title: Effect of desert dust exposure on allergic symptoms: A natural experiment in Japan.
abstract: Desert dust originating from arid and semiarid areas is transported to widespread regions, including Japan. Desert dust particles exert adjuvant effects in animals.
  
  
  
  To examine whether desert dust enhances allergic symptoms in real-life settings and to explore its effect modifiers.
  
  
  
  We conducted an observational study of 3,327 pregnant women during spring and fall in October 2011 to May 2013 in 3 regions in Japan as an adjunct study of the Japan Environment & Children's Study. We acquired participants' daily symptom scores by sending a questionnaire to their mobile phones on high desert-dust days (>0.07/km) and on some randomly selected other days (control days) for each participant.
  
  
  
  Pregnant women had an increased risk of allergic symptoms on high desert-dust days (adjusted odds ratio [OR], 1.10; 95% CI, 1.04-1.18). The increased OR was mostly driven by those who showed positive IgE to Japanese cedar pollen when pollen simultaneously dispersed (adjusted OR, 1.25; 95% CI, 1.13-1.38), whereas no clear risk increase was observed in the absence of pollen or for participants with negative IgE to Japanese cedar pollen. The risk elevation was observed from low levels of desert dust in a dose-dependent manner even on control days.
  
  
  
  Ambient desert dust level was associated with an increased risk of allergic symptoms in pollen-sensitized pregnant women when pollen was present in the air. The risk increase was dose dependent and was observed from low levels of desert dust. These results support a hypothesis that ambient desert dust particles exert adjuvant effects in human in real-life settings.
  
  
  
  clinicaltrials.gov Identifier: UMIN000010826.
authors.affiliation: Department of Health Informatics, Kyoto University School of Public Health, Kyoto, Japan.
authors.forename: Kumiko T
authors.initials: KT
authors.lastname: Kanatani
authors.affiliation: Department of Public Health, University of Toyama, Toyama, Japan.
authors.forename: Kei
authors.initials: K
authors.lastname: Hamazaki
authors.affiliation: Department of Public Health, University of Toyama, Toyama, Japan.
authors.forename: Hidekuni
authors.initials: H
authors.lastname: Inadera
authors.affiliation: Center for Environmental Measurement and Analysis, National Institute for Environmental Studies, Tsukuba, Ibaragi, Japan.
authors.forename: Nobuo
authors.initials: N
authors.lastname: Sugimoto
authors.affiliation: Center for Regional Environmental Research, National Institute for Environmental Studies, Tsukuba, Ibaragi, Japan.
authors.forename: Atsushi
authors.initials: A
authors.lastname: Shimizu
authors.affiliation: Department of Data Science, The Institute of Statistical Mathematics, Tokyo, Japan; Department of Biostatistics, Kyoto University School of Public Health, Kyoto, Japan.
authors.forename: Hisashi
authors.initials: H
authors.lastname: Noma
authors.affiliation: Department of Social Medicine, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Kazunari
authors.initials: K
authors.lastname: Onishi
authors.affiliation: Department of Health Informatics, Kyoto University School of Public Health, Kyoto, Japan; Department of Social and Behavioral Sciences, Harvard School of Public Health, Boston, Massachusetts.
authors.forename: Yoshimitsu
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Department of Pediatrics, Faculty of Medicine, University of Toyama, Toyama, Japan.
authors.forename: Toshiko
authors.initials: T
authors.lastname: Itazawa
authors.affiliation: Department of Gynecology and Obstetrics, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Miho
authors.initials: M
authors.lastname: Egawa
authors.affiliation: Institute for Advancement of Clinical and Translational Science, Kyoto University Hospital, Kyoto, Japan; Kyoto Unit Centre for Japan Environment & Children's Study, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Keiko
authors.initials: K
authors.lastname: Sato
authors.affiliation: Kyoto Unit Centre for Japan Environment & Children's Study, Graduate School of Medicine, Kyoto University, Kyoto, Japan.
authors.forename: Tohshin
authors.initials: T
authors.lastname: Go
authors.affiliation: Department of Respiratory Medicine, Kyoto University Hospital, Kyoto, Japan.
authors.forename: Isao
authors.initials: I
authors.lastname: Ito
authors.affiliation: Department of Social Medicine, Faculty of Medicine, Tottori University, Yonago, Japan.
authors.forename: Youichi
authors.initials: Y
authors.lastname: Kurozawa
authors.affiliation: Department of Gynecology and Obstetrics, Kyoto University Graduate School of Medicine, Kyoto, Japan.
authors.forename: Ikuo
authors.initials: I
authors.lastname: Konishi
authors.affiliation: Department of Pediatrics, Faculty of Medicine, University of Toyama, Toyama, Japan.
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Adachi
authors.affiliation: Department of Health Informatics, Kyoto University School of Public Health, Kyoto, Japan. Electronic address: nakayama.takeo.4a@kyoto-u.ac.jp.
authors.forename: Takeo
authors.initials: T
authors.lastname: Nakayama
mesh_terms: D000328:Adult; D000393:Air Pollutants / Q000009:adverse effects; D000485:Allergens / Q000276:immunology; D032485:Cryptomeria / Q000276:immunology; D029781:Cupressus / Q000276:immunology; D004391:Dust; D004781:Environmental Exposure / Q000009:adverse effects; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000453:epidemiology* / Q000276:immunology; D007073:Immunoglobulin E / Q000276:immunology; D007564:Japan / Q000453:epidemiology; D008875:Middle Aged; D016017:Odds Ratio; D011058:Pollen / Q000276:immunology; D011247:Pregnancy / Q000276:immunology*; D012621:Seasons; D011795:Surveys and Questionnaires
chemical_list: D000393:Air Pollutants; D000485:Allergens; D004391:Dust; D007073:Immunoglobulin E