A Statistical Model for Assessing Genetic Susceptibility as a Risk Factor in Multifactorial Diseases: Lessons from Occupational Asthma

BACKGROUND: Incorporating the influence of genetic variation in the risk assessment process is often considered, but no generalized approach exists. Many common human diseases such as asthma, cancer, and cardiovascular disease are complex in nature, as they are influenced variably by environmental, physiologic, and genetic factors. The genetic components most responsible for differences in individual disease risk are thought to be DNA variants (polymorphisms) that influence the expression or function of mediators involved in the pathological processes. OBJECTIVE: The purpose of this study was to estimate the combinatorial contribution of multiple genetic variants to disease risk. METHODS: We used a logistic regression model to help estimate the joint contribution that multiple genetic variants would have on disease risk. This model was developed using data collected from molecular epidemiology studies of allergic asthma that examined variants in 16 susceptibility genes. RESULTS: Based on the product of single gene variant odds ratios, the risk of developing asthma was assigned to genotype profiles, and the frequency of each profile was estimated for the general population. Our model predicts that multiple disease variants broaden the risk distribution, facilitating the identification of susceptible populations. This model also allows for incorporation of exposure information as an independent variable, which will be important for risk variants associated with specific exposures. CONCLUSION: The present model provided an opportunity to estimate the relative change in risk associated with multiple genetic variants. This will facilitate identification of susceptible populations and help provide a framework to model the genetic contribution in probabilistic risk assessment

Up-to-date on mortality in COPD - report from the OLIN COPD study

<p>Abstract</p> <p>Background</p> <p>The poor recognition and related underdiagnosis of COPD contributes to an underestimation of mortality in subjects with COPD. Data derived from population studies can advance our understanding of the true burden of COPD. The objective of this report was to evaluate the impact of COPD on mortality and its predictors in a cohort of subjects with and without COPD recruited during the twenty first century.</p> <p>Methods</p> <p>All subjects with COPD (n = 993) defined according to the GOLD spirometric criteria, FEV₁/FVC < 0.70, and gender- and age-matched subjects without airway obstruction, non-COPD (n = 993), were identified in a clinical follow-up survey of the Obstructive Lung Disease in Northern Sweden (OLIN) Studies cohorts in 2002-2004. Mortality was observed until the end of year 2007. Baseline data from examination at recruitment were used in the risk factor analyses; age, smoking status, lung function (FEV₁% predicted) and reported heart disease.</p> <p>Results</p> <p>The mortality was significantly higher among subjects with COPD, 10.9%, compared to subjects without COPD, 5.8% (p < 0.001). Mortality was associated with higher age, being a current smoker, male gender, and COPD. Replacing COPD with FEV₁% predicted in the multivariate model resulted in the decreasing level of FEV₁being a significant risk factor for death, while heart disease was not a significant risk factor for death in any of the models.</p> <p>Conclusions</p> <p>In this cohort COPD and decreased FEV₁were significant risk factors for death when adjusted for age, gender, smoking habits and reported heart disease.</p

The health impact of remarriage behavior on chronic obstructive pulmonary disease: findings from the US longitudinal survey

<p>Abstract</p> <p>Background</p> <p>Chronic obstructive pulmonary disease (COPD) is a major disease among adults, and its deterioration was reported to be associated with psychological imbalance. Meanwhile, bereavement and divorce have proven harmful to the health status of a surviving spouse. But few studies have been conducted to evaluate the remedial effect on survivors' health outcome by remarriage after bereavement. The present study thus examined the associations between remarriage and the onset of COPD.</p> <p>Methods</p> <p>Our cohort was drawn from Health and Retirement Study participants in the United States, and consisted of 2676 subjects who were divorced or bereaved from 1992 to 2002. We then followed them for up to 11 years and assessed the incidence rate of COPD using a Cox proportional hazard model after adjusting for marital status, age, gender, education and the number of cigarettes smoked.</p> <p>Results</p> <p>Among all subjects, 224 who remarried after bereavement or divorce tended to be younger and more male dominated. Remarriage after bereavement/divorce was associated with significantly decreased risk of COPD onset for overall subjects [hazard ratio (HR): 0.51, 95% confidence interval (95% CI): 0.28-0.94], female subjects [HR: 0.36, 95% CI: 0.13-0.98], and for those under 70 years old [HR: 0.36, 95% CI: 0.17-0.79].</p> <p>Conclusion</p> <p>This study investigates the impact of remarriage on health outcome based on a large-scale population survey and indicates that remarriage significantly correlates with reduced risk of COPD incidence, even after adjusting smoking habit.</p

Systemic Inflammation in Young Adults Is Associated with Abnormal Lung Function in Middle Age

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 (FEV(1)) (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 FEV(1) (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 FEV(1). 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

MRI of the lung (3/3)-current applications and future perspectives

BACKGROUND: MRI of the lung is recommended in a number of clinical indications. Having a non-radiation alternative is particularly attractive in children and young subjects, or pregnant women. METHODS: Provided there is sufficient expertise, magnetic resonance imaging (MRI) may be considered as the preferential modality in specific clinical conditions such as cystic fibrosis and acute pulmonary embolism, since additional functional information on respiratory mechanics and regional lung perfusion is provided. In other cases, such as tumours and pneumonia in children, lung MRI may be considered an alternative or adjunct to other modalities with at least similar diagnostic value. RESULTS: In interstitial lung disease, the clinical utility of MRI remains to be proven, but it could provide additional information that will be beneficial in research, or at some stage in clinical practice. Customised protocols for chest imaging combine fast breath-hold acquisitions from a "buffet" of sequences. Having introduced details of imaging protocols in previous articles, the aim of this manuscript is to discuss the advantages and limitations of lung MRI in current clinical practice. CONCLUSION: New developments and future perspectives such as motion-compensated imaging with self-navigated sequences or fast Fourier decomposition MRI for non-contrast enhanced ventilation- and perfusion-weighted imaging of the lung are discussed. Main Messages • MRI evolves as a third lung imaging modality, combining morphological and functional information. • It may be considered first choice in cystic fibrosis and pulmonary embolism of young and pregnant patients. • In other cases (tumours, pneumonia in children), it is an alternative or adjunct to X-ray and CT. • In interstitial lung disease, it serves for research, but the clinical value remains to be proven. • New users are advised to make themselves familiar with the particular advantages and limitations

Lifetime environmental tobacco smoke exposure and the risk of chronic obstructive pulmonary disease

BACKGROUND: Exposure to environmental tobacco smoke (ETS), which contains potent respiratory irritants, may lead to chronic airway inflammation and obstruction. Although ETS exposure appears to cause asthma in children and adults, its role in causing COPD has received limited attention in epidemiologic studies. METHODS: Using data from a population-based sample of 2,113 U.S. adults aged 55 to 75 years, we examined the association between lifetime ETS exposure and the risk of developing COPD. Participants were recruited from all 48 contiguous U.S. states by random digit dialing. Lifetime ETS exposure was ascertained by structured telephone interview. We used a standard epidemiologic approach to define COPD based on a self-reported physician diagnosis of chronic bronchitis, emphysema, or COPD. RESULTS: Higher cumulative lifetime home and work exposure were associated with a greater risk of COPD. The highest quartile of lifetime home ETS exposure was associated with a greater risk of COPD, controlling for age, sex, race, personal smoking history, educational attainment, marital status, and occupational exposure to vapors, gas, dusts, or fumes during the longest held job (OR 1.55; 95% CI 1.09 to 2.21). The highest quartile of lifetime workplace ETS exposure was also related to a greater risk of COPD (OR 1.36; 95% CI 1.002 to 1.84). The population attributable fraction was 11% for the highest quartile of home ETS exposure and 7% for work exposure. CONCLUSION: ETS exposure may be an important cause of COPD. Consequently, public policies aimed at preventing public smoking may reduce the burden of COPD-related death and disability, both by reducing direct smoking and ETS exposure

Projected WIMP sensitivity of the LUX-ZEPLIN dark matter experiment

LUX-ZEPLIN (LZ) is a next-generation dark matter direct detection experiment that will operate 4850 feet underground at the Sanford Underground Research Facility (SURF) in Lead, South Dakota, USA. Using a two-phase xenon detector with an active mass of 7 tonnes, LZ will search primarily for low-energy interactions with weakly interacting massive particles (WIMPs), which are hypothesized to make up the dark matter in our galactic halo. In this paper, the projected WIMP sensitivity of LZ is presented based on the latest background estimates and simulations of the detector. For a 1000 live day run using a 5.6-tonne fiducial mass, LZ is projected to exclude at 90% confidence level spin-independent WIMP-nucleon cross sections above 1.4×10-48 cm2 for a 40 GeV/c2 mass WIMP. Additionally, a 5σ discovery potential is projected, reaching cross sections below the exclusion limits of recent experiments. For spin-dependent WIMP-neutron(-proton) scattering, a sensitivity of 2.3×10-43 cm2 (7.1×10-42 cm2) for a 40 GeV/c2 mass WIMP is expected. With underground installation well underway, LZ is on track for commissioning at SURF in 2020

COPD uncovered: an international survey on the impact of chronic obstructive pulmonary disease [COPD] on a working age population

Background: Approximately 210 million people are estimated to have chronic obstructive pulmonary disease [COPD] worldwide. The burden of disease is known to be high, though less is known about those of a younger age. The aim of this study was to investigate the wider personal, economic and societal burden of COPD on a cross country working-age cohort. Methods: A cross-country [Brazil, China, Germany, Turkey, US, UK] cross-sectional survey methodology was utilised to answer the research questions. 2426 participants aged 45-67 recruited via a number of recruitment methods specific to each country completed the full survey. Inclusion criteria were a recalled physician diagnosis of COPD, a smoking history of > 10 pack years and the use of COPD medications in the previous 3 months prior to questioning. The survey included items from the validated Work Productivity and Activity Impairment [WPAI] scale and the EuroQoL 5 Dimension [EQ-5D] scale. Disease severity was measured using the 5-point MRC [Medical Research Council] dyspnoea scale as a surrogate measure. Results: 64% had either moderate [n = 1012] or severe [n = 521] COPD, although this varied by country. 75% of the cohort reported at least one comorbid condition. Quality of life declined with severity of illness [mild, mean EQ-5D score = 0.84; moderate 0.58; severe 0.41]. The annual cost of healthcare utilisation [excluding treatment costs and diagnostic tests] per individual was estimated to be $2,364 [1,500] pound. For those remaining in active employment [n: 677]: lost time from work cost the individual an average of$880 [556] pound per annum and lifetime losses of $7,365 [4,661] pound amounting to$596,000 [377,000] pound for the cohort. 447 [similar to 40%] of the working population had retired prematurely because of COPD incurring individual estimated lifetime income losses of $316,000 [200,000] pound or a combined total of$141 m [89.6 pound m]. As the mean age of retirees was 58.3 and average time since retirement was 4 years, this suggests the average age of retirement is around 54. This would mean a high societal and economic impact in all study countries, particularly where typical state retirement ages are higher, for example in Brazil, Germany and the UK [65] and the US [65,66,67], compared to Turkey [58 for women, 60 for men] and China [60]. Conclusions: Although generalisation across a broader COPD population is limited due to the varied participant recruitment methods, these data nevertheless suggest that COPD has significant personal, economic and societal burden on working age people. Further efforts to improve COPD diagnosis and management are required

Evaluation of Current Knowledge, Awareness and Practice of Spirometry among Hospital -based Nigerian Doctors

<p>Abstract</p> <p>Background</p> <p>Spirometry is a cost-effective diagnostic tool for evaluation of lung function and for case-finding in a resource-limited setting. The acceptance of this test depends on the awareness of its indications and the ability to interpret the results. No studies have assessed the knowledge of spirometry among Nigerian doctors. The aim of this study was to evaluate the current knowledge, awareness and practice of spirometry among hospital-based Nigerian doctors.</p> <p>Methods</p> <p>We carried out a cross-sectional survey among 321 doctors working in Nigerian hospitals between March 2008 and June 2008. Information on knowledge, awareness, practice of and barriers to spirometry were obtained using a pre-tested, self-administered structured questionnaire and the data were then analysed.</p> <p>Results</p> <p>Of the 321 doctors that participated, 108 (33.6%) reported that they have good knowledge of spirometry. One hundred and ninety-five (60.7%) were aware of the importance of spirometry in aiding the diagnosis of respiratory diseases; 213(66.4%) were aware of the importance of spirometry in determining the severity of diseases. Medical school was the most common source of knowledge on spirometry (64.5%). Eighty-one (25.2%) doctors reported having a spirometer in their hospitals. Doctors having access to a spirometer used it more frequently for aiding the diagnosis of COPD (40.7% vs.27.5%) and for monitoring of asthma (18.5% vs.11.3%) than those without access to a spirometer. The doctors working in University Teaching Hospitals and Federal Medical Centres (FMC) (22.4% vs. 4.5%) and those having access to a spirometer (40.7 vs.11.3%) were very confident of interpreting spirometry results compared to those working in District and General Hospitals and without access to a spirometer. Irrespective of access to a spirometer or the type of hospital they were employed in, doctors reported that unavailability of a spirometer was the greatest barrier to its use (62.5%) followed by lack of awareness about its usefulness (17.2%).</p> <p>Conclusion</p> <p>The knowledge and practice of spirometry were poor among hospital-based Nigerian doctors because of unavailability of spirometers in most hospitals. These findings have implications for further evaluation, planning and management of patient care in respiratory disease. Spirometers should be made available in all hospitals, and the knowledge of spirometry should be improved among doctors.</p

Risk factors for hospitalization among adults with asthma: the influence of sociodemographic factors and asthma severity

BACKGROUND: The morbidity and mortality from asthma have markedly increased since the late 1970s. The hospitalization rate, an important marker of asthma severity, remains substantial. METHODS: In adults with health care access, we prospectively studied 242 with asthma, aged 18–50 years, recruited from a random sample of allergy and pulmonary physician practices in Northern California to identify risk factors for subsequent hospitalization. RESULTS: Thirty-nine subjects (16%) reported hospitalization for asthma during the 18-month follow-up period. On controlling for asthma severity in multiple logistic regression analysis, non-white race (odds ratio [OR], 3.1; 95% confidence interval [CI], 1.1–8.8) and lower income (OR, 1.1 per $10,000 decrement; 95$10,000 decrement; 95% CI, 1.02–1.4). CONCLUSION: In adult asthmatics with access to health care, non-white race, low income, and greater asthma severity were associated with a higher risk of hospitalization. Targeted interventions applied to high-risk asthma patients may reduce asthma morbidity and mortality