The reciprocal influences of asthma and obesity on lung function testing, ahr, and airway inflammation in prepubertal children

Abstract

Although asthma and obesity are among the major chronic disorders their reciprocal or independent influences on lung function testing, airways hyperresponsiveness (AHR) and bronchial inflammation has not been completely elucidated. In 118 pre-pubertal Caucasian children anthropometric measurements functional respiratory parameters (flow/volume curves at baseline and after 6-minute walk test [6MWT]) together with bronchial inflammatory index (FeNO) were assessed. The study population was divided into four groups according to BMI and the presence or absence of asthma: Obese asthmatic (ObA) Normal-weight asthmatic (NwA), Obese non-asthmatic (Ob), non-asthmatic normal-weight children (Nw). Baseline PEF and MEF(75) (%-expected) were significantly different across the four groups with significantly lower values of MEF(75) in ObA and Ob children when compared to Nw children (P = 0.004 and P = .0001, respectively) and this independent role of obesity on upper respiratory flows was confirmed by multiple analysis of covariance. After 6 MWT respiratory parameters decreased only in ObA and NwA children and 12 children presented a positive fall in FEV(1), in contrast no changes of respiratory function testing were detected in Ob and Nw children, and only 2 Ob children presented a significant fall in FEV(1). FeNO analysis demonstrated significantly higher values in ObA and NwA children when compared to Ob (P = 0.008 and P = 0.0002, respectively) and Nw children (P = 0.0001 and P = 0.0003, respectively), although a significant difference was found between Ob and Nw children (P = 0.0004). Multiple analysis of covariance confirmed an independent role of asthma on this parameter. In conclusion while AHR and airway inflammation are clearly associated with an asthmatic status, obesity seems to induce reduction of upper airways flows associated with a certain degree of pro-inflammatory changes.

Obesity-Associated Asthma in Children

“…Further, controller medication use may have also contributed to or obesity have demonstrated a similar lack of association. 37 Other pediatric studies that demonstrated a correlation between PFTs and adiposity included adolescents, raising the question as to whether change in body fat distribution occurring during adolescence may have played a role 38 and may provide an explanation for the discordance between pediatric Although the infl ammatory pattern in obese asthmatic children did not differ from that in obese nonasthmatic children in our study, several factors can be hypothesized for the occurrence of asthma in some, but not all, obese children. The pattern of fat distribution may play a role, because central adiposity has been associated with asthma in children.…”

Associations of obesity and asthma with functional exercise capacity in urban minority adolescents

“…However, since all asthmatics had ER visits with or without hospitalizations for asthma exacerbations for several years prior to study participation, irrespective of obesity status, we do not believe that there was a misclassification bias based on our selection criteria. Moreover, we did not perform spirometry testing after completion of the 6MWT, which could have elucidated exercise induced pulmonary function changes and hence differences between the four study groups, as recently reported in a Caucasian pre‐pubertal population 33. Further, the relatively small sample, particularly in the normal‐weight asthmatic group, may have played a role in the borderline significance of some associations.…”

“…We recognize that 6MWT has not been routinely used to measure functional exercise capacity among children. However, recent studies19, 28, 33 have increasingly utilized it given the ease of its application in clinical settings. While correlating closely with the results of maximal exercise testing,19 it obviates the need for specialized testing equipment and trained personnel required for exercise testing.…”

Body mass index, asthma and exhaled nitric oxide in U.S. Adults, 2007–2010

“…Two of them reported results for persons with asthma, with one finding no association [14] and the other a negative association [15]. Several other more recent studies have issued similarly inconsistent findings [18][19][20].…”