title: A retrospective cohort study of shift work and risk of cancer-specific mortality in German male chemical workers.
abstract: OBJECTIVE
  Human evidence of carcinogenicity concerning shift work is inconsistent. In a previous study, we observed no elevated risk of total mortality in shift workers followed up until the end of 2006. The present study aimed to investigate cancer-specific mortality, relative to shift work.
  
  
  METHODS
  The cohort consisted of male production workers (14,038 shift work and 17,105 day work), employed at BASF Ludwigshafen for at least 1 year between 1995 and 2005. Vital status was followed from 2000 to 2009. Cause-specific mortality was obtained from death certificates. Exposure to shift work was measured both as a dichotomous and continuous variable. While lifetime job history was not available, job duration in the company was derived from personal data, which was then categorized at the quartiles. Cox proportional hazard model was used to adjust for potential confounders, in which job duration was treated as a time-dependent covariate.
  
  
  RESULTS
  Between 2000 and 2009, there were 513 and 549 deaths among rotating shift and day work employees, respectively. Risks of total and cancer-specific mortalities were marginally lower among shift workers when taking age at entry and job level into consideration and were statistically significantly lower when cigarette smoking, alcohol intake, job duration, and chronic disease prevalence at entry to follow-up were included as explanatory factors. With respect to mortality risks in relation to exposure duration, no increased risks were found in any of the exposure groups after full adjustment and there was no apparent trend suggesting an exposure-response relation with duration of shift work.
  
  
  CONCLUSIONS
  The present analysis extends and confirms our previous finding of no excess risk of mortality associated with work in the shift system employed at BASF Ludwigshafen. More specifically, there is also no indication of an increased risk of mortality due to cancer.
authors: Occupational Medicine and Health Protection Department, BASF Societas Europaea, GUA-H306, Ludwigshafen, Germany, mei.yong@basf.com.
authors: Mei
authors: M
authors: Yong
authors: Michael
authors: M
authors: Nasterlack
authors: Peter
authors: P
authors: Messerer
authors: Christoph
authors: C
authors: Oberlinner
authors: Stefan
authors: S
authors: Lang
mesh_terms: D000368:Aged; D002617:Chemical Industry; D005858:Germany / Q000453:epidemiology; D006801:Humans; D008297:Male; D008875:Middle Aged; D009369:Neoplasms / Q000401:mortality*; D016272:Occupational Health; D010561:Personnel Staffing and Scheduling; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D018570:Risk Assessment; D013997:Time Factors; D014940:Work Schedule Tolerance
references: Dtsch Arztebl Int. 2010 Sep;107(37):638-43
references: 20959891
references: J Occup Environ Med. 2004 Apr;46(4):379-85
references: 15076656
references: Am J Epidemiol. 2006 Sep 15;164(6):549-55
references: 16829554
references: Int Arch Occup Environ Health. 2010 Dec;83(8):887-94
references: 20186547
references: IARC Monogr Eval Carcinog Risks Hum. 2010;98:9-764
references: 21381544
references: Scand J Work Environ Health. 2005 Feb;31(1):30-5
references: 15751616
references: Scand J Work Environ Health. 2009 Jul;35(4):309-18
references: 19471844
references: Scand J Work Environ Health. 2010 Mar;36(2):163-79
references: 20126969
references: J Occup Med. 1992 Oct;34(10):979-88
references: 1403198
references: Scand J Work Environ Health. 2010 Mar;36(2):134-41
references: 20039012
references: Int J Epidemiol. 2009 Aug;38(4):963-70
references: 19380369
references: Lancet Oncol. 2007 Dec;8(12):1065-6
references: 19271347
references: Occup Med (Lond). 2011 Mar;61(2):78-89
references: 21355031
references: Br J Ind Med. 1972 Apr;29(2):201-7
references: 5021999
references: Acta Oncol. 2009;48(5):646-790
references: 19925375
references: Occup Environ Med. 1999 Sep;56(9):640-5
references: 10615298
references: J Natl Cancer Inst. 2003 Jun 4;95(11):825-8
references: 12783938
references: Cancer Epidemiol Biomarkers Prev. 2011 May;20(5):934-8
references: 21467237
references: J Occup Environ Med. 2009 Feb;51(2):221-31
references: 19209044
references: Am J Epidemiol. 2010 May 1;171(9):953-9
references: 20375193
references: J Natl Cancer Inst. 2011 Apr 6;103(7):602-6
references: 21335547
references: PLoS One. 2011 Apr 13;6(4):e18395
references: 21533241
references: Am J Ind Med. 1996 Dec;30(6):655-63
references: 8914712
references: Arh Hig Rada Toksikol. 2012 Jun 1;63(2):153-60
references: 22728797
references: Chronobiol Int. 2010 Jul;27(5):1135-48
references: 20636221
references: Br J Ind Med. 1990 Nov;47(11):721-5
references: 2173946
references: Am J Ind Med. 2011 Jul;54(7):499-509
references: 21472744
references: N Engl J Med. 2012 Mar 15;366(11):981-90
references: 22417251
references: Br J Cancer. 2004 Mar 8;90(5):941-3
references: 14997186
references: J Natl Cancer Inst. 1993 Jul 7;85(13):1063-8
references: 8515493
references: Chronobiol Int. 2004;21(6):1055-61
references: 15646250
references: Ann Occup Hyg. 1985;29(3):305-55
references: 4073702
references: Med Hypotheses. 2011 Sep;77(3):430-6
references: 21723672
references: Chronobiol Int. 2004;21(6):1049-53
references: 15646249
references: Int J Cancer. 2008 Nov 1;123(9):2148-51
references: 18697199
references: Int J Urol. 2011 Mar;18(3):206-11
references: 21332815
references: Am J Epidemiol. 2011 Jun 1;173(11):1272-9
references: 21454824
references: Rev Environ Health. 2007 Jan-Mar;22(1):1-37
references: 17508696
references: J Occup Environ Med. 2002 Nov;44(11):1048-58
references: 12448356