Plasma selenium and glutathione peroxidase in relation to cancer, angina pectoris and short-term mortality in 68-year-old men.

Plasma selenium and plasma glutathione peroxidase were measured in 483 68-year-old men participating in a longitudinal population study, in which the probands were representatively selected. The prevalence of cancer and coronary heart disease was assessed by a structured interview. In plasma the concentration of selenium was 1.08 +/- 0.18 mumol X l-1 and the activity of glutathione peroxidase 540 +/- 90 mumol X l-1 X min-1. Plasma selenium was correlated to glutathione peroxidase activity (r = 0.49, p less than 0.001), but not significantly to plasma albumin levels (r = 0.18). Plasma selenium and glutathione peroxidase values in subjects with cancer or angina pectoris were not significantly different from those in subjects without these diseases. Plasma selenium concentration and glutathione peroxidase activity in the subjects who died within 1 year of screening were 89% and 88%, respectively, of the values among survivors (p less than 0.01). For the subjects who died during the second year after screening, these variables did not differ significantly from the values among survivors, 97% and 99%, respectively. Since the relation of low selenium and glutathione peroxidase to mortality was observed only for the first year, it was probably due to a disturbed nutritional state prior to death, rather than to a long-term negative influence of low plasma selenium on the mortality risk. Furthermore, the data have failed to demonstrate a relationship between selenium status and cancer or angina pectoris.