Allen 2008

Methods	Matched, nested case‐control study Countries: Denmark, Germany, Greece, Italy, the Netherlands, Spain, Sweden, the UK
Participants	Participants: approximately 130,000 men Inclusion criteria: male participants of the EPIC study Name of parent cohort: European Prospective Investigation into Cancer and Nutrition (EPIC) Recruitment: 1992 to 2000 Outcome assessment: at each country's study closure date (between June 1999 and January 2003) Number of cases: Prostate cancer: 959 (male/female: 959/0)  Case definition: incidence Years of follow‐up: median 2.6 years (Greece) to 9.2 years (Sweden) Type of selenium marker: plasma
Interventions	d.n.a.
Outcomes	Statistical methods: conditional logistic regression Variables controlled in analysis: BMI, smoking, alcohol consumption, physical activity, marital status, education Variables controlled by matching: age, study centre, time of day of blood collection, time between blood collection and last meal, sex
Risk estimates [95% CI]	Reference category: lowest quintile Results: Prostate cancer highest quintile: OR 0.96 (95% CI 0.70 to 1.31)
Selenium levels in exposure categories	lowest quintile < 62.0 µg/l highest quintile ≥ 84.1 µg/l
Notes