title: Employment and work schedule are related to telomere length in women.
abstract: OBJECTIVE
  To examine the association of employment and work schedule with shorter DNA telomeres, a marker of cellular ageing and disease risk factor, and consider whether differences were related to health, behaviours and sociodemographic factors, or varied by stress levels or menopausal status.
  
  
  METHODS
  This cross-sectional analysis of 608 women aged 35-74 in the Sister Study examined determinants of relative telomere length (rTL) measured by quantitative PCR in leucocyte DNA. Age-adjusted regression models estimated base pair (bp) rTL differences for current and lifetime schedule characteristics (ie, part-time, full-time or overtime hours; multiple jobs; irregular hours; shiftwork; work at night). Covariates included race, smoking, perceived stress, sleep, physical activity, health and menopausal status, education, marital status, live births, children under 18, measured body mass index and urinary stress hormones.
  
  
  RESULTS
  Compared with non-employed women with moderate or substantial past work histories (n=190), those currently working full-time (n=247; median 40 h/week) had a shorter rTL, an age-adjusted difference of -329 bp (95% CI -110 to -548). Longer-duration full-time work was also associated with shorter rTL (age-adjusted difference of -472 bp, 95% CI -786 to -158 for 20+ vs 1-5 years). Findings were not explained by health and demographic covariates. However, rTL differences for working at least full-time were greater in women with higher stress and epinephrine levels.
  
  
  CONCLUSIONS
  Current and long-term full-time work were associated with shorter rTL, with differences of similar magnitude to smoking and history of heart disease or diabetes. Longitudinal data with specific stress measures are needed to further evaluate the impact of work schedule on rTL.
authors.affiliation: Epidemiology Branch, National Institute of Environmental Health Sciences, National Insititues of Health, Research Triangle Park, NC 27599, USA. parks1@mail.nih.gov
authors.forename: C G
authors.initials: CG
authors.lastname: Parks
authors.forename: L A
authors.initials: LA
authors.lastname: DeRoo
authors.forename: D B
authors.initials: DB
authors.lastname: Miller
authors.forename: E C
authors.initials: EC
authors.lastname: McCanlies
authors.forename: R M
authors.initials: RM
authors.lastname: Cawthon
authors.forename: D P
authors.initials: DP
authors.lastname: Sandler
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000235:genetics; D015415:Biomarkers / Q000652:urine; D003430:Cross-Sectional Studies; D004651:Employment; D004837:Epinephrine / Q000652:urine; D005260:Female; D006801:Humans; D007962:Leukocytes / Q000648:ultrastructure; D008875:Middle Aged; D009784:Occupational Diseases / Q000235:genetics / Q000652:urine; D012959:Socioeconomic Factors; D013315:Stress, Psychological / Q000235:genetics / Q000652:urine; D016615:Telomere / Q000648:ultrastructure*; D013997:Time Factors; D014940:Work Schedule Tolerance / Q000502:physiology*
chemical_list: D015415:Biomarkers; D004837:Epinephrine