title: The association between blood lead level and clinical mental disorders in fifty thousand lead-exposed male workers.
abstract: BACKGROUND
  While there has been research into the relationship between blood lead (BPb) level and mental disorders, there have been few investigations that use clinically diagnosed mental disorders in the adult population with a retrospective cohort study design. Hence, our study investigated the association between BPb level and risk of clinically diagnosed mental disorders.
  
  
  METHODS
  The data of male workers exposed to lead (Pb; n=54,788) were collected from annual Pb associated medical check-ups from 2000 to 2004 in Korea. The workers' hospital admission histories due to mental disorders (International Classification of Diseases, 10th revision, F00-F99) were used to identify clinically diagnosed mental disorders. After merging the data, the hazard ratio (HR) with a 95% confidence interval (95% CI) was calculated by survival analysis using the Cox proportional hazards model according to the quartile level of BPb (1st quartile<4.10 μg/dl, 2nd quartile<6.04 μg/dl, 3rd quartile<10.00 μg/dl, and 4th quartile≥10 μg/dl).
  
  
  RESULTS
  In a total of 54,788 workers, there were 223 admission cases of mental disorders (F00-F99) during the follow-up period. The HR (95% CI) of total mental and behavioral disorders (F00-F99) was 1.63 (1.12-2.39) in the 4th quartile group compared to the HR of the 1st quartile group after adjusting for age. The HR (95% CI) of the 4th quartile group was 2.59 (1.15-5.82) for mood (affective) disorders (F30-F39).
  
  
  CONCLUSIONS
  The hospital admission data, not outpatient data, were used for current study while almost affective disorder treated at outpatient clinic level.
  
  
  CONCLUSIONS
  Our study highlighted that Pb exposure can cause clinical mental disorders that require hospital admission in adult male workers. Our relatively large sample size strengthens the evidence of the association between BPb level and risk of clinically diagnosed mental disorders.
authors.affiliation: The Institute for Occupational Health, Yonsei University College of Medicine, Seoul, South Korea; Department of Preventive Medicine, Yonsei University College of Medicine, Seoul, South Korea.
authors.forename: Jin-Ha
authors.initials: JH
authors.lastname: Yoon
authors.affiliation: Department of Occupational and Environmental Medicine, Dongguk University Ilsan Hospital, Goyang, South Korea. Electronic address: ysahn@dongguk.ac.kr.
authors.forename: Yeon-Soon
authors.initials: YS
authors.lastname: Ahn
mesh_terms: D000328:Adult; D015897:Comorbidity; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D007854:Lead / Q000097:blood*; D007855:Lead Poisoning / Q000097:blood* / Q000453:epidemiology*; D008297:Male; D001523:Mental Disorders / Q000097:blood* / Q000453:epidemiology*; D008875:Middle Aged; D009784:Occupational Diseases / Q000097:blood* / Q000453:epidemiology*; D016016:Proportional Hazards Models; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D016019:Survival Analysis
chemical_list: D007854:Lead
keywords: Affective disorder; Blood lead; Cohort study; Occupational health