Positive Health Online
Your Country
Research: CONNELLY-FROST and COLLEAGUES,
Listed in Issue 179
Abstract
CONNELLY-FROST and COLLEAGUES, Department of Epidemiology, University of North Carolina, Chapel Hill, NC, USA. FrostConsulting@hotmail.com investigated the association between selenium and colon cancer.
Background
Selenium is an essential trace element that has been implicated in cancer risk; however, study results have been inconsistent with regard to colon cancer. The authors' objectives were to 1) investigate the association between selenium and colon cancer, 2) evaluate possible effect measure modifiers, and 3) evaluate potential biases associated with the use of postdiagnostic serum selenium measures.
Methodology
The North Carolina Colon Cancer Study is a large population-based, case-control study of colon cancer in North Carolina between 1996 and 2000 (n = 1,691). Nurses interviewed patients about diet and lifestyle and drew blood specimens, which were used to measure serum selenium.
Results
Individuals who had both high serum selenium (> 140 mcg/l) and high reported folate (> 354 mcg/day) had a reduced relative risk of colon cancer [odds ratio (OR) = 0.5, 95% confidence interval (CI) = 0.4-0.8). The risk of colon cancer for those with high selenium and low folate was approximately equal to the risk among those with low selenium and low folate (OR = 1.1, 95% CI = 0.7-1.5) as was the risk for those with low selenium and high folate (OR = 0.9, 95% CI = 0.7-1.2). We did not find evidence of bias due to weight loss, stage at diagnosis, or time from diagnosis to selenium measurement. High levels of serum selenium and reported folate jointly were associated with a substantially reduced risk of colon cancer.
Conclusion
Folate status should be taken into account when evaluating the relation between selenium and colon cancer in future studies. Importantly, weight loss, stage at diagnosis, or time from diagnosis to blood draw did not appear to produce strong bias in our study.
References
Connelly-Frost A, Poole C, Satia JA, Kupper LL, Millikan RC and Sandler RS. Selenium, folate, and colon cancer. Nutrition & Cancer. 61(2):165-78, 2009. Other ID Source: NLM. NIHMS99773 [Available on 01/01/10] Source: NLM. PMC2743456 [Available on 01/01/10].