Gender differences in effects of obesity and asthma on adolescent lung function: Results from a population-based study

ABSTRACT

Objective: To investigate lung function associated with asthma and body mass index (BMI) among adolescents at 96 northern Taiwan junior high schools participating in an asthma screening program. Methods: The questionnaires and lung function test results measured for 3669 boys and 3523 girls were included in this study for data analysis. Measures of forced vital capacity (FVC), forced expiratory volume in 1 second (FEV₁) and FEV₁/FVC ratio were compared by sex, asthma status and BMI. Results: Overall mean FVC levels were similar between students with and without asthma, 3.71 L vs. 3.71 L for boys (p = 0.991) and 2.79 vs. 2.78 for girls (p = 0.517). The overall mean FEV₁ levels were also similar between girls with and without asthma. Asthmatic boys had lower FEV₁ than non-asthmatic boys. Mean FEV₁/FVC was significantly lower in students with asthma than those without asthma. Mean FVC and FEV₁ increased with BMI in both sexes. A lower mean FEV₁/FVC was observed among students with asthma and high BMI, and was more pronounced in boys than in girls. Multivariable regression analysis also showed that FEV₁/FVC ratios were negatively associated with asthma and high BMI, stronger in boys than in girls for asthma (β = −2.176 (standard errors (SE) = 0.268) vs. −1.085 (SE = 0.258) and for BMI (β = −0.309 (SE = 0.025) vs. −0.218 (SE = 0.029)). Conclusion: This northern Taiwan study suggests that FEV₁/FVC is negatively associated with asthma and high BMI in adolescents, stronger for boys than for girls.

KEYWORDS:

• Body mass index
• forced vital capacity
• sex
• spirometry
• wheeze

View correction statement:

Corrigenda

Acknowledgments

We would like to thank all the members of the study teams, as well as the nurses and teachers at participating junior high schools for their assistance in data collection and processing.

Declaration of interest

The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the article.

Funding

This work was supported by the Taiwan Environmental Protection Administration (grant no. EPA-85-1404-09-06), National Science Council (grant no. NSC 98-2621-M-039-001), and the Ministry of Health and Welfare of Excellence (MOHW103-TDU-B-212-113002).