Ann Pediatr Res | Volume 3, Issue 2 | Research Article | Open Access
Lauren Elizabeth Faricy1*, Kensho I Wanaga2 and Ngoc P Ly2
1Department of Pediatrics, University of Vermont Medical Center Burlington, USA 2Department of Pediatrics, University of California San Francisco, USA
*Correspondance to: Lauren Elizabeth Faricy
Fulltext PDFBackground: In Cystic Fibrosis (CF), low aerobic capacity (VO2 peak) is a predictor of increased mortality. Lung function has been used to monitor long-term outcomes in patients with CF. Patients with mild CF tend to have normal lung function, hence aerobic capacity may provide an alternative for predicting outcomes. Little is known about predictors of VO2 peak in patients with mild CF and normal lung function. Recent studies have shown higher mortality in Hispanic CF patients, though data comparing aerobic capacity and physical activity between Hispanic and non-Hispanic CF patients are limited. Methods: This is a cross-sectional analysis of twenty-one subjects with mild CF, ages 10 to 20 years seen at one Cystic Fibrosis Center between September 2015 and March 2017. VO2 peak was measured by cardiopulmonary exercise testing on a cycle ergo meter. Physical activity was assessed using a validated questionnaire. Bivariate analyses was used to examine the relationship between VO2 peak and physical activity, ethnicity, sex, Pseudomonas aeruginosa infection, CFTR mutation class severity, and BMI z-score, age, and lung function. A multivariate model was created to assess predictors of VO2 peak. Results: This cohort (mean age 14.4 years) had normal lung function (FEV1 95% predicted) and normal VO2 peak (96% predicted). Habitual activity and percent-predicted VO2 peak did not differ significantly by sex. Hispanics with CF had lower VO2 peak (30.3 ml/kg/min vs. 39.5 ml/kg/min, p=0.022) compared to non-Hispanics and reported fewer hours spent in vigorous physical activity (2.4 vs. 6.0 h/week, p=0.035). Lung function did not differ by ethnicity. In the multivariate model, significant predictors of aerobic capacity were vigorous physical activity and CFTR mutation severity. Aerobic capacity was reduced in Hispanics (p=0.067) and those with chronic Pseudomonas aeruginosa infection (p=0.053) but results did not reach statistical significance. Conclusion: In a small cohort of children and young adults with mild CF and normal lung function, we found that vigorous physical activity and CFTR mutation severity were significant predictors of aerobic capacity (VO2 peak). Twenty-four percent of subjects in this cohort were Hispanic. Hispanics had comparable lung function but lower VO2 peak, longer recovery time, and lower participation in vigorous physical activity than non-Hispanics. While this study was limited by small sample size, early measurement of aerobic capacity may be clinically important. Larger studies are needed to further understand the relationship between VO2 peak and mortality, particularly with respect to ethnicity.
Cardiopulmonary exercise testing; Aerobic capacity; Cystic fibrosis; Physical activity; Hispanic
Faricy LE, Wanaga KI, Ly NP. What is Learned from Measuring Aerobic Capacity in Healthy Children and Young Adults with Cystic Fibrosis. Ann Pediatr Res. 2019;3(2):1026..