Associations of body fat percent and body mass index with childhood asthma by age and gender

Abstract

Objective: 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. Results: 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 ¼ 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. Conclusions: 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.

Asthma and Obesity during Childhood: A Review of More than an Occasional Association

“…Hacihamdioglu et al add that a neck circumference over the ninetieth percentile is associated with severe asthma in children -severe asthma was defined as children who needed Step three, Step four, or Step five treatment options according to the Global Initiative for Asthma guidelines [15]. Body fat percentage, one more index for obesity, displays a U-shaped association with asthma instead of the linear association between asthma and Body Mass Index therefore implying a greater risk of asthma for both lower and higher body fat percentages [16].…”

Childhood body mass index and wheezing disorders: a systematic review and meta‐analysis

“…A total of seven studies presented data on the number of cases and non-cases in underweight and normal BMI groups comprising a total of 772,040 children (7,(41)(42)(43)(44)(45)(46). The summary risk estimate of the studies showed that there was a significant decrease odds of wheezing disorders (OR = 0.85, 95% CI: 0.75 to 0.97; p = 0.02) for the underweight children ( Fig.…”

“…A total of 29 studies presented data on the number of cases and non-cases in the overweight and normal BMI groups that included a total of 1,075,042 children (7,8,(41)(42)(43)(44)(45)(46)(50)(51)(52)(53)(54)(55)(56)(57)(58)(59)(60)(61)(62)(63)(64)(65)(66)(67)(68)(69). The summary of the ORs showed that there was a significant increased risk of wheezing disorders (OR: 1.23, 95% CI: 1.17-1.29; p < 0.001) ( Fig.…”

Review of different anthropometric and nutritional measurements in children with bronchial asthma

“…It was concluded that the body fat percentage was significantly higher in the children with BA in the age of 7-8 years and 16-17 years, but not in the age groups in between [56].…”