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In this paper, we propose a new test for checking the parametric form of the conditional variance based on distance covariance in nonlinear and nonparametric regression models. Inherit from the nice properties of distance covariance, our test is very easy to implement in practice and less effected by the dimensionality of covariates. The asymptotic properties of the test statistic are investigated under the null and alternative hypotheses. We show that the proposed test is consistent against any alternative and can detect local alternatives converging to the null hypothesis at the parametric rate 1/root(n) in both the nonlinear and nonparametric settings. As the limiting null distribution of the test statistic is intractable, we propose a residual bootstrap to approximate the limiting null distribution. Simulation studies are presented to assess the finite sample performance of the proposed test. We also apply the proposed test to a real data set for illustration.

Background: The prevalence of cow's milk allergy (CMA) is approximately 2-4.5% in infants and less than 0.5% in adults. Most children outgrow cow's milk allergy in early childhood, particularly that to the baked milk products. Immunotherapy with unheated cow's milk has been used as a treatment option for those who have not yet outgrown CMA, but the benefits must be balanced with the adverse effects. Objective: These evidence-based guidelines from the World Allergy Organization (WAO) intend to support patients, clinicians, and others in decisions about the use of oral and epicutaneous immunotherapy for the treatment of IgE-mediated CMA. Methods: WAO formed a multidisciplinary guideline panel balanced to include the views of all stakeholders and to minimize potential biases from competing interests. The McMaster University GRADE Centre supported the guideline-development process, including updating or performing systematic evidence reviews. The panel prioritized clinical questions and outcomes according to their importance for clinicians and patients. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was used, including GRADE Evidence-to-Decision frameworks, which were subject to public comment. Results: After a careful review of the summarized evidence and thorough discussions the WAO guideline panel suggests: a) using oral immunotherapy with unheated cow's milk in those individuals with confirmed IgE-mediated CMA who value the ability to consume controlled quantities of milk more than avoiding the large adverse effects of therapy, b) not using oral immunotherapy with unheated cow's milk in those who value avoiding large adverse effects of therapy more than the ability to consume controlled quantities of milk, c) using omalizumab in those starting oral immunotherapy with unheated cow's milk, d) not using oral immunotherapy with baked cow's milk in those who do not tolerate both unheated and baked milk, and e) not using epicutaneous immunotherapy outside of a research setting. The recommendations are labeled "conditional" due to the low certainty about the health effects based on the available evidence. Conclusions: Clinicians, patients, and their family members might want to discuss all the potential desirable and undesirable effects of oral immunotherapy for IgE-mediated CMA and integrate them with the patients' values and preferences before deciding on a treatment option. More robust research is needed to determine with greater certainty which interventions are likely to be the most beneficial with the least harms, and to develop safer, low-cost, and equitable treatments.

Background: The 2010 Diagnosis and Rationale for Action against Cow's Milk Allergy (DRACMA) guidelines are the only Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines for cow's milk allergy (CMA). They indicate oral food challenge (OFC) as the reference test for diagnosis, and suggest the choice of specific alternative formula in different clinical conditions. Their recommendations are flexible, both in diagnosis and in treatment. Objectives & methods: Using the Scopus citation records, we evaluated the influence of the DRACMA guidelines on milk allergy literature. We also reviewed their impact on successive food allergy and CMA guidelines at national and international level. We describe some economic consequences of their application. Results: DRACMA are the most cited CMA guidelines, and the second cited guidelines on food allergy. Many subsequent guidelines took stock of DRACMA's metanalyses adapting recommendations to the local context. Some of these chose not to consider OFC as an absolute requirement for the diagnosis of CMA. Studies on their implementation show that in this case, the treatment costs may increase and there is a risk of overdiagnosis. Interestingly, we observed a reduction in the cost of alternative formulas following the publication of the DRACMA guidelines. Conclusions: DRACMA reconciled international differences in the diagnosis and management of CMA. They promoted a cultural debate, improved clinician's knowledge of CMA, improved the quality of diagnosis and care, reduced inappropriate practices, fostered the efficient use of resources, empowered patients, and influenced some public policies. The accruing evidence on diagnosis and treatment of CMA necessitates their update in the near future.