en Pulmonary Disease Pulmonary Disease Original Research Original Research <p dir="ltr" style="text-align: justify;"><strong>Background: </strong>Chronic obstructive pulmonary disease (COPD) is a major public health problem worldwide. Smoking is the number one cause of COPD; however, genetic, environmental and dietary factors contribute to the etiology of this disease. In this study, we assessed the association between three diet quality indices -the Healthy Eating Index-2005 (HEI-2005), the Healthy Eating Index-2010 (HEI-2010), and Mediterranean Diet Score (MED)- and the severity of disease in COPD patients.</p> <p dir="ltr" style="text-align: justify;"><strong>&nbsp; Methods</strong>: This cross-sectional study was performed at&nbsp; Rasul-e-Akram Hospital in Tehran on 121 COPD patients with the mean age of (SD) of 66.1(10.9) years. A pulmonary specialist diagnosed all participants based on a spirometry test. They were categorized into four groups (1, 2, 3, 4 stages of disease). Three diet quality indices, spirometry test and determination of disease severity were performed for all the participants. ANCOVA and Kruskal-Wallis test were used to assess the relationship between dietary quality indices and severity of the disease. The relationship between HEI-2010, HEI-2005, MED score, their components and lung function was assessed using a multiple linear regression analysis. All analyses were done using SPSS 18.</p> <p dir="ltr" style="text-align: justify;"><strong>&nbsp; Results</strong>: Reduction of the Healthy Eating Index-2010 and MED score were observed along with the increase in disease severity, but they were not significant. The relationship between the three diet quality indices and lung function showed a significant association between MED score and Forced expiratory volume in one second (FEV1), The Forced Vital Capacity (FVC) (&beta;=2.9, 95% CI (1.1, 4.8), p=0.002), (&beta;=2.8, 95% CI (0.9, 4.8), p=0.007), respectively.</p> <p dir="ltr" style="text-align: justify;"><strong>&nbsp; Conclusion</strong>: Mediterranean dietary pattern and obtaining a better score on HEI-2010 diet were associated with a better lung function test.</p> <p></p> COPD, Diet Quality Index, nutrition, Mediterranean Diet. 557 569 http://mjiri.iums.ac.ir/browse.php?a_code=A-10-1-1011&slc_lang=en&sid=1 Leila Yazdanpanah yazdanpanah_l@yahoo.com 200319475328460022656 200319475328460022656 No Faculty of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan, Iran. Zamzam Paknahad 200319475328460022657 200319475328460022657 Yes Food Security Research Center, Isfahan University of Medical Sciences, Isfahan, Iran, & Department of Clinical Nutrition, Faculty of Nutrition and Food Sciences, Isfahan University of Medical Sciences, Isfahan, Iran. Ali Javad Moosavi dr_moosavi_pul@yahoo.ca 200319475328460022658 200319475328460022658 No Pulmonologist, Hazrat-e-Rasool Akram Hospital, Iran University of Medical Sciences, Tehran, Iran. Mohammad Reza Maracy mrmaracy @yahoo.co.uk 200319475328460022659 200319475328460022659 No Department of Epidemiology and Biostatistics, School of Health, Isfahan University of Medical Sciences, Isfahan, Iran. Mohammad Masoud Zaker masoud_zaker@yahoo.com 200319475328460022660 200319475328460022660 No , Milad Hospital, Tehran, Iran.