Single-center, cross-sectional, longitudinal, observational, population based cohort study with stratified sample (by age group, gender, and residential area).
This study will involve schoolchildren (aged 6-18 years), population cohort based on differential exposure and susceptibility to allergy(paediatric population, allergic vs. healthy subjects). participants will be selected based on proven sensitization to at least one food allergen (preferentially but not only to seafood) with a diagnosis of at least one allergic disease (i.e. allergic asthma, allergic rhinitis (AR), atopic dermatitis (AD) and/or food allergy) for at least a year. Subjects will be recruited from three distinct and different geographical regions in Croatia: 2 continental regions (Zagreb, urban) and Slavonia (urban and rural) and 1 Mediterranean region (urban and rural population), differing in the levels of exposure (allergens, pollutants), consumption of water (main water source- bottled water, public water source, well water), food consumption (food packed in plastic material, use of fertilizers in agriculture), nutrition (food from marine environments, industrially processed food, homegrown food) as well as different environmental protection measures and human activities.In each region and subgroup, we will recruit 70 allergic children and 140 healthy (non-allergic) children in a cross-sectionalstudy protocol, summing up to al total of 630 participants. The study will include visits: 1. Initial (screening) visit (V0 +3-6 months): written consent, assessment of inclusion and exclusion criteria, spirometry, Fractional exhaled nitric oxide (FeNO), questionnaires… 2. V2 (V0+6-9 months), questionnaires, environmental skin prick test (APT), sIgE (+ISAC), spirometry, FeNO, blood collection stool, 3. V2-V5 (V0+months 6-30 months)- regular visits (assessment) every 6 months, stool samples (second sampling) 4. Visit 4 (V0+18-24 months): environmental assessments, skin prick test (APT), sIgE (+ISAC), spirometry, FeNO, blood collection 5. V5 (last visit, V0+24-30 months)- final assessment of the study outcome measures, check and document consumption, adherence, preventive measures, level of control, therapy correction Participants in the control group will be involved in collaboration with other outpatient clinics (eg. from surgical outpatient clinics who have had minor surgical procedures, from the Otorhinolaryngology- Ear, Nose, Throat (ENT) outpatient clinics at least 7 days after acute ear inflammation or laryngitis, from emergency ambulatory patients at least 7 days after acute respiratory illness, etc.). All participants who will be included in the control group should have a negative history of allergic diseases, as well as other severe chronic diseases, including malignant, autoimmune, or mental illnesses. They will need to fulfil the ISAAC questionnaire for children perform spirometry and prick test with a standard palette of inhalational and nutritional allergens to exclude allergic diseases. No intervention tests or methods will be involved in this study. Patients who will be involved in the study will continue to take their regular therapy (according to guidelines) i.e. conduct treatment and all other non-therapeutic measures as if they were not involved in the study. Any deterioration or emergency intervention will be specifically evaluated and recorded as additional visits.
Study Type
OBSERVATIONAL
Enrollment
1,156
Children's Hospital Srebrnjak
Zagreb, City of Zagreb, Croatia
Lung function tests
Forced expiratory volume in one second (FEV1), Forced vital capacity (FVC) and the ratio of the two volumes (FEV1/FVC) will be recorded for each patient at each visit. FEV1 is the volume of air (in liters) exhaled in the first second during forced exhalation after maximal inspiration. It's measured in % of predicted values which are the average readings that would be expected in a healthy person of similar age, gender, body size, and ethnicity. Forced vital capacity (FVC) is the volume of air that can forcibly be blown out after full inspiration, measured in liters.
Time frame: 6 months, Asthmatic patients will be regularly controlled even more often in case of exacerbations.
Fractional exhaled nitric oxide (FeNO)
FeNO test measures the level of nitric oxide gas in an exhaled sample of breath. It is measured in "parts per billion" (ppb).
Time frame: 6 months, Asthmatic patients will be regularly controlled even more often in case of exacerbations
Childhood Asthma Control Test (C-ACT)
C-ACT questionnaire will be used to tell us if the asthma treatment plan is optimal and if asthma is being properly controlled. For children 4 to 11 years maximal score is 27, and for those older then 12 years maximal score is 25. Higher scores reflect greater asthma control, and if the score is 19 or less may be a sign that asthma is not controlled as well as it could be.
Time frame: 6 months, Asthmatic patients will be regularly controlled even more often in case of exacerbations
Daily burden of disease (Global evaluation)
Participants' daily burden of disease will be evaluated by visual analogue scale (VAS) Visual analogue scale levels \<20/100 were categorized as "Low" burden and VAS levels ≥50/100 as "High" burden.
Time frame: 6 months, Asthmatic patients will be regularly controlled even more often in case of exacerbations
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Daily burden of disease (affecting Nose)
Participants with AR will be evaluated by visual analogue scale (VAS).Visual analogue scale levels \<20/100 were categorized as "Low" burden and VAS levels ≥50/100 as "High" burden.
Time frame: 6 months
Daily burden of disease (affecting Eyes)
Participants' daily burden of the disease affecting eyes will be evaluated by visual analogue scale (VAS).Visual analogue scale levels \<20/100 were categorized as "Low" burden and VAS levels ≥50/100 as "High" burden.
Time frame: 6 months
Daily burden of disease (Asthma)
Participants' daily burden of asthma will be evaluated by visual analogue scale (VAS).Visual analogue scale levels \<20/100 were categorized as "Low" burden and VAS levels ≥50/100 as "High" burden.
Time frame: 6 months, Asthmatic patients will be regularly controlled even more often in case of exacerbations
SCORing Atopic Dermatitis (SCORAD)
SCORAD as a clinical tool will be used to assess the extent and severity of eczema. The SCORAD Index formula is: A/5 + 7B/2 + C. In this formula A is defined as the extent (0- 100), B is defined as the intensity (0- 18) and C is defined as the subjective symptoms (0- 20). The maximal score of the SCORAD Index is 103.
Time frame: 6 months for patients with AD