Mini-symposium: Kendig pediatric pulmonary symposiumThe weighty issue of obesity in paediatric respiratory medicine
Section snippets
Overview
There is a tendency to downplay this recent evolutionary change of the “obesity epidemic” as societies seek to “normalise” being overweight and obese rather than effectively address the problem. In a fashion sense: “fat is the new black”, but like much in fashion, obesity comes at a personal cost with a reduced life expectancy of up to 20 years [1], [2]. Of concern is that childhood obesity tracks into adulthood and that the prevalence of obesity is increasing in younger children, notably the
Obesity worldwide
In paediatric terms obesity is considered for a BMI >95% for age whilst being overweight is reflected by a BMI >85% [or standard deviation score > +1.64] but <95% [7]. As adulthood approaches, the numerical cut off for adults is a BMI between 25 kg/m2 and 30 kg/m2 to reflect being overweight and a BMI >30 kg/m2 for being obese. In Australia, despite our proud outdoor lifestyle and sporting ethos, 26% of our children are overweight or obese and 63% of our adult population are similarly disposed [8].
Antenatal influences
Obesity in pregnancy is an adverse factor for problems in pregnancy such as hypertension and gestational diabetes, complications at delivery and risks to the foetus [12], but there is evidence that when the developing foetus is exposed to maternal gestational diabetes or obesity, the large for gestation foetus is at an increased risk of developing the metabolic syndrome in childhood [13]. Thus, there may be an obesogenic environment confronting the foetus, adding to the genetic factors which
Postnatal dietary influences
Dietary influences have a significant impact on the evolution of excessive weight gain in children. The use of excessive volumes of infant formula and the earlier introduction of solids [protein] may be associated with early obesity [15]. The choice of foods, quality of the foods and the quantity served to a young child will set up patterns of eating behaviour that become entrenched [16]. As the child becomes older, more frequent intake of fast foods, soft drinks and calorie dense snack foods
Activity levels
Whilst dietary intake is the major determinant of overweight and obesity, its presence may be mitigated to an extent by physical activity. As part of a healthy life balance at any age, physical activity through regular exercise in daily activities and organised sport has become supplanted to a large extent by the access to computer, tablet and mobile phone screen time [18].
Obesity and asthma
Asthma affects approximately 15% of children worldwide [19]. Obesity is associated with a clinically significant reduction in quality of life in asthmatic children [5]. In children with asthma, obesity is associated with poorer asthma control, increased exacerbations and increased use of medications [20]. Obese asthmatic children in one study were approximately 2.5 times more likely to be admitted to hospital with an exacerbation of asthma [21].
One study suggested that up to 45% of asthmatic
Lung function testing results in obese children
As with obese adults, increased weight in children and adolescents is associated with reduced lung volume measurements, which may reflect impaired lung function, increased respiratory symptoms and reduced functional status [24]. Specifically, obesity is associated with a restrictive pattern in lung function testing, manifesting in some studies with a reduced FEV1/FVC ratio, whilst other studies have relied on lung volumes, rather than spirometry to show abnormalities; lower residual volume [RV]
Lung function testing in asthmatics who are obese
Obese asthmatics may not demonstrate abnormal spirometry compared to non-obese asthmatics [5]. However, in this study, obese asthmatics demonstrated reductions in ERV compared to non-obese children without asthma. Thus, as suggested by Jensen et al. [5], it may be that there is a greater element of gas trapping in obese asthmatics, leading to preservation of their RV and so it may be prudent to measure lung volumes in obese asthmatic patients so as to detect an abnormality of lung mechanics.
It
Deconditioning versus asthma in obese children
It is common for families, school teachers, and often in the primary care setting, to presume shortness of breath on exertion is asthma. Perhaps out of concerns for wanting to do something for an obese child who gets “puffed” running around and may cough but usually not be heard to wheeze, children may be placed on bronchodilators and preventative asthma medications, usually inhaled corticosteroids. From a clinical viewpoint, the absence of audible wheeze is usual in the history and the onset
Obesity and sleep
We sleep less now than ever. This is evident from the toddler age group to adulthood [35]. There is an emerging appreciation of the potentially significant role of sleep and sleep disordered breathing aggravating obesity and its inherent metabolic and cardiorespiratory complications [36]. Less sleep has correlated in epidemiological studies with increased weight gain, and this seems stronger in children and adolescents than adults [37]. Although it should be noted that most studies quoting
Obstructive sleep apnoea
It is apparent that up to 5% of children may develop obstructive sleep apnoea [OSA], with its additional consequences of altered behavioural, concentration and cognitive implications [40]. OSA is more severe and less likely to be cured by adenotonsillectomy in an obese child [36], [41], [42]. In theory, this may be because obese children have less lymphoid tissue and larger para-pharyngeal fat pads compared to non-obese children with a similar degree of OSA as well as their altered chest wall
Weight loss as a treatment for respiratory problems of obesity
Weight loss works for exertional dyspnoea, obesity complicating asthma, OSA and hypertension and other metabolic problems such as Type 2 diabetes mellitus resulting from obesity. It is just that it is hard to achieve and so parents and patients often resist what is an obvious but confronting treatment. The success rates of the scarce and frightfully expensive multidisciplinary services are low with typical results showing a reduction in BMI of <2 kg/m2 over a year of intensive follow-up in
The future needs for meeting the challenges of obesity
An emphasis on effective interventions for overweight and obesity require changes in health care policy regarding access for clinical assessment, testing respiratory function and polysomnography, reduced waiting times for interventions such as adenotonsillectomy and provision of non-invasive support. Long term outcomes need to be monitored as part of ongoing improvements in care as well as expanding our knowledge of the impacts of the life-shortening consequences of obesity.
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