incidence (30 new cases, median follow-up: 89 months), prevalence (205 baseline cases), and mortality (28 deaths, median follow-up: 85 months). DNA methylation was measured by bisulfite pyrosequencing.
Results
Individuals with low LINE-1 methylation (
Conclusion
These findings suggest that individuals with lower repetitive element methylation are at high risk of developing and dying from cancer.
doi:10.1007/s10552-010-9715-2
PMCID: PMC3752839  PMID: 21188491
Repetitive elements; DNA methylation; Epigenetics; Blood; Cancer risk
Thorax  2013;68(7):634-642.
Background
Cigarette smoking is the major cause of chronic obstructive pulmonary disease and emphysema. Recent studies suggest that susceptibility to cigarette smoke may vary by race/ethnicity; however, they were generally small and relied on self-reported race/ethnicity.
Objective
To test the hypothesis that relationships of smoking to lung function and percent emphysema differ by genetic ancestry and self-reported race/ethnicity among Whites, African-Americans, Hispanics and Chinese-Americans.
Design
Cross-sectional population-based study of adults age 45-84 years in the United States
Measurements
Principal components of genetic ancestry and continental ancestry estimated from one-million genome-wide single nucleotide polymorphisms. Pack-years calculated as years smoking cigarettes-per-day/20. Spirometry measured for 3,344 and percent emphysema on computed tomography for 8,224 participants.
Results
The prevalence of ever-smoking was: Whites, 57.6%; African-Americans, 56.4%; Hispanics, 46.7%; and Chinese-Americans, 26.8%. Every 10 pack-years was associated with −0.73% (95% CI −0.90%, −0.56%) decrement in the forced expiratory volume in one second to forced vital capacity (FEV1/FVC) and a 0.23% (95% CI 0.08%, 0.38%) increase in percent emphysema. There was no evidence that relationships of pack-years to the FEV1/FVC, airflow obstruction and percent emphysema varied by genetic ancestry (all p>0.10), self-reported race/ethnicity (all p>0.10) or, among African-Americans, African ancestry. There were small differences in relationships of pack-years to the FEV1 among male Chinese-Americans and to the FEV1/FVC with African and Native American ancestry among male Hispanics only.
Conclusions
In this large cohort, there was little-to-no evidence that the associations of smoking to lung function and percent emphysema differed by genetic ancestry or self-reported race/ethnicity.
doi:10.1136/thoraxjnl-2012-202116
PMCID: PMC4020409  PMID: 23585509
cigarette smoke; genetic ancestry; lung function; chronic obstructive pulmonary disease; COPD; emphysema; FVC; Forced Vital Capacity; FEV1; Forced Expiratory Volume in 1 second
Respiratory Research  2008;9(1):31.
Background
Lung function at the end of life depends on its peak and subsequent decline. Because obesity is epidemic in young adulthood, we quantified age-related changes in lung function relative to body mass index (BMI).
Methods
The Coronary Artery Risk Development in Young Adults (CARDIA) study in 1985–86 (year 0) recruited 5,115 black and white men and women, aged 18–30. Spirometry testing was conducted at years 0, 2, 5 and 10. We estimated 10 year change in FVC, FEV1 and FEV1/FVC according to baseline BMI and change in BMI within birth cohorts with initial average ages 20, 24, and 28 years, controlling for race, sex, smoking, asthma, physical activity, and alcohol consumption.
Measurements and Main Results
Participants with baseline BMI < 21.3 kg/m2 experienced 10 year increases of 71 ml in FVC and 60 ml in FEV1 and neither measure declined through age 38. In contrast, participants with baseline BMI ≥ 26.4 kg/m2 experienced 10 year decreases of 185 ml in FVC and 64 ml in FEV1. FEV1/FVC increased with increasing BMI. Weight gain was also associated with lung function. Those who gained the most weight over 10 years had the largest decrease in FVC, but FVC increased with weight gain in those initially thinnest. In contrast, FEV1 decreased with increasing weight gain in all participants, with maximum decline in obese individuals who gained the most weight during the study.
Conclusion
Among healthy young adults, increasing BMI in the initially thin participants was associated with increasing then stable lung function through age 38, but there were substantial lung function losses with higher and increasing fatness. These results suggest that the obesity epidemic threatens the lung health of the general population.
doi:10.1186/1465-9921-9-31
PMCID: PMC2386787  PMID: 18394165
BMC Cancer  2010;10:44.
Background
Alu methylation is correlated with the overall level of DNA methylation and recombination activity of the genome. However, the maintenance and methylation status of each CpG site within Alu elements (Alu) and its methylation status have not well characterized. This information is useful for understanding natural status of Alu in the genome and helpful for developing an optimal assay to quantify Alu hypomethylation.
Methods
Bisulfite clone sequencing was carried out in 14 human gastric samples initially. A Cac8I COBRA-DHPLC assay was developed to detect methylated-Alu proportion in cell lines and 48 paired gastric carcinomas and 55 gastritis samples. DHPLC data were statistically interpreted using SPSS version 16.0.
Results
From the results of 427 Alu bisulfite clone sequences, we found that only 27.2% of CpG sites within Alu elements were preserved (4.6 of 17 analyzed CpGs, A ~ Q) and that 86.6% of remaining-CpGs were methylated. Deamination was the main reason for low preservation of methylation targets. A high correlation coefficient of methylation was observed between Alu clones and CpG site J (0.963), A (0.950), H (0.946), D (0.945). Comethylation of the sites H and J were used as an indicator of the proportion of methylated-Alu in a Cac8I COBRA-DHPLC assay. Validation studies showed that hypermethylation or hypomethylation of Alu elements in human cell lines could be detected sensitively by the assay after treatment with 5-aza-dC and M.SssI, respectively. The proportion of methylated-Alu copies in gastric carcinomas (3.01%) was significantly lower than that in the corresponding normal samples (3.19%) and gastritis biopsies (3.23%).
Conclusions
Most Alu CpG sites are deaminated in the genome. 27% of Alu CpG sites represented in our amplification products. 87% of the remaining CpG sites are methylated. Alu hypomethylation in primary gastric carcinomas could be detected with the Cac8I COBRA-DHPLC assay quantitatively.
doi:10.1186/1471-2407-10-44
PMCID: PMC2834620  PMID: 20163738
Background
Lung function is a strong predictor of cardiovascular and all-cause mortality. Previous studies suggest that alcohol exposure may be linked to impaired pulmonary function through oxidant-antioxidant mechanisms. Alcohol may be an important source of oxidants; however, wine contains several antioxidants. In this study we analyzed the relation of beverage specific alcohol intake with forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) in a random sample of 1555 residents of Western New York, USA.
Methods
We expressed pulmonary function as percent of predicted normal FEV1 (FEV1%) and FVC (FVC%) after adjustment for height, age, gender and race. To obtain information on alcohol intake we used a questionnaire that reliably queries total alcohol and beverage specific recent (past 30 days) and lifetime alcohol consumption. Results: Using multiple linear regression analysis after adjustment for covariates (pack-years of smoking, weight, smoking status, education, nutritional factors and for FEV1%, in addition, eosinophil count), we observed no significant correlation between total alcohol intake and lung function. However, we found positive associations of recent and lifetime wine intake with FEV1% and FVC%. When we analyzed white and red wine intake separately, the association of lung function with red wine was weaker than for white wine.
Conclusion
While total alcohol intake was not related to lung function, wine intake showed a positive association with lung function. Although we cannot exclude residual confounding by healthier lifestyle in wine drinkers, differential effects of alcoholic beverages on lung health may exist.
doi:10.1186/1471-2466-2-3
PMCID: PMC113742  PMID: 12000686
Background
Variation in epigenetic modifications, arising from either environmental exposures or internal physiological changes, can influence gene expression, and may ultimately contribute to complex diseases such as asthma and allergies. We examined the association of asthma and allergic phenotypes with DNA methylation levels of retrotransposon-derived elements.
Methods
We used data from 704 men (mean age 73) in the longitudinal Normative Aging Study to assess the relationship between asthma, allergic phenotypes and DNA methylation levels of the retrotransposon derived elements Alu and LINE-1. Retrotransposons represent a large fraction of the genome (> 30%), and are heavily methylated to prevent expression. Percent methylation of Alu and LINE-1 elements in peripheral white blood cells was quantified using PCR pyrosequencing. Data on sensitization to common allergens by skin prick testing, asthma, and methacholine responsiveness was gathered approximately 8 years prior to DNA methylation analysis.
Results
Prior allergen sensitization was associated with increased methylation of Alu (β=0.32 [sensitized vs. non-sensitized], p value 0.003), in models adjusted for pack-years, BMI, smoking, air pollutants, percent eosinophils, white blood cell count and age. Of the men interviewed, 5 % of subjects reported diagnosis of asthma. Neither Alu, nor LINE-1 methylation was associated with asthma.
Conclusions
These data suggest that increased DNA methylation of repetitive elements may be associated with allergen sensitization, but does not appear to be associated with asthma. Future work is needed to identify potential underlying mechanisms for these relationships.
doi:10.1159/000343004
PMCID: PMC3730837  PMID: 23257623
allergen sensitization; DNA methylation; Alu; and LINE-1
Rationale: Vitamin D has immunomodulatory and antiinflammatory effects that may be modified by cigarette smoke and may affect lung function.
Objectives: To examine the effect of vitamin D deficiency and smoking on lung function and lung function decline.
Methods: A total of 626 men from the Normative Aging Study had 25-hydroxyvitamin D levels measured at three different times between 1984 and 2003 with concurrent spirometry. Vitamin D deficiency was defined as serum level ≤ 20 ng/ml. Statistical analysis was performed using multivariable linear regression and mixed effects models.
Measurements and Main Results: In the overall cohort, there was no significant effect of vitamin D deficiency on lung function or on lung function decline. In both cross-sectional and longitudinal multivariable models, there was effect modification by vitamin D status on the association between smoking and lung function. Cross-sectional analysis revealed lower lung function in current smokers with vitamin D deficiency (FEV1, FVC, and FEV1/FVC; P ≤ 0.0002), and longitudinal analysis showed more rapid rates of decline in FEV1 (P = 0.023) per pack-year of smoking in subjects with vitamin D deficiency as compared with subjects who were vitamin D sufficient.
Conclusions: Vitamin D deficiency was associated with lower lung function and more rapid lung function decline in smokers over 20 years in this longitudinal cohort of elderly men. This suggests that vitamin D sufficiency may have a protective effect against the damaging effects of smoking on lung function. Future studies should seek to confirm this finding in the context of smoking and other exposures that affect lung function.
doi:10.1164/rccm.201110-1868OC
PMCID: PMC3480523  PMID: 22822023
vitamin D; vitamin D deficiency; lung function decline; smoking; effect modification
OBJECTIVES—To estimate lung function prediction equations and to identify appropriate normal reference values for the population of about 250 000 of South African gold miners.
METHODS—Data from a lung function screening programme conducted at a large South African gold mine from 1994 to 1998 were used to estimate the lung function prediction equations. The most reliable period of lung function testing was identified in a previous study of a temporal pattern in reliability, and lung function tests from this period were used. Miners with a history of pulmonary tuberculosis or with radiological abnormalities were excluded from the study. The prediction equations were estimated cross sectionally on 15 772 black and 2752 white miners, and published reference equations that fitted most closely the observed data were identified.
RESULTS—The estimated prediction equations for forced vital capacity (FVC) are as follows: for black men, FVC (l)=− 2.901−0.025×age+4.655×height; and for white men, FVC(l)=−4.407−0.036×age+ 5.940×height. For forced expiratory volume in one second (FEV1) these equations are: for black men, FEV1(l)=−1.654− 0.30×age+3.665×height; and for white men, FEV1(l)= −2.341− 0.038×age+4.314×height. Units are years for age and metres for height. Knudson's and the European Community of Coal and Steel (ECCS) reference values provided the closest fit to the data on lung function of white miners, but the lower limits of normal from the ECCS equations were the closest to the observed one sided lower 95% confidence intervals (95% CIs). For black miners, reference equations that fitted best were derived by Louw et al on asymptomatic black South African men unexposed to occupational dust. There were significant differences between the two groups of miners in the estimated height adjusted mean lung function values for a 40 year old 1.7 m tall man (220 ml (5.2%) for FVC and 110 ml (3.2%) for FEV1); white men had higher FVC and FEV1, but lower FEV1/FVC ratio. The ECCS reference values scaled by a conversion factor of 0.93 for the FVC and 0.95 for the FEV1 provided close fits to the data for black miners, but the rate of decline with age was higher than that in the observed data. None of the linear equations provided a good fit for the 20-29 and more than 55 years old age categories.
CONCLUSION—The ECCS and Knudson equations provided the best fit to the data for white miners, whereas the equations by Louw et al estimated on asymptomatic black South African bank workers provided the best fit to the data for black miners. The ECCS reference values scaled by a factor of 0.93 for FVC and by 0.95 for FEV1 provided close fits, but the rate of decline with age was higher than that in the data for black miners.


Keywords: silica dust; miners; pulmonary function reference equations
doi:10.1136/oem.57.10.698
PMCID: PMC1739875  PMID: 10984343
PLoS ONE  2013;8(8):e70386.
A decrease in genomic methylation commonly occurs in aging cells; however, whether this epigenetic modification leads to age-related phenotypes has not been evaluated. Alu elements are the major interspersed repetitive DNA elements in humans that lose DNA methylation in aging individuals. Alu demethylation in blood cells starts at approximately 40 years of age, and the degree of Alu hypomethylation increases with age. Bone mass is lost with aging, particularly in menopausal women with lower body mass. Consequently, osteoporosis is commonly found in thin postmenopausal women. Here, we correlated the Alu methylation level of blood cells with bone density in 323 postmenopausal women. Alu hypomethylation was associated with advanced age and lower bone mass density, (P<0.05). The association between the Alu methylation level and bone mass was independent of age, body mass, and body fat, with an odds ratio [1]  = 0.4316 (0.2087–0.8927). Individuals of the same age with osteopenia, osteoporosis, and a high body mass index have lower Alu methylation levels (P = 0.0005, 0.003, and ≤0.0001, respectively). Finally, when comparing individuals with the same age and body mass, Alu hypomethylation was observed in individuals with lower bone mass (P<0.0001). In conclusion, there are positive correlations between Alu hypomethylation in blood cells and several age-related phenotypes in bone and body fat. Therefore, reduced global methylation may play a role in the systemic senescence process. Further evaluation of Alu hypomethylation may clarify the epigenetic regulation of osteoporosis in post-menopausal women.
doi:10.1371/journal.pone.0070386
PMCID: PMC3749148  PMID: 23990903
BMC Medical Genetics  2007;8(Suppl 1):S8.
Background
Pulmonary function measures obtained by spirometry are used to diagnose chronic obstructive pulmonary disease (COPD) and are highly heritable. We conducted genome-wide association (GWA) analyses (Affymetrix 100K SNP GeneChip) for measures of lung function in the Framingham Heart Study.
Methods
Ten spirometry phenotypes including percent of predicted measures, mean spirometry measures over two examinations, and rates of change based on forced expiratory volume in one second (FEV1), forced vital capacity (FVC), forced expiratory flow from the 25th to 75th percentile (FEF25–75), the FEV1/FVC ratio, and the FEF25–75/FVC ratio were examined. Percent predicted phenotypes were created using each participant's latest exam with spirometry. Predicted lung function was estimated using models defined in the set of healthy never-smokers, and standardized residuals of percent predicted measures were created adjusting for smoking status, pack-years, and body mass index (BMI). All modeling was performed stratified by sex and cohort. Mean spirometry phenotypes were created using data from two examinations and adjusting for age, BMI, height, smoking and pack-years. Change in pulmonary function over time was studied using two to four examinations with spirometry to calculate slopes, which were then adjusted for age, height, smoking and pack-years.
Results
Analyses were restricted to 70,987 autosomal SNPs with minor allele frequency ≥ 10%, genotype call rate ≥ 80%, and Hardy-Weinberg equilibrium p-value ≥ 0.001. A SNP in the interleukin 6 receptor (IL6R) on chromosome 1 was among the best results for percent predicted FEF25–75. A non-synonymous coding SNP in glutathione S-transferase omega 2 (GSTO2) on chromosome 10 had top-ranked results studying the mean FEV1 and FVC measurements from two examinations. SNPs nearby the SOD3 and vitamin D binding protein genes, candidate genes for COPD, exhibited association to percent predicted phenotypes.
Conclusion
GSTO2 and IL6R are credible candidate genes for association to pulmonary function identified by GWA. These and other observed associations warrant replication studies. This resource of GWA results for pulmonary function measures is publicly available at .
doi:10.1186/1471-2350-8-S1-S8
PMCID: PMC1995616  PMID: 17903307
Environmental Health Perspectives  2009;118(3):370-374.
Background
Global DNA methylation levels have been reported to be inversely associated with blood levels of persistent organic pollutants (POPs), xenobiotics that accumulate in adipose tissue. Whether these associations extend to a population with much lower concentrations of POPs is not known.
Objectives
This study was performed to examine whether low-dose exposure to POPs was associated with global DNA hypomethylation in Koreans.
Methods
The amount of global DNA hypomethylation was estimated by the percent 5-methyl-cytosine (%5-mC) in Alu and LINE-1 assays in 86 apparently healthy Koreans. Among various POPs, organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), and polybrominated diphenylethers (PBDEs) were measured.
Results
Most OC pesticides were inversely and significantly associated with %5-mC in the Alu assay, with correlation coefficients in the range −0.2 to −0.3 after adjusting for age, sex, body mass index, smoking, and alcohol. The strongest OC pesticide associations with %5-mC in the Alu assay were observed with oxychlordane, trans-nonachlor, and p,p′-dichlorodiphenyldichloroethylene. The correlation coefficient of age with %5-mC in the Alu assay was −0.24, similar to correlations of OC pesticides with %5-mC in the Alu assay. Most PCBs and PBDEs showed nonsignificant inverse trends with %5-mC in the Alu assay, but for some PCBs the U-shaped association was significant. On the other hand, POPs were not associated with %5-mC in the LINE-1 assay.
Conclusions
We found that low-dose exposure to POPs, in particular OC pesticides, was associated with global DNA hypomethylation in apparently healthy Koreans.
doi:10.1289/ehp.0901131
PMCID: PMC2854765  PMID: 20064773
epigenetics; hypomethylation; organochlorine pesticides; persistent organic pollutants
Rationale
Antioxidant enzymes play an important role in the defense against oxidative stress in the lung and in the pathogenesis of chronic obstructive pulmonary disease (COPD). Sequence variation in genes encoding antioxidant enzymes may alter susceptibility to COPD by affecting longitudinal change in lung function in adults.
Methods
We genotyped 384 sequence variants in 56 candidate genes in 1,281 African-American and 1,794 European-American elderly adults of the Health, Aging, and Body Composition study. Single-marker associations and gene-by-smoking interactions with rate of change in FEV1 and FEV1/ FVC were evaluated using linear mixed effects models, stratified by race/ethnicity.
Results
In European-Americans, rs17883901 in GCLC was statistically significantly associated with rate of change in FEV1/FVC; the recessive genotype (TT) was associated with a 0.9% per year steeper decline (P = 4.50 × 10−5). Statistically significant gene-by-smoking interactions were observed for variants in two genes in European-Americans: the minor allele of rs2297765 in mGST3 attenuated the accelerated decline in FEV1/FVC in smokers by 0.45% per year (P = 1.13 × 10−4); for participants with greater baseline smoking pack-years, the minor allele of rs2073192 in IDH3B was associated with an accelerated decline in FEV1/FVC (P = 2.10 × 10−4). For both genes, nominally significant interactions (P < 0.01) were observed at the gene-level in African-Americans (P = 0.007 and 4.60 × 10−4, respectively). Nominally significant evidence of association was observed for variants in SOD3 and GLRX2 in multiple analyses.
Conclusions
This study identifies two novel genes associated with longitudinal lung function phenotypes in both African- and European-Americans, and confirms a prior finding for GCLC. These findings suggest novel mechanisms and molecular targets for future research and advance the understanding of genetic determinants of lung function and COPD risk.
doi:10.1016/j.freeradbiomed.2013.05.016
PMCID: PMC4060265  PMID: 23688726
Antioxidant enzymes; cigarette smoking; gene by environment interaction; genetic association; longitudinal change; lung function; oxidative stress
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
Background Estimates of global DNA methylation from repetitive DNA elements, such as Alu and LINE-1, have been increasingly used in epidemiological investigations because of their relative low-cost, high-throughput and quantitative results. Nevertheless, determinants of these methylation measures in healthy individuals are still largely unknown. The aim of this study was to examine whether age, gender, smoking habits, alcohol drinking and body mass index (BMI) are associated with Alu or LINE-1 methylation levels in blood leucocyte DNA of healthy individuals.
Methods Individual data from five studies including a total of 1465 healthy subjects were combined. DNA methylation was quantified by PCR-pyrosequencing.
Results Age [β = −0.011% of 5-methyl-cytosine (%5mC)/year, 95% confidence interval (CI) −0.020 to −0.001%5mC/year] and alcohol drinking (β = −0.214, 95% CI −0.415 to −0.013) were inversely associated with Alu methylation. Compared with females, males had lower Alu methylation (β = −0.385, 95% CI −0.665 to −0.104) and higher LINE-1 methylation (β = 0.796, 95% CI 0.261 to 1.330). No associations were found with smoking or BMI. Percent neutrophils and lymphocytes in blood counts exhibited a positive (β = 0.036, 95% CI 0.010 to 0.061) and negative (β = −0.038, 95% CI −0.065 to −0.012) association with LINE-1 methylation, respectively.
Conclusions Global methylation measures in blood DNA vary in relation with certain host and lifestyle characteristics, including age, gender, alcohol drinking and white blood cell counts. These findings need to be considered in designing epidemiological investigations aimed at identifying associations between DNA methylation and health outcomes.
doi:10.1093/ije/dyq154
PMCID: PMC3304518  PMID: 20846947
Blood; DNA methylation; epigenetics; meta-analysis; repetitive elements
Thorax  1996;51(8):787-792.
BACKGROUND: Previous reports on the relationship between serum immunoglobulin E (IgE) concentration and the level and rate of decline of pulmonary function in the general population have produced conflicting results. The relationship between total serum IgE concentration and pulmonary function was therefore examined in 1078 men aged 41-86 years followed in the Normative Aging Study. METHODS: The serum IgE concentration determined at the start of the three year follow up period was examined in relation to both the level and longitudinal rate of decline of forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC. RESULTS: In a cross sectional analysis restricted to subjects who had ever smoked cigarettes, multiple linear regression models indicated an inverse association between total serum IgE concentration and both FEV1 (beta = -0.090 1/log10 IU/ml; SE = 0.030; p < 0.005) and FVC (beta = -0.110 1/log10 IU/ml; SE = 0.034; p < 0.005) but not FEV1/FVC, after adjustment for age and height. This relationship persisted when individuals with diagnosed asthma or methacholine hyperresponsiveness were excluded. In subjects who had never smoked cigarettes the total serum IgE concentration was unrelated to spirometric indices. No association was observed in smokers or non-smokers between the serum IgE concentration measured at the beginning of the period of follow up and the decline in FEV1, FVC, or FEV1/FVC. CONCLUSION: Increased levels of serum IgE measured at the beginning of the follow up period are associated with lower levels of pulmonary function but are not predictive of an accelerated rate in the decline of pulmonary function among middle aged and older men.
PMCID: PMC472538  PMID: 8795665
BACKGROUND
Lower blood DNA methylation has been associated with atherosclerosis and high cardiovascular risk. Mechanisms linking DNA hypomethylation to increased cardiovascular risk are still largely unknown.
In a population of community-dwelling elderly individuals, we evaluated whether DNA methylation in LINE-1 repetitive element, heavily methylated sequences dispersed throughout the human genome, was associated with circulating Vascular Cell Adhesion Molecule-1 (VCAM-1), Inter-Cellular Adhesion Molecule-1 (ICAM-1), and C-reactive protein (CRP).
METHODS AND RESULTS
We measured LINE-1 methylation by bisulfite PCR-Pyrosequencing on 742 blood DNA samples from male participants in the Boston area Normative Aging Study (mean age=74.8 years). Mean serum VCAM-1 increased progressively in association with LINE-1 hypomethylation (from 975.2 to 1063.4 ng/ml in the highest vs. lowest methylation quintiles; p-trend=0.004). The association between VCAM-1 and LINE-1 hypomethylation was significant in individuals without ischemic heart disease or stroke (n=480; p=0.001), but not in those with prevalent disease (n=262; p=0.57). Serum ICAM-1 and CRP were not associated with LINE-1 methylation (p-trend=>0.25). All results were confirmed by multivariable analyses adjusting for age, BMI, smoking, pack-years, and ischemic heart disease/stroke.
CONCLUSIONS
LINE-1 element hypomethylation is associated with higher serum VCAM-1. Our data provide new insights into epigenetic events that may accompany the development of cardiovascular disease.
PMCID: PMC3155741  PMID: 20305373
cell adhesion molecules; epidemiology; cardiovascular diseases; risk factors; LINE-1; VCAM-1
Journal of clinical immunology  2013;33(6):1134-1142.
Purpose
World Trade Center (WTC) exposure caused airflow obstruction years after exposure. Chitinases and IgE are innate and humoral mediators of obstructive airway disease. We investigated if serum expression of chitinases and IgE early after WTC exposure predicts subsequent obstruction.
Methods
With a nested case-control design, 251 FDNY personnel had chitotriosidase, YKL-40 and IgE measured in serum drawn within months of 9/11/2001. The main outcome was subsequent Forced Expiratory Volume after one second/Forced Vital Capacity (FEV1/FVC) less than the lower limit of normal (LLN). Cases (N=125) had abnormal FEV1/FVC whereas controls had normal FEV1/FVC (N=126). In a secondary analysis, resistant cases (N=66) had FEV1 (≥107%) one standard deviation above the mean. Logistic regression adjusted for age, BMI, exposure intensity and post-exposure FEV1/FVC modeled the association between early biomarkers and later lung function.
Results
Cases and Controls initially lost lung function. Controls recovered to pre-9/11 FEV1 and FVC while cases continue to decline. Cases expressed lower serum chitotriosidase and higher IgE levels. Increase in IgE increased the odds of airflow obstruction and decreased the odds of above average FEV1. Alternately, increasing chitotriosidase decreased the odds of abnormal FEV1/FVC and increased the odds of FEV1≥107%. Serum YKL-40 was not associated with FEV1/FVC or FEV1 in this cohort.
Conclusions
Increased serum chitotriosidase reduces the odds of developing obstruction after WTC-particulate matter exposure and is associated with recovery of lung function. Alternately, elevated IgE is a risk factor for airflow obstruction and progressive lung function decline.
doi:10.1007/s10875-013-9913-2
PMCID: PMC3722498  PMID: 23744081
Chitotriosidase; Immunoglobulin E; WTC Particulate Matter; Pulmonary Function Testing
Respiratory Research  2014;15(1):134.
Background
Reduced forced expiratory volume in 1 second (FEV1) and the ratio of FEV1 to forced vital capacity (FVC) are strong predictors of mortality and lung function is higher among individuals with exceptional longevity. However, genetic factors associated with lung function in individuals with exceptional longevity have not been identified.
Method
We conducted a genome wide association study (GWAS) to identify novel genetic variants associated with lung function in the Long Life Family Study (LLFS) (n = 3,899). Replication was performed using data from the CHARGE/SpiroMeta consortia. The association between SNPs and FEV1 and FEV1/FVC was analyzed using a linear mixed effects model adjusted for age, age2, sex, height, field center, ancestry principal components and kinship structure to adjust for family relationships separately for ever smokers and never smokers. In the linkage analysis, we used the residuals of the FEV1 and FEV1/FVC, adjusted for age, sex, height, ancestry principal components (PCs), smoking status, pack-years, and field center.
Results
We identified nine SNPs in strong linkage disequilibrium in the CYP2U1 gene to be associated with FEV1 and a novel SNP (rs889574) associated with FEV1/FVC, none of which were replicated in the CHARGE/SpiroMeta consortia. Using linkage analysis, we identified a novel linkage peak in chromosome 2 at 219 cM for FEV1/FVC (LOD: 3.29) and confirmed a previously reported linkage peak in chromosome 6 at 28 cM (LOD: 3.33) for FEV1.
Conclusion
Future studies need to identify the rare genetic variants underlying the linkage peak in chromosome 6 for FEV1.
Electronic supplementary material
The online version of this article (doi:10.1186/s12931-014-0134-x) contains supplementary material, which is available to authorized users.
doi:10.1186/s12931-014-0134-x
PMCID: PMC4228089  PMID: 25409777
GWAS; Lung function; Aging
Journal of Medical Genetics  2006;43(8):e43.
Inducible heme oxygenase (HO‐1) acts against oxidants that are thought to play a major role in the pathogenesis of chronic obstructive pulmonary disease (COPD), characterised by impaired lung function. A (GT)n repeat polymorphism in the HO‐1 gene promoter can modulate the gene transcription in response to oxidative stress. We hypothesised that this polymorphism could be associated with the level of lung function and decline in subjects exposed to oxidative agression (smokers). We genotyped 749 French subjects (20–44 years, 50% men, 40% never smokers) examined in both 1992 and 2000 as part of the ECRHS. Lung function was assessed by forced expiratory volume in 1 second (FEV1) and FEV1/forced ventilatory capacity (FVC) ratio. We compared long (L) allele carriers ((GT)n ⩾33 repeats for one or two alleles) to non‐carriers. Cross sectionally, in 2000, L allele carriers showed lower FEV1/FVC than non‐carriers. During the 8 year period, the mean annual FEV1 and FEV1/FVC declines were −30.9 (31.1) ml/year and −1.8 (6.1) U/year, respectively. FEV1/FVC decline was steeper in L allele carriers than in non‐carriers (−2.6 (5.5) v −1.5 (6.4), p = 0.07). There was a strong interaction between the L allele and smoking. In 2000, the L allele was associated with lower FEV1 and FEV1/FVC in heavy smokers (⩾20 cigarettes/day) only (p for interaction = 0.07 and 0.002 respectively). Baseline heavy smokers carrying the L allele showed the steepest FEV1 decline (−62.0 (29.5 ml/year) and the steepest FEV1/FVC decline (−8.8 (5.4 U/year) (p for interaction = 0.009 and 0.0006).These results suggest that a long (L) HO‐1 gene promoter in heavy smokers is associated with susceptibility to develop airway obstruction.
doi:10.1136/jmg.2005.039743
PMCID: PMC2564599  PMID: 16882737
lung function; decline; polymorphism; heme oxygenase; smoking
Thorax  2009;64(11):944-949.
Background
A study was undertaken to determine if quantitative CT estimates of lung parenchymal overinflation and airway dimensions in smokers with a normal forced expiratory volume in 1 s (FEV1) can predict the rapid decline in FEV1 that leads to chronic obstructive pulmonary disease (COPD).
Methods
Study participants (n = 143; age 45–72 years; 54% male) were part of a lung cancer screening trial, had a smoking history of >30 pack years and a normal FEV1 and FEV1/forced vital capacity (FVC) at baseline (mean (SD) FEV1 99.4 (12.8)%, range 80.2–140.7%; mean (SD) FEV1/FVC 77.9 (4.4), range 70.0–88.0%). An inspiratory multislice CT scan was acquired for each subject at baseline. Custom software was used to measure airway lumen and wall dimensions; the percentage of the lung inflated beyond a predicted maximal lung inflation, the low attenuation lung area with an x ray attenuation lower than −950 HU and the size distribution of the overinflated lung areas and the low attenuation area were described using a cluster analysis. Multiple regression analysis was used to test the hypothesis that these CT measurements combined with other baseline characteristics might identify those who would develop an excessive annual decline in FEV1.
Results
The mean (SD) annual change in FEV1 was −2.3 (4.7)% predicted (range −23.0% to +8.3%). Multiple regression analysis revealed that the annual change in FEV1%predicted was significantly associated with baseline percentage overinflated lung area measured on quantitative CT, FEV1%predicted, FEV1/FVC and gender.
Conclusion
Quantitative CT scan evidence of overinflation of the lung predicts a rapid annual decline in FEV1 in smokers with normal FEV1.
doi:10.1136/thx.2008.112433
PMCID: PMC3035577  PMID: 19734130
PLoS ONE  2014;9(6):e100429.
The changes in DNA methylation status in cancer cells are characterized by hypermethylation of promoter CpG islands and diffuse genomic hypomethylation. Alu and long interspersed nucleotide element-1 (LINE-1) are non-coding genomic repetitive sequences and methylation of these elements can be used as a surrogate marker for genome-wide methylation status. This study was designed to evaluate the changes of Alu and LINE-1 hypomethylation during breast cancer progression from normal to pre-invasive lesions and invasive breast cancer (IBC), and their relationship with characteristics of IBC. We analyzed the methylation status of Alu and LINE-1 in 145 cases of breast samples including normal breast tissue, atypical ductal hyperplasia/flat epithelial atypia (ADH/FEA), ductal carcinoma in situ (DCIS) and IBC, and another set of 129 cases of IBC by pyrosequencing. Alu methylation showed no significant changes during multistep progression of breast cancer, although it tended to decrease during the transition from DCIS to IBC. In contrast, LINE-1 methylation significantly decreased from normal to ADH/FEA, while it was similar in ADH/FEA, DCIS and IBC. In IBC, Alu hypomethylation correlated with negative estrogen receptor (ER) status, and LINE-1 hypomethylation was associated with negative ER status, ERBB2 (HER2) amplification and p53 overexpression. Alu and LINE-1 methylation status was significantly different between breast cancer subtypes, and the HER2 enriched subtype had lowest methylation levels. In survival analyses, low Alu methylation status tended to be associated with poor disease-free survival of the patients. Our findings suggest that LINE-1 hypomethylation is an early event and Alu hypomethylation is probably a late event during breast cancer progression, and prominent hypomethylation of Alu and LINE-1 in HER2 enriched subtype may be related to chromosomal instability of this specific subtype.
doi:10.1371/journal.pone.0100429
PMCID: PMC4074093  PMID: 24971511
Rationale: A significant proportion of smokers have lung function impairment characterized by a reduced FEV1 with a preserved FEV1/FVC ratio. These smokers are a poorly characterized group due to their systematic exclusion from chronic obstructive pulmonary disease (COPD) studies.
Objectives: To characterize the clinical, functional, and radiographic features of Global Initiative for Chronic Obstructive Lung Disease (GOLD)-Unclassified (FEV1/FVC ≥ 0.7 and FEV1 < 80% predicted) and lower limits of normal (LLN)-unclassified (FEV1/FVC ≥ LLN and FEV1 < LLN) subjects compared to smokers with normal lung function and subjects with COPD.
Methods: Data from the first 2,500 subjects enrolled in the COPDGene study were analyzed. All subjects had 10 or more pack-years of smoking and were between the ages of 45 and 80 years. Multivariate regression models were constructed to determine the clinical and radiological variables associated with GOLD-Unclassified (GOLD-U) and LLN-Unclassified status. Separate multivariate regressions were performed in the subgroups of subjects with complete radiologic measurement variables available.
Measurements and Main Results: GOLD-U smokers account for 9% of smokers in COPDGene and have increased body mass index (BMI), a disproportionately reduced total lung capacity, and a higher proportion of nonwhite subjects and subjects with diabetes. GOLD-U subjects exhibit increased airway wall thickness compared to smoking control subjects and decreased gas trapping and bronchodilator responsiveness compared to subjects with COPD. When LLN criteria were used to define the “unclassified” group, African American subjects were no longer overrepresented. Both GOLD-U and LLN-Unclassified subjects demonstrated a wide range of lung function impairment, BMI, and percentage of total lung emphysema.
Conclusions: Subjects with reduced FEV1 and a preserved FEV1/FVC ratio are a heterogeneous group with significant symptoms and functional limitation who likely have a variety of underlying etiologies beyond increased BMI.
Clinical trial registered with www.clinicaltrials.gov (NCT000608764).
doi:10.1164/rccm.201101-0021OC
PMCID: PMC3172890  PMID: 21493737
lung diseases, classification; lung diseases, diagnosis; lung diseases, epidemiology
The American journal of medicine  2011;124(4):334-341.
Background
The impact of abnormal spirometric findings on risk for incident heart failure among older adults without clinically apparent lung disease is not well elucidated.
Methods
We evaluated the association of baseline lung function with incident heart failure, defined as first hospitalization for heart failure, in 2125 participants of the community-based Health, Aging, and Body Composition Study (age, 73.6±2.9 years; 50.5% men; 62.3% white; 37.7% black) without prevalent lung disease or heart failure. Abnormal lung function was defined either as forced vital capacity (FVC) or forced expiratory volume in 1st second (FEV1) to FVC ratio below lower limit of normal. Percent predicted FVC and FEV1 were also assessed as continuous variables.
Results
During follow-up (median, 9.4years), heart failure developed in 68 of 350 (19.4%) participants with abnormal baseline lung function, as compared to 172 of 1775 (9.7%) participants with normal lung function (hazard ratio [HR], 2.31; 95% confidence interval [CI], 1.74-3.07; P<.001). This increased risk persisted after adjusting for previously identified heart failure risk factors in the Health ABC Study, body mass index, incident coronary heart disease, and inflammatory markers (HR, 1.83; 95% CI, 1.33-2.50; P<.001). Percent predicted (%) FVC and FEV1 had a linear association with heart failure risk (HR, 1.21; 95%CI, 1.11-1.32 and 1.18; 95%CI, 1.10-1.26, per 10% lower %FVC and %FEV1, respectively; both P<.001 in fully adjusted models). Findings were consistent in sex and race subgroups, and for heart failure with preserved or reduced ejection fraction.
Conclusions
Abnormal spirometric findings in older adults without clinical lung disease are associated with increased heart failure risk.
doi:10.1016/j.amjmed.2010.12.006
PMCID: PMC3073738  PMID: 21435424
Elderly; Epidemiology; Heart Failure; Pulmonary Function Test
Aims: To investigate the effect of exposure to coke oven emissions on the lung function of coke oven workers.
Methods: The study population, followed from 1978 and 1990, was 580 male workers with at least two sets of lung function measurements (FVC, FEV1, FEV1/FVC, and FEF25–75%). An annual rate of change (time slope) for age and height adjusted lung function index was estimated for each subject. This "time slope" was then treated as the response variable in a weighted multiple regression analysis with selected predictors.
Results: For all 580 subjects, each year of working in the "operation" group (the most exposed) was found to increase the FVC decline by around 0.7 ml/year (95% CI 0.1 to 1.3 ml/year). After the exclusion of 111 subjects without detailed work history, the above finding was confirmed and each year of exposure in "operation" was also found to increase the FEV1 decline by around 0.8 ml/year (95% CI 0.1 to 1.4 ml/year).
Conclusions: These findings are consistent with the results of previous cross-sectional studies. Work duration in the most exposed position in the coke ovens was associated with increased annual decline for FVC and FEV1. The estimated effect of one year of work exposure in "operation" is equivalent, in terms of the reduction in lung function, to an estimated 2.1 pack-years of smoking for FVC and 1.2 pack-years of smoking for FEV1.
doi:10.1136/oem.2003.009381
PMCID: PMC1740828  PMID: 15258275

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