Research Article: Obesity disproportionately impacts lung volumes, airflow and exhaled nitric oxide in children

Date Published: April 4, 2017

Publisher: Public Library of Science

Author(s): Tsung-Chieh Yao, Hui-Ju Tsai, Su-Wei Chang, Ren-Hua Chung, Jing-Ya Hsu, Ming-Han Tsai, Sui-Ling Liao, Man-Chin Hua, Shen-Hao Lai, Li-Chen Chen, Kuo-Wei Yeh, Yu-Lun Tseng, Wan-Chen Lin, Su-Ching Chang, Jing-Long Huang, Yang-Ching Chen.


The current literature focusing on the effect of obesity and overweight on lung function and fraction of exhaled nitric oxide (FeNO) in children, particularly among healthy children of non-European descent, remains controversial. Furthermore, whether the relationship of obesity and overweight with lung function and FeNO in children is modified by atopy is unclear. The objective of this study was to examine the effect of excess weight on lung function parameters and FeNO among Asian children, with a particular focus on exploring the potential effect modification by atopy.

We investigated the effect of excess weight on lung function and FeNO in a population sample of 1,717 children aged 5 to 18 years and explored the potential modifying effect of atopy.

There were positive associations of body mass index (BMI) z-score with forced vital capacity (FVC), forced expiratory volume in 1 second (FEV1), peak expiratory flow (PEF), and forced expiratory flow at 25–75% (FEF25-75) (all P<0.001), after controlling for confounders. The beta coefficient for FEV1 (0.084) was smaller than that for FVC (0.111). In contrast, a negative association was found between BMI z-score and FEV1/FVC ratio (P<0.001) and FeNO (P = 0.03). A consistent pattern of association for lung function variables was observed when stratifying by atopy. There was a negative association of BMI z-score with FeNO in atopic subjects (P = 0.006), but not in non-atopic subjects (P = 0.46). Excess weight disproportionately impacts lung volumes and airflow in children from the general population, independent of atopic status. Excess weight inversely affects FeNO in atopic but not in non-atopic children.

Partial Text

Excess weight represents a major global health challenge because of the established health risks and substantial increase in prevalence of overweight and/or obesity in children and adults worldwide, both in developed and developing countries [1–3]. In 2013, 23.8% of boys and 22.6% of girls were overweight or obese in developed countries [1]. Similar to many countries, Taiwan has experienced a substantial increase in the prevalence of childhood overweight and obesity, specifically, from 5.7% to 14.2% for overweight and from 7.9% to 17.4% for obesity in male students; and from 11.1% to 13.4% for overweight and from 3.1% to 4.1% for obesity in female students during the study period of 1991 and 2003 [3]. Excess weight is potentially associated with increased morbidity and mortality in children as well as in adults, which is attributed to obesity-related adverse health outcomes, including respiratory diseases (i.e., asthma, chronic obstructive pulmonary disease, and obstructive sleep apnea syndrome), metabolic syndrome, type 2 diabetes, cardiovascular diseases, and psychological problems [4]. One major concern is that excess weight in childhood is likely to persist into adulthood as revealed by several prospective studies [5]. During recent years, growing attention has therefore been directed towards the potential health consequences of childhood obesity and overweight.

Obesity is a worldwide public health problem that poses a significant health threat as well as a considerable economic and societal burden. This study investigated the relationship of BMI status with lung function and FeNO in a population-based study of 1,717 Asian children. The major finding of the current study is that increasing BMI disproportionately impacts lung volumes and airflow among children in a population setting which is reflected by increase in FVC, FEV1, and PEF, and FEF25-75, but decrease in FEV1/FVC ratio, independent of atopic status. Another interesting finding is that increasing BMI is inversely associated with FeNO in atopic but not in non-atopic children. To our knowledge, this is one of the first population-based studies to investigate the relationship between obesity, lung function, and FeNO in a large population sample of Asian children according to atopic status.




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