Serum selenium has been implicated as a risk factor for lung cancer, but the issue remains unsettled. We tested in a cohort of 3,333 males aged 53 to 74 years the hypothesis that a low serum selenium would be associated with an increased risk of lung cancer mortality.
During 16 years, 167 subjects(5.1%) died from lung cancer; 48 males (5.0%) among males with low serum selenium, 0.4–1.0 μmol·l−1, n=965, 57 males (5.1%) among males with medium serum selenium, 1.1–1.2 μmol·l−1, n=1,141, and 62 males (5.1%) among males with high serum selenium, 1.3–3.0 μmol·l−1, n=1,227. After adjustment for age, referencing the lowest level of serum selenium hazard ratios with 95% CI (HR) for medium and high levels of serum selenium were 0.97(0.66–1.43), and 0.99(0.68–1.45), respectively. Taking into account pack years of smoking, spirits intake, dietary markers (salt and fat preferences), and health measures (chronic bronchitis and peak flow), referencing the lowest level of serum selenium HRs were 1.17(0.79–1.75), and 1.43(0.96–2.14), respectively. Among heavy smokers a high serum selenium was associated with a significantly increased risk of lung cancer mortality after taking into account all potential confounders. The hypothesis that low serum selenium is an independent risk factor for lung cancer was not supported.