Investigators found poor asthma control in obese or overweight patients despite optimal treatment and significantly higher BMI values in those with uncontrolled asthma than in those with partially or totally controlled asthma.
Accumulating evidence indicates that obesity is a major risk factor for the development of asthma. Mechanisms proposed to explain this association include lung mechanics, obesity-associated inflammation, oxidative stress, the greater prevalence of asthma-related comorbidities in the obese, and genetic and environmental factors.
Moreover, in the obese, asthma is often severe, poorly controlled, and less responsive to treatment. In addition, early morning symptoms, dyspnea and wheezing, limitation in activities of daily living, and nighttime awakening are more prevalent and persistent in obese asthma patients than in normal-weight ones.
To determine the effect of obesity or overweightness on asthma control in a group of adult patients, a team of investigators retrospectively studied 218 patients diagnosed with asthma and followed up for at least 1 year at the Ankara University School of Medicine in Ankara, Turkey. Results of the study were published in the July/August, 2016, issue of Allergy and Asthma Proceedings.
Only patients with complete body mass index (BMI) records at the time of diagnosis (baseline) were eligible to participate in the study. The study population was primarily composed of women (87%), whose baseline and current BMI were higher than those of the men in the study. The mean age of the study population was 52 ± 12 years. Obesity was noted in 54%; 28% were overweight, and 18% were normal weight.
The team noted that BMI increased correspondent with age or disease duration. In addition, they observed that asthma was poorly controlled in obese or overweight patients despite optimal treatment.
They also found that patients with uncontrolled asthma had significantly higher BMI values than those with partially or totally controlled asthma (P = 0.03). However, they found this significant relationship in women but not in men. They attributed the difference to the predominance of women in their study group.
In addition, the team found that asthma control was worse in patients who gained weight during the follow-up period (P = 0.04). This was particularly the case for non-atopic patients. Non-atopic patients who gained weight during follow-up had the worst asthma control of all groups in the study.
This finding led the investigators to conclude that weight gain combined with having non-atopic asthma worsened asthma control. It also led them to comment, “To our knowledge, this is the first study to demonstrate the relationship of atopy and asthma control in patients who are obese.”
On the basis of this finding, the team stressed the importance of preventing obesity in non-atopic patients in particular and of encouraging non-atopic obese patients to lose weight to achieve better asthma control.
In conclusion, the team suggested that because gaining weight led to a decrease in asthma control in their study, losing weight might improve the course of asthma. To support this suggestion, they noted that most of the studies in the literature showed improvement in asthma control and severity with weight loss.