Selenium Blood Levels and Prostate Cancer Risk, European Results
Preventing Prostate Cancer - Selenium
Selenium Blood Levels and Prostate Cancer Risk, European Results
Monday, December 08 2008 07:10
Early evidence suggested that selenium does protect men against this too often deadly disease. To investigate this claimed protective effect on a larger scale than previously attempted, study groups on both sides of the Atlantic gathered evidence over several years.
European and Scandinavian health organizations report this month that their case-control study involving almost two thousand men, the European Prospective Investigation into Cancer and Nutrition (EPIC), found selenium does not prevent prostate cancer. This negative finding follows a more complex result from a separate study conducted in the USA and Denmark, which reported in January 2007 that selenium has no protective effect against prostate caner except in men who take vitamin E or a multivitamin or who are smokers.
The new study reporting this month compared 959 men who developed prostate cancer and 1059 men matched with them as controls. Controls are as alike as possible to the primary study subjects with exception of the factor under study, i.e. the controls were prostate cancer free.
In addition to investigating possible association between selenium levels and subsequent prostate cancer risk, this study examined this association by stage and grade of disease and other factors.
The study found no association between blood levels of selenium and prostate cancer.
"Overall," the authors write, "plasma selenium concentration was not associated with prostate cancer risk; the multivariate relative risk for men in the highest fifth of selenium concentration compared with the lowest fifth was 0.96 (95% CI: 0.70, 1.31; P for trend = 0.25). There were no significant differences in the association of plasma selenium with risk when analyzed by stage or grade of disease. Similarly, the association of selenium with risk did not differ by smoking status or by plasma alpha- or gamma-tocopherol concentration."
"Plasma selenium concentration was not associated with prostate cancer risk in this large cohort of European men," the authors state.
Last year a study led by Uklrike Peters of the Fred Hutchinson Cancer Research Center in Seattle and including a team in Denmark arrived at a similar conclusion with significant exceptions for men taking vitamin E or high dose multivitamins and men who smoked.
Peters' group compared 724 prostate cancer patients and 879 cancer-free control subjects, matched for age, time since initial screen, and year of blood draw. The men were followed for up to 8 years.
Overall, Peters study found, like the Europeans, that serum selenium was not associated with prostate cancer risk. However, her group found that a higher blood level of selenium was associated with lower risks in men reporting a high (more than the median: 28.0 IU/d) vitamin E intake and in multivitamin users. Furthermore, among smokers, high serum selenium concentrations were related to reduced prostate cancer risk. Sources:
Plasma selenium concentration and prostate cancer risk: results from the European Prospective Investigation into Cancer and Nutrition (EPIC), Naomi E Allan, Timothy J Key et al, Am. J. Clinical Nutrition, Dec 2008; 88 1567 - 1575.
Serum selenium and risk of prostate cancer—a nested case-control study Ulrike Peters, et al, American Journal of Clinical Nutrition, Vol. 85, No. 1, 209-217, January 2007.
Compiled and edited by J. Strax.
