| Abstract |
Body composition influences thoracic mechanics, lung expansion, and respiratory muscle performance, making
it a key determinant of pulmonary function. This study was conducted to examine the effects of body mass index(BMI),
height, and weight on forced vital capacity(FVC) and forced expiratory volume in 1s(FEV1) among 2 30 adults and develop
predictive models based on body composition. Methods: Height, weight, BMI, FVC, and FEV₁ were measured in 230
healthy adults. Descriptive statistics, Pearson correlation analyses, and multiple regression analyses(models 1-3) were
conducted to determine the independent contributions of body composition variables. Model performance was evaluated
using R², adjusted R², Akaike information criterion(AIC), and Bayesian information criterion(BIC). Independent-samples
t-tests were performed to compare pulmonary function between sexes. Results: Height demonstrated the strongest
positive correlation with both FVC(r=0.488) and FEV1(r=0.486), followed by weight. Although BMI exhibited a positive
correlation in the univariate analysis, it emerged as a significant negative predictor in multivariable regression models.
Among the models tested, model 3(included BMI, height, weight, age, and sex) demonstrated the highest explanatory
power and the lowest AIC and BIC, indicating superior predictive performance. Sex-based analysis revealed that men had
significantly higher FVC and FEV1 than women(p<.001). Conclusion: In this study, height was the strongest positive
determinant of pulmonary function in adults, whereas BMI was independently associated with reduced lung capacity. The
proposed multivariable prediction model incorporating both body composition and demographic variables yielded the
most accurate estimates of FVC and FEV1. These findings support the value of body composition-based prediction models
to improve respiratory assessment in clinical practice. |