Obesity is a risk factor for the development of asthma Obesity is significantly associated with the development of asthma, worsening of asthma symptoms and poor asthma control. This leads to increased medication use and hospitalisations. People with a BMI of 30 or more have a much higher risk of asthma than those with a lower BMI. Seven percent of adults with a BMI in the normal range have asthma, but 11 percent of adults with a BMI classified as obese have asthma.
And, for reasons we do not yet understand, this seems to be a particular problem for women: almost 15 per cent of obese women suffer from asthma. The impact of obesity on the diagnosis, control and severity of asthma exacerbations is increasingly recognised; however, the underlying pathophysiology of this association is not well understood. Standard clinical practice has not yet adopted aggressive management of obesity as a modifiable risk factor in asthma care, as is the case with a risk factor such as smoking or allergen exposure. This review summarises the existing data supporting the pathophysiological mechanisms underlying the association between obesity and asthma, as well as the current and future status of management of the obese patient with asthma.
Our review suggests that evidence of chronic inflammatory response linking obesity and asthma indicates the need to address obesity during asthma management, possibly using patient-centred approaches such as shared decision-making. Research is needed to better understand the mechanisms of asthma in the obese patient and to develop new therapies specifically targeted to this unique patient population. Obesity is a risk factor for asthma in multiple demographic groups, 7,38 Female sex is significantly associated with asthma and obesity, 39 In addition, obese asthmatics have a lower quality of life and higher resource utilisation compared to their non-obese counterparts, 40 Factors that may contribute to the pathogenesis of asthma in the obese include both mechanical factors and altered inflammation and immune responses related to the obese state. International guidelines advise that the diagnosis of asthma should be based both on the presence of symptoms and on objective measurements of variable airflow obstruction or bronchial hyperresponsiveness when bronchodilators are administered, 61. However, physicians often diagnose asthma based on symptoms without confirmation by pulmonary function tests or spirometry, 63. In something of a medical trap, asthma also appears to increase the risk of obesity.
Obesity is a common co-morbidity of asthma, especially severe asthma. Asthma and obesity interact and are associated with poorer asthma control, more frequent exacerbations and poorer quality of life (Tay et al. This suggests that obesity contributes to the disease burden of asthma. It is possible that the factors determining susceptibility do not depend solely on being obese, but rather on interactions with other phenotypic characteristics, such as age at asthma onset, gender and race, to name a few.
The effect of childhood obesity on lung volumes has been less well studied, with only a handful of reports describing conflicting results. Obese individuals breathe close to the closing volume of the airways, which may favour a reduction in operative lung volume. Currently, 71 percent of men and 56 percent of women in Australia are classified as obese or overweight (AIHW Risk Factors to Health Web Report). This review will provide a concise examination of the association between asthma and obesity and provide conclusions on the current body of literature.
Whether alterations in the microbiome or immune system early in life predispose individuals to both obesity and asthma. Obese children experienced a 67n decrease in asthma severity after MDS compared to non-obese children, although the result was not statistically significant. It was hypothesised that obese patients would have benefited less from the MDS intervention than overweight or normal weight patients. The parallel increase in the prevalence of asthma and obesity has led to several studies examining the possible relationship between these two conditions.
In a cohort of 12 severely obese asthmatics, bariatric surgery and the resulting decrease in BMI from 51.2 to 34.4 led to improved lung function, better performance on the methacholine test and a decrease in self-reported asthma symptoms. Obese subjects are at increased risk for asthma, and obese asthmatics have more symptoms, more frequent and severe exacerbations, poorer response to various asthma medications and poorer quality of life.
