Background

It has been long established that body composition affects pulmonary function but little attention has been given to assess lung function in healthy adolescents and determine the influence of body composition on these variables.

Methods

We measured 399 boys (mean age 16.7 ± 1.2 yrs) and 46 girls (mean age 17.1 ± 1.2 yrs). We used multi-frequency segmental bioimpedance analyser Tanita MC 980-MA Plus for body composition parameters and Micro Direct MicroGP Spirometer MS07 for spirometry parameters.

Results

Mean body height was 179.5 cm and mean BMI was found to be 22.5 kg/m2 in boys. In girls, mean body height was 166.9 cm and BMI was 22.5 kg/m2. After adjusting for age, body height, body weight and smoking status, we found significant (P = 0.01) association (β = 0.35–0.43) between forced vital capacity (FVC) and fat-free mass (FFM) or trunk fat-free mass only in boys. Similarly, body fat mass (BFM) showed significant (P = 0.01) negative association (β = -0.29 to -0.20) with spirometry parameters only in boys. In girls, the results showed a similar trend but without significance.

Conclusions

In conclusion, FFM or trunk FFM is more closely related to lung capacity than BFM or trunk BFM after adjustment confounding variables in healthy adolescent boys. Body height explains up to 23% variability of FVC and fat-free mass explains up to 27% in linear regression model.