title: Association of serum ferritin levels with smoking and lung function in the Korean adult population: analysis of the fourth and fifth Korean National Health and Nutrition Examination Survey.
abstract: BACKGROUND
  Iron-catalyzed oxidative stress contributes to lung injury after exposure to various toxins, including cigarette smoke. An oxidant/antioxidant imbalance is considered to play a critical role in the pathogenesis of COPD. Ferritin is a key protein in iron homeostasis, and its capacity to oxidize and sequester the metal preventing iron prooxidant activity implicates its possible role in the alteration of antioxidant imbalance. We investigated the relationship among cigarette smoking, lung function, and serum ferritin concentration in a large cohort representative of the Korean adult population.
  
  
  METHODS
  Among 50,405 participants of the Korean National Health and Nutrition Examination Survey from 2010 to 2014, 15,239 adult subjects older than 40 years with serum ferritin levels and spirometric data were selected for this study.
  
  
  RESULTS
  The mean age was 56.5 years for men (43%) and 56.9 years for women (57%). The prevalence of airway obstruction was 13.4%, which was significantly higher in men than in women, and increased in former or current smokers. The median levels of serum ferritin were highest in the airway obstruction group, followed by the restrictive pattern group, and lowest in the normal lung function group. The median ferritin levels were increased by smoking status and amounts in each spirometric subgroup. In multivariable regression analysis, serum ferritin was positively associated with forced expiratory volume in 1 second and forced expiratory volume in 1 second/forced vital capacity, whereas the smoking amount was negatively associated with the adjustment with age, sex, height, and weight.
  
  
  CONCLUSIONS
  Serum ferritin levels were increased in former or current smokers and were increased with smoking amount in all subgroups of participants categorized according to spirometric results. The result was also evident in the subgroups divided by obstructive severity. While smoking amount was inversely related to lung function, higher levels of serum ferritin were associated with enhanced spirometric results in a representative sample of the general Korean adult population. Future prospective studies will be needed to clarify the causality between serum ferritin and lung functions and their role in COPD morbidity.
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Chan Ho
authors.initials: CH
authors.lastname: Lee
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Eun Kyung
authors.initials: EK
authors.lastname: Goag
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Su Hwan
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Kyung Soo
authors.initials: KS
authors.lastname: Chung
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Ji Ye
authors.initials: JY
authors.lastname: Jung
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Moo Suk
authors.initials: MS
authors.lastname: Park
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Young Sam
authors.initials: YS
authors.lastname: Kim
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Se Kyu
authors.initials: SK
authors.lastname: Kim
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Joon
authors.initials: J
authors.lastname: Chang
authors.affiliation: Division of Pulmonology and Critical Care Medicine, Department of Internal Medicine, Institute of Chest Disease, Severance Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea.
authors.forename: Joo Han
authors.initials: JH
authors.lastname: Song
mesh_terms: D000328:Adult; D000368:Aged; D000402:Airway Obstruction / Q000097:blood* / Q000175:diagnosis / Q000453:epidemiology / Q000503:physiopathology; D015415:Biomarkers / Q000097:blood; D003430:Cross-Sectional Studies; D005260:Female; D005293:Ferritins / Q000097:blood*; D005541:Forced Expiratory Volume; D006801:Humans; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D009749:Nutrition Surveys; D015995:Prevalence; D056910:Republic of Korea / Q000453:epidemiology; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects / Q000097:blood* / Q000453:epidemiology; D013147:Spirometry; D015854:Up-Regulation; D014797:Vital Capacity
chemical_list: D015415:Biomarkers; D005293:Ferritins
keywords: airway obstruction; ferritin; smoking