Rotating Nightshift Work and Hematopoietic Cancer Risk in US Female Nurses

Yin Zhang; Brenda M Birmann; Kyriaki Papantoniou; Eric S Zhou; Astrid C Erber; Eva S Schernhammer

doi:10.1093/jncics/pkz106

Rotating Nightshift Work and Hematopoietic Cancer Risk in US Female Nurses

JNCI Cancer Spectr. 2020 Jan 8;4(2):pkz106. doi: 10.1093/jncics/pkz106. eCollection 2020 Apr.

Authors

Yin Zhang^{1

2

3}, Brenda M Birmann¹, Kyriaki Papantoniou⁴, Eric S Zhou^{5

6}, Astrid C Erber⁴, Eva S Schernhammer^{1

3

4

5}

Affiliations

¹ Channing Division of Network Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
² Department of Medical Oncology, Dana-Farber Cancer Institute and Harvard Medical School, Boston, MA, USA.
³ Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA, USA.
⁴ Department of Epidemiology, Center for Public Health, Medical University of Vienna, Vienna, Austria.
⁵ Division of Sleep Medicine, Harvard Medical School, Boston, MA, USA.
⁶ Department of Psychosocial Oncology and Palliative Care, Dana-Farber Cancer Institute, Boston, MA, USA.

Abstract

Background: Nightshift work is a plausible risk factor for hematologic cancer, but epidemiological evidence remains sparse, especially for individual subtypes. We prospectively examined the association of rotating nightshift work with hematopoietic cancer risk.

Methods: This cohort study included US women from the Nurses' Health Study (NHS: n = 76 846, 1988-2012) and Nurses' Health Study II (NHSII: n = 113 087, 1989-2013). Rotating nightshift work duration was assessed at baseline (both cohorts) and cumulatively updated (NHSII). Cox regression was used to estimate hazard ratios (HRs) and 95% confidence intervals (CIs) for overall hematopoietic cancer and specific histologic subtypes. All statistical tests were two-sided.

Results: We documented 1405 (NHS) and 505 (NHSII) incident hematopoietic cancer cases during follow-up. In NHS, compared with women who never worked rotating nightshifts, longer rotating nightshift work duration was associated with an increased risk of overall hematopoietic cancer (HR_1-14y = 0.93, 95% CI = 0.83 to 1.04; HR_≥15y = 1.28, 95% CI = 1.06 to 1.55; P _trend = .009). In NHSII, results were similar though not statistically significant (HR_1-14y = 0.99, 95% CI = 0.82 to 1.21; HR_≥15y = 1.41, 95% CI = 0.88 to 2.26; P _trend = .47). In the subtype analyses in the NHS, the association of history of rotating nightshift work with risk of diffuse large B-cell lymphoma varied by duration (HR_1-14y = 0.71, 95% CI = 0.51 to 0.98; HR_≥15y = 1.69, 95% CI = 1.07 to 2.67; P _trend = .01) compared with those who never worked rotating nightshifts. Women reporting a longer history of rotating nightshifts also had suggestive (statistically nonsignificant) increased risks of overall non-Hodgkin lymphoma (HR_≥15y = 1.19, 95% CI = 0.95 to 1.49), Hodgkin lymphoma (HR_≥15y = 1.32, 95% CI = 0.43 to 4.06), and multiple myeloma (HR_≥15y = 1.42, 95% CI = 0.85 to 2.39).

Conclusions: Longer duration (≥15 years) of rotating nightshift work was associated with increased risks of overall and several subtypes of hematopoietic cancer.