Employment and work schedule are related to telomere length in women

• Published in: Occupational and environmental medicine (London, England) Vol. 68; no. 8; pp. 582 - 589
• Main Authors: Parks, C G, DeRoo, L A, Miller, D B, McCanlies, E C, Cawthon, R M, Sandler, D P
• Format: Journal Article
• Language: English
• Published: London BMJ Publishing Group Ltd 01.08.2011; BMJ Publishing Group; BMJ Publishing Group LTD
• Subjects: Adult; Age; Aged; ageing; Aging; Aging - genetics; Biological and medical sciences; Biomarkers - urine; Breast cancer; Cardiovascular diseases; Children; Chronic illnesses; Cross-Sectional Studies; Deoxyribonucleic acid; DNA; Employment; epidemiological studies; epidemiology; Epinephrine - urine; Ethnicity; Female; Health risks; Hispanic people; Hormones; Humans; Leukocytes - ultrastructure; Medical sciences; Middle Aged; Miscellaneous; Multiple jobs; Occupational Diseases - genetics; Occupational Diseases - urine; Occupational medicine; Overtime; Oxidative stress; Public health. Hygiene-occupational medicine; Questionnaires; Ratios; Referents; Risk factors; Socioeconomic Factors; Stress, Psychological - genetics; Stress, Psychological - urine; Telomerase; Telomere; Telomere - ultrastructure; Telomeres; Time Factors; tolerance; women; Womens health; work schedule; Work Schedule Tolerance - physiology; Work schedules; working; Working women; Workplace; Yeast; United States; North America; America; Human; Employment; Length; Health; Female; Working time table; Woman; Telomere; Stress
• ISSN: 1351-0711; 1470-7926
• DOI: 10.1136/oem.2010.063214

ObjectivesTo 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.MethodsThis 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.ResultsCompared 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.ConclusionsCurrent 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.