Methacholine Challenge Test in School Children With/Without Asthma RISKA

Study type: Observational study Study sites: Skin and Allergy Hospital, Helsinki, Finland Inclusion criteria: Age 7-15 years, diagnosed with asthma and on regular asthma medication with physician-assessed good asthma control (55 participants), suboptimal asthma control (55 participants), or healthy controls with no inhaled asthma medication or asthma-related symptoms in the preceding two years (150 participants). Exclusion criteria: Other respiratory, cardiovascular, or neurological diseases; acute respiratory infection within 2 weeks; respiratory disorders related to prematurity; implanted or external active medical devices. Sample size: 110 asthma patients and 150 healthy controls. Study duration: Until the end of 2027 Study visits: One study visit; in addition, consent will be sought to contact participants during the 15-year storage period of the study data, for example, regarding questionnaire follow-ups. Objectives: Primary: To determine whether airway hyperresponsiveness differs clinically significantly (PD20FEV1 at least twofold difference) between children with well-controlled asthma, those requiring intensified asthma medication, and healthy controls. To determine whether a corresponding difference exists in exhaled nitric oxide levels between the groups. Secondary: To assess how age correlates with airway hyperresponsiveness (PD20FEV1 value) in the methacholine challenge among healthy controls. To assess how sensitization to airborne allergens correlates with PD20FEV1 values in healthy controls and asthma patients. To assess how blood eosinophil levels correlate with PD20FEV1 values in the methacholine challenge in both healthy controls and asthma patients. Implementation: Healthy controls will undergo a pre-study telephone interview to assess eligibility. At the study visit, background information and asthma questionnaires will be completed. The study visit will include a methacholine challenge test measuring airway hyperresponsiveness and an exhaled nitric oxide measurement. The effect of medication intensification in asthma patients will be evaluated via a telephone interview 1-2 months after the medication adjustment.