Night work and breast cancer risk among norwegian nurses: Assessment by different exposure metrics

Jenny Anne S. Lie, Helge Kjuus, Shan Zienolddiny, Aage Haugen, Richard G. Stevens, Kristina Kjærheim

Research output: Contribution to journalArticle

94 Citations (Scopus)

Abstract

Associations between night work and breast cancer risk were investigated in a nested case-control study within a cohort of 49,402 Norwegian nurses. A total of 699 (74%) of the live cases diagnosed in 1990-2007 and 895 (65%) controls, cancer free at the time of sampling, were interviewed about work history and potential risk factors. The odds ratios for risk of breast cancer in relation to different exposure metrics were estimated by multivariate unconditional logistic regression models. No increase of risk was found after long duration of work by nurses working ≥3 night shifts per month. Small, nonsignificantly increased risks were observed for exposure to ≥30 years in hospitals or other institutions (odds ratio (OR) = 1.1), ≥12 years in schedules including night work (OR = 1.3), ≥1,007 night shifts during the lifetime (OR = 1.2), and lifetime average number of ≥4 night shifts per month (OR = 1.2). Nonsignificantly increased risks of breast cancer were observed in nurses who worked ≥5 years with ≥4 (OR = 1.4) and ≥5 (OR = 1.6) consecutive night shifts. Significantly increased risks were seen in nurses who worked ≥5 years with ≥6 consecutive night shifts (OR = 1.8, 95% confidence interval: 1.1, 2.8). The results suggest that risk may be related to number of consecutive night shifts.

Original languageEnglish (US)
Pages (from-to)1272-1279
Number of pages8
JournalAmerican journal of epidemiology
Volume173
Issue number11
DOIs
StatePublished - Jun 6 2011

Fingerprint

Odds Ratio
Nurses
Breast Neoplasms
Logistic Models
Case-Control Studies
Appointments and Schedules
Confidence Intervals
Neoplasms

Keywords

  • Norway
  • breast neoplasms
  • case-control studies
  • chronobiology phenomena
  • nurses
  • risk

ASJC Scopus subject areas

  • Epidemiology

Cite this

Night work and breast cancer risk among norwegian nurses : Assessment by different exposure metrics. / Lie, Jenny Anne S.; Kjuus, Helge; Zienolddiny, Shan; Haugen, Aage; Stevens, Richard G.; Kjærheim, Kristina.

In: American journal of epidemiology, Vol. 173, No. 11, 06.06.2011, p. 1272-1279.

Research output: Contribution to journalArticle

Lie, Jenny Anne S. ; Kjuus, Helge ; Zienolddiny, Shan ; Haugen, Aage ; Stevens, Richard G. ; Kjærheim, Kristina. / Night work and breast cancer risk among norwegian nurses : Assessment by different exposure metrics. In: American journal of epidemiology. 2011 ; Vol. 173, No. 11. pp. 1272-1279.
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