Article Text
Abstract
Background Few large prospective studies have investigated the impact of body mass index (BMI) on lung function during childhood.
Methods Using data collected between 2002 and 2013, we analysed associations between BMI status and lung function (assessed by spirometry) from 8 to 16 years, as well as cross-sectional associations with small airway function (impulse oscillometry) at 16 years in the BAMSE cohort (n=2889). At 16 years, cross-sectional associations with local and systemic inflammation were investigated by analysing FENO, blood eosinophils and neutrophils.
Results Overweight and obesity at 8 years were associated with higher FVC, but lower FEV1/FVC ratio at 8 and 16 years. In boys, but not girls, obesity at 8 years was associated with a further reduction in FEV1/FVC between 8 and 16 years. In cross-sectional analyses, overweight and obesity were associated with higher frequency dependence of resistance (R5–20) and larger area under the reactance curve (AX0.5) at 16 years. Increased blood neutrophil counts were seen in overweight and obese girls, but not in boys. No association was found between BMI status and FENO. Persistent, but not transient, overweight/obesity between 8 and 16 years was associated with higher R5–20 and AX0.5 and lower FEV1/FVC (−2.8% (95% CI −4.1 to −1.2) in girls and −2.7% (95% CI −4.4 to −1.1) in boys) at 16 years, compared with persistent normal weight.
Conclusion In childhood and adolescence, overweight and obesity, particularly persistent overweight, were associated with evidence of airway obstruction, including the small airways.
- asthma epidemiology
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Footnotes
AB and EM contributed equally.
Contributors EM, AB and IK are principal investigators of the BAMSE cohort. SE, AB and EM designed the study. SE, JH, IK, JLPP, PT, PMG, AB and EM planned the analyses and interpreted the results. SE performed the statistical analyses and prepared the first manuscript draf. MB provided statistical expertise for the analyses. SE, JH, IK, JLPP, PT, MB, PMG, AB and EM critically revised the manuscript. All authors approved the final version of the manuscript.
Funding This work was supported by the Swedish Research Council (VR), the Stockholm County Council (ALF), the Swedish Heart and Lung Foundation, the Swedish Research Council for Health, Working Life and Welfare, the Swedish Asthma and Allergy Foundation, the European Commission’s Seventh Framework 29 Program MeDALL under grant agreement no 261357, the Freemason Child House Foundation in Stockholm and the Swedish Research Council Formas.
Competing interests None declared.
Ethics approval Regional Ethical Review Board in Stockholm.
Provenance and peer review Not commissioned; externally peer reviewed.