Childhood asthma is markedly increasing in developing countries. The first line of management according to national asthma guidelines is inhaled corticosteroids (ICS). Accurate body composition analysis with persisted asthma controlled by steroid therapy is essential at childhood, as the potential effects of the long-term treatment are still a matter of concern. Aim: The purpose of this study was to assess the total and segmental body composition especially the lean body mass in Egyptian children with asthma receiving inhaled steroid therapy. Methods: Lean body mass was measured by the gold standard, dual-energy X-ray absorptiometry (DEXA) in a cross-section study of 130 Egyptian pre-pubertal school-aged children (4-12 years); 50 asthmatic children with long-term steroid therapy (for two years) and results were compared with lean body mass values of 50 healthy children. Also, 30 asthmatic children with short-term steroid therapy (less than 6 months) were examined to rule of the duration therapy effect. Results: Asthmatic children received long-term steroid therapy had significantly higher chest lean mass than healthy children, which had highly significant association with weight, height, body mass index (BMI), total lean mass and total fat mass. However, no statistical significance is detected with short-term steroid therapy.
Also, there is no significant sex difference. Conclusion: The lean chest mass is increased in children with asthma controlled by long-term steroid therapy, evaluation of those children using DEXA provides an accurate analysis of both total and segmental body composition. Keywords: lean body mass, DEXA, asthma, steroids Introduction Childhood asthma is the most common chronic inflammatory disease of lung [1, 2]. It is characterized by inflammation of airway with episodes of coughing, wheezing and shortness of breath . Proper diagnosis of asthma is essential for the management; to detect accurate treatment and its dose . Asthma cannot be cured, but it can be controlled by medications to reduce symptoms during acute attacks . Inhaled corticosteroids (ICSs) are used as long-term controllers to reduce asthma-related morbidity and mortality and improve quality of life. National guidelines recommend corticosteroid therapy as a standard treatment for long-term control of childhood asthma [6, 7]. Hence, the effects of long-term ICS therapy on asthmatic children must be clearly defined. Analysis of body composition is essential for clinical and research settings . The majority of studies on asthma had concentrated on obesity and used body mass index (BMI) as a fat indicator, its results reflect limitation to predict body fatness and health risks in children; BMI cannot differentiate between muscle and fat mass as well as bone mineral content (BMC), also it cannot measure fat distribution but only indicate fatness in the whole body [9-12]. Alternatively, measurement of body composition by dual energy x-ray absorptiometry (DEXA) provides an accurate assessment of the tissue level . Careful consideration of the body composition changes and differentiation between fat and lean body mass may be an important factor in examining the lung functions in asthmatic children [13, 14].
The aim of this study was to assess the total and segmental body composition especially the lean body mass in Egyptian children with asthma receiving inhaled steroid therapy. Cross section data were collected and reported in this manuscript. Results The present study includes three groups: children with asthma controlled by long-term steroid therapy (32 males and 18 females), healthy children (26 males and 24 females) and children with asthma used short-term steroid therapy (9 males and 21 females). Their mean age of both groups is 8.5 ?± 3.0 SD. Regarding the frequency distribution of BMI; the asthmatic group of long-term steroid therapy included (42 of normal weight and 8 overweight and obese), while the asthmatic group of short-term steroid therapy included (24 of normal weight and 6 overweight and obese) and the healthy group included (43 normal weight and 7 overweight and obese). The means and standard deviations (SD) of the anthropometric measurements and significant body compositions values (lean mass and fat mass) of asthmatic with long-term steroid therapy and the healthy group showed in (Table 1), while between asthmatic with long-term versus short-term steroid therapy shown in (Table 2). These data indicated that weight and BMI were significantly higher in asthmatic patients with long-term steroid therapy compared to healthy group. Therefore, the chest lean mass had significantly higher in the asthmatic group with long-term steroid therapy (P <0.008) comparing to the healthy group, however no statistically significant was detected with short-term steroid therapy. The fat mass had no statistically significant between groups. Also, a comparison between asthmatic with short-term steroid therapy and the healthy group was done with no statistically significant detected. In spite of the absence of significant sex difference, we conducted several additional analyses to find the association between body composition (lean mass especially chest and fat mass) with each other as well as with anthropometric measurements that shown in Table (3), using Pearson's correlations. These data indicated that lean chest, total lean and total fat masses had highly association with weight, height, BMI as well as with each other.
Correlation is significant at the 0.01 level (p-value). Discussion Asthma and obesity represent serious complex chronic health conditions with high prevalence that have been studied in many studies and systematic reviews, reported a significant association between them [16-19]. Obesity considers a significant risk factor of asthma as more frequent symptoms with severe exacerbations could be detected in obsessing child, reduced response to medications as well [20- 25]. The excess fat and lean masses increasing risk of asthma . Careful consideration of the body composition changes during growth and development of a child is essential for prediction of obesity and other health risks latterly in life. Although body mass index (BMI) is used as a fat indicator at many studies, although its limitation to predict body composition and health risks in children; as BMI cannot differentiate between lean and fat masses as well as bone mineral content (BMC), also it cannot measure fat distribution but only indicate fatness in the whole body [10-13]. Dual-energy X-ray absorptiometry (DEXA) is used to analyze body composition based on a three-compartment model; fat mass, lean mass and the bone mass. Every compartment has a unique density and attenuates different energy beams; allowing an accurate quantification of each tissue with a convenient analysis of the whole and segmental body composition [14, 26]. Differences of body composition are detected among sex (males and females) at all ages; the included children in this study were selected in a pre-pubertal school-age period to avoid the obvious differences in body composition which emerge at adolescence with greater fat mass within females, while lean mass more prominent within males . Few studies assessed the lean mass; total and regional distribution in children [14, 28, 29]. Some researches indicated the importance of studying thoracic adiposity in asthmatic adults [10, 24]. In this study, the lean chest mass within Egyptian asthmatic children was increased, who received long-term inhaled corticosteroids therapy, as steroids had anabolic action on protein metabolism by increasing synthesis and inhibition of breakdown, causing muscle growth.
Moreover, the present study revealed a highly positive association between lean mass with weight, height and BMI, this agrees with Granell et al., (2014) that found the increased lean mass and fat mass in high risk asthma in mid-childhood, which persisted to age 15 years in birth cohort study . Jensen et al., in (2014) have assessed the association between lean mass in obese Australia children aged (8-17 years) by DEXA. It was suggested that lean mass may be more important than fat mass in relation to the respiratory function of asthmatic children . Findings of this study showed no significant difference in the fat mass between healthy and asthmatic children received short or long-term inhaled steroid therapy. Consistent results were found in a previous study concluded that short-term treatment with inhaled corticosteroids does not provoke growth alteration and fat accumulation . Studies on obesity with respiratory disorders reported that in addition to the amount of fat mass is contributing to impaired pulmonary function; fat distribution plays a role as well . Abdominal fat was increased with decreased respiratory functions in asthmatic children [31, 32]. Therefore, it was suggested that children with long-term therapy of asthma accumulate more adipose tissue on the trunk [33, 34]. In conclusion, this cross-sectional study is based on an accurate body composition analysis by (DEXA) that allowing the evaluation of total and segmental body composition in relation to the duration of steroid therapy. The lean chest mass is increased in asthmatic children controlled by long-term steroid therapy. Conflict of interest No conflict of interest associated with this manuscript. Acknowledgments Authors are grateful to all children participated in this study and their parents.
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