AIM: To evaluate the effect of proton pump inhibitors (PPIs) on the development of gastrointestinal tuberculosis.

METHODS: All patients who were more than 20 years old and who had received a prescription for PPIs among those who visited Seoul National University Hospital from January 1, 2005 to December 31, 2009 were identified. Due to the low sensitivity of the microbiologic test and the nonspecific pathologic findings, the diagnosis of gastrointestinal tuberculosis was confirmed through the presence of active ulcerations and the responses to anti-tuberculosis medications. The patients were divided into two groups according to treatment duration (group 1: ≤ 3 mo; group 2: > 3 mo) and were followed up from the time they took the first prescription of PPIs until their last visit. Logistic regression analysis was used to calculate the relative risks (RR) and 95%CI, adjusting for covariates.

RESULTS: Among the 61  834 patients exposed to PPIs (50  534 in group 1; 11  300 in group 2), 21 patients were diagnosed with PPI-associated gastrointestinal tuberculosis during 124  274 person-years of follow-up. Of 21 patients, the 12 who revealed only scar changes in the colonoscopy were excluded from the statistical analyses. Of those who remained, 2 were excluded because they underwent gastrointestinal endoscopy within 4 wk of the first prescription for PPIs. Longer exposure to PPI was associated with a higher mean age (55.0 ± 14.5 in group 1 vs 58.2 ± 13.3 in group 2, P < 0.001) and a higher Charlson co-morbidity index (0.50 ± 0.93 in group 1 vs 0.77 ± 1.14 in group 2, P < 0.001). The true incidence of active gastrointestinal tuberculosis was 0.65 per 1000 person-years in group 1 and 0.03 per 1 000 person-years in group 2. Like the less-than-three-month PPI treatment period in group 1, the over-three-month PPI therapy period in group 2 was not associated with increased risk of acquiring gastrointestinal tuberculosis, after adjusting for age and co-morbidities, whereas the Charlson co-morbidity index was associated with increased risk of acquiring gastrointestinal tuberculosis based on the score [RR: (reference 1) in group 1 vs 1.518 in group 2; 95% CI: 1.040-2.216, P = 0.03].

CONCLUSION: Long-term PPI therapy does not seem to be associated with increased risk of acquiring gastrointestinal tuberculosis, but a higher Charlson co-morbidity index is associated with such.

Background

Transglutaminase 2 (TG2) is a post-translational protein-modifying enzyme that catalyzes the transamidation reaction, producing crosslinked or polyaminated proteins. Increased TG2 expression and activity have been reported in various inflammatory conditions, such as rheumatoid arthritis, inflammation-associated pulmonary fibrosis, and autoimmune encephalitis. In particular, TG2 from epithelial cells is important during the initial inflammatory response in the lung. In this study, we evaluated the role of TG2 in the pathogenesis of allergic asthma, particularly whether TG2 affects initial activation signaling leading to Th2 differentiation against antigens.

Methods

We induced allergic asthma by ovalbumin sensitization and intranasal challenge in wild-type (WT) BALB/c and TG2-deficient mice. Broncheoalveolar lavage fluid cells and intracellular cytokine production were analyzed by flow cytometry. Interleukin (IL)-33 and TG2 expression in lung epithelial cells was detected by confocal microscopy.

Results

Airway responsiveness was attenuated in TG2-deficient mice compared to that in the WT control. In addition, recruitment of eosinophils and Th2 and Th17 differentiation decreased in TG2-deficient mice. Treatment with cysteamine, a transglutaminase inhibitor, also reduced airway hypersensitivity, inflammatory cell recruitment, and T helper cell differentiation. TG2-deficient mice showed reduced IL-33 expression following induction of allergic asthma compared to those in the WT control.

Conclusions

We found that pulmonary epithelial cells damaged by allergens triggered TG2-mediated IL-33 expression leading to type 2 responses by recruiting both innate and adaptive arms of the immune system.

Allopurinol is one of the causative drugs that induce fixed drug eruption (FDE). The lymphocyte transformation test (LTT) is a safe and reliable diagnostic procedure for drug allergy, but is reported to be rarely positive in patients with FDE. In the current case, we performed an LTT and successfully confirmed allopurinol as the offending drug. This case report suggests that an LTT should be an optional diagnostic tool for FDE or delayed reaction due to allopurinol.

Hepatic adverse drug reactions (ADRs) to certain drugs may differ within each country, reflecting different patterns of prescription, socioeconomic status, and culture. The purpose of this study was to assess the suspected cause of hepatic ADRs using the spontaneously reported pharmacovigilance data from Korea. A total of 9,360 spontaneously reported adverse drug events (ADEs) from nine Pharmacovigilance Centers were analyzed. Risk of hepatic ADEs was assessed by calculating the reporting odds ratio (ROR). Of the 9,360 cases, 567 hepatic ADEs were reported. The most frequently prescribed drug classes inducing hepatic ADEs were anti-tuberculotics, cephalosporins, valproic acids, penicillins, quinolones, non-steroidal anti-inflammatory drugs (NSAIDs), anti-viral agents, and statins. ROR values were especially high in anti-tuberculosis drugs, systemic antifungal drugs for systemic use, anti-epileptics, propylthiouracil, and herbal medicines. Underlying diseases such as tuberculosis (6.9% vs 0.9%), pneumonia (4.9% vs 1.7%), intracranial injury including skull fracture (4.5% vs 0.9%), HIV (3.4% vs 0.4%), subarachnoid hemorrhage (2.8% vs 0.5%), and osteoporosis (2.4% vs 1.4%) were significantly more common in hepatic ADE group. In conclusion, anti-infective drugs, anti-epileptics, NSAIDs and statins are the most common suspects of the spontaneously reported hepatic ADEs, in Korea. Careful monitoring for such reactions is needed for the prescription of these drugs.

Background

HLA-B58 is a very strong marker of allopurinol-induced severe cutaneous adverse reactions (SCARs), especially in population with high frequency of HLA-B58, such as Chinese, Thai, and Korean. Although allopurinol is frequently prescribed to patients receiving chemotherapy for the prevention of tumor lysis syndrome, the risk of allopurinol-related SCARs in patients with hematologic malignancies is not evaluated. This study was conducted to find out the incidence of allopurinol-induced hypersensitivity in patients with hematologic malignancy during chemotherapy according to HLA-B58 and clinical usefulness of HLA-B58 as a risk marker for the development of allopurinol-induced hypersensitivity.

Methods

We retrospectively reviewed the medical records of patients with hematologic malignancy who ever took allopurinol and underwent serologic HLA typing for bone marrow transplantation from January 2000 to May 2010.

Results

Among total 463 patients, 13 (2.8%) patients experienced allopurinol hypersensitivity reactions which were simple maculopapular rash and none of those were compatible with SCARs. The mean duration of allopurinol exposure in total patients was 26.46 days (1∼2,173) and the mean duration until development of rash was 5.54 ± 1.20 days. Fifty patients (10.8%) had HLA-B58. However, the incidence of allopurinol induced rash was not different according to HLA-B58 (4% (2/50) and 2.66% (11/413) in B58 (+) and B58 (-) patients, respectively). Frequency of B58 was slightly higher in patients with rash (15.4%) compared with tolerant patients (10.7%) but the difference was statistically insignificant (P > 0.05).

Conclusions

The results of this study that HLA-B58 does not increase the risk of allopurinol induced SCARs as well as simple rash among patients with hematologic malignancy. Allopurinol can be used safely in most patients with hematologic malignancy during chemotherapy and HLA typing does not give additional advantage for clinical decision.

Purpose

Allergic rhinitis is clinically defined as a disorder of the nose induced by IgE mediated inflammation after allergen exposure of the nasal mucosa. Many reports have stated that Panax ginseng and fermented red ginseng have anti-inflammatory effects, especially against Th2-type inflammation. This study was conducted to evaluate the therapeutic effects of fermented red ginseng in allergic rhinitis.

Methods

In this 4-week, double-blind, placebo-controlled study, 59 patients with persistent perennial allergic rhinitis were randomly divided into two groups: those receiving fermented red ginseng tablets (experimental group) and those receiving placebo (control group). The primary efficacy variable was the total nasal symptom score (TNSS; rhinorrhea, sneezing, itchy nose, and nasal congestion). Secondary efficacy variables were the Rhinitis Quality of Life (RQoL) score and skin reactivity to inhalant allergens, as determined by the skin prick test.

Results

There was no significant difference in the TNSS score and TNSS duration score between the experimental and placebo groups in weeks 1, 2, 3, or 4. For nasal congestion, fermented red ginseng was significantly effective (P<0.005), while placebo caused no change. The activity and emotion of RQoL improved markedly secondary to treatment with fermented red ginseng (P<0.05), while placebo caused no change. Additionally, fermented red ginseng reduced skin reactivity to sensitized perennial allergens (P<0.05). Fermented red ginseng was well tolerated.

Conclusions

Fermented red ginseng improved nasal congestion symptoms and RQoL in patients with perennial allergic rhinitis.

Background

Bronchial asthma is usually associated with high sputum eosinophil levels. However, recent reports have suggested the importance of noneosinophilic asthma (NEA) as a distinct phenotype of asthma.

Objective

The aim of this study was to evaluate clinical significance of sputum eosinophilia and long-term treatment outcomes related to sputum eosinophilia in Korean asthmatics.

Methods

A total of 201 steroid-naive asthmatics who had undergone induced sputum analysis at baseline were selected from the Cohort for Reality and Evolution of Adult Asthma study population. Clinical evaluation, spirometry, a skin-prick test, a methacholine bronchial provocation test, and sputum eosinophil analysis were performed initially, and patients received the treatment recommended by the Global Initiative for Asthma. Lung function was evaluated every 6 months, and 53 patients completed 24 months of regular follow-up visits. Sputum eosinophilia was defined as a sputum eosinophil count of >3%.

Results

Of the 201 steroid-naive asthmatics, 97 patients had NEA and 104 had eosinophilic asthma (EA). Only 52% of steroid-naive asthmatic subjects had elevated baseline sputum eosinophil levels. A higher percentage of sputum eosinophils was associated with a lower PC20 (r = -0.193; p = 0.009, Spearman correlation), but not with forced expiratory volume in one second (FEV1) (r = 0.045; p = 0.525). During the 24-month study period, the percentage change of FEV1 was significantly lower in the NEA group than in the EA group at 6, 12, 18, and 24 months (p < 0.05). The NEA group, unlike the EA group, showed no significant improvement in FEV1 at 6, 12, 18, or 24 months (p > 0.05).

Conclusion

A higher sputum eosinophil percentage was correlated with a higher airway hyperresponsiveness. Compared with EA patients, NEA patients had poor treatment outcomes in the 2-year follow-up of a Korean asthma cohort population.

Purpose

Patient care based on asthma guidelines is cost-effective and leads to improved treatment outcomes. However, ineffective implementation strategies interfere with the use of these recommendations in clinical practice. This study investigated physicians' preferences for asthma guidelines, including content, supporting evidence, learning strategies, format, and placement in the clinical workplace.

Methods

We obtained information through a questionnaire survey. The questionnaire was distributed to physicians attending continuing medical education courses and sent to other physicians by airmail, e-mail, and facsimile.

Results

A total of 183 physicians responded (male to female ratio, 2.3:1; mean age, 40.4±9.9 years); 89.9% of respondents were internists or pediatricians, and 51.7% were primary care physicians. Physicians preferred information that described asthma medications, classified the disease according to severity and level of control, and provided methods of evaluation/treatment/monitoring and management of acute exacerbation. The most effective strategies for encouraging the use of the guidelines were through continuing medical education and discussions with colleagues. Physicians required supporting evidence in the form of randomized controlled trials and expert consensus. They preferred that the guidelines be presented as algorithms or flow charts/flow diagrams on plastic sheets, pocket cards, or in electronic medical records.

Conclusions

This study identified the items of the asthma guidelines preferred by physicians in Korea. Asthma guidelines with physicians' preferences would encourage their implementation in clinical practice.

The Global Initiative of Chronic Obstructive Lung Disease (GOLD) guidelines define chronic obstructive pulmonary disease (COPD) in subjects with FEV1/FVC <0.7. However, the use of this fixed ratio may result in over-diagnosis of COPD in the elderly, especially with mild degree of COPD. The lower limit of normal (LLN) can be used to minimize the potential misclassification. The aim of this study was to evaluate the impact of different definitions of airflow obstruction (LLN or fixed ratio of FEV1/FVC) on the estimated prevalence of COPD in a population-based sample. We compared the prevalence of COPD and its difference diagnosed by different methods using either fixed ratio (FEV1/FVC <0.7) or LLN criterion (FEV1/FVC below LLN). Among the 4,816 subjects who had performed spirometry, 2,728 subjects met new ATS/ERS spirometry criteria for acceptability and repeatability. The prevalence of COPD was 10.9% (14.7% in men, 7.2% in women) by LLN criterion and 15.5% (21.8% in men, 9.1% in women) by fixed ratio of FEV1/FVC among subjects older than 45 yr. The difference of prevalence between LLN and fixed ratio of FEV1/FVC was even higher among subjects with age ≥65, 14.9% and 31.1%, respectively. In conclusion, the prevalence of COPD by LLN criterion was significantly lower in elderly compared to fixed ratio of FEV1/FVC. Implementing LLN criterion instead of fixed ratio of FEV1/FVC may reduce the risk of over-diagnosis of COPD in elderly people.

Introduction

Limited data are available regarding the diagnostic and prognostic utility of brain natriuretic peptide (BNP) in patients with chronic kidney disease (CKD) in the intensive care unit (ICU) setting.

Methods

All patients with CKD and a serum creatinine (Cr) of 2.0 mg/dl or higher admitted to the ICU between January 2006 and September 2007 were enrolled in this study. The CKD group was divided according to the presence or absence of acute decompensated heart failure (ADHF) into CKD + ADHF and CKD - ADHF groups, respectively. Other patients with ADHF having low Cr (<1.2 mg/dl) in the coronary care unit were also recruited as a control group during the same period. BNP levels at the time of admission (admission BNP) were compared amongst these groups. We then sought to determine whether BNP levels could predict the outcome in patients with CKD.

Results

Of 136 patients with CKD for whom data were available, including 58 on dialysis (42.6%), 81 (59.6%) had ADHF and their estimated glomerular filtration rate (eGFR) was 12.8 ± 7.3 ml/min/1.73 m2. BNP levels at admission were 2708.6 ± 1246.9, 567.9 ± 491.7 and 1418.9 ± 1126.5 pg/ml in the CKD + ADHF, CKD - ADHF and control groups (n = 33), respectively (P = 0.000). The optimal cutoff level in patients with CKD was 1020.5 pg/ml (area under the curve = 0.944) to detect ADHF from the receiver operating characteristic (ROC) curve. This level was not associated with in-hospital mortality, all-cause death or a composite event (all-cause death and/or new cardiac event). However, a borderline significant association was observed with new cardiac events (hazard ratio (HR) = 4.551; P = 0.078) during the follow-up period (521.1 ± 44.7 days). Furthermore, continuous variables of BNP and BNP quartiles were significantly associated with new cardiac events in the multivariate Cox model (HR = 1.001, P = 0.041; HR = 2.212, P = 0.018).

Conclusions

The findings suggest that the level of BNP at the time of admission may be a useful marker for detecting ADHF and predicting cardiac events in patients with CKD in the ICU setting.

Transforming growth factor (TGF)-β1 is an essential regulatory cytokine that has been implicated in the pathogenesis of diverse facets of the injury and repair responses in the lung. The types of responses that it elicits can be appreciated in studies from our laboratory that demonstrated that the transgenic (Tg) overexpression of TGF-β1 in the murine lung causes epithelial apoptosis followed by fibrosis, inflammation, and parenchymal destruction. Because a cyclin-dependent kinase inhibitor, p21, is a key regulator of apoptosis, we hypothesized that p21 plays an important role in the pathogenesis of TGF-β1–induced tissue responses. To test this hypothesis we evaluated the effect of TGF-β1 on the expression of p21 in the murine lung. We also characterized the effects of transgenic TGF-β1 in mice with wild-type and null mutant p21 loci. These studies demonstrate that TGF-β1 is a potent stimulator of p21 expression in the epithelial cells and macrophages in the murine lung. They also demonstrate that TGF-β1–induced lung inflammation, fibrosis, myofibroblast accumulation, and alveolar destruction are augmented in the absence of p21, and that these alterations are associated with exaggerated levels of apoptosis and caspase-3 activation. Finally, our studies further demonstrated that TGF-β1 induces p21 via a TNF-α–signaling pathway and that p21 is a negative modulator of TGF-β1–induced TNF-α expression. Collectively, our studies demonstrate that p21 regulates TGF-β1–induced apoptosis, inflammation, fibrosis, and alveolar remodeling by interacting with TNF-α–signaling pathways.

Semaphorin (SEMA) 7A regulates neuronal and immune function. In these studies, we tested the hypothesis that SEMA 7A is also a critical regulator of tissue remodeling. These studies demonstrate that SEMA 7A and its receptors, plexin C1 and β1 integrins, are stimulated by transforming growth factor (TGF)-β1 in the murine lung. They also demonstrate that SEMA 7A plays a critical role in TGF-β1–induced fibrosis, myofibroblast hyperplasia, alveolar remodeling, and apoptosis. TGF-β1 stimulated SEMA 7A via a largely Smad 3–independent mechanism and stimulated SEMA 7A receptors, matrix proteins, CCN proteins, fibroblast growth factor 2, interleukin 13 receptor components, proteases, antiprotease, and apoptosis regulators via Smad 2/3–independent and SEMA 7A–dependent mechanisms. SEMA 7A also played an important role in the pathogenesis of bleomycin-induced pulmonary fibrosis. TGF-β1 and bleomycin also activated phosphatidylinositol 3-kinase (PI3K) and protein kinase B (PKB)/AKT via SEMA 7A–dependent mechanisms, and PKB/AKT inhibition diminished TGF-β1–induced fibrosis. These observations demonstrate that SEMA 7A and its receptors are induced by TGF-β1 and that SEMA 7A plays a central role in a PI3K/PKB/AKT-dependent pathway that contributes to TGF-β1–induced fibrosis and remodeling. They also demonstrate that the effects of SEMA 7A are not specific for transgenic TGF-β1, highlighting the importance of these findings for other fibrotic stimuli.

Inflammation and tissue remodeling with pathologic fibrosis are common consequences of Th2 responses in the lung and other organs. Interleukin (IL)-13 and transforming growth factor-β1 (TGF-β1) are frequently coexpressed in these responses and are believed to play important roles in the pathogenesis of Th2-induced pathologies. To shed light on the mechanisms of these responses, overexpression transgenic approaches were used to selectively target each of these cytokines to the murine lung. IL-13 proved to be a potent stimulator of eosinophilic inflammation, mucus metaplasia, tissue fibrosis, and alveolar remodeling. CC chemokines, specific chemokine receptors (CCR2, CCR1), adenosine metabolism, vascular endothelial growth factor, and IL-11 contributed to the genesis of these responses. IL-13 also induced tissue fibrosis, at least in part, via its ability to induce and activate TGF-β1. In the TGF-β1 transgenic mouse, epithelial apoptosis preceded the onset of tissue fibrosis and alveolar remodeling. In addition, chemical (Z-VAD-fmk) and genetic (null mutations of early growth response gene 1) interventions blocked apoptosis and ameliorated TGF-β1–induced fibrosis and alveolar restructuring. These studies define an IL-13–TGF-β1 pathway of tissue remodeling that regulates inflammation, mucus metaplasia, apoptosis, vascular responses, and fibrosis in the lung. They also highlight the intimate relationship between apoptosis and fibrosis induced by TGF-β1. By defining the complexities of this pathway, these studies highlight sites at which therapies can be directed to control these important responses.

We report here a case with hypereosinophilia and peripheral artery occlusion. A 32-yr-old Korean woman presented to us with lower extremity swelling and pain. Angiography revealed that multiple lower extremity arteries were occlusive. The biopsy specimen showed perivascular and periadnexal dense eosinophilic infiltration in dermis and subcutaneous adipose tissue. Laboratory investigations revealed a persistent hypereosinophilia. She was prescribed prednisolone 60 mg daily. Her skin lesion and pain were improved and the eosinophil count was dramatically decreased. After discharge, eosinophil count gradually increased again. Cyanosis and pain of her fingers recurred. She had been treated with cyclophosphamide pulse therapy. Her eosinophilia was decreased, but the cyanosis and tingling sense were progressive. The extremity arterial stenoses were slightly progressed. Skin biopsy showed perivascular eosinophilic infiltration in the dermis and CD40 ligand (CD40L) positive eosinophilic infiltration. The serum TNF-α was markedly increased. These results suggest that CD40L (a member of TNF-α superfamily) could play a role in the inflammatory processes when eosinophil infiltration and activation are observed. We prescribed prednisolone, cyclophosphamide, clopidogrel, cilostazol, beraprost and nifedipine, and she was discharged.

Occupational asthma is induced by many agents, including herbal materials, that are exposed in working places. Although there are a few case reports for occupational allergy induced by herbal materials, there is none for that induced by Wonji (Polygala tenuifolia). This study was conducted to evaluate clinical characteristics and immunologic mechanism of Wonji-induced asthma in a exposed-worker. A patient who complained of asthma and rhinitis symptoms, and who had worked in a herbal manufacturing factory for 8 yr, underwent a skin prick test with crude extract of Wonji under the impression of occupational asthma induced by the agent. The patient had a strong positive response to the extract on the skin prick test. Allergen bronchial challenge to the extract demonstrated a typical dual response. Serum specific IgE level to the extract was higher in the patient than in healthy controls, and ELISA inhibition test revealed complete inhibition of IgE binding with the extract, but no inhibition with Der p 2 or mugwort extracts. Six IgE binding components to the extract (10, 25, 28, 36, 50, and 90 kDa) were detected using SDS-PAGE and immunoblot analysis. These findings suggest that Polygala tenuifolia, a herbal material, can induce IgE-mediated bronchoconstriction in exposed workers.

During the preclinical study of new therapeutic modality, we evaluate whether the treatment can reverse the established asthma phenotypes in animal model. However, few have reported on the long term persistence of asthma phenotypes upon re-challenge with allergen (secondary challenge) in animal model. We evaluated the persistence of asthma phenotypes by secondary challenge at different times in previously challenged murine asthma model. BALB/c mice sensitized by intraperitoneal injections of 20 µgram of ovalbumin and 1 mg of alum on days 1 and 14 were challenged initially by the inhalation of 1% ovalbumin for 30 min on days 21, 22, and 23. Each group of mice was rechallenged at 5, 7, 9, or 12 weeks after the initial challenge. Airway hyperresponsiveness, BAL fluid, airway histology and serum ovalbumin-specific IgE level were evaluated. Airway eosinophilia, airway inflammation and serum ovalbumin-specific IgE production persisted upon secondary allergen challenges at least 12 weeks after the initial challenge. However, airway hyperresponsiveness persisted only until mice were rechallenged 7 weeks after the initial challenge. Airway inflammation and allergen specific IgE production may persist longer than airway hyperresponsiveness in a mouse asthma model of secondary allergen challenge.

Stenotrophomonas maltophilia (previously named Xanthomonas maltophilia) is an aerobic, non-fermentive, Gram-negative bacillus that is wide spread in the environment. It was considered to be an organism with limited pathogenic potential, which was rarely capable of causing diseases in human other than those who were in debilitated or immunocompromised state. More recent studies have established that Stenotrophomonas maltophilia can behave as a true pathogen. Endocarditis due to this organism is rare, and only 24 cases of Stenotrophomonas maltophilia endocarditis have been reported in the medical literature. Most cases were associated with risk factors, including intravenous drug abuse, dental treatment, infected intravenous devices, and previous cardiac surgery. We present a case with two episodes of Stenotrophomonas maltophilia endocarditis after mitral valve prosthesis implantation, which was treated with antibiotics initially, and a combination of antibiotics and surgery later. To our knowledge, this is the first case of repetitive endocarditis due to Stenotrophomonas maltophilia.

Background

Fractional exhaled nitric oxide (FeNO) is widely used as an inflammatory marker for asthma. However, reference values and influencing factors of FeNO using Niox Mino, which is the only device achieving US FDA approval, are not well described in healthy Asian adults. This study aimed to suggest the reference values and influencing factors of FeNO in healthy Korean adults.

Methods

Subjects who were over 19 years old and did not have any history of rhinitis, asthma or recent respiratory symptoms were enrolled. FeNO levels were measured using Niox Mino. Age, gender, body mass index (BMI), smoking status and lung function were also measured to analyze factors associated with FeNO levels.

Results

The mean value of FeNO was 16.14 ± 10.04 ppb. The reference value of FeNO, which was defined as the value of 95% in distribution curve, was same or less than 34 ppb. In a univariate analysis, FeNO levels were not associated with age, BMI and smoking history. However, atopy status (18.2 ± 11.8 for atopy and 15.1 ± 8.5 for nonatopy groups, P = 0.008) and gender (17.8 ± 10.2 for male and 14.8 ± 9.8 for female groups, P < 0.001) were positively associated with FeNO levels. In stratified analysis, the significance of both variables remained unchanged (P < 0.001).

Conclusions

Our data suggested that the reference value of FeNO in healthy Korean adults seemed to be same or less than 34 ppb. Reference values of FeNO in Korean adults are influenced by gender and atopy status.