title: Insomnia as a sequela of sarin toxicity several years after exposure in Tokyo subway trains.
abstract: More than 5,000 passengers on Tokyo subway trains were injured with toxic chemicals including the nerve gas "sarin" on March 20, 1995. The purpose of this study was to identify the effect of sarin exposure on insomnia in a cross-sectional study. A self-administered questionnaire concerning sleep-related items was distributed to victims of sarin exposure in October and November, 2003. Questionnaires were completed by 161 of the 163 participants (98.8%), who were selected from 1,500 subjects. Among them, the authors selected 75 women 30 to 69 years of age. Control participants were collected from inhabitants living in Maebachi City, Gunma Prefecture, Japan. For the younger exposed group (under 50 yr. of age), percentages of poor sleep, difficulty falling asleep, intermittent awakening, early morning awakening, a feeling of light overnight sleep, and insomnia were significantly higher than those for the control group. In contrast, the older exposed group (ages 50 to 69 years) had significantly higher prevalence of poor sleep, a feeling of light overnight sleep, and early morning awakening for the exposed group when compared with the control group. The high prevalence of insomnia and insomnia-related factors for victims especially under 50 years of age suggests a need for research on sleep quality after sarin exposure. Although posttraumatic stress disorder is assumed to be a psychological effect of exposure to a toxic substance, a cause-and-effect relationship has not been established.
authors.affiliation: Department of Hygiene and Public Health, Nippon Medical School, 1-1-5 Sendagi, Bunkyo-Ku, Tokyo 113-8602, Japan. kawada@nms.ac.jp
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kawada
authors.forename: Masao
authors.initials: M
authors.lastname: Katsumata
authors.forename: Hiroko
authors.initials: H
authors.lastname: Suzuki
authors.forename: Qing
authors.initials: Q
authors.lastname: Li
authors.forename: Hirofumi
authors.initials: H
authors.lastname: Inagaki
authors.forename: Ari
authors.initials: A
authors.lastname: Nakadai
authors.forename: Takako
authors.initials: T
authors.lastname: Shimizu
authors.forename: Kimiko
authors.initials: K
authors.lastname: Hirata
authors.forename: Yukiyo
authors.initials: Y
authors.lastname: Hirata
mesh_terms: D000328:Adult; D000368:Aged; D015984:Causality; D002619:Chemical Warfare Agents / Q000633:toxicity*; D015897:Comorbidity; D003430:Cross-Sectional Studies; D005260:Female; D005500:Follow-Up Studies; D006306:Health Surveys; D006801:Humans; D008875:Middle Aged; D011890:Railroads; D012524:Sarin / Q000633:toxicity*; D007319:Sleep Initiation and Maintenance Disorders / Q000139:chemically induced* / Q000453:epidemiology; D013313:Stress Disorders, Post-Traumatic / Q000453:epidemiology / Q000523:psychology; D023481:Terrorism; D014041:Tokyo / Q000453:epidemiology
chemical_list: D002619:Chemical Warfare Agents; D012524:Sarin