Differing associations of BMI and body fat with asthma and lung function in children

Authors

  • Ran Wang MBChB, BSc,

    1. Manchester Academic Health Science Centre, University of Manchester, University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK
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  • Adnan Custovic MD, PhD,

    1. Manchester Academic Health Science Centre, University of Manchester, University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK
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  • Angela Simpson MD, PhD,

    1. Manchester Academic Health Science Centre, University of Manchester, University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK
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  • Danielle C. Belgrave MSc,

    1. Manchester Academic Health Science Centre, University of Manchester, University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK
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  • Lesley A. Lowe PhD,

    1. Manchester Academic Health Science Centre, University of Manchester, University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK
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  • Clare S. Murray MD

    Corresponding author
    1. Manchester Academic Health Science Centre, University of Manchester, University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK
    • Correspondence to: Clare S. Murray, University of Manchester, University Hospital of South Manchester, Education and Research Building, 2nd Floor, Manchester M23 9LT, UK. E-mail: clare.murray@manchester.ac.uk

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  • The copyright line for this article was changed on 26 September after original online publication.
  • Conflict of interest: None.

Summary

Background

Current evidence suggests that in children there is a significant, albeit weak, association between asthma and obesity. Studies generally use body mass index (BMI) in evaluating body adiposity, but there are limitations to its use.

Method

Children from a population-based study attending follow-up (age 11 years) were weighed, measured and had percent body (PBF) and truncal (PTF) fat assessed using bioelectrical impedance. They were skin prick tested and completed spirometry. Parents completed a validated respiratory questionnaire. Children were defined as normal or overweight according to BMI and PBF cut-offs. We tested the association between these adiposity markers with wheeze, asthma, atopy, and lung-function.

Results

Six hundred forty-six children (339 male) completed follow-up. BMI z-score, PBF, and PTF were all positively associated with current wheeze (odds ratio [95% CI]: 1.27 [1.03, 1.57], P = 0.03; 1.05 [1.00, 1.09], P = 0.03; 1.04 [1.00, 1.08], P = 0.04, respectively). Similar trends were seen with asthma. However, when examining girls and boys separately, significant positive associations were found with PBF and PTF and asthma but only in girls (gender interaction P = 0.06 and 0.04, respectively). Associations between being overweight and wheezing and asthma were stronger when overweight was defined by PBF (P = 0.007, 0.03) than BMI (P > 0.05). Higher BMI was significantly associated with an increase in FEV1 and FVC, but only in girls. Conversely, increasing body fat (PBF and PTF) was associated with reduced FEV1 and FVC, but only in boys. No associations between adiposity and atopy were found.

Conclusion

All adiposity measures were associated with wheeze, asthma, and lung function. However, BMI and PBF did not have the same effects and girls and boys appear to be affected differently. Pediatr Pulmonol. 2014; 49:1049–1057. © 2013 The Authors. Pediatric Pulmonology published by Wiley Periodicals, Inc.

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