BACKGROUND:Calcium and vitamin D both appear to have antineoplastic effects in the large bowel. Although these nutrients are inter-related metabolically in bone and in the normal intestine, their potential interactions in large-bowel carcinogenesis are not well understood. METHODS: We assessed independent and joint effects of calcium supplementation and vitamin D status on adenoma recurrence in 803 subjects in a multi-center, placebo-controlled randomized clinical trial of calcium supplementation for the prevention of colorectal adenoma recurrence. Serum levels of 25-hydroxy [25-(OH)] vitamin D and 1,25-dihydroxy [1,25-(OH)2] vitamin D levels were determined, and the Taq I and Fok I polymorphisms in the vitamin D receptor (VDR) gene were analyzed by polymerase chain reaction. Risk ratios (RRs) for any adenoma recurrence were computed for calcium supplementation within groups defined by serum vitamin D levels and for serum vitamin D levels within treatment groups. Associations of VDR polymorphisms with recurrence risk were also evaluated. All statistical tests were two-sided. RESULTS: Among subjects with baseline 25-(OH) vitamin D levels at or below the median (29.1 ng/mL), calcium supplementation was not associated with adenoma recurrence, whereas among those with levels above the median, calcium supplementation was associated with a reduced risk (RR = 0.71, 95 % confidence interval [CI] = 0.57 to 0.89, P for interaction =.012). Conversely, serum 25-(OH) vitamin D levels were associated with a reduced risk only among subjects receiving calcium supplements (RR per 12 ng/mL increase of vitamin D = 0.88, 95% CI = 0.77 to 0.99, P for interaction =.006). VDR polymorphisms were not related to adenoma recurrence and did not modify the associations with vitamin D or calcium. CONCLUSIONS:Calcium supplementation and vitamin D status appear to act largely together, not separately, to reduce the risk of colorectal adenoma recurrence. VDR genotype does not appear to be associated with risk.
RCT Entities:
BACKGROUND:Calcium and vitamin D both appear to have antineoplastic effects in the large bowel. Although these nutrients are inter-related metabolically in bone and in the normal intestine, their potential interactions in large-bowel carcinogenesis are not well understood. METHODS: We assessed independent and joint effects of calcium supplementation and vitamin D status on adenoma recurrence in 803 subjects in a multi-center, placebo-controlled randomized clinical trial of calcium supplementation for the prevention of colorectal adenoma recurrence. Serum levels of 25-hydroxy [25-(OH)] vitamin D and 1,25-dihydroxy [1,25-(OH)2] vitamin D levels were determined, and the Taq I and Fok I polymorphisms in the vitamin D receptor (VDR) gene were analyzed by polymerase chain reaction. Risk ratios (RRs) for any adenoma recurrence were computed for calcium supplementation within groups defined by serum vitamin D levels and for serum vitamin D levels within treatment groups. Associations of VDR polymorphisms with recurrence risk were also evaluated. All statistical tests were two-sided. RESULTS: Among subjects with baseline 25-(OH) vitamin D levels at or below the median (29.1 ng/mL), calcium supplementation was not associated with adenoma recurrence, whereas among those with levels above the median, calcium supplementation was associated with a reduced risk (RR = 0.71, 95 % confidence interval [CI] = 0.57 to 0.89, P for interaction =.012). Conversely, serum 25-(OH) vitamin D levels were associated with a reduced risk only among subjects receiving calcium supplements (RR per 12 ng/mL increase of vitamin D = 0.88, 95% CI = 0.77 to 0.99, P for interaction =.006). VDR polymorphisms were not related to adenoma recurrence and did not modify the associations with vitamin D or calcium. CONCLUSIONS:Calcium supplementation and vitamin D status appear to act largely together, not separately, to reduce the risk of colorectal adenoma recurrence. VDR genotype does not appear to be associated with risk.
Authors: Veronika Fedirko; Roberd M Bostick; Michael Goodman; W Dana Flanders; Myron D Gross Journal: Am J Epidemiol Date: 2010-07-22 Impact factor: 4.897
Authors: Eduard Sidelnikov; Roberd M Bostick; W Dana Flanders; Qi Long; Veronika Fedirko; Aasma Shaukat; Carrie R Daniel; Robin E Rutherford Journal: Cancer Epidemiol Biomarkers Prev Date: 2010-03-23 Impact factor: 4.254
Authors: Jenny N Poynter; Elizabeth T Jacobs; Jane C Figueiredo; Won H Lee; David V Conti; Peter T Campbell; A Joan Levine; Paul Limburg; Loic Le Marchand; Michelle Cotterchio; Polly A Newcomb; John D Potter; Mark A Jenkins; John L Hopper; David J Duggan; John A Baron; Robert W Haile Journal: Cancer Epidemiol Biomarkers Prev Date: 2010-01-19 Impact factor: 4.254
Authors: Veronika Fedirko; Roberd M Bostick; Qi Long; W Dana Flanders; Marjorie L McCullough; Eduard Sidelnikov; Carrie R Daniel; Robin E Rutherford; Aasma Shaukat Journal: Cancer Epidemiol Biomarkers Prev Date: 2010-01 Impact factor: 4.254