Selenium Status And Risk Of Prostate Cancer In A Danish Population

Malene OUTZEN, Danish Cancer Society Research Center, Denmark
TJØNNELAND A. 1 , LARSEN E. 2 , FRIIS S. 3 , LARSEN S. 4 , CHRISTENSEN J. 3 , OVERVAD K. 5 , OLSEN A. 1

1 Diet, Genes, and Environment, Danish Cancer Society Research Center, Copenhagen, Denmark
2 Division of Food Chemistry, National Food Institute, Technical University of Denmark, Søborg, Denmark
3 Statistics, Bioinformatics and Registry, Danish Cancer Society Research Center, Copenhagen, Denmark
4 Survivorship, Danish Cancer Society Research Center, Copenhagen, Denmark
5 Department of Public Health, Section for Epidemiology, Aarhus University, Aarhus, Denmark

Purpose: Low selenium status may be associated with higher risk of notably advanced prostate cancer. In a population with a relatively low selenium intake, we investigated the association between pre-diagnostic selenium status, and 1) risk of total, advanced and high-grade prostate cancer, and 2) all-cause and prostate cancer-specific mortality among men with prostate cancer.
Methods: Among 27,179 men included in the Danish “Diet, Cancer and Health” cohort, we identified 784 incident prostate cancer cases through 2007. Each case was risk set matched to one control. Two-thirds (525) of the cases had advanced disease at the time of diagnosis and among these 170 had high-grade disease; 305 cases died (212 from prostate cancer) during follow-up through 2012. Plasma selenium was assessed by inductively coupled plasma-mass spectrometry (ICP-MS), and plasma selenoprotein P using high performance liquid chromatography coupled to ICP-MS. Conditional logistic regression and cox proportional hazard models were used for the statistical analyses.
Results: Plasma selenium was not associated with total or advanced prostate cancer, but higher selenium levels were associated with lower risk of high-grade disease (HR (95% CI): 0.77 (0.64, 0.94), P = 0.009). In survival analyses, higher plasma selenium was associated with lower all-cause (HR (95% CI): 0.92 (0.85, 1.00), P = 0.04), but not prostate cancer-specific mortality. Higher levels of selenoprotein P were associated with lower risk of high-grade disease (95% CI): 0.85 (0.74, 0.97), P = 0.01), but not with risk of or mortality from advanced prostate cancer. 
Conclusion: Levels of plasma selenium and selenoprotein P were not associated with risk of total and advanced prostate cancer, but higher levels of these two biomarkers were associated with lower risk of high-grade disease.
Funding sources: Bjarne Saxhof Foundation, Danish Cancer Society, Wereld Kanker Onderzoek Fonds (WCRF NL; grant 2015/1412) as part of the WCRF International grant program.