Prediction of response to anti-PD-1 therapy in patients with non-small-cell lung cancer by electronic nose analysis of exhaled breath.

BACKGROUND: Immune checkpoint inhibitors have improved survival outcome of advanced non-small-cell lung cancer (NSCLC). However, most patients do not benefit. Therefore, biomarkers are needed that accurately predict response. We hypothesized that molecular profiling of exhaled air may capture the inflammatory milieu related to the individual responsiveness to anti-programmed death ligand 1 (PD-1) therapy. This study aimed to determine the accuracy of exhaled breath analysis at baseline for assessing nonresponders versus responders to anti-PD-1 therapy in NSCLC patients. METHODS: This was a prospective observational study in patients receiving checkpoint inhibitor therapy using both a training and validation set of NSCLC patients. At baseline, breath profiles were collected in duplicate by a metal oxide semiconductor electronic nose (eNose) positioned at the rear end of a pneumotachograph. Patients received nivolumab or pembrolizumab of which the efficacy was assessed by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 at 3-month follow-up. Data analysis involved advanced signal-processing and statistics based on independent t-tests followed by linear discriminant and receiver operating characteristic (ROC) analysis. RESULTS: Exhaled breath data of 143 NSCLC patients (training: 92, validation: 51) were available at baseline. ENose sensors contributed significantly (P < 0.05) at baseline in differentiating between patients with different responses at 3 months of anti-PD-1 treatment. The eNose sensors were combined into a single biomarker with an ROC-area under the curve (AUC) of 0.89 [confidence interval (CI) 0.82-0.96]. This AUC was confirmed in the validation set: 0.85 (CI 0.75-0.96). CONCLUSION: ENose assessment was effective in the noninvasive prediction of individual patient responses to immunotherapy. The predictive accuracy and efficacy of the eNose for discrimination of immunotherapy responder types were replicated in an independent validation set op patients. This finding can potentially avoid application of ineffective treatment in identified probable nonresponders.

Early-life antibiotic exposure increases the risk of developing allergic symptoms later in life: A meta-analysis.

This study systematically reviewed and quantified the relationship between exposure to antibiotics during the first 2 years of life and the risk of allergies/atopies including hay fever, eczema, food allergy, positive skin prick testing (SPT), or elevated allergen-specific serum/plasma immunoglobulin (Ig) E levels later in life. PubMed and Web of Science databases were searched for observational studies published from January 1966 through November 11, 2015. Overall pooled estimates of the odds ratios (ORs) were obtained using fixed or random-effects models. Early-life exposure to antibiotics appears to be related to an increased risk of allergic symptoms of hay fever, eczema, and food allergy later in life. The summary OR for the risk of hay fever (22 studies) was 1.23, 95% confidence interval (CI):1.13-1.34; I2 : 77.0%. The summary OR for the risk of eczema (22 studies) was 1.26, 95% CI: 1.15-1.37; I2 : 74.2%, and the summary OR for food allergy (3 studies) was 1.42, 95% CI: 1.08-1.87; I2 : 80.8%. However, no association was found for antibiotics exposure early in life and objective atopy measurements including positive SPT or elevated allergen-specific serum/plasma IgE levels.

NOACs replace VKA as preferred oral anticoagulant among new patients: a drug utilization study in 560 pharmacies in The Netherlands.

BACKGROUND: In 2012, around 400.000 patients in the Netherlands were treated with Vitamin K Antagonists (VKA) for thromboembolic diseases. Since 2011, non-VKA oral anticoagulants (NOACs) are available. NOACs do not require frequent INR monitoring which benefits patients, but also imposes a risk of reduced therapy adherence. The objective of this study is to describe uptake and patient adherence of NOACs in The Netherlands until October 2016. METHODS: Prescription data for 247.927 patients across 560 pharmacies were used to describe patient profiles, uptake of NOACs among new naive patients and switch between VKA and NOACs, and calculate therapy adherence as the Proportion of Days Covered (PDC). RESULTS: During the studied period the share of NOACs in oral anticoagulants has grown to 57% of prescriptions to new patients. More than 70% of new NOAC users were new naive patients and around 26% switched from VKA. The overall share of NOACs among starters is largest in the group of patients of 50-80 years. Calculated compliance rate for NOAC patients shows that 88% of all users are adherent with a PDC higher than 80%. CONCLUSIONS: NOAC have overtaken VKA as the major treatment prescribed to new oral anticoagulant patients, and the number of starters on VKA is decreasing. Patients are generally adherent to NOACs during the implementation phase, the period that the medication is used. Fear for inadherence by itself does not need to be a reason for not prescribing NOACs instead of VKA.

Use of oral immunosuppressive drugs in the treatment of atopic dermatitis in the Netherlands.

BACKGROUND: Although atopic dermatitis (AD) is a very common skin disease, data on the percentage of patients with really difficult-to-treat AD are scarce. From socio-economic perspective, it is important to have more insight into these numbers, as new very effective, but expensive, treatment options will be available in the near future for difficult-to-treat AD. Estimating the number of patients with AD using oral immunosuppressive drugs can give an impression of the percentage of difficult-to-treat patients in the total AD population. OBJECTIVE: To give an overview of the use of oral immunosuppressive drugs in patients with AD in the Netherlands. METHODS: Prescription data of oral immunosuppressive drugs in the Netherlands were extracted from a pharmaceutical database (NControl) containing data of 557 million prescriptions and 7.2 million patients. An algorithm, based on the WHO Anatomical Therapeutic Chemical (ATC) codes, was used to identify patients with AD. The prescription of oral immunosuppressive drugs in patients with AD between 1 January 2012 and 1 January 2017 was evaluated. RESULTS: Based on the algorithm, 65 943 patients with AD were selected. 943 patients with AD (1.4%) used cyclosporine A, methotrexate, azathioprine or mycophenolic acid. Methotrexate was most commonly used, followed by azathioprine and cyclosporine A. A switch in medication was rarely seen. In the evaluation period, a decrease in the prescription of cyclosporine A was seen, together with an increase in the prescription of methotrexate. In 31% of the patients who stopped treatment, the discontinuation took place within the first months of treatment. CONCLUSION: In this study population, 1.4% of the patients with AD used oral immunosuppressive drugs for their eczema in a 5-year period. Methotrexate was the most commonly used systemic drug in the Netherlands for the treatment of AD.

Assessment of pharmacogenetic tests: presenting measures of clinical validity and potential population impact in association studies.

The progressing discovery of genetic variants associated with drug-related adverse events has raised expectations for pharmacogenetic tests to improve drug efficacy and safety. To further the use of pharmacogenetics in health care, tests with sufficient potential to improve efficacy and safety, as reflected by good clinical validity and population impact, need to be identified. The potential benefit of pharmacogenetic tests is often concluded from the strength of the association between the variant and the adverse event; measures of clinical validity are generally not reported. This paper describes measures of clinical validity and potential population health impact that can be calculated from association studies. We explain how these measures are influenced by the strength of the association and by the frequencies of the variant and the adverse event. The measures are illustrated using examples of testing for HLA-B*5701 associated with abacavir-induced hypersensitivity and SLCO1B1 c.521T>C (*5) associated with simvastatin-induced adverse events.

Pharmacogenomics of inhaled corticosteroids and leukotriene modifiers: a systematic review.

BACKGROUND: Pharmacogenetics studies of anti-inflammatory medication of asthma have expanded rapidly in recent decades, but the clinical value of their findings remains limited. OBJECTIVE: To perform a systematic review of pharmacogenomics and pharmacogenetics of inhaled corticosteroids (ICS) and leukotriene modifiers (LTMs) in patients with asthma. METHODS: Articles published between 1999 and June 2015 were searched using PubMed and EMBASE. Pharmacogenomics/genetics studies of patients with asthma using ICS or LTMs were included if ≥1 of the following outcomes were studied: lung function, exacerbation rates or asthma symptoms. The studies of Single Nucleotide Polymorphisms (SNPs) that had been replicated at least once were assessed in more detail. RESULTS: In total, 59 publications were included in the systematic review: 26 addressed LTMs (including two genomewide Genome-Wide association studies [GWAS]) and 33 addressed ICS (including four GWAS). None of the GWAS reported similar results. Furthermore, none of the SNPs assessed in candidate gene studies were identified in a GWAS. No consistent reports were found for candidate gene studies of LTMs. In candidate gene studies of ICS, the most consistent results were found for rs28364072 in FCER2. This SNP was associated with all three outcomes of poor response, and the largest effect was reported with the risk of exacerbations (hazard ratio, 3.95; 95% CI, 1.64-9.51). CONCLUSION AND CLINICAL RELEVANCE: There is a lack of replication of genetic variants associated with poor ICS or LTM response. The most consistent results were found for the FCER2 gene [encoding for a low-affinity IgE receptor (CD23)] and poor ICS response. Larger studies with well-phenotyped patients are needed to assess the clinical applicability of ICS and LTM pharmacogenomics/genetics.

Atopic dermatitis characteristics and medication-use patterns in school-age children with AD and asthma symptoms.

BACKGROUND: Atopic dermatitis (AD) and asthma often coexist. Both diseases can have a major impact on the lives of children with AD and their caregivers. AIM: To investigate the association of patient characteristics, comorbidities and impact of AD on children who have both asthma and AD. METHODS: Children with AD (n = 140) were selected from a larger cohort of children with a reported use of asthma medication. The Children's Dermatology Life Quality Index (CDLQI) was used to assess Quality of Life (QoL), and the Self-Assessed Eczema Area and Severity Index (SA-EASI) was used to measure AD severity. Characteristics assessed included: age, sex, and the number and type of atopic comorbidities. Medication use for AD was defined using the total number of AD prescriptions, the number of different topical AD prescriptions and the highest potency topical corticosteroid (TCS) used. Determinants of AD severity and QoL were evaluated using Spearman rank tests. RESULTS: The following factors were most strongly associated with a lower QoL: characteristics of AD lesions (Spearman Rs = 0.61-0.69, P < 0.01), a higher SA-EASI score (Rs = 0.54, P < 0.01) and a larger number of different topical AD prescriptions (Rs = 0.38, P < 0.01). The following factors were correlated with more severe AD: age (Rs = -0.36, P < 0.01), larger number of different TCS preparations used (Rs = 0.27, P < 0.05) and larger number of TCS prescriptions (Rs = 0.25, P < 0.05). CONCLUSION: In children with asthma and AD, the number of TCS preparations used is associated with lower QoL and increased AD severity.

Cost-effectiveness of pharmacogenetic-guided dosing of warfarin in the United Kingdom and Sweden.

We aimed to assess the cost-effectiveness of pharmacogenetic-guided dosing of warfarin in patients with atrial fibrillation (AF) in the United Kingdom and Sweden. Data from EU-PACT, a randomized controlled trial in newly diagnosed AF patients, were used to model the incremental costs per quality-adjusted life-year (QALY) gained by pharmacogenetic-guided warfarin dosing versus standard treatment over a lifetime horizon. Incremental lifetime costs were £26 and 382 Swedish kronor (SEK) and incremental QALYs were 0.0039 and 0.0015 in the United Kingdom and Sweden, respectively. The corresponding incremental cost-effectiveness ratios (ICERs) were £6 702 and 253 848 SEK per QALY gained. The ICER was below the willingness-to-pay threshold of £20 000 per QALY gained in 93% of the simulations in the United Kingdom and below 500 000 SEK in 67% of the simulations in Sweden. Our data suggest that pharmacogenetic-guided dosing of warfarin is a cost-effective strategy to improve outcomes of patients with AF treated with warfarin in the United Kingdom and in Sweden.

Genetic variation in uncontrolled childhood asthma despite ICS treatment.

Genetic variation may partly explain asthma treatment response heterogeneity. We aimed to identify common and rare genetic variants associated with asthma that was not well controlled despite inhaled corticosteroid (ICS) treatment. Data of 110 children was collected in the Children Asthma Therapy Optimal trial. Associations of genetic variation with measures of lung function (FEV1%pred), airway hyperresponsiveness (AHR) to methacholine (Mch PD20) and treatment response outcomes were analyzed using the exome chip. The 17q12-21 locus (containing ORMDL3 and GSMDB) previously associated with childhood asthma was investigated separately. Single-nucleotide polymorphisms (SNPs) in the 17q12-21 locus were found nominally associated with the outcomes. The strongest association in this region was found for rs72821893 in KRT25 with FEV1%pred (P=3.75*10(-5)), Mch PD20 (P=0.00095) and Mch PD20-based treatment outcome (P=0.006). No novel single SNPs or burden tests were significantly associated with the outcomes. The 17q12-21 region was associated with FEV1%pred and AHR, and additionally with ICS treatment response.

A genome-wide association study identifies variants in KCNIP4 associated with ACE inhibitor-induced cough.

The most common side effect of angiotensin-converting enzyme inhibitor (ACEi) drugs is cough. We conducted a genome-wide association study (GWAS) of ACEi-induced cough among 7080 subjects of diverse ancestries in the Electronic Medical Records and Genomics (eMERGE) network. Cases were subjects diagnosed with ACEi-induced cough. Controls were subjects with at least 6 months of ACEi use and no cough. A GWAS (1595 cases and 5485 controls) identified associations on chromosome 4 in an intron of KCNIP4. The strongest association was at rs145489027 (minor allele frequency=0.33, odds ratio (OR)=1.3 (95% confidence interval (CI): 1.2-1.4), P=1.0 × 10(-8)). Replication for six single-nucleotide polymorphisms (SNPs) in KCNIP4 was tested in a second eMERGE population (n=926) and in the Genetics of Diabetes Audit and Research in Tayside, Scotland (GoDARTS) cohort (n=4309). Replication was observed at rs7675300 (OR=1.32 (1.01-1.70), P=0.04) in eMERGE and at rs16870989 and rs1495509 (OR=1.15 (1.01-1.30), P=0.03 for both) in GoDARTS. The combined association at rs1495509 was significant (OR=1.23 (1.15-1.32), P=1.9 × 10(-9)). These results indicate that SNPs in KCNIP4 may modulate ACEi-induced cough risk.

ST13 polymorphisms and their effect on exacerbations in steroid-treated asthmatic children and young adults.

BACKGROUND: The clinical response to inhaled corticosteroids (ICS) is associated with single nucleotide polymorphisms (SNPs) in various genes. This study aimed to relate variations in genes in the steroid pathway and asthma susceptibility genes to exacerbations in children and young adults treated with ICS. METHODS: We performed a meta-analysis of three cohort studies: Pharmacogenetics of Asthma Medication in Children: Medication with Anti-Inflammatory effects (n = 357, age: 4-12 years, the Netherlands), BREATHE (n = 820, age: 3-22 years, UK) and Paediatric Asthma Gene Environment Study (n = 391, age: 2-16 years, UK). Seventeen genes were selected based on a role in the glucocorticoid signalling pathway or a reported association with asthma. Two outcome parameters were used to reflect exacerbations: hospital visits and oral corticosteroid (OCS) use in the previous year. The most significant associations were tested in three independent validation cohorts; the Childhood Asthma Management Programme (clinical trial, n = 172, age: 5-12 years, USA), the Genes- environment and Mixture in Latino Americans II- study (n = 745, age: 8-21, USA) and the Pharmacogenetics of adrenal suppression cohort (n = 391, age: 5-18, UK) to test the robustness of the findings. Finally, all results were meta-analysed. RESULTS: Two SNPs in ST13 (rs138335 and rs138337), but not in the other genes, were associated at a nominal level with an increased risk of exacerbations in asthmatics using ICS in the three cohorts studied. In a meta-analysis of all six studies, ST13 rs138335 remained associated with an increased risk of asthma-related hospital visits and OCS use in the previous year; OR = 1.22 (P = 0.013) and OR = 1.22 (P = 0.0017), respectively. CONCLUSION AND CLINICAL RELEVANCE: A novel susceptibility gene, ST13, coding for a cochaperone of the glucocorticoid receptor, is associated with exacerbations in asthmatic children and young adults despite their ICS use. Genetic variation in the glucocorticoid signalling pathway may contribute to the interindividual variability in clinical response to ICS treatment in children and young adults.

Association of polymorphisms in the beta-2 adrenergic receptor gene with fracture risk and bone mineral density.

UNLABELLED: Signaling through the beta-2 adrenergic receptor (B2AR) on the osteoblast influences bone remodeling in rodents. In the B2AR gene, three polymorphisms influence receptor function. We show that these polymorphisms are not associated with fracture risk or bone mineral density in the UCP, Rotterdam Study, and GEFOS cohorts. INTRODUCTION: Signaling through the beta-2 adrenergic receptor (B2AR) on the osteoblast influences bone remodeling in rodents. In the B2AR gene, three polymorphisms are known to influence receptor function in vitro and in vivo (rs1042713, rs1042714, and rs1800888). We examined the role of these polymorphisms in the B2AR gene on human bone metabolism. METHODS: We performed nested case-control studies to determine the association of these polymorphisms with fracture risk in the Utrecht Cardiovascular Pharmacogenetics (UCP) cohort and in three cohorts of the Rotterdam Study. We also determined the association of these polymorphisms with bone mineral density (BMD) in the GEFOS Consortium. UCP contains drug-dispensing histories from community pharmacies linked to national registrations of hospital discharges in the Netherlands. The Rotterdam Study is a prospective cohort study investigating demographics and risk factors of chronic diseases. GEFOS is a large international collaboration studying the genetics of osteoporosis. Fractures were defined by ICD-9 codes 800-829 in the UCP cohort (158 cases and 2617 unmatched controls) and by regular X-ray examinations, general practitioner, and hospital records in the Rotterdam Study (2209 cases and 8559 unmatched controls). BMD was measured at the femoral neck and lumbar spine using dual-energy X-ray absorptiometry in GEFOS (N = 32,961). RESULTS: Meta-analysis of the two nested case-control studies showed pooled odds ratios of 0.98 (0.91-1.05, p = 0.52), 1.04 (0.97-1.12, p = 0.28), and 1.16 (0.83-1.62, p = 0.38) for the associations between rs1042713, rs1042714, and rs1800888 per minor allele and fractures, respectively. There were no significant associations of the polymorphisms and BMD in GEFOS. CONCLUSION: In conclusion, polymorphisms in the beta-2 adrenergic receptor gene are not associated with fracture risk or BMD.

Application of routine electronic health record databases for pharmacogenetic research.

Inter-individual variability in drug responses is a common problem in pharmacotherapy. Several factors (non-genetic and genetic) influence drug responses in patients. When aiming to obtain an optimal benefit-risk ratio of medicines and with the emergence of genotyping technology, pharmacogenetic studies are important for providing recommendations on drug treatments. Advances in electronic healthcare information systems can contribute to increasing the quality and efficiency of such studies. This review describes the definition of pharmacogenetics, gene selection and study design for pharmacogenetic research. It also summarizes the potential of linking pharmacoepidemiology and pharmacogenetics (along with its strengths and limitations) and provides examples of pharmacogenetic studies utilizing electronic health record databases.

Added value of pharmacogenetic testing in predicting statin response: results from the REGRESS trial.

It was investigated whether pharmacogenetic factors, both as single polymorphism and as gene-gene interactions, have an added value over non-genetic factors in predicting statin response. Five common polymorphisms were selected in apolipoprotein E, angiotensin-converting enzyme, hepatic lipase and toll-like receptor 4. Linear regression models were built and compared on R(2) to estimate the added value of single polymorphisms and gene-gene interactions. The selected polymorphisms and the gene-gene interactions had a small added value in predicting change in low-density lipoprotein cholesterol levels (LDL-c) as response to statins over the non-genetic predictors (P=0.104), and also in predicting LDL-c in non-treated patients (P=0.016). Moreover, four gene-gene interactions with statin therapy were identified. The added value of genetic factors over non-genetic variables is for the greater part produced by gene-gene interactions. This underlines the importance to examine gene-gene interactions in future (pharmaco)genetic research.

Single nucleotide polymorphisms in genes that are associated with a modified response to statin therapy: the Rotterdam Study.

The objective of this study was to investigate whether common variation in genes involved in lipid metabolism modify the effect of statins on serum total cholesterol concentration. Statin users were identified in the Rotterdam Study, a prospective population-based cohort study of subjects >55 years of age. We studied the association between single nucleotide polymorphisms (SNPs) in genes involved in lipid metabolism and total cholesterol response to statin therapy, using linear regression analysis and adjusting for potential confounders. Replication was performed in an independent extended cohort of the Rotterdam Study. Genotype data and total cholesterol concentrations after start of statin therapy were available for 554 newly started statin users. Two SNPs were associated with a significantly higher cholesterol concentration under statin therapy: SNP rs1532624 in the CETP gene (ß: 0.141 mmol l(-1), P=0.004 per additional allele) and SNP rs533556 in the APOA1 gene (ß: 0.138 mmol l(-1), P=0.005 per additional allele). In the replication sample, only the CETP rs1532624 SNP again showed a significant association. The SNPs were not related to baseline total cholesterol in non-statin users. In conclusion, we found that the CETP rs1532624 polymorphism is associated with cholesterol response to statin therapy in a cohort of elderly subjects in the general population.

Biomarkers of therapy responsiveness in asthma: pitfalls and promises.

Asthma is one of the most common chronic diseases worldwide. There is a large inter-individual variability in response to asthma treatment. Most patients respond well to standard therapy; however, a small proportion of the patients remain symptomatic despite treatment with high dosages of corticosteroids. Uncontrolled asthma leads to a decreased quality of life. Therefore, it is important to identify individuals who will respond poorly to standard asthma medication, especially to standard maintenance therapy with inhaled corticosteroids, at an early stage. Response to anti-inflammatory therapy is generally monitored by the assessment of clinical symptoms, which only partially correlates with underlying airway inflammation. The identification of specific inflammatory biomarkers might help to guide treatment or predict a corticosteroid response more accurately. Some inflammatory biomarkers are already finding their way into clinical practice (e.g. fraction of nitric oxide in exhaled breath), whereas others are predominantly used as a research tool (e.g. profiles of volatile organic compounds). Currently, there is no inflammatory biomarker used in routine clinical practice to predict a corticosteroid response. More knowledge on the underlying biological mechanism(s) of heterogeneous therapeutic responses could help to identify novel biomarkers. This review will focus on inflammatory patterns and genetic variations that may underlie differences in treatment response in patients with asthma, and will provide an overview of inflammatory biomarkers that could potentially serve as response predictors.

FCER2 T2206C variant associated with chronic symptoms and exacerbations in steroid-treated asthmatic children.

BACKGROUND: The T2206C FCER2 variant was found previously to be associated with IgE levels, exacerbation rates and decreased FCER2 expression in children on inhaled corticosteroids (ICS) participating in a clinical trial. This finding has not been replicated. We sought to replicate the association between the FCER2 gene and exacerbations in children with asthma. In addition, we tested the hypothesis that the T2206C variant may be associated with other markers of steroid resistance such as asthma symptom scores and asthma medication use. METHODS: The influence of the T2206C variant on asthma exacerbations (emergency department visits or hospitalization), symptoms scores and medication use was explored using data from two populations of asthmatic children using ICS: Pharmacogenetics of Asthma medication in Children: Medication with ANti-inflammatory effects study (n = 386) and BREATHE study (n = 939). RESULTS: The T2206C variant was associated with increased risk of asthma-related hospital visits in both cohorts (OR: 1.91, 95% CI: 1.08-3.40), and meta-analysis with previously published results was highly significant (OR: 2.38, 95% CI: 1.47-3.85, P = 0.0004). The FCER2 variant was also associated with increased risk of uncontrolled asthma measured by Asthma Control Questionnaire (OR: 2.64, 95% CI: 1.00-6.98) and was associated with increased daily steroid dose (OR: 2.46, 95% CI: 1.38-4.39). CONCLUSION: The association between the FCER2 T2206C variant and asthma-related hospitalizations in steroid-treated asthma appears robust and may also be associated with other indicators of lack of ICS efficacy such as asthma symptoms and a requirement for higher daily doses of ICS. Our results suggest that the FCER2 T2206C variant might be a useful pharmacogenetic predictor of steroid refractory patients.

Effects of short-term exposures to ultrafine particles near an airport in healthy subjects.

BACKGROUND: Recent studies reported elevated concentrations of ultrafine particles (UFP) near airports. Little is known about the health effects of UFP from aviation. Since UFP can deposit deep into the lungs and other organs, they may cause significant adverse health effects. OBJECTIVE: We investigated health effects of controlled short-term human exposure to UFP near a major airport. METHODS: In this study, 21 healthy non-smoking volunteers (age range: 18-35 years) were repeatedly (2-5 visits) exposed for 5 h to ambient air near Schiphol Airport, while performing intermittent moderate exercise (i.e. cycling). Pre- to post-exposure changes in cardiopulmonary outcomes (spirometry, forced exhaled nitric oxide, electrocardiography and blood pressure) were assessed and related to total- and size-specific particle number concentrations (PNC), using linear mixed effect models. RESULTS: The PNC was on average 53,500 particles/cm3 (range 10,500-173,200). A 5-95th percentile increase in exposure to UFP (i.e. 125,400 particles/cm3) was associated with a decrease in FVC of -73.8 mL (95% CI -138.8 - -0.4) and a prolongation of the corrected QT (QTc) interval by 9.9 ms (95% CI 2.0 - 19.1). These effects were associated with particles < 20 nm (mainly UFP from aviation), but not with particles > 50 nm (mainly UFP from road traffic). DISCUSSION: Short-term exposures to aviation-related UFP near a major airport, was associated with decreased lung function (mainly FVC) and a prolonged QTc interval in healthy volunteers. The effects were relatively small, however, they appeared after single exposures of 5 h in young healthy adults. As this study cannot make any inferences about long-term health impacts, appropriate studies investigating potential health effects of long-term exposure to airport-related UFP, are urgently needed.

Determinants of DNA yield and purity collected with buccal cell samples.

Buccal cells are an important source of DNA in epidemiological studies, but little is known about factors that influence amount and purity of DNA. We assessed these factors in a self-administered buccal cell collection procedure, obtained with three cotton swabs. In 2,451 patients DNA yield and in 1,033 patients DNA purity was assessed. Total DNA yield ranged from 0.08 to 1078.0 microg (median 54.3 microg; mean 82.2 microg +/- SD 92.6). The median UV 260:280 ratio, was 1.95. Samples from men yielded significantly more DNA (median 58.7 microg) than those from women (median 44.2 microg). Diuretic drug users had significantly lower purity (median 1.92) compared to other antihypertensive drug users (1.95). One technician obtained significantly lower DNA yields. Older age was associated with lower DNA purity. In conclusion, DNA yield from buccal swabs was higher in men and DNA purity was associated with age and the use of diuretics.