Obesity-related asthma in adults

Association of inflammatory cytokines with obesity and pulmonary function testing

BACKGROUND

The World Health Organization (WHO) reported that the prevalence of obesity in the Kingdom of Saudi Arabia (KSA) is 33.7% (women 39.5% and men 29.5%), respectively. The effects of obesity on airway inflammation and respiratory mechanics as well as the function of adipose tissue has a key role in the development of various lung diseases. Therefore, this study aimed to compare the level of cytokines between obese (BMI ≥ 30) and non-obese participants and to assess their association with BMI, airways inflammation and pulmonary function.

METHOD

One-hundred and seven non-smoking students (18-25 years of age) were recruited using convenience sampling technique for comparative cross-sectional study. Of them, 80 students were eligible and included in the analysis; 54 were non-obese (BMI<30) and 26 were obese (BMI ≥ 30). All the participants underwent anthropometric measurements, fractional exhaled nitric oxide (FeNO) measurement, spirometry and cytokines measurement (IL-6, IL-1β, GM-CSF, IL-7, IL-8 and IL-10). Measurements were compared between obese and non-obese groups. Then a correlation test was made between pro- and anti-inflammatory cytokines with BMI, pulmonary function test finding and FeNO.

RESULTS

The prevalence of obesity was 32.5% in the study population. Levels of pro-inflammatory cytokine IL-6 levels was significantly higher in obese than non-obese participants (p = 0.044). The level of FeNO log was significantly higher in obese participants than non-obese (p = 0.002). The pro-inflammatory cytokine IL-6 showed positive correlation with BMI while GMCSF showed negative correlation with FVC (p<0.05).

CONCLUSION

The levels of pro-inflammatory cytokine IL-6 was found to be significantly higher in obese participants than non-obese participants. Furthermore, it showed positive correlation with BMI whereas pro-inflammatory cytokine GMCSF showed negative correlation with FVC.

Effect of bariatric surgery on lung function and asthma control after 8 years of follow-up

Background: Bariatric surgery has a proven beneficial effect on asthma symptoms and lung function in patients with class III obesity and asthma. The effects of bariatric surgery on asthma control and small airway function persist for at least 12 months after bariatric surgery. However, long-term follow-up data are lacking. Objectives: To evaluate the very-long term effects of bariatric surgery on asthma symptoms and lung function. Methods: In a prospective, longitudinal follow-up study, we planned an 8-year follow-up visit for patients previously included in the OBAS 1.0 trial, which evaluated the effects of bariatric surgery on asthma control and lung function in patients with asthma and class III obesity in The Netherlands. Results: Fifteen of 78 patients from the OBAS trial completed the 8-year follow-up visit. Nine patients underwent bariatric surgery, and six patients did not. After 8 years of follow-up, asthma control (Asthma Control Questionnaire [ACQ] score at 12 months of 0,4 versus an ACQ score of 0.7 at 8 years of follow-up; p = 0.075) and small airway function (R₅-R₂₀ (frequency-dependent resistance at 5Hz-20Hz); score at 12 months of 0,25 versus an ACQ score of 0.07 at 8 years of follow-up; p = 0.345) remained clinically stable compared with 12 months of follow-up. Patients who underwent bariatric surgery had a statistically significant weight regain between 12 months of follow-up and 8 years of follow-up (median [interquartile range] body mass index 30.2 kg/m² [23.9-43.4 kg/m²] versus 32.3 kg/m² [24.0-36.4 kg/m²]; p = 0.025). However, the impact of weight regain on asthma control, and asthma quality of life was clinically insignificant (ACQ, β (regression coefficient) = 0.04; 95% Confidence Interval [0.02; 0.06]; p < 0.001; and AQLQ; β = -0.04 CI [-0.07; -0.009]; p = 0.013). Conclusion: These results emphasize the importance of bariatric surgery in treating obesity-related asthma.

An increased asthma risk continued until young adulthood after early-childhood hospitalisation for wheezing

AIM

The aim of this cohort study was to evaluate doctor-diagnosed and self-reported asthma in young adults after early-childhood hospitalisation for wheezing.

METHODS

In this prospective-controlled follow-up, questionnaires were sent to 95 subjects aged 24-28 years, who had been hospitalised for their first episodes of wheezing under 24 months of age. Fifty-eight cases and 100 controls returned the questionnaires.

RESULTS

The risk of doctor-diagnosed asthma was 2.14-fold (95% confidence interval 0.61-7.41), and the risk of self-reported asthma 2.39-fold (1.14-4.99) in cases compared to controls. The increased risk of self-reported asthma remained as statistically significant in analyses adjusted for current smoking, overweight and allergic rhinitis. Study subjects presented with wheezing symptoms, use of bronchodilators and inhaled corticosteroids, and with seasonal symptoms presumptive for allergic rhinitis during the last 12 months, more often than controls. The identification of a respiratory syncytial virus or rhinovirus during hospitalisation in early childhood was not anymore associated with asthma risk in adulthood. As expected, previous asthma during early childhood was a strong risk factor for asthma in young adulthood.

CONCLUSION

In this controlled questionnaire study, early-childhood hospitalisation for lower respiratory infection with wheezing was an independently significant risk factor of asthma in young adults.

The Effect of Adiposity Markers on Fractional Exhaled Nitric Oxide (FeNO) and Pulmonary Function Measurements

Background

The effect of increasing body weight on pulmonary function and the fractional exhaled nitric oxide (FeNO) remains controversial and the role of different body compositions in the relationship between obesity with pulmonary function and FeNO is still unrevealed. Thus, we aim to determine the effect of overweight/obesity on lung function and FeNO, focusing on the relationship with different body compositions.

Methods

Eighty-two non-smoker students (20 ± 1.9 years) were divided into two groups: 38 subjects with normal weight (BMI = 18.5–24.99) and 44 overweight/obese subjects (BMI ≥ 25). Spirometric parameters and FeNO were measured and compared between groups and were correlated with different adiposity markers.

Results

FeNO measurements were elevated in the overweight/obese group [median (IQR) 19.5 (13)] in comparison to the normal weight group [11 (10), p value = 0.017]. A positive correlation was found between FeNO measurements and body mass index (BMI), waist circumference, hip circumference, waist-hip ratio, and visceral fat percentage (all p values < 0.01). The absolute values of forced vital capacity (FVC) forced expiratory volume in the first second (FEV₁), peak expiratory flow (PEF), forced expiratory flow during mid-expiration (FEF_25–75%), and FEV₁/FVC ratio showed no significant differences between groups. However, the percentage of the predicted values of FEV₁ and FVC was significantly higher and the value of percentage predicted FEF_25–75% was reduced significantly in the overweight/obese subjects.

Conclusion

Increase in BMI could significantly increase airway inflammation as measured by FeNO, as well as on distal airway function as determined by the percentage predicted values of FEF_25–75%. A significant correlation was also identified between visceral fat and FeNO measurement.

Factors reducing omalizumab response in severe asthma

BACKGROUND

Despite adding Omalizumab to conventional therapy, several severe asthmatics still show poor disease control. We investigated the factors that may affect a reduced Omalizumab response in a large population of severe asthmatics.

METHODS

340 patients were retrospectively evaluated. FEV₁%, FVC%, Asthma Control Test (ACT), fractional exhaled nitric oxide (FENO), possible step-downs/step-ups of concomitant therapies, exacerbations, disease control levels, ICS doses and SABA use, observed at the end of treatment, were considered as a response to Omalizumab.

RESULTS

Age was an independent risk factor for a reduced response concerning FEV₁%, FVC%, ACT and for a lower asthma control. Obesity (vs normal weight) was a determinant condition for exacerbations (OR:3.114[1.509-6.424], p = 0.002), for a disease partial/no control (OR:2.665[1.064-6.680], p = 0.036), for excessive SABA use (OR:4.448[1.837-10.768], p = 0.002) and for an unchanged/increased level of concomitant asthma medications. Furthermore, obesity also reduced the response in FEV₁ (β = -6.981,p = 0.04), FVC (β = -11.689,p = 0.014) and ACT (β = -2.585, p = 0.027) and was associated with a higher FENO level (β = 49.045,p = 0.040). Having at least one comorbidity was a risk factor for exacerbations (OR:1.383[1.128-1.697], p = 0.008) and for an ACT <20 (OR:2.410[1.071-3.690], p = 0.008). Specifically, chronic heart disease was associated with both a lower ACT and FVC% whereas gastroesophageal reflux with a partial/no asthma control. Nasal polyps were a predisposing factor leading both to exacerbations and to the use of higher inhaled corticosteroids doses. Moreover, smoking habits, pollen or dog/cat dander co-sensitizations may negatively influence Omalizumab response.

CONCLUSION

Age, obesity, comorbidities, smoking habits, nasal polyps, allergic poly-sensitization might reduce Omalizumab effectiveness independently to other asthma-influencing factors.

Addressing unmet needs in understanding asthma mechanisms: From the European Asthma Research and Innovation Partnership (EARIP) Work Package (WP)2 collaborators

Asthma is a heterogeneous, complex disease with clinical phenotypes that incorporate persistent symptoms and acute exacerbations. It affects many millions of Europeans throughout their education and working lives and puts a heavy cost on European productivity. There is a wide spectrum of disease severity and control. Therapeutic advances have been slow despite greater understanding of basic mechanisms and the lack of satisfactory preventative and disease modifying management for asthma constitutes a significant unmet clinical need. Preventing, treating and ultimately curing asthma requires co-ordinated research and innovation across Europe. The European Asthma Research and Innovation Partnership (EARIP) is an FP7-funded programme which has taken a co-ordinated and integrated approach to analysing the future of asthma research and development. This report aims to identify the mechanistic areas in which investment is required to bring about significant improvements in asthma outcomes.