Michael Epton

Cord-Blood 25-Hydroxyvitamin D Levels and Risk of Respiratory Infection, Wheezing, and Asthma

OBJECTIVE: Higher maternal intake of vitamin D during pregnancy is associated with a lower risk of wheezing in offspring. The relationship between cord-blood levels of 25-hydroxyvitamin D (25[OH]D) and childhood wheezing is unknown. We hypothesized that cord-blood levels would be inversely associated with risk of respiratory infection, wheezing, and asthma. PATIENTS AND METHODS: Cord blood from 922 newborns was tested for 25(OH)D. Parents were asked if their child had a history of respiratory infection at 3 months of age or a history of wheezing at 15 months of age and then annually thereafter. Incident asthma was defined as doctor-diagnosed asthma by the time the child was 5 years old and reported inhaler use or wheezing since the age of 4 years. RESULTS: The median cord-blood level of 25(OH)D was 44 nmol/L (interquartile range: 29–78). Follow-up was 89% at the age of 5 years. Adjusting for the season of birth, 25(OH)D had an inverse association with risk of respiratory infection by 3 months of age (odds ratio: 1.00 [reference] for ≥75 nmol/L, 1.39 for 25–74 nmol/L, and 2.16 [95% confidence interval: 1.35–3.46] for <25 nmol/L). Likewise, cord-blood 25(OH)D levels were inversely associated with risk of wheezing by 15 months, 3 years, and 5 years of age (all P < .05). Additional adjustment for more than 12 potential confounders did not materially change these results. In contrast, we found no association between 25(OH)D levels and incident asthma by the age of 5 years. CONCLUSIONS: Cord-blood levels of 25(OH)D had inverse associations with risk of respiratory infection and childhood wheezing but no association with incident asthma.

Lung cancer gene associated with COPD: triple whammy or possible confounding effect?

Recently, several large genome-wide association studies have identified a putative “lung cancer” locus in the nicotinic acetylcholine receptor subunit genes (nAChR) on 15q25. However, these findings may be confounded by the presence of chronic obstructive pulmonary disease (COPD), which is also strongly associated with smoking exposure and lung cancer. This is likely as the prevalence of COPD in lung cancer cohorts is as much as two-fold greater than that reported in smoking control populations (50 versus 20%). The present authors compared the genotype frequencies of the most strongly associated single nucleotide polymorphism (rs16969968) in the α5 subunit of the nAChR gene cluster between three matched smoking cohorts. The AA genotype was found to be more frequent and was seen in 437 (16%) lung cancer cases and 445 (14%) COPD cases compared with 475 (9%) healthy smoking controls. More importantly, when 429 lung cancer cases were divided according to spirometry results (performed within 3 months of diagnosis, prior to surgery and in the absence of effusions or collapse), the AA genotype was present in 19 and 11% of cases with and without COPD, respectively. These findings suggest that the association between the α5 subunit nicotinic acetylcholine receptor single nucleotide polymorphism and lung cancer may, in part, be confounded by chronic obstructive pulmonary disease.

The effect of ambient air pollution on respiratory health of school children: a panel study.

BackgroundAdverse respiratory effects of particulate air pollution have been identified by epidemiological studies. We aimed to examine the health effects of ambient particulate air pollution from wood burning on school-age students in Christchurch, New Zealand, and to explore the utility of urine and exhaled breath condensate biomarkers of exposure in this population.MethodsA panel study of 93 male students (26 with asthma) living in the boarding house of a metropolitan school was undertaken in the winter of 2004. Indoor and outdoor pollution data was continuously monitored. Longitudinal assessment of lung function (FEV1 and peak flow) and symptoms were undertaken, with event studies of high pollution on biomarkers of exposure (urinary 1-hydroxypyrene) and effect (exhaled breath condensate (EBC) pH and hydrogen peroxide concentration).ResultsPeak levels of air pollution were associated with small but statistically significant effects on lung function in the asthmatic students, but not healthy students. No significant effect of pollution could be seen either on airway inflammation and oxidative stress either in healthy students or students with asthma. Minor increases in respiratory symptoms were associated with high pollution exposure. Urinary 1-hydroxypyrene levels were raised in association with pollution events by comparison with low pollution control days.ConclusionThere is no significant effect of ambient wood-smoke particulate air pollution on lung function of healthy school-aged students, but a small effect on respiratory symptoms. Asthmatic students show small effects of peak pollution levels on lung function. Urinary 1-hydroxypyrene shows potential as a biomarker of exposure to wood smoke in this population; however measurement of EBC pH and hydrogen peroxide appears not to be useful for assessment of population health effects of air pollution.Some of the data presented in this paper has previously been published in Kingham and co-workers Atmospheric Environment, 2006 Jan; 40: 338–347 (details of pollution exposure), and Cavanagh and co-workers Sci Total Environ. 2007 Mar 1;374(1):51-9 (urine hydroxypyrene data).

Self-management plans in the primary care of patients with chronic obstructive pulmonary disease

Objective and background:  The role of COPD self‐management plans in improving health outcomes remains unclear. The objective of this study was to assess whether self‐management plans administered in primary care have beneficial effects on quality of life, self‐care behaviour and health outcomes in the long term for patients with COPD.

Individual and Cumulative Effects of GWAS Susceptibility Loci in Lung Cancer: Associations after Sub-Phenotyping for COPD

Epidemiological studies show that approximately 20–30% of chronic smokers develop chronic obstructive pulmonary disease (COPD) while 10–15% develop lung cancer. COPD pre-exists lung cancer in 50–90% of cases and has a heritability of 40–77%, much greater than for lung cancer with heritability of 15–25%. These data suggest that smokers susceptible to COPD may also be susceptible to lung cancer. This study examines the association of several overlapping chromosomal loci, recently implicated by GWA studies in COPD, lung function and lung cancer, in (n = 1400) subjects sub-phenotyped for the presence of COPD and matched for smoking exposure. Using this approach we show; the 15q25 locus confers susceptibility to lung cancer and COPD, the 4q31 and 4q22 loci both confer a reduced risk to both COPD and lung cancer, the 6p21 locus confers susceptibility to lung cancer in smokers with pre-existing COPD, the 5p15 and 1q23 loci both confer susceptibility to lung cancer in those with no pre-existing COPD. We also show the 5q33 locus, previously associated with reduced FEV1, appears to confer susceptibility to both COPD and lung cancer. The 6p21 locus previously linked to reduced FEV1 is associated with COPD only. Larger studies will be needed to distinguish whether these COPD-related effects may reflect, in part, associations specific to different lung cancer histology. We demonstrate that when the “risk genotypes” derived from the univariate analysis are incorporated into an algorithm with clinical variables, independently associated with lung cancer in multivariate analysis, modest discrimination is possible on receiver operator curve analysis (AUC = 0.70). We suggest that genetic susceptibility to lung cancer includes genes conferring susceptibility to COPD and that sub-phenotyping with spirometry is critical to identifying genes underlying the development of lung cancer.

Chromosome 4q31 locus in COPD is also associated with lung cancer.

Chronic obstructive pulmonary disease (COPD) is the single greatest risk factor for lung cancer in smokers and is found in 50–90% of lung cancer cases. The link between COPD and lung cancer may stem in part from the matrix remodelling and repair processes underlying COPD, and the development of epithelial–mesenchymal transition (EMT) that underlies lung carcinogenesis. The Hedgehog-interacting protein (HHIP), which mediates the epithelial response (EMT) to smoking, has been implicated in COPD and lung cancer. Recent genome-wide and candidate gene studies of COPD implicate genetic variants on the chromosomal 4q31 (HHIP/glycophorin A (GYPA)) locus. In a case–control study of smokers with normal lung function, COPD and lung cancer (subphenotyped for COPD), we show the GG genotype of the rs 1489759 HHIP single-nucleotide polymorphism (SNP) and the CC genotype of the rs 2202507 GYPA SNP confers a “protective” effect on COPD (OR 0.59, p = 0.006 for HHIP and OR = 0.65, p = 0.006 for GYPA) and lung cancer (OR = 0.70 (p = 0.05) for HHIP and OR 0.70 (p = 0.02) for GYPA). This study suggests that, in smokers, genetic variants of the 4q31 locus conferring a protective effect for COPD are also protective in lung cancer. We conclude that genetic susceptibility to lung cancer includes COPD-related gene variants.

Detection of 2-Pentylfuran in the breath of patients with Aspergillus fumigatus

Aspergillus fumigatus produces 2-pentylfuran (2-PF) when cultured on blood agar, nutrient agar and other media. As 2-PF is not known to be produced by mammalian metabolism we hypothesized that it is detectable in breath of patients colonized or infected with A. fumigatus. Breath was tested for 2-PF from normal subjects, those undergoing chemotherapy, and adults at risk of colonization or infection with A. fumigatus because of bronchiectasis, cystic fibrosis, or immune suppression. Breath samples were collected in five L tedlar bags and analyzed by Gas Chromatography/Mass Spectroscopy (GC/MS) in MS-MS mode. 2-PF was not detected in breath 14 healthy controls, in one of 10 neutropenic subjects and 16 of 32 patients with lung disease. The sensitivity and specificity of the 2-PF breath tests when compared with recurrent isolation of aspergillus from sputum or from bronchoalveolar lavage over two months was 77% and 78% respectively. As 2-PF is not normally found in human breath its presence may reflect the active metabolism of A. fumigatus in the airways and form the basis of a new diagnostic breath test for Aspergillus infection.

The association of early life exposure to antibiotics and the development of asthma, eczema and atopy in a birth cohort: confounding or causality?

Background In general, studies reporting positive associations between antibiotic exposure and respiratory and allergic disease have been unable to determine the nature of this association.

Breastfeeding Protects against Current Asthma up to 6 Years of Age

OBJECTIVE To investigate the effects of breastfeeding on wheezing and current asthma in children 2 to 6 years of age. STUDY DESIGN Infants (n=1105) were enrolled in a prospective birth cohort in New Zealand. Detailed information about infant feeding was collected using questionnaires administered at birth and at 3, 6, and 15 months. From this, durations of exclusive and any breastfeeding were calculated. Information about wheezing and current asthma was collected at 2, 3, 4, 5, and 6 years. Logistic regression was used to model associations between breastfeeding and outcomes with and without adjustment for confounders. RESULTS After adjustment for confounders, each month of exclusive breastfeeding was associated with significant reductions in current asthma from 2 to 6 years (all, P<.03). Current asthma at 2, 3, and 4 years was also reduced by each month of any breastfeeding (all, P<.005). In atopic children, exclusive breastfeeding for ≥ 3 months reduced current asthma at ages 4, 5, and 6 by 62%, 55%, and 59%, respectively. CONCLUSION Breastfeeding, particularly exclusive breastfeeding, protects against current asthma up to 6 years. Although exclusive breastfeeding reduced risk of current asthma in all children to age 6, the degree of protection beyond 3 years was more pronounced in atopic children.

Predicting corticosteroid response in chronic obstructive pulmonary disease using exhaled nitric oxide.

RATIONALE Predicting corticosteroid response in COPD is important but difficult. Response is more likely to occur in association with eosinophilic airway inflammation, for which the fraction of exhaled nitric oxide (Fe(NO)) is a good surrogate marker. OBJECTIVES We aimed to establish whether Fe(NO) levels would predict the clinical response to oral corticosteroid in COPD. METHODS We performed a double-blind, crossover trial of steroid in patients with COPD. After a 4-week washout of inhaled steroids, patients received prednisone 30 mg/d or matching placebo, in random order, with an intervening 4-week washout. The predictive values of Fe(NO) for clinically significant changes in 6-minute-walk distance (6MWD), spirometry (FEV(1)), and St. Georges Respiratory Questionnaire (SGRQ) were calculated. MEASUREMENTS AND MAIN RESULTS A total of 65 patients (mean FEV(1) = 57% predicted) were randomized. With prednisone, there was a net increase of 13 m in 6MWD (P = 0.02) and 0.06 L in postbronchodilator FEV(1) (P = 0.02) compared with placebo. The change in SGRQ was not significant. Using receiver operator characteristic analysis, the area under the curve for an increase of 0.2 L in FEV(1) was 0.69 (P = 0.04) with an optimum Fe(NO) cut-point of 50 ppb. The positive and negative predictive values were 67 and 82%, respectively. FE(NO) was not a significant predictor for changes in 6MWD or SGRQ. CONCLUSIONS Fe(NO) is a weak predictor of short-term response to oral corticosteroid in COPD, its usefulness being limited to predicting increase in FEV(1). Clinical trial registered with www.anzctr.org.au (ACTRN12605000683639).