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Table 1 Male breast cancer risk by night shift work in the Norwegian Offshore Petroleum Workers cohort

From: Excess risk of male breast cancer in the Norwegian Offshore Petroleum Workers (NOPW) cohort: a possible link to extreme night shift work?

 

Obs

Exp

SIR (95% CI)a

SIR analysis

Overall

14

6.66

2.10 (1.15–3.53)

Night shift work

   

 Never

5

2.83

1.77 (0.57–4.12)

 Ever

9

3.61

2.49 (1.14–4.73)

 Missing

0

0.22

-

 

Complete case (n = 24,438)

Multiple imputationc (n = 25,284; 14 cases)

No. of participants

No. of cases

HR (95% CI)

HR (95% CI)

Cox regression analysisb

Night shift work

 Never

10,489

5

1.00 (reference)

1.00 (reference)

 Ever

13,949

8

1.18 (0.38, 3.63)

1.33 (0.44, 3.98)

  1. Follow-up period was from 1st July 1999 to 31st December 2019
  2. Analyses were performed using Stata 17 (StataCorp, TX, USA)
  3. Obs. observed, CI confidence interval, Exp. expected, No. number, HR hazard ratio, SIR standardized incidence ratio
  4. aSIRs calculated from sex-, age- (5-year) and time- (1-year) specific incidence
  5. rates for the Norwegian population, assuming a Poisson distribution of the observed cases
  6. bCox proportional hazards model adjusted for age (timescale) and education
  7. c3% of the cohort had missing information on education and night shift work, and 5 datasets were imputed
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Breast Cancer Research

ISSN: 1465-542X

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