title: Decreased concentration of serum melatonin in nighttime compared with daytime female medical technologists in South Korea.
abstract: Working during the night can disrupt the normal circadian rhythm by altering the melatonin level. A low level of melatonin is associated with an increased risk of cancer, possibly by decreasing the expression of tumor-suppressor genes, such as p53. To determine whether nighttime work is associated with melatonin level in serum as well as the expression of related genetic markers, we enrolled 100 female nighttime medical technologists employed at a hospital in South Korea. Melatonin concentration and melatonin receptor 1 (MT1) expression were significantly lower in nighttime than in daytime workers (1.84 pg/mL versus 4.04 pg/mL; 1.16 versus 1.61, respectively). However, p53 expression showed no difference between the groups. In summary, nighttime work could be an important risk factor for circadian disruption, but not a direct risk factor for cancer in medical technologists in South Korea.
authors.affiliation: a Seegene Medical Foundation , Seoul , Korea.|c Samkwang Medical Laboratories , Seoul , Korea.
authors.forename: GiSeon
authors.initials: G
authors.lastname: Song
authors.affiliation: b College of Veterinary Medicine, Konkuk University , Seoul , Korea.
authors.forename: Kyong-Ah
authors.initials: KA
authors.lastname: Yoon
authors.affiliation: c Samkwang Medical Laboratories , Seoul , Korea.
authors.forename: HyunYoung
authors.initials: H
authors.lastname: Chi
authors.affiliation: d The Institute for Occupational Health , Department of Preventive Medicine and Public Health , Seoul , Korea.|e The Institute for Occupational Health , Yonsei University College of Medicine , Seoul , Korea.|f Graduate School of Public Health , Yonsei University College of Medicine , Seoul , Korea.
authors.forename: Jaehoon
authors.initials: J
authors.lastname: Roh
authors.affiliation: g Department of Biomedical Laboratory Science, College of Health Science , Cheongju University , Cheongju , Korea.
authors.forename: Jin-Hee
authors.initials: JH
authors.lastname: Kim
mesh_terms: D000328:Adult; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology; D006801:Humans; D007962:Leukocytes / Q000378:metabolism; D053511:Matrix Metalloproteinase 14 / Q000235:genetics / Q000378:metabolism; D017056:Medical Laboratory Personnel; D008550:Melatonin / Q000097:blood* / Q000378:metabolism; D008875:Middle Aged; D056910:Republic of Korea; D000073577:Shift Work Schedule; D016159:Tumor Suppressor Protein p53 / Q000235:genetics / Q000378:metabolism; D055815:Young Adult
chemical_list: D016159:Tumor Suppressor Protein p53; D053511:Matrix Metalloproteinase 14; D008550:Melatonin
keywords: circadian rhythm; medical technologist; melatonin; melatonin receptor 1; p53; shift workers