Background: To determine the effect of threshold inspiratory muscle training (IMT) on functional fitness and respiratory muscle strength (RMS) compared to incentive spirometry (IS) in children/adolescents with obesity.Methods: A total of 60 obese children/adolescents aged 8–15 years were randomized into the threshold IMT group (n= 20), the IS group (n= 20), or the control group (n= 20). The IMT group performed 30 inspiratory breaths with the intensity set at 40% of baseline maximal inspiratory pressure (MIP) twice daily for 8 weeks; the IS group performed 30 breaths with sustained maximum inspiration twice daily for 8 weeks; and, the control group was assigned no training device for 8 weeks. Six-min walk test (6-MWT), RMS, and spirometry were compared between baseline and 8 weeks.Results: Six-MWT distance (528.5 ± 36.2 vs. 561.5 ± 35.2 m,p= 0.002) and MIP (121.2 ± 26.8 vs. 135.3 ± 32.1%Predicted,p= 0.03) were significantly improved after 8 weeks of IMT training. There was no significant difference in any evaluated pulmonary function parameters between baseline and 8 weeks in the IS or control groups; however, 6-MWT distance demonstrated a trend toward significant improvement in the IS group (526.9 ± 59.1 vs.549.0 ± 50.6 m,p= 0.10). No significant difference among groups was found for any variable relative to change from baseline to post-training.Conclusion: Eight weeks of threshold IMT training significantly improved both inspiratory muscle strength (MIP) and functional fitness (6-MWT) in children/adolescents with obesity. Eight weeks of IS training yielded a trend toward significantly improved functional fitness.

Background: To investigate the longitudinal effects of obesity on change in lung function after 1 year of follow-up in obese children and adolescents. Methods: Obese children/adolescents aged 8–15 years with pulmonary function test (PFT) results and recorded anthropometric obesity indices from 1 year earlier for comparison were recruited. Multiple linear regression of change in each lung function parameter was applied to determine the effect of sex, change in body mass index (ΔBMI), change in chest circumference (ΔCC), change in waist circumference (ΔWC), and change in waist circumference-to-height ratio (ΔWC/Ht). Results: Sixty-six children/adolescents (mean age: 12.5 ± 2.6 years) were recruited. Multiple linear regression analysis showed that ΔWC negatively affects the ratio of the forced expiratory volume in the first 1 s to the forced vital capacity of the lungs Δ(FEV₁/FVC) (b = −0.3, p = 0.002), forced expiratory flow rate within 25–75% of vital capacity (ΔFEF_25–75%) (b = −0.92, p = 0.006), and Δ(FEF_25–75%/FVC) (b = −0.99, p = 0.003). When replacing ΔWC with Δ(WC/Ht) as the independent variable, Δ(WC/Ht) also negatively affects Δ(FEV₁/FVC) (b = −33.71, p = 0.02), ΔFEF_25–75% (b = −102.9, p = 0.03) and Δ(FEF_25–75%/FVC) (b = −102.7, p = 0.03). Conclusion: After 1 year of follow-up, change in abdominal adiposity determined by WC and WC/Ht exerted significant negative effect on lung function change specific to FEV₁/FVC, FEF_25–75% /FVC, and FEF_25–75%. Impact: Longitudinal effects of change in obesity on lung function in obese children and adolescents are evidenced. Change in waist circumference or waist-to-height ratio, which indicates abdominal adiposity, was inversely correlated with a change in FEV1/FVC, FEF25–75% /FVC, and FEF25–75% in children and adolescents with obesity after 1 year of follow-up. Our results suggest using waist circumference and/or waist-to-height ratio in addition to BW and/or BMI for monitoring obesity. Fat loss programs, especially those focused on reducing abdominal adiposity should be encouraged to prevent late lung function impairment.

Background and Objective: There are only a few reports of long COVID including pulmonary function in children after COVID‐19 pneumonia. We determined the incidence of long COVID and abnormal pulmonary function in those children and identify risk factors.Methods: This cohort study enrolled children admitted with COVID‐19 pneumonia during 2021–2022. We gathered clinical characteristics during admission and at follow‐up 3 months after.Results: We determined the incidence of long COVID at 39.7% (95% confidence interval [CI]: 30.7%–49.1%). All severe pneumonia cases consistently reported persistent symptoms. Exercise intolerance, cough, and fatigue were the three most common persistent symptoms in 26 (22.4%), 21 (18.1%), and 18 (15.5%) of the patients, respectively. At the follow‐up, 21 cases (18.1%) demonstrated persistent abnormal chest radiographs. Three cases (6.9%) demonstrated restrictive ventilatory defects. Among those, one case (2.3%) demonstrated concomitant diffusion defect. Three cases (6.0%) demonstrated exercise‐induced hypoxemia after the 6‐minute walk test. Comparing spirometry variables between children with long COVID and without revealed significant difference of FEF25‐75 (z score) between two groups. Age [adjusted OR (95% CI): 1.13 (1.05–1.22), p value 0.002], allergic diseases [adjusted OR (95% CI): 4.05 (1.36–12.06), p value 0.012], and living in polluted areas [adjusted OR (95% CI): 2.73 (1.18–6.33), p value 0.019] were significantly associated with long COVID.Conclusion: A significant percentage of children developed long COVID after COVID‐19 pneumonia. We should give additional attention to those who have exercise intolerance, chronic cough, or fatigue, especially older children, severe cases, children with allergic diseases, and those living in polluted areas.

Background: Few studies have explored the polysomnographic features of children with obesity.Purpose: This study aimed to explore the demographic and polysomnographic features of obese children and determine whether body mass index (BMI) could predict severe obstructive sleep apnea (OSA).Methods: This cross-sectional study recruited obese children who underwent diagnostic polysomnography between January 2019 and March 2022. We explored demographic and anthropometric measures as well as polysomnographic abnormalities among them. We used receiver operating characteristic curves and logistic regression analyses to determine the optimal cutoff values of anthropometric variables for predicting severe OSA.Results: A total of 132 children with obesity (76.5% male; mean age, 12.5±3.2 years) were included. Severe OSA was identified in 64 children (48.5%). Desaturation was observed in 59.8%, while 23.5% had hyperarousal, 20.5% had sleep-related hypoventilation, 60.6% had positional OSA, 40.2% had rapid eye movement-related OSA, and 5.0% had obesity hypoventilation syndrome. Among them, BMI (odds ratio [OR], 1.11; 95% confidence interval [CI], 1.05–1.17; P<0.001), neck circumference (OR, 1.15; 95% CI, 1.07–1.25; P<0.001), and waist circumference (OR, 1.04; 95% CI, 1.02– 1.07; P=0.001) were significantly associated with severe OSA. These findings suggest a cutoff BMI for predicting severe OSA of greater than 29.2 kg/m2 with 81.3% sensitivity and 48.5% specificity.Conclusion: Severe OSA is common in children with obesity; thus, we recommend screening children with obesity and a BMI greater than 29.2 kg/m2 for severe OSA.

Objectives: We aimed to determine the obesity indices that affect 6-min walk test (6-MWT) distance in children and adolescents with obesity and to compare the 6-MWT distance of obese subjects with that of normal-weight subjects.Methods: Obese children and adolescents aged 8–15 years and normal-weight age- and gender-matched controls were enrolled. All participants performed the 6-MWT; respiratory muscle strength (RMS), including maximal inspiratory pressure and maximal expiratory pressure; and spirometry. Data between groups were compared. In the obesity group, correlation between obesity indices and pulmonary function testing (6-MWT, RMS, and spirometry) was analyzed.Results: The study included 37 obese and 31 normal-weight participants. The following parameters were all significantly lower in the obesity group than in the normal-weight group: 6-MWT distance (472.1 ± 66.2 vs. 513.7 ± 72.9 m; p = 0.02), forced expiratory volume in one second/forced vital capacity (FEV₁/FVC) (85.3 ± 6.7 vs. 90.8 ± 4.5%; p < 0.001), forced expiratory flow rate within 25–75% of vital capacity (FEF_25−75%) (89.8 ± 23.1 vs. 100.4 ± 17.3 %predicted; p = 0.04), and peak expiratory flow (PEF) (81.2 ± 15 vs. 92.5 ± 19.6 %predicted; p = 0.01). The obesity indices that significantly correlated with 6-MWT distance in obese children and adolescents were waist circumference-to-height ratio (WC/Ht) (r = −0.51; p = 0.001), waist circumference (r = −0.39; p = 0.002), body mass index (BMI) (r = −0.36; p = 0.03), and chest circumference (r = −0.35; p = 0.04). WC/Ht was the only independent predictor of 6-MWT distance by multiple linear regression.Conclusions: Children and adolescents with obesity had a significantly shorter 6-MWT distance compared with normal-weight subjects. WC/Ht was the only independent predictor of 6-MWT distance in the obesity group.

Background: The increasing global prevalence of obesity poses significant public health problems, as obesity exerts adverse effects on many systems and lung function. However, research on the lung function of preschool children with obesity is limited and inconclusive. In addition, studies specific to obesity indices that influence lung function in young children with obesity are limited.Purpose: This study aimed to evaluate lung function of obese versus normal-weight preschool children using impulse oscillometry (IOS) and identify obesity indices predictive of altered lung function.Methods: We enrolled obese children aged 3–7 years as well as age- and sex-matched normal-weight controls. The participants underwent IOS assessments that measured the resistance at 5 Hz (R5) and 20 Hz (R20), the difference in resistance between these frequencies (R5–R20), reactance at 5 Hz (X5), resonance frequency, and reactance area (AX). We compared these parameters between groups and analyzed the correlations between obesity indices and IOS measures within the obese group using multiple linear regression.Results: The study included 68 participants (n=34 each group). In the obese group, significantly higher values were observed for R5 (adjusted for height, P=0.02; % predicted, P=0.01; z score, P<0.001), R5–R20 (absolute value, P=0.002; adjusted for height, P=0.001), and AX (z score, P=0.01). AX adjusted for height showed a greater trend (P=0.07). The waist-to-height ratio was the most robust independent predictor of total and peripheral airway resistance, with increases in R5 (b=1.65, P=0.02) and R5–R20 (b=1.39, P=0.03) and a near-significant correlation with AX (b=12.12, P=0.06).Conclusion: Preschool children with obesity exhibit impaired lung function, characterized by elevated total and peripheral airway resistance. Waist-to-height ratio was the strongest predictor of these changes.