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I read with interest the recent publication by Subharta Moitra et al in Thorax.(1) The authors concluded that adult asthmatics have a higher risk of developing obesity than non-asthmatics. An association was found especially in non-atopic asthmatics with longer disease duration and the use of oral corticosteroids (OCS).
Obesity is the strongest risk factor for sleep apnea, and sleep apnea is associated also with asthma.(2) Obesity has been regarded also as a risk factor for developing asthma,(3) but the reverse association is still not clear. Both asthma and obesity begin often in early childhood, and they may share a common background.(3)
The relationships between smoking, physical activity, use of OCS and lung function were discussed in the paper. But why would asthma per se increase weight? Obesity may be considered also as a central nervous system disorder. Obesity and sleep apnea are associated with asthma. Short night sleep, sleep deprivation and chronic insomnia are associated with the development of obesity.(4) Studies have also shown an association between anxiety, depressive symptoms and the development of obesity.(4)
The ECHRS cohort was initiated in 1990. The study was focused on asthma, and unfortunately the original questionnaires did not include questions on sleep, sleep disorders or mental health. Also, no sleep studies or psychological testing were done. This explains the lack of information on anxiety, depres...
The ECHRS cohort was initiated in 1990. The study was focused on asthma, and unfortunately the original questionnaires did not include questions on sleep, sleep disorders or mental health. Also, no sleep studies or psychological testing were done. This explains the lack of information on anxiety, depression, sleep duration, sleep deprivation, snoring and sleep apnea. As these factors are linked to both asthma and obesity, it is difficult to conclude that asthma would be directly related to the development of obesity. A minor problem in this prospective study is also that only 30% of the original members in the cohort (collected 1990-1994) were included in the ECHRS III. Altogether 10,681 subjects were lost to follow-up leaving 5,901 subjects in the third phase. Did those with missing information differ in characteristics from the remaining study subjects?
In sum, obesity is a huge problem, and asthma is an important disease. Understanding the associations between obesity and asthma is important. Could the association be explained by shared associations with sleep-disordered breathing and/or insomnia and/or sleep deprivation and/or anxiety and/or depression, or other common risk factors for both asthma and obesity?
1. Moitra S, Carsin AE, Abramson MJ, Accordini S, Amaral AFS, Anto J, . . . Garcia-Aymerich J. Long-term effect of asthma on the development of obesity among adults: an international cohort study, ECRHS. Thorax 2022. 10.1136/thoraxjnl-2021-217867
2. Thompson C, Legault J, Moullec G, Baltzan M, Cross N, Dang-Vu TT, . . . Gosselin N. A portrait of obstructive sleep apnea risk factors in 27,210 middle-aged and older adults in the Canadian Longitudinal Study on Aging. Scientific Reports 2022;12. 10.1038/s41598-022-08164-6
3. Litonjua AA, Gold DR. Asthma and obesity: common early-life influences in the inception of disease. J Allergy Clin Immunol 2008;121:1075-84; quiz 85-6. 10.1016/j.jaci.2008.03.005
4. Sivertsen B, Lallukka T, Salo P, Pallesen S, Hysing M, Krokstad S, Simon O. Insomnia as a risk factor for ill health: results from the large population-based prospective HUNT Study in Norway. J Sleep Res 2014;23:124-32. 10.1111/jsr.12102