title: Risks and Cough-Aggravating Factors in Prolonged Cough. Epidemiological Observations from the Nagahama Cohort Study.
abstract: BACKGROUND
  Chronic cough hypersensitivity, a potentially important concept of chronic or prolonged cough, is featured by heightened cough response to low-intensity stimuli, which may be generated in the absence of airflow limitations or allergic conditions. However, there is little epidemiological evidence to support this.
  
  
  OBJECTIVE
  In this large-scale community survey, we aimed to determine risks and cough-aggravating factors of prolonged cough while focusing on serum IgE levels.
  
  
  METHODS
  Prevalence of prolonged cough, defined as cough lasting 3 weeks or longer, was determined in 9,804 residents from a baseline measurement of the Nagahama Cohort Study, conducted from 2008 to 2010. Risk assessment of prolonged cough was confined to subjects without asthma (n = 9,402). A follow-up measurement of the Nagahama Study was successively conducted from 2013 to 2015, recruiting the same residents living in Nagahama City, Japan (n = 8,292). Validation analysis was performed in the follow-up measurement.
  
  
  RESULTS
  In a baseline measurement, prolonged cough was reported by 9.5% of subjects without asthma and 32.3% of subjects with asthma. In subjects without asthma, various cough-aggravating factors were associated with prolonged cough. On the multivariate analysis, several cough-aggravating factors, including nighttime or early morning, weather, pollen season, and common cold, were associated with prolonged cough, independent of female sex, younger age, chronic obstructive pulmonary disease, postnasal drip, daytime sputum, and lower serum total IgE. Serum-specific IgE levels against Japanese cedar pollen were significantly higher in subjects who responded "yes" to "cough in the pollen season" than in those who did not respond, whereas, among subjects who responded "yes" to "cough in the pollen season," prolonged coughers showed lower serum IgE levels against Japanese cedar pollen than temporal coughers. Validation analysis in a follow-up measurement confirmed the associations between prolonged cough and cough-aggravating factors observed in the baseline measurement.
  
  
  CONCLUSIONS
  The presence of several cough-aggravating factors in the absence of severe allergic conditions may support the presence of cough hypersensitivity.
authors.affiliation: 1 Department of Respiratory Medicine.
authors.forename: Hisako
authors.initials: H
authors.lastname: Matsumoto
authors.affiliation: 1 Department of Respiratory Medicine.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Izuhara
authors.affiliation: 1 Department of Respiratory Medicine.|2 Department of Respiratory Medicine, Allergy, and Clinical Immunology, Nagoya City University Graduate School of Medical Sciences, Aichi, Japan; and.
authors.forename: Akio
authors.initials: A
authors.lastname: Niimi
authors.affiliation: 3 Center for Genomic Medicine.
authors.forename: Yasuharu
authors.initials: Y
authors.lastname: Tabara
authors.affiliation: 1 Department of Respiratory Medicine.
authors.forename: Tadao
authors.initials: T
authors.lastname: Nagasaki
authors.affiliation: 1 Department of Respiratory Medicine.
authors.forename: Yoshihiro
authors.initials: Y
authors.lastname: Kanemitsu
authors.affiliation: 1 Department of Respiratory Medicine.|4 Department of Respiratory Care and Sleep Control Medicine, and.
authors.forename: Kimihiko
authors.initials: K
authors.lastname: Murase
authors.affiliation: 1 Department of Respiratory Medicine.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Oguma
authors.affiliation: 1 Department of Respiratory Medicine.
authors.forename: Isao
authors.initials: I
authors.lastname: Ito
authors.affiliation: 1 Department of Respiratory Medicine.
authors.forename: Shigeo
authors.initials: S
authors.lastname: Muro
authors.affiliation: 5 Pharmacogenomics Project, Kyoto University Graduate School of Medicine, Kyoto, Japan.|6 Center for Preventive Medical Science, Chiba University, Chiba, Japan.
authors.forename: Akihiro
authors.initials: A
authors.lastname: Sekine
authors.affiliation: 3 Center for Genomic Medicine.
authors.forename: Fumihiko
authors.initials: F
authors.lastname: Matsuda
authors.affiliation: 7 Department of Medical Ethics and Medical Genetics and.
authors.forename: Shinji
authors.initials: S
authors.lastname: Kosugi
authors.affiliation: 8 Department of Health Informatics, Kyoto University School of Public Health, Kyoto, Japan.
authors.forename: Takeo
authors.initials: T
authors.lastname: Nakayama
authors.affiliation: 4 Department of Respiratory Care and Sleep Control Medicine, and.
authors.forename: Kazuo
authors.initials: K
authors.lastname: Chin
authors.affiliation: 1 Department of Respiratory Medicine.
authors.forename: Michiaki
authors.initials: M
authors.lastname: Mishima
mesh_terms: D000328:Adult; D000368:Aged; D002908:Chronic Disease; D015331:Cohort Studies; D003371:Cough / Q000453:epidemiology* / Q000209:etiology*; D005260:Female; D006801:Humans; D007073:Immunoglobulin E / Q000097:blood*; D007564:Japan / Q000453:epidemiology; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D015999:Multivariate Analysis; D011058:Pollen / Q000009:adverse effects / Q000276:immunology*; D006255:Rhinitis, Allergic, Seasonal / Q000150:complications*; D018570:Risk Assessment; D012307:Risk Factors; D011795:Surveys and Questionnaires
chemical_list: D007073:Immunoglobulin E
keywords: allergic sensitization; cough epidemiology; cough hypersensitivity syndrome; cough-aggravating factors; prolonged cough