Objectives We investigated the association of shift and night work with the incidence of prostate cancer using data of the population-based prospective Heinz Nixdorf Recall Study (HNR) from the highly industrialised Ruhr Area in Germany.

Methods Participants for the baseline survey of the HNR, which included questions with respect to shift work, lifestyle, and socio-economic status, were recruited between 2000–2003 (n = 4,814). A follow-up survey was conducted from 2011–2014.

We included 1,757 men who answered a detailed follow-up interview and did not report a history of prostate cancer at baseline. Incident prostate cancers were recorded through September 2014. We calculated hazard ratios (HR) of shift exposure by Cox proportional hazards regression with age at event as time scale, adjusting for physical activity (Metabolic Equivalent Task (MET)-hours), alcohol consumption (g/week), smoking status (never, former, current smoker), family history of prostate cancer, vitamin D status at baseline (low, high), school education (≤13, 14–17, ≥18 years), and equivalent income (low, medium, high).

Results During follow-up 76 men with shift work information were diagnosed with primary prostate cancer. We observed twofold increased HRs for prostate cancer both among shift and night workers (HR (unadjusted) = 2.01; 95% CI: 1.28–3.18), HR (adjusted) = 2.29; 95% CI: 1.43–3.67). Being employed for ≥20 years in shift or night work was associated with strongly elevated risks (e.g. for night work HR (unadjusted) = 2.99; 95% CI: 1.68–5.29, HR (adjusted) = 4.01; 95% CI: 2.15–7.46). Further adjustment for body mass index did not change these results.

Conclusions We identified increased risks for prostate cancer among men with increasing duration of employment in shift or night work. Risk estimates were strongly elevated among long-term employed shift workers.