Disclosure The authors declared no conflict of interest.
Associations of body fat percent and body mass index with childhood asthma by age and gender
Article first published online: 21 MAY 2013
Copyright © 2012 The Obesity Society
Volume 21, Issue 9, pages E474–E482, September 2013
How to Cite
Yiallouros, P. K., Lamnisos, D., Kolokotroni, O., Moustaki, M. and Middleton, N. (2013), Associations of body fat percent and body mass index with childhood asthma by age and gender. Obesity, 21: E474–E482. doi: 10.1002/oby.20284
- Issue published online: 23 SEP 2013
- Article first published online: 21 MAY 2013
- Accepted manuscript online: 2 JAN 2013 07:15PM EST
- Manuscript Accepted: 19 NOV 2012
- Manuscript Revised: 1 OCT 2012
- Manuscript Received: 22 MAY 2012
High body mass index (BMI) has been shown to be associated with asthma, but the pattern of this association is still unclear and may differ by gender or stage of puberty. BMI is only a proxy of adiposity, whereas estimation of body fat percent (BF%) by the bioimpedance technique is considered an accurate measure of adiposity. We investigated whether BMI and BF% behave differently in their association with asthma between genders, before and during adolescence.
Design and Methods
In this cross-sectional study of 10,981 schoolchildren, we used logistic regression models to examine the pattern of association of BMI and BF% with asthma.
In the case of BF%, both the highest (odds ratio [OR]: 1.68, 95% confidence interval [95% CI]: 1.21-2.30) and lowest (OR: 1.59, 95% CI: 1.13-2.23) z-score categories conferred an increased adjusted risk for active asthma. The likelihood ratio test (LRT) of nonlinearity yielded significant results (P < 0.01) for BF%. In contrast, the LRT for BMI yielded a nonsignificant result (P = 0.45) indicating a linear association of asthma with BMI. A unit increase in BMI z-score conferred an increase in the adjusted odds of active asthma (OR: 1.14, 95% CI: 1.02-1.27). In the case of BF%, the adjusted ORs for active asthma at the highest and lowest z-score categories in both genders, before and during adolescence, were similarly elevated, exhibiting a U-shape pattern.
In contrast to the linear association observed with BMI, BF% displayed a U-shaped association with asthma and may be the preferred measure of adiposity in epidemiological studies of asthma in children.