RESULTS
Cat sensitization was detected by skin prick testing in 182 children with asthma and/or allergic rhinitis. All these patients had been under medical treatment and follow-up in our pediatric allergy and immunology clinic for at least three months, and all were requested to participate in the study. However, 11 declined and 41 were excluded due to meeting the exclusion criteria. Ninety-six age and sex-matched children were randomly selected for the healthy control group. However, seven declined to participate, three were unable to cooperate with the pulmonary function tests, and 16 were excluded due to passive smoking exposure. The study flowchart is shown in Figure 1.
A comparison of demographic and clinical data between the children with respiratory allergic diseases and the HC group is presented in Table 1. No differences were determined between the groups in terms of the demographic characteristics of sex or age, or weight, height, and BMI z scores (p>0.05).
The median enduration size was 5.5 mm (range 4.5mm to 6.12 mm) at skin prick testing with a standardized cat allergen solution. Only 9.23% (n=12) of the CS group experienced domestic cat exposure in the home. When atopy status was evaluated, 91.53% (n=119) of those were polysensitized, and pollen allergy was the most frequent allergen accompanying cat sensitization. Eosinophilia was detected in 36.92% (n=48) of the patients.
At IOS analysis, zR5, R5-20, Fres, and AX levels were higher and zX5 and zX20 lower in children with respiratory allergic disease compared to the healthy controls (p=0.029, p=0.008, p=0.001, p<0.001, p=0.001, and p<0.001, respectively). A comparison of IOS parameters between the children with respiratory allergic disease and controls is shown in Table 2 and Figure 2.
A comparison of the IOS and spirometry values of groups I, II, and III is shown in Table 3. No differences were determined between those groups in terms of the demographic characteristics of sex and age, weight, height and BMI z-scores (p>0.05). Analysis of the IOS and spirometry parameters revealed no significant difference was found among the three groups (p>0.05).
A comparison of IOS parameters according to cat exposure is shown in Table 4. No difference was observed in terms of IOS parameters or spirometric values between the Do+ and Do- groups (p>0.005).
A comparison of IOS parameters according to age groups is given in Table 5. In terms of airway resistance, R5-20 was higher in preschool age compared to the older age group (p<0.001). In terms of airway reactance, zX20 was lower, Fres and AX were higher in the pre-school age group, than in the older age group (p<0.001).
No difference in terms of IOS parameters was observed between the step 2 and step 3-4 treatment groups (p>0.05). No correlation was found between zFEV1, zFVC, zFEV1/FVC, zFEF25-75, and any IOS parameter in the CS group (p>0.05). Similarly, no strong correlation was detected between IOS and spirometry values, according to gender, treatment step of asthma, allergic respiratory disease subgroups, and cat exposure. However a moderate positive correlation between zFEV1 and zR20 in girls (r=0.428, p=0.016), and a moderate negative correlation between zFEV1/FVC and AX in asthma patients (r=-653, p=0.11) were detected.