A spatial and temporal characterisation of single proton acoustic waves in proton beam cancer therapy.

An in vivo range verification technology for proton beam cancer therapy, preferably in real-time and with submillimeter resolution, is desired to reduce the present uncertainty in dose localization. Acoustical imaging technologies exploiting possible local interactions between protons and microbubbles or nanodroplets might be an interesting option. Unfortunately, a theoretical model capable of characterising the acoustical field generated by an individual proton on nanometer and micrometer scales is still missing. In this work, such a model is presented. The proton acoustic field is generated by the adiabatic expansion of a region that is locally heated by a passing proton. To model the proton heat deposition, secondary electron production due to protons has been quantified using a semi-empirical model based on Rutherford's scattering theory, which reproduces experimentally obtained electronic stopping power values for protons in water within 10% over the full energy range. The electrons transfer energy into heat via electron-phonon coupling to atoms along the proton track. The resulting temperature increase is calculated using an inelastic thermal spike model. Heat deposition can be regarded as instantaneous, thus, stress confinement is ensured and acoustical initial conditions are set. The resulting thermoacoustic field in the nanometer and micrometer range from the single proton track is computed by solving the thermoacoustic wave equation using k-space Green's functions, yielding the characteristic amplitudes and frequencies present in the acoustic signal generated by a single proton in an aqueous medium. Wavefield expansion and asymptotic approximations are used to extend the spatial and temporal ranges of the proton acoustic field.

Error analysis and reliability of zero-order Lamb mode inversion for waveguide characterization.

In recent years, several fitting techniques have been presented to reconstruct the parameters of a plate from its Lamb wave dispersion curves. Published studies show that these techniques can yield high accuracy results and have the potential of reconstructing several parameters at once. The precision with which parameters can be reconstructed by inverting Lamb wave dispersion curves, however, remains an open question of fundamental importance to many applications. In this work, we introduce a method of analyzing dispersion curves that yields quantitative information on the precision with which the parameters can be extracted. In our method, rather than employing error minimization algorithms, we compare a target dispersion curve to a database of theoretical ones that covers a given parameter space. By calculating a measure of dissimilarity (error) for every point in the parameter space, we reconstruct the distribution of the error in that space, beside the location of its minimum. We then introduce dimensionless quantities that describe the distribution of this error, thus yielding information about the spread of similar curves in the parameter space. We demonstrate our approach by considering both idealized and realistic scenarios, analyzing the dispersion curves obtained numerically for a plate and experimentally for a pipe. Our results show that the precision with which each parameter is reconstructed depends on the mode used, as well as the frequency range in which it is considered.

Tapering of the interventricular septum can affect ultrasound shear wave elastography: An in vitro and in silico study.

Shear wave elastography (SWE) has the potential to determine cardiac tissue stiffness from non-invasive shear wave speed measurements, important, e.g., for predicting heart failure. Previous studies showed that waves traveling in the interventricular septum (IVS) may display Lamb-like dispersive behaviour, introducing a thickness-frequency dependency in the wave speed. However, the IVS tapers across its length, which complicates wave speed estimation by introducing an additional variable to account for. The goal of this work is to assess the impact of tapering thickness on SWE. The investigation is performed by combining in vitro experiments with acoustic radiation force (ARF) and 2D finite element simulations, to isolate the effect of the tapering curve on ARF-induced and natural waves in the heart. The experiments show a 11% deceleration during propagation from the thick to the thin end of an IVS-mimicking tapered phantom plate. The numerical analysis shows that neglecting the thickness variation in the wavenumber-frequency domain can introduce errors of more than 30% in the estimation of the shear modulus, and that the exact tapering curve, rather than the overall thickness reduction, determines the dispersive behaviour of the wave. These results suggest that septal geometry should be accounted for when deriving cardiac stiffness with SWE.

Describing fluctuating indoor aerosol dust measurements with application to house dust mite allergens.

Measuring house dust mite aeroallergen concentrations is essential in understanding mite allergen exposure. Physically, the aerolized house dust mite faeces are part of indoor particulate matter. We studied the statistical ways of summarizing measurements of fluctuating mite aeroallergen exposure inside homes through indoor particulate matter. To study emissions from beddings, we measured the time-related airborne dust concentration after shaking a duvet. Analysis was performed both by a method based on the estimated mean and by a non-linear model. Twenty-eight studies reported a sum of concentrations; only one also reported the peak. In our four experiments on shaking a duvet (245 to 275 measurements each), the peak value was two to four times higher than the mean. The mean-based and non-linear models both predicted the sum of concentrations exactly. A 1% upper prediction bound and the non-linear model predicted the peak emission rate moderately well (64 to 92%, and 63 to 93%, respectively). Mean levels of indoor particulate matter measurements differ substantially from peak concentrations. The use of the mean is only sufficient to predict the sum of concentrations. We suggest that, mite aeroallergen measurements should include information on the peak as well as the mean.

Finding the match between healthcare worker and expert for optimal audit and feedback on antimicrobial resistance prevention measures.

BACKGROUND: The potentials of audit and feedback (AF) to improve healthcare are currently not exploited. To unlock the potentials of AF, this study focused on the process of making sense of audit data and translating data into actionable feedback by studying a specific AF-case: limiting antimicrobial resistance (AMR). This was done via audit and feedback of AMR prevention measures (APM) that are executed by healthcare workers (HCW) in their day-to-day contact with patients. This study's aim was to counterbalance the current predominantly top-down, expert-driven audit and feedback approach for APM, with needs and expectations of HCW. METHODS: Qualitative semi-structured interviews were held with sixteen HCW (i.e. physicians, residents and nurses) from high-risk AMR departments at a regional hospital in The Netherlands. Deductive coding was succeeded by open and axial coding to establish main codes, subcodes and variations within codes. RESULTS: HCW demand insights from audits into all facets of APM in their working routines (i.e. diagnostics, treatment and infection control), preferably in the form of simple and actionable feedback that invites interdisciplinary discussions, so that substantiated actions for improvement can be implemented. AF should not be seen as an isolated ad-hoc intervention, but as a recurrent, long-term, and organic improvement strategy that balances the primary aims of HCW (i.e. improving quality and safety of care for individual patients and HCW) and AMR-experts (i.e. reducing the burden of AMR). CONCLUSIONS: To unlock the learning and improvement potentials of audit and feedback, HCW' and AMR-experts' perspectives should be balanced throughout the whole AF-loop (incl. data collection, analysis, visualization, feedback and planning, implementing and monitoring actions). APM-AF should be flexible, so that both audit (incl. collecting and combining the right data in an efficient and transparent manner) and feedback (incl. persuasive and actionable feedback) can be tailored to the needs of various target groups. To balance HCW' and AMR-experts' perspectives a participatory holistic AF development approach is advocated.

Results from the Netherlands' 2018 Report Card and Report Card+ on physical activity for children and youth with and without chronic medical condition.

OBJECTIVE: The objective of this study was to summarize the results of the 2018 the Netherlands' Physical Activity Report Card (PARC) for children and youth as well as for children and youth with a chronic medical condition (CMC; PARC+). STUDY DESIGN: This study is a survey. METHODS: A total of 12 indicators were graded using the Active Healthy Kids Global Alliance PARC development process, which includes a synthesis of the best available research, surveillance, policy and practice findings and expert consensus. Grades were based on the best available evidence and ranged from grade A (>80% of the children succeed) to grade F (less than 20% succeed) or incomplete (INC). Sources included national surveys, peer-reviewed literature and grey literature such as government and non-government reports and online content. RESULTS: Grades assigned for PARC/PARC+ were as follows: Overall Physical Activity: C-/D+; Organized Sports Participation: B/B-; Active Play: D/D; Active Transportation: A-/B+; Sedentary Behaviour: D/D; Physical Fitness: INC /INC; Family and Peers: C/INC; School: C+/A-; Community and Environment: INC /INC; Government: INC /INC; Sleep: A-/B+ and Weight Status: A-/A-, respectively. CONCLUSIONS: The report shows that the Netherlands' youth scores well on (organized) participation in sports and active transport to and from school. However, they do not participate enough in overall physical activity. Despite the fact that outdoor play is the most important exercise activity for children, outdoor play scores an insufficient score for both healthy children and children with a CMC. Sports participation also contributed significantly to daily physical activity. However, sports participation alone is not enough to comply with the national activity guidelines.

Fundamental modeling of wave propagation in temporally relaxing media with applications to cardiac shear wave elastography.

Shear wave elastography (SWE) might allow non-invasive assessment of cardiac stiffness by relating shear wave propagation speed to material properties. However, after aortic valve closure, when natural shear waves occur in the septal wall, the stiffness of the muscle decreases significantly, and the effects of such temporal variation of medium properties on shear wave propagation have not been investigated yet. The goal of this work is to fundamentally investigate these effects. To this aim, qualitative results were first obtained experimentally using a mechanical setup, and were then combined with quantitative results from finite difference simulations. The results show that the amplitude and period of the waves increase during propagation, proportional to the relaxation of the medium, and that reflected waves can originate from the temporal stiffness variation. These general results, applied to literature data on cardiac stiffness throughout the heart cycle, predict as a major effect a period increase of 20% in waves propagating during a healthy diastolic phase, whereas only a 10% increase would result from the impaired relaxation of an infarcted heart. Therefore, cardiac relaxation can affect the propagation of waves used for SWE measurements and might even provide direct information on the correct relaxation of a heart.

Cross-border comparison of antimicrobial resistance (AMR) and AMR prevention measures: the healthcare workers' perspective.

Background: Cross-border healthcare may promote the spread of multidrug-resistant microorganisms (MDRO) and is challenging due to heterogeneous antimicrobial resistance (AMR) prevention measures (APM). The aim of this article is to compare healthcare workers (HCW) from Germany (DE) and The Netherlands (NL) on how they perceive and experience AMR and APM, which is important for safe patient exchange and effective cross-border APM cooperation. Methods: A survey was conducted amongst HCW (n = 574) in hospitals in DE (n = 305) and NL (n = 269), using an online self-administered survey between June 2017 and July 2018. Mann-Whitney U tests were used to analyse differences between answers of German and Dutch physicians (n = 177) and German and Dutch nurses (n = 397) on 5-point Likert Items and Scales. Results: Similarities between DE and NL were a high awareness about the AMR problem and the perception that the possibility to cope with AMR is limited (30% respondents perceive their contribution to limit AMR as insufficient). Especially Dutch nurses scored significantly lower than German nurses on their contribution to limit AMR (means 2.6 vs. 3.1, p ≤ 0.001). German HCW were more optimistic about their potential role in coping with AMR (p ≤ 0.001), and scored higher on feeling sufficiently equipped to perform APM (p ≤ 0.003), although the mean scores did not differ much between German and Dutch respondents. Conclusions: Although both German and Dutch HCW are aware of the AMR problem, they should be more empowered to contribute to limiting AMR through APM (i.e. screening diagnostics, infection diagnosis, treatment and infection control) in their daily working routines. The observed differences reflect differences in local, national and cross-border structures, and differences in needs of HCW, that need to be considered for safe patient exchange and effective cross-border APM.

Promoting and achieving excellence in the delivery of Integrated Allergy Care: the European Academy of Allergy & Clinical Immunology competencies for allied health professionals working in allergy.

The multi-disciplinary team approach is an effective model for patient care. Allied health professionals (AHPs) are an important part of such teams, bringing specific knowledge and skills related to the target patient population. The AHPs most often involved in allergy care are nurses and dietitians. Nurses are often involved in the care of patients with all types of allergy and also with asthma, whilst allergy-specialist dietitians provide vital nutritional and dietary support for the diagnosis and management of food allergy. There are many other AHPs who have a role to play in allergy care, including physiotherapists, psychologists, pharmacists and speech therapists, and their involvement is likely to develop as allergy care becomes more rooted in the community. With the development of multi-professional teams comes the requirement for disease-specific knowledge and skill sets, with all allergy team members required to have baseline knowledge and competency of the condition being managed. Whilst some competencies for AHPs practising in other disease states have been published, none are available for allergic disease against which AHPs can be benchmarked. The European Academy of Allergy & Clinical Immunology (EAACI) recognised this need, and supported the establishment of a Task Force to develop allergy-focussed competencies for AHPs. The varied skills, expertise and professional background of the Task Force members enabled the creation of a set of allergy competencies relevant to all AHPs working in allergy. It is recognised that the training and allergy expertise of AHPs, and their role within the allergy setting, will vary considerably depending on the country. However, it is important for patient care, that all AHP involved in allergy services have access to training, of a sufficiently high enough level to be aspirational and enable the continued growth and development of a wide range of allergy services, given the increasing need. The EAACI competencies will provide an important benchmark for allergy knowledge and skills against which education and training can be designed and health care professionals can subsequently be measured. However, more importantly, the EAACI AHP allergy competencies will enable the development and reach of specialist allergy services, with allergy-specialist AHPs undertaking key roles, especially in the community care setting.

Assessment of human left ventricle flow using statistical shape modelling and computational fluid dynamics.

Blood flow patterns in the human left ventricle (LV) have shown relation to cardiac health. However, most studies in the literature are limited to a few patients and results are hard to generalize. This study aims to provide a new framework to generate more generalized insights into LV blood flow as a function of changes in anatomy and wall motion. In this framework, we studied the four-dimensional blood flow in LV via computational fluid dynamics (CFD) in conjunction with a statistical shape model (SSM), built from segmented LV shapes of 150 subjects. We validated results in an in-vitro dynamic phantom via time-resolved optical particle image velocimetry (PIV) measurements. This combination of CFD and the SSM may be useful for systematically assessing blood flow patterns in the LV as a function of varying anatomy and has the potential to provide valuable data for diagnosis of LV functionality.

Multiline 3D beamforming using micro-beamformed datasets for pediatric transesophageal echocardiography.

Until now, no matrix transducer has been realized for 3D transesophageal echocardiography (TEE) in pediatric patients. In 3D TEE with a matrix transducer, the biggest challenges are to connect a large number of elements to a standard ultrasound system, and to achieve a high volume rate (>200 Hz). To address these issues, we have recently developed a prototype miniaturized matrix transducer for pediatric patients with micro-beamforming and a small central transmitter. In this paper we propose two multiline parallel 3D beamforming techniques (µBF25 and µBF169) using the micro-beamformed datasets from 25 and 169 transmit events to achieve volume rates of 300 Hz and 44 Hz, respectively. Both the realizations use angle-weighted combination of the neighboring overlapping sub-volumes to avoid artifacts due to sharp intensity changes introduced by parallel beamforming. In simulation, the image quality in terms of the width of the point spread function (PSF), lateral shift invariance and mean clutter level for volumes produced by µBF25 and µBF169 are similar to the idealized beamforming using a conventional single-line acquisition with a fully-sampled matrix transducer (FS4k, 4225 transmit events). For completeness, we also investigated a 9 transmit-scheme (3 × 3) that allows even higher frame rates but found worse B-mode image quality with our probe. The simulations were experimentally verified by acquiring the µBF datasets from the prototype using a Verasonics V1 research ultrasound system. For both µBF169 and µBF25, the experimental PSFs were similar to the simulated PSFs, but in the experimental PSFs, the clutter level was ~10 dB higher. Results indicate that the proposed multiline 3D beamforming techniques with the prototype matrix transducer are promising candidates for real-time pediatric 3D TEE.

[An activity-friendly environment: that's also the doctor's business]. / Een beweegvriendelijke omgeving.

Achieving and maintaining sufficient levels of physical activity is important for the health of the Dutch population. However, the vast majority of the Dutch population - including children - does not comply with the current physical activity guideline. This is the case despite excellent infrastructure which allows safe movement and facilitates walking or cycling to school or work. Perhaps the layout of our living environment is unattractive for movement. It may possibly be unchallenging for young people or too much concrete for adults. In this article we discuss the role of the physical environment on physical activity and ultimately our health. Ways in which the environment could influence the levels of physical activity of the population are also considered.

Duration and exclusiveness of breastfeeding and risk of childhood atopic diseases.

BACKGROUND: Breastfeeding may have immune modulatory effects that influence the development of childhood allergic sensitization and atopic diseases. We aimed to examine the associations of breastfeeding with childhood allergic sensitization, inhalant or food allergy and eczema, and whether any association was affected by disease-related modification of the exposure or modified by maternal history of allergy, eczema, or asthma. METHODS: This study among 5828 children was performed in a population-based prospective cohort from fetal life onwards. We collected information on duration (<2 months, 2-4 months, 4-6 months, and ≥6 months) and exclusiveness (nonexclusive vs exclusive for 4 months) of breastfeeding in infancy by postal questionnaires. At age 10 years, inhalant allergic sensitization and food-allergic sensitization were measured by skin prick tests, and physician-diagnosed inhalant and food allergy by a postal questionnaire. Data on parental-reported eczema were available from birth until age 10 years. RESULTS: We observed no association of breastfeeding with any allergic sensitization, physician-diagnosed allergy, or combination of these outcomes. Shorter breastfeeding duration was associated with an overall increased risk of eczema (P-value for trend <.05). Nonexclusively breastfed children had an overall increased risk of eczema (adjusted odds ratio [95% confidence interval]: 1.11 [1.01, 1.23]), compared with children exclusively breastfed for 4 months. Risk period-specific sensitivity analyses, additional adjustment for ointment use for eczema at age 2 months, and cross-lagged modeling showed no consistent results for disease-related modification of the exposure. Results were not modified by maternal history of allergy, eczema, or asthma (lowest P-value for interaction=.13). CONCLUSION: Shorter duration or nonexclusiveness of breastfeeding is associated with a weak overall increased risk of eczema but not allergic sensitization or physician-diagnosed allergy at age 10 years.

Low percentage of clinically relevant pistachio nut and mango co-sensitisation in cashew nut sensitised children.

BACKGROUND: Cashew nut, pistachio nut and mango belong to the Anacardiaceae family and are botanically related. Therefore, cashew nut sensitised children are frequently advised to eliminate cashew nuts and pistachio nuts from their diet. The 'Improvement of Diagnostic mEthods for ALlergy assessment (IDEAL trial number NTR3572) study showed that cashew nut sensitised children were co-sensitised to pistachio nut in 98% of cases and to mango in 21% of cases. The aim of this follow-up study to IDEAL is to assess the clinical relevance of co-sensitisation to pistachio nut and mango in cashew nut sensitised children. METHODS: Children were recruited from the study: 'Improvement of Diagnostic mEthods for ALlergy assessment (IDEAL trial number NTR3572). Inclusion criterion for the IDEAL study was sensitization to cashew nut as demonstrated by either SPT or sIgE, and a clinical history of reactions to cashew nuts or no previous (known) exposure. Sensitized children who were tolerant to cashew nuts were excluded. Inclusion criterion for this IDEAL follow-up study was co-sensitization to pistachio nut, regardless the result of the DBPCFC with cashew nut. In this follow-up study a double-blind placebo-controlled food challenge with pistachio nut and an open food challenge with mango were performed. RESULTS: Twenty-nine children (mean age of 11.6 years, 62% male) were included. Pistachio nut sensitisation was clinically relevant in only 34% of cashew-sensitised children and only 31% of cashew challenge positive children. None of the children was challenge positive to mango. CONCLUSION: Although co-sensitisation between cashew nut and pistachio nut was observed in 98%, pistachio nut sensitisation was only clinically relevant in 34% of the children. Therefore, a challenge test with pistachio nut is recommended in children with cashew nut and pistachio nut sensitisation. Trial registration The study was registered in the Dutch trial register (registration number 3572) on 10 August 2012 (retrospectively registered).

Maternal psychiatric symptoms during pregnancy and risk of childhood atopic diseases.

BACKGROUND: Maternal psychiatric symptoms during pregnancy might affect the developing immune system and subsequent risk of childhood atopic diseases. OBJECTIVE: Our aim was to examine the associations of maternal psychiatric symptoms during pregnancy with allergic sensitization, allergy and eczema in children until age 10 years. METHODS: This study among 5205 children was performed in a population-based prospective cohort from foetal life onwards. We assessed maternal and paternal psychiatric symptoms (overall, depressive, anxiety) during pregnancy and at 36 months after delivery, and maternal psychiatric symptoms at 2 and 6 months after delivery using the Brief Symptom Inventory. Inhalant and food allergic sensitization were measured by skin prick tests, and physician-diagnosed inhalant and food allergy or eczema by questionnaires from birth until age 10 years. We used multivariate logistic regression, multinomial logistic regression or generalized estimating equation models where appropriate. RESULTS: We observed no association of maternal psychiatric symptoms during pregnancy with allergic sensitization. Maternal overall psychiatric, depressive and anxiety symptoms during pregnancy were associated with an increased risk of inhalant allergy only (adjusted odds ratio (95% confidence interval) 1.96 (1.44, 2.65), 1.58 (1.25, 1.98) and 1.61 (1.27, 2.03), respectively, per 1-unit increase). Maternal overall psychiatric and anxiety symptoms during pregnancy were associated with an increased risk of eczema (1.21 (1.05, 1.39) and 1.15 (1.02, 1.29), respectively, per 1-unit increase). Effect estimates did not materially change when maternal psychiatric symptoms after delivery, or paternal psychiatric symptoms during pregnancy and after delivery were taken into account. CONCLUSIONS AND CLINICAL RELEVANCE: Maternal psychiatric symptoms during pregnancy were associated with increased risks of childhood inhalant allergy and eczema, independent of maternal psychiatric symptoms after delivery and of paternal psychiatric symptoms.

To what extent can PBL principles be applied in blended learning: Lessons learned from health master programs.

INTRODUCTION: Maastricht University has been actively exploring blended learning approaches to PBL in Health Master Programs. Key principles of PBL are, learning should be constructive, self-directed, collaborative, and contextual. The purpose is to explore whether these principles are applicable in blended learning. METHODS: The programs, Master of Health Services Innovation (case 1), Master Programme in Global Health (case 2), and the Master of Health Professions Education (case 3), used a Virtual Learning Environment for exchanging material and were independently analyzed. Quantitative data were collected for cases 1 and 2. Simple descriptive analyses such as frequencies were performed. Qualitative data for cases 1 and 3 were collected via (focus group) interviews. RESULTS: All PBL principles could be recognized in case 1. Case 2 seemed to be more project-based. In case 3, collaboration between students was not possible because of a difference in time-zones. Important educational aspects: agreement on rules for (online) sessions; visual contact (student-student and student-teacher), and frequent feedback. CONCLUSION: PBL in a blended learning format is perceived to be an effective strategy. The four principles of PBL can be unified in PBL with a blended learning format, although the extent to which each principle can be implemented can differ.

sIgE Ana o 1, 2 and 3 accurately distinguish tolerant from allergic children sensitized to cashew nuts.

BACKGROUND: The double-blind, placebo-controlled food challenge test (DBPCFC) is the gold standard in cashew nut allergy. This test is costly, time consuming and not without side effects. Analysis of IgE reactivity to cashew nut components may reduce the need for food challenge tests. METHODS: In a prospective and multicentre study, children with suspected cashew nut allergy underwent a DBPCFC with cashew nut. Specific IgE to cashew nut and to the components Ana o 1, 2 and 3 were determined. A skin prick test (SPT) with cashew nut extract was performed. The association between the outcome of the food challenge test and specific IgE to Ana o 1, 2 and 3 was assessed with logistic regression analyses, unadjusted and adjusted for other diagnostic variables. Discriminative ability was quantified with a concordance index (c). RESULTS: A total of 173 children (103 boys, 60%) with a median age of 9 years were included. About 79% had a positive challenge test outcome. A steep rise in the risk of a positive challenge was observed for specific IgE to each individual component Ana o 1, 2 and 3 with estimated risks up to approximately 100%. Median values of Ana o 1, 2, 3 were 1.29 kU/l (range 0-100 kU/l), 4.77 kU/l (range 0-100 kU/l) and 8.33 kU/l (range 0-100 kU/l) respectively and varied significantly (p < 0.001). Specific IgE to Ana o 1, 2 and 3 was better distinguished between cashew-allergic and tolerant children (c = 0.87, 0.85 and 0.89, respectively) than specific IgE to cashew nut or SPT (c = 0.76 and 0.83, respectively). CONCLUSION: The major cashew nut allergens Ana o 1, 2 and 3 are each individually predictive for the outcome of food challenge tests in cashew-allergic children.

No difference in health-related quality of life, after a food challenge with cashew nut in children participating in a clinical trial.

BACKGROUND: Previous studies showed that health-related quality of life (HRQL) significantly improved after the food challenge, with greater improvements in HRQL after a negative outcome than after a positive outcome. It is currently unknown whether this also occurs in patients undergoing DBPCFCs with cashew nut in the context of a clinical trial. METHODS: Quality of life was studied in children enrolled in a cashew nut study using Food Allergy Quality of Life Questionnaires (FAQLQs). Children, teenagers and parents of the children completed the questionnaires before the challenge test and 6 months after the DBPCFC with cashew nut. The difference in the change in HRQL between the children with a positive and negative DBPCFC outcome was studied by Mann-Whitney U-test. RESULTS: In total, 112 children (67 boys, median age of 9 years) were included. The children, teenagers and parents of the children completed 143 sets of questionnaires in total. There were no significant differences in baseline total and domain scores compared to the follow-up scores in the FAQLQ-CF, FAQLQ-TF and FAQLQ-PF. In children, the delta FAIM score in the negative DBPCFC tested group was significantly better than the delta FAIM score in the positive challenged group (p = 0.026). There were no significant differences in the changes in the scores of the FAQLQ-CF and FAQLQ-PF in the children with a positive challenge outcome, compared to the children with a negative challenge result. However, there was a significant difference in the change in score between the latter groups in the domain 'accidental exposure' of the FAQLQ-TF (p = 0.049). CONCLUSION: This study showed no difference in the change in HRQL scores after a DBPCFC with cashew nut in children participating in a clinical trial. The utility of HRQL as an outcome for clinical trials in food allergy may be limited if participant baseline HRQL is relatively unimpaired.