Sex Differences in the Effects of Obesity on Lung Volume.

BACKGROUND: Obesity is linked to variation of lung volume; however, it is still unclear whether a sex difference exists. The study aimed to find out the effect of obesity on lung volume and sex difference among the Chinese population.

METHOD: Pulmonary function test results were collected from 300 patients (aged 18 to ~80 years) with normal airway function and a wide range of body mass indexes (BMI). Measures of total lung capacity, vital capacity (VC), inspiratory capacity (IC), reserve volume, expiratory reserve volume (ERV) and functional reserve capacity (FRC) were analyzed by sex and different BMI groups.

RESULTS: BMI was correlated with VC inversely and IC positively in liner relationships (VC: r = -0.115, P < 0.05; IC: r = 0.168, P < 0.05, respectively), whereas ERV and FRC decreased exponentially with increasing BMI (FRC: r = -0.298, P < 0.01; ERV: r=-0.348, P < 0.01, respectively). Significant correlations were identified for the effect of BMI on ERV and IC and FRC in females (r = -0.354, P < 0.01; r = 0.206, P < 0.05; r = -0.335, P < 0.01), whereas only on ERV in males (r = -0.230, P < 0.05).

CONCLUSIONS: BMI affected the lung volume, and females were more susceptible to the effects than males.