Association between obesity and asthma in the elderly population: potential roles of abdominal subcutaneous adiposity and sarcopenia Woo-Jung Song, MD * ,†,‡ ; Sae-Hoon Kim, MD * ,†,‡ ; Soo Lim, PhD * ,‡ ; Young-Joo Park, PhD *; Min-Hye Kim, MD * ,† ; Sang-Min Lee, MD § ; Seok-Bum Lee, PhD ¶ ; Ki-Woong Kim, PhD ,# ; Hak-Chul Jang, PhD * ,‡ ; Sang-Heon Cho, PhD * ,† ; Kyung-Up Min, PhD * ,† ; and Yoon-Seok Chang, PhD * ,†,‡ * Department of Internal Medicine, Seoul National University College of Medicine, Seoul, South Korea † Institute of Allergy and Clinical Immunology, Seoul National University Medical Research Center, Seoul, South Korea ‡ Department of Internal Medicine, Seoul National University Bundang Hospital, Seongnam, South Korea § Department of Internal Medicine, Gachon University Gil Medical Center, Incheon, South Korea ¶ Department of Psychiatry, Dankook University Hospital, Cheonan, South Korea  Department of Neuropsychiatry, Seoul National University Bundang Hospital, Seongnam, South Korea # Department of Psychiatry, Seoul National University College of Medicine, Seoul, South Korea ARTICLE INFO Article history: Received for publication April 26, 2012 Received in revised form June 30, 2012 Accepted for publication July 18, 2012. ABSTRACT Background: Obesity is a significant risk factor for asthma; however, the association of asthma with obesity has rarely been studied in the elderly population. The role of central obesity has been suggested as a link between the 2 entities but has not been comprehensively studied in elderly populations. Objective: To investigate the mechanisms of association between obesity and asthma in the elderly population. Methods: This cross-sectional analysis included 994 participants (aged 65 years) in the Korean Longitudi- nal Study on Health and Aging. Asthma was defined by using questionnaires. Spirometry and chest radiog- raphy were performed to exclude asthma-mimicking conditions. Measurements of abdominal subcutaneous and visceral fat were calculated by computed tomography of the abdomen, and regional body compositions were measured by dual energy X-ray absorptiometry. Biochemical parameters were also measured. Results: The prevalence of asthma was 5.4%. The study population had a mean body mass index (BMI) of 24.0. Multivariate logistic regression tests revealed that the risk of asthma increased in proportion to an increase in BMI or abdominal subcutaneous adiposity. However, no association was found with visceral adiposity, serum adiponectin levels, or serum vitamin D levels. The dual energy X-ray absorptiometry–measured appendicular fat-free mass index was inversely related to asthma among patients with a BMI of 25.0 or greater. Conclusion: Our findings suggest that the relationships between obesity and asthma in the elderly popula- tion may be mediated by factors such as abdominal subcutaneous adiposity and sarcopenia. These associa- tions warrant further investigations to identify their potential roles.  2012 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved. Introduction Obesity is a major risk factor for asthma. 1 A number of epide- miologic studies have implicated significant associations be- tween body mass index (BMI) and incident asthma 2,3 or severity and control status. 4,5 Waist circumference (WC), as a marker of central obesity, also has been demonstrated to be predictive of asthma risk in cross-sectional 6 or longitudinal studies. 7 How- ever, it remains unknown how obesity and asthma are related. There are several hypotheses, such as mechanical effects in the lungs or systemic inflammatory roles of visceral fat adipokine secretion. 1,8 Particularly, the role of visceral adiposity has gained scientific interests because its significance was demonstrated with cardiovascular or metabolic diseases. 9–11 Visceral fat is the main source of proinflammatory cytokines because it has more abundant inflammatory cells than subcutaneous fat. 12 However, with regard to asthma, the role of visceral fat has not been elucidated yet. The adipokine-asthma association has been sug- gested by cross-sectional studies, but the results were contro- versial. 1 Moreover, there are no published studies on asthma that directly measured visceral fat areas by computed tomogra- phy (CT). Reprints: Yoon-Seok Chang, MD, PhD, Department of Internal Medicine, Seoul National University Bundang Hospital, 300 Gumi-dong, Bundang-gu, Seongnam 463-802, South Korea; E-mail: addchang@snu.ac.kr. Disclosures: Authors have nothing to disclose. Funding Sources: This study was supported by the Grant for Developing Seongnam Health Promotion Program for the Elderly from Seongnam City Government in Republic of Korea (grant No. 800-20050211) and the Grant from the Korean Health 21 R&D Project, Ministry of Health, Welfare and Family Affairs in Republic of Korea (grant No. A102065). Ann Allergy Asthma Immunol xx (2012) xxx Contents lists available at SciVerse ScienceDirect 1081-1206/12/$36.00 - see front matter  2012 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved. http://dx.doi.org/10.1016/j.anai.2012.07.017