We propose to investigate the effect of selenium intake on neoplastic polyp formation, an intermediate stage of human colorectal carcinogenesis. We propose to conduct a nested case-control study using data and stored serum samples from a large, multi-centered polyps prevention trial designed to test the efficacy of oral betacarotene, vitamin C and vitamin E supplementation in reducing adenoma occurrences. The study was comprised of patients with a history of adenoma from six clinical centers. At study entry, participants completed a health habits and history questionnaire and provided dietary intake data (using a standardize food frequency questionnaire). Medical history information was updated semi- annually. Serum samples were collected under mineral-free conditions throughout the study. All participants were free of polyps at study entry and underwent a colonoscopic evaluation after one year to ensure that no polyps were missed,and after four years to identify new adenoma occurrences. All biopsies were reviewed by two pathologists for the presence of neoplasia. For the proposed nested case-control study, we will select as cases, all 278 participants who had an adenoma occurrence between the year one and year four examinations. For comparison, we will randomly choose and equal number of participants who completed the year four examinations but had not developed any adenoma. Prediagnostic serum selenium concentrations (an indicator of dietary selenium) will be determined using instrumental neutron activation analysis. We will estimated the relative risk of adenoma occurrence associated with serum selenium concentrations using stratified and logistic regression analysis. We will further assess the relation between serum selenium levels and the number, size and location of adenoma occurrences. A major advantage of our study design is that patients were followed with endoscopic examination at prescribed intervals, rather than for symptoms or based on patient or physician preferences. Therefore, our results will not be subject to the detection bias which cannot be avoided in most longitudinal studies. Also, the proposed study can be conducted in considerable less time and expense than initiating a new study of this size. Thus, our findings should contribute valuable insights for planning future intervention studies with chemopreventive and nutritional agents, and to the understanding of large bowel carcinogenesis and its prevention.
| Hibler, Elizabeth A; Sardo Molmenti, Christine L; Dai, Qi et al. (2016) Physical activity, sedentary behavior, and vitamin D metabolites. Bone 83:248-255 |
| Hibler, Elizabeth A; Klimentidis, Yann C; Jurutka, Peter W et al. (2015) CYP24A1 and CYP27B1 Polymorphisms, Concentrations of Vitamin D Metabolites, and Odds of Colorectal Adenoma Recurrence. Nutr Cancer 67:1131-41 |
| Bea, Jennifer W; Jurutka, Peter W; Hibler, Elizabeth A et al. (2015) Concentrations of the vitamin D metabolite 1,25(OH)2D and odds of metabolic syndrome and its components. Metabolism 64:447-59 |
| Jacobs, Elizabeth T; Martinez, Maria Elena; Jurutka, Peter W (2011) Vitamin D: marker or mechanism of action? Cancer Epidemiol Biomarkers Prev 20:585-90 |
| Jacobs, Elizabeth T; Martínez, Maria E; Campbell, Peter T et al. (2010) Genetic variation in the retinoid X receptor and calcium-sensing receptor and risk of colorectal cancer in the Colon Cancer Family Registry. Carcinogenesis 31:1412-6 |
| Egan, Jan B; Thompson, Patricia A; Ashbeck, Erin L et al. (2010) Genetic polymorphisms in vitamin D receptor VDR/RXRA influence the likelihood of colon adenoma recurrence. Cancer Res 70:1496-504 |
| Ashbeck, Erin L; Jacobs, Elizabeth T; Martínez, María Elena et al. (2009) Components of metabolic syndrome and metachronous colorectal neoplasia. Cancer Epidemiol Biomarkers Prev 18:1134-43 |
| Jacobs, Elizabeth T; Alberts, David S; Foote, Janet A et al. (2008) Vitamin D insufficiency in southern Arizona. Am J Clin Nutr 87:608-13 |
| Jacobs, Elizabeth T; Martinez, Maria Elena; Alberts, David S et al. (2008) Plasma insulin-like growth factor I is inversely associated with colorectal adenoma recurrence: a novel hypothesis. Cancer Epidemiol Biomarkers Prev 17:300-5 |
| Jacobs, Elizabeth T; Martinez, Maria Elena; Alberts, David S et al. (2007) Association between body size and colorectal adenoma recurrence. Clin Gastroenterol Hepatol 5:982-90 |
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