Paediatrics (RCH) - Research Publications

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    Age at onset and persistence of eczema are related to subsequent risk of asthma and hay fever from birth to 18 years of age
    Lowe, AJ ; Angelica, B ; Su, J ; Lodge, CJ ; Hill, DJ ; Erbas, B ; Bennett, CM ; Gurrin, LC ; Axelrad, C ; Abramson, MJ ; Allen, KJ ; Dharmage, SC (WILEY, 2017-06)
    BACKGROUND: Few studies have simultaneously addressed the importance of age of onset and persistence of eczema for the subsequent development of asthma and hay fever, particularly into early adulthood. METHODS: A high-risk birth cohort was recruited comprising 620 infants, who were then followed up frequently until 2 years of age, annually from age 3 to 7, then at 12 and 18 years, to document any episodes of eczema, current asthma, and hay fever. The generalized estimation equation technique was used to examine asthma and hay fever outcomes at 6 (n = 325), 12 (n = 248) and 18 (n = 240) years, when there was consistency of associations across the follow-ups. RESULTS: Very early-onset persistent (onset <6 months, still present from 2 to 5 years) eczema was related to current asthma (adjusted OR = 3.2 [95% CI = 1.7-6.1]), as was very early-onset remitting eczema (onset <6 months but not present from 2-5 years, OR = 2.7, 95% CI = 1.0-7.2) and early-onset persistent eczema (onset from 6-24 months, OR = 2.3, 95% CI = 1.2-4.7). Late-onset eczema (commenced from 2-5 years) was associated with increased risk of asthma at 12 years (OR = 3.0, 95% CI=1.1-8.2) but not at age 6 years. Only very early-onset persistent eczema was associated with increased risk of hay fever (aOR = 2.4, 95% CI = 1.4-4.1). CONCLUSION AND CLINICAL RELEVANCE: Eczema which commences in early infancy and persists into toddler years is strongly associated with asthma, and to a lesser extent hay fever, in high-risk children. If these associations are causal, prevention of early-life eczema might reduce the risk of respiratory allergy.
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    The practice and perception of precautionary allergen labelling by the Australasian food manufacturing industry
    Zurzolo, GA ; Peters, RL ; Koplin, JJ ; de Courten, M ; Mathai, ML ; Tye-Din, JA ; Tang, MLK ; Campbell, DE ; Ponsonby, A-L ; Prescott, SL ; Gurrin, L ; Dharmage, SC ; Allen, KJ (WILEY, 2017-07)
    BACKGROUND: The precautionary allergen labelling (PAL) and Voluntary Incidental Trace Allergen Labelling (VITAL® ) tools were designed by industry to assist consumers with selecting safe foods for consumption. However, a sizeable proportion of food products bear no label, and it is unclear whether these products are free from allergens and therefore safe to consume or have simply not undergone a risk assessment and therefore remain unlabelled for that reason. OBJECTIVE: To assess the prevalence of unlabelled products that have undergone a risk assessment process and to examine the factors influencing industry's uptake of the VITAL® process. METHODS: A web-based questionnaire was distributed to Australasian food and grocery manufacturers. RESULTS: One hundred and thirty-seven Australasian manufacturers were contacted, and 59 questionnaires were returned (response rate: 43%). The respondents represented 454 different manufacturing sites. Manufacturers reported that 23% (95% CI 19-28) of products (n=102/434) that had been through the VITAL® risk assessment process had no PAL statement on the label. 34% (95% CI 30-38), (n=204/600) of products that had undergone another (non-VITAL® ) risk assessment process had no PAL statement. In examining the factors that influenced industry's uptake of the VITAL® process, 25 manufacturers reported on factors that influenced the uptake of the VITAL® process, 76% (CI 95% 55-91) reported that VITAL® was an effective tool because it was based on science; 52% (CI 95% 31-72) reported that it was too time-consuming and 36% (CI 95% 18-57) identified a concern with it not being endorsed by the government. CONCLUSION AND CLINICAL RELEVANCE: Currently, we estimate that at least 30% of products may have been through a risk assessment process and yet bear no PAL statement on the label. Permissive labelling could be incorporated onto these products if they have been assessed to be safe for consumption.
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    The skin barrier function gene SPINK5 is associated with challenge-proven IgE-mediated food allergy in infants
    Ashley, SE ; Tan, H-TT ; Vuillermin, P ; Dharmage, SC ; Tang, MLK ; Koplin, J ; Gurrin, LC ; Lowe, A ; Lodge, C ; Ponsonby, A-L ; Molloy, J ; Martin, P ; Matheson, MC ; Saffery, R ; Allen, KJ ; Ellis, JA ; Martino, D (WILEY, 2017-09)
    BACKGROUND: A defective skin barrier is hypothesized to be an important route of sensitization to dietary antigens and may lead to food allergy in some children. Missense mutations in the serine peptidase inhibitor Kazal type 5 (SPINK5) skin barrier gene have previously been associated with allergic conditions. OBJECTIVE: To determine whether genetic variants in and around SPINK5 are associated with IgE-mediated food allergy. METHOD: We genotyped 71 "tag" single nucleotide polymorphisms (tag-SNPs) within a region spanning ~263 kb including SPINK5 (~61 kb) in n=722 (n=367 food-allergic, n=199 food-sensitized-tolerant and n=156 non-food-allergic controls) 12-month-old infants (discovery sample) phenotyped for food allergy with the gold standard oral food challenge. Transepidermal water loss (TEWL) measures were collected at 12 months from a subset (n=150) of these individuals. SNPs were tested for association with food allergy using the Cochran-Mantel-Haenszel test adjusting for ancestry strata. Association analyses were replicated in an independent sample group derived from four paediatric cohorts, total n=533 (n=203 food-allergic, n=330 non-food-allergic), mean age 2.5 years, with food allergy defined by either clinical history of reactivity, 95% positive predictive value (PPV) or challenge, corrected for ancestry by principal components. RESULTS: SPINK5 variant rs9325071 (A⟶G) was associated with challenge-proven food allergy in the discovery sample (P=.001, OR=2.95, CI=1.49-5.83). This association was further supported by replication (P=.007, OR=1.58, CI=1.13-2.20) and by meta-analysis (P=.0004, OR=1.65). Variant rs9325071 is associated with decreased SPINK5 gene expression in the skin in publicly available genotype-tissue expression data, and we generated preliminary evidence for association of this SNP with elevated TEWL also. CONCLUSIONS: We report, for the first time, association between SPINK5 variant rs9325071 and challenge-proven IgE-mediated food allergy.
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    HFE p.C282Y homozygosity predisposes to rapid serum ferritin rise after menopause: A genotype-stratified cohort study of hemochromatosis in Australian women
    Warne, CD ; Zaloumis, SG ; Bertalli, NA ; Delatycki, MB ; Nicoll, AJ ; McLaren, CE ; Hopper, JL ; Giles, GG ; Anderson, GJ ; Olynyk, JK ; Powell, LW ; Allen, KJ ; Gurrin, LC (WILEY, 2017-04)
    BACKGROUND AND AIM: Women who are homozygous for the p.C282Y mutation in the HFE gene are at much lower risk of iron overload-related disease than p.C282Y homozygous men, presumably because of the iron-depleting effects of menstruation and pregnancy. We used data from a population cohort study to model the impact of menstruation cessation at menopause on serum ferritin (SF) levels in female p.C282Y homozygotes, with p.C282Y/p.H63D simple or compound heterozygotes and those with neither p.C282Y nor p.H63D mutations (HFE wild types) as comparison groups. METHODS: A sample of the Melbourne Collaborative Cohort Study was selected for the "HealthIron" study (n = 1438) including all HFE p.C282Y homozygotes plus a random sample stratified by HFE-genotype (p.C282Y and p.H63D). The relationship between the natural logarithm of SF and time since menopause was examined using linear mixed models incorporating spline smoothing. RESULTS: For p.C282Y homozygotes, SF increased by a factor of 3.6 (95% CI (1.8, 7.0), P < 0.001) during the first 10 years postmenopause, after which SF continued to increase but at less than half the previous rate. In contrast, SF profiles for other HFE genotype groups increase more gradually and did not show a distinction between premenopausal and postmenopausal SF levels. Only p.C282Y homozygotes had predicted SF exceeding 200 μg/L postmenopause, but the projected SF did not increase the risk of iron overload-related disease. CONCLUSIONS: These data provide the first documented evidence that physiological blood loss is a major factor in determining the marked gender difference in expression of p.C282Y homozygosity.
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    Nut allergy prevalence and differences between Asian-born children and Australian-born children of Asian descent: a state-wide survey of children at primary school entry in Victoria, Australia
    Panjari, M ; Koplin, JJ ; Dharmage, SC ; Peters, RL ; Gurrin, LC ; Sawyer, SM ; McWilliam, V ; Eckert, JK ; Vicendese, D ; Erbas, B ; Matheson, MC ; Tang, MLK ; Douglass, J ; Ponsonby, A-L ; Dwyer, T ; Goldfeld, S ; Allen, KJ (WILEY, 2016-04)
    BACKGROUND: Asian infants born in Australia are three times more likely to develop nut allergy than non-Asian infants, and rates of challenge-proven food allergy in infants have been found to be unexpectedly high in metropolitan Melbourne. To further investigate the risk factors for nut allergy, we assessed the whole-of-state prevalence distribution of parent-reported nut allergy in 5-year-old children entering school. METHODS: Using the 2010 School Entrant Health Questionnaire administered to all 5-year-old children in Victoria, Australia, we assessed the prevalence of parent-reported nut allergy (tree nut and peanut) and whether this was altered by region of residence, socio-economic status, country of birth or history of migration. Prevalence was calculated as observed proportion with 95% confidence intervals (CI). Risk factors were evaluated using multivariable logistic regression and adjusted for appropriate confounders. RESULTS: Parent-reported nut allergy prevalence was 3.1% (95% CI 2.9-3.2) amongst a cohort of nearly 60 000 children. It was more common amongst children of mothers with higher education and socio-economic index and less prevalent amongst children in regional Victoria than in Melbourne. While children born in Australia to Asian-born mothers (aOR 2.67, 95% CI 2.28-3.27) were more likely to have nut allergy than non-Asian children, children born in Asia who subsequently migrated to Australia were at decreased risk of nut allergy (aOR 0.1, 95% CI 0.03-0.31). CONCLUSION: Migration from Asia after the early infant period appears protective for the development of nut allergy. Additionally, rural regions have lower rates of nut allergy than urban areas.
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    Timing of routine infant vaccinations and risk of food allergy and eczema at one year of age
    Kiraly, N ; Koplin, JJ ; Crawford, NW ; Bannister, S ; Flanagan, KL ; Holt, PG ; Gurrin, LC ; Lowe, AJ ; Tang, MLK ; Wake, M ; Ponsonby, A-L ; Dharmage, SC ; Allen, KJ (WILEY, 2016-04)
    BACKGROUND: Epidemiological evidence suggests that routine vaccinations can have nontargeted effects on susceptibility to infections and allergic disease. Such effects may depend on age at vaccination, and a delay in pertussis vaccination has been linked to reduced risk of allergic disease. We aimed to test the hypothesis that delay in vaccines containing diphtheria-tetanus-acellular pertussis (DTaP) is associated with reduced risk of food allergy and other allergic diseases. METHODS: HealthNuts is a population-based cohort in Melbourne, Australia. Twelve-month-old infants were skin prick-tested to common food allergens, and sensitized infants were offered oral food challenges to determine food allergy status. In this data linkage study, vaccination data for children in the HealthNuts cohort were obtained from the Australian Childhood Immunisation Register. Associations were examined between age at the first dose of DTaP and allergic disease. RESULTS: Of 4433 children, 109 (2.5%) received the first dose of DTaP one month late (delayed DTaP). Overall, delayed DTaP was not associated with primary outcomes of food allergy (adjusted odds ratio (aOR) 0.77; 95% CI: 0.36-1.62, P = 0.49) or atopic sensitization (aOR: 0.66; 95% CI: 0.35-1.24, P = 0.19). Amongst secondary outcomes, delayed DTaP was associated with reduced eczema (aOR: 0.57; 95% CI: 0.34-0.97, P = 0.04) and reduced use of eczema medication (aOR: 0.45; 95% CI: 0.24-0.83, P = 0.01). CONCLUSIONS: There was no overall association between delayed DTaP and food allergy; however, children with delayed DTaP had less eczema and less use of eczema medication. Timing of routine infant immunizations may affect susceptibility to allergic disease.
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    Egg allergen specific IgE diversity predicts resolution of egg allergy in the population cohort HealthNuts
    Dang, TD ; Peters, RL ; Koplin, JJ ; Dharmage, SC ; Gurrin, LC ; Ponsonby, A-L ; Martino, DJ ; Neeland, M ; Tang, MLK ; Allen, KJ (WILEY, 2019-02)
    BACKGROUND: IgE-mediated egg allergy presents as one of the most common food allergies in children. Measurement of egg white specific IgE (sIgE) levels in serum or skin prick test has been shown to be a poor predictor of clinical allergy to raw egg white, and also to baked or cooked egg. Recent developments in component resolved diagnostic (CRD) technology have enabled us to improve the way in which we diagnose and predict peanut allergy by examining IgE specificity to individual peptides. OBJECTIVES: We aimed to investigate whether egg CRD could improve current methods to diagnose various egg allergy phenotypes as well as predict the development of tolerance to egg. METHODS: Using the HealthNuts cohort of food challenge-proven egg allergic and egg-sensitized and egg-tolerant, age-matched 12-month infants with longitudinal follow-up at 2 and 4 years (n = 451), we measured serum egg white, Gal d 1, 2, 3 and 5 sIgE using ImmunoCAP. RESULTS: Gal d 1 sensitization increased the risk of persistent egg allergy by 2.5-fold. The production of sIgE to all four egg allergens (Gal d 1, 2, 3 or 5) increased the risk of having persistent raw egg allergy fourfold (OR 4.19 (95% CI: 1.25-14.07). We did not find any improvements of using Gal d 1, 2, 3 or 5 to diagnose current egg allergy compared to egg white sIgE. CONCLUSION: Sensitization to multiple egg allergens Gal d 1, 2, 3 or 5 may be a prognostic marker that could be useful for patient management and identifying individuals at risk of developing persistent egg allergy.
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    Peanut Allergen Threshold Study (PATS): validation of eliciting doses using a novel single-dose challenge protocol
    Zurzolo, GA ; Allen, KJ ; Taylor, SL ; Shreffler, WG ; Baumert, JL ; Tang, MLK ; Gurrin, LC ; Mathai, ML ; Nordlee, JA ; DunnGalvin, A ; Hourihane, JO (BMC, 2013-09-12)
    BACKGROUND: The eliciting dose (ED) for a peanut allergic reaction in 5% of the peanut allergic population, the ED05, is 1.5 mg of peanut protein. This ED05 was derived from oral food challenges (OFC) that use graded, incremental doses administered at fixed time intervals. Individual patients' threshold doses were used to generate population dose-distribution curves using probability distributions from which the ED05 was then determined. It is important to clinically validate that this dose is predictive of the allergenic response in a further unselected group of peanut-allergic individuals. METHODS/AIMS: This is a multi-centre study involving three national level referral and teaching centres. (Cork University Hospital, Ireland, Royal Children's Hospital Melbourne, Australia and Massachusetts General Hospital, Boston, U.S.A.) The study is now in process and will continue to run until all centres have recruited 125 participates in each respective centre.A total of 375 participants, aged 1-18 years will be recruited during routine Allergy appointments in the centres. The aim is to assess the precision of the predicted ED05 using a single dose (6 mg peanut = 1.5 mg of peanut protein) in the form of a cookie. Validated Food Allergy related Quality of Life Questionnaires-(FAQLQ) will be self-administered prior to OFC and 1 month after challenge to assess the impact of a single dose OFC on FAQL. Serological and cell based in vitro studies will be performed. CONCLUSION: The validation of the ED05 threshold for allergic reactions in peanut allergic subjects has potential value for public health measures. The single dose OFC, based upon the statistical dose-distribution analysis of past challenge trials, promises an efficient approach to identify the most highly sensitive patients within any given food-allergic population.
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    The Natural History of IgE-Mediated Food Allergy: Can Skin Prick Tests and Serum-Specific IgE Predict the Resolution of Food Allergy?
    Peters, RL ; Gurrin, LC ; Dharmage, SC ; Koplin, JJ ; Allen, KJ (MDPI, 2013-10)
    IgE-mediated food allergy is a transient condition for some children, however there are few indices to predict when and in whom food allergy will resolve. Skin prick test (SPT) and serum-specific IgE levels (sIgE) are usually monitored in the management of food allergy and are used to predict the development of tolerance or persistence of food allergy. The aim of this article is to review the published literature that investigated the predictive value of SPT and sIgE in development of tolerance in children with a previous diagnosis of peanut, egg and milk allergy. A systematic search identified twenty-six studies, of which most reported SPT or sIgE thresholds which predicted persistent or resolved allergy. However, results were inconsistent between studies. Previous research was hampered by several limitations including the absence of gold standard test to diagnose food allergy or tolerance, biased samples in retrospective audits and lack of systematic protocols for triggering re-challenges. There is a need for population-based, prospective studies that use the gold standard oral food challenge (OFC) to diagnose food allergy at baseline and follow-up to develop SPT and sIgE thresholds that predict the course of food allergy.
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    Bivariate mixture models for the joint distribution of repeated serum ferritin and transferrin saturation measured 12 years apart in a cohort of healthy middle-aged Australians
    McLaren, CE ; Chen, W-P ; Bertalli, NA ; Delatycki, MB ; Giles, GG ; English, DR ; Hopper, JL ; Allen, KJ ; Gurrin, LC ; Kronenberg, F (PUBLIC LIBRARY SCIENCE, 2019-03-26)
    Homozygosity for the p.C282Y substitution in the HFE protein encoded by the hemochromatosis gene on chromosome 6p (HFE) is a common genetic trait that increases susceptibility to iron overload. McLaren et al. used bivariate mixture modeling to analyze the joint population distribution of transferrin saturation (TS) and serum ferritin concentration (SF) measured for participants in the Hemochromatosis and Iron Overload Screening (HEIRS) Study. They identified four components (C1, C2, C3, and C4) with successively increasing means for TS and SF. They demonstrated that bivariate mixture modeling in TS and SF reflect the genetic locus of HFE and may isolate p.C282Y homozygotes from the general population. In the current study we used data from the another large cohort, the Australian HealthIron study of genetic and environmental modifiers of hereditary hemochromatosis, to validate the component analysis approach, to examine stability of component proportions over time and to determine if TS and SF values from an individual move between components at baseline and follow-up. Because sampling fractions from each p.C282Y / p.H63D genotype stratum are not equal, we used frequency weights based on the inverse of the probability of selection for invitation to participate. In the weighted female analytic cohorts, C4 captured most of C282Y homozygotes, and C2 was the largest component. We identified four components from the weighted male analytic cohort and C4 captured most of p.C282Y homozygotes. The bivariate mixture modeling approach suggested that the model is transferable from one white population to another, although estimated means within components may differ.