Impact of Common Vitamin D-Binding Protein Isoforms on Supplemental Vitamin D3 and/or Calcium Effects on Colorectal Adenoma Recurrence Risk: A Secondary Analysis of a Randomized Clinical Trial.

Importance: Variants in the vitamin D-binding protein (DBP) gene (GC) encode DBP isoforms that may affect vitamin D metabolism. However, whether these isoforms modify the effects of vitamin D3 and/or calcium supplementation on colorectal adenoma recurrence is unclear. We hypothesized that supplementation effects may be stronger among those with the DBP2 isoform (encoded by the rs4588*A allele), which is associated with vitamin D deficiency and modified the associations of circulating vitamin D with risk for colorectal neoplasms in observational studies. Objective: To estimate supplemental vitamin D3 and/or calcium effects on colorectal adenoma recurrence according to 3 common DBP isoforms (DBP1s, DBP1f, DBP2) encoded by 2 missense variants: rs7041 (NG_012837.3:g.57904T>G NP_001191235.1:p.Asp432Glu) and rs4588 (NG_012837.3:g.57915C>A NP_001191235.1:p.Thr436Lys). Design, Setting, and Participants: Secondary analysis of a randomized, double-blind, placebo-controlled clinical trial of 2259 participants with a recently diagnosed adenoma and no remaining polyps after complete colonoscopy in the US from July 1, 2004, to August 31, 2013. The current analyses were performed from August 12, 2019, to July 16, 2022. Interventions: Daily vitamin D3 (1000 IU), calcium (1200 mg), both, or placebo. Main Outcomes and Measures: One or more adenomas diagnosed during 3 to 5 years of follow-up. Treatment effects were estimated according to DBP isoform as risk ratios (RRs) and 95% CIs using Poisson regression analysis. Results: Of the 2259 participants randomized (mean [SD] age, 58 [6.8] years; 1033 [64%] men), 1604 non-Hispanic White participants (chosen to avoid population stratification bias) were included in the analysis. Among those with the DBP2 isoform (rs4588*AC or AA), the RRs (95% CI) for adenoma recurrence were 0.84 (0.72-1.00) with vitamin D3 relative to no vitamin D3, 0.83 (95% CI, 0.70-0.99) with calcium relative to no calcium, and 0.76 (95% CI, 0.59-0.98) with both agents relative to neither agent. Conversely, among those without DBP2 (rs4588*CC), the corresponding values were 1.08 (95% CI, 0.93-1.26; P = .03 for interaction) with vitamin D3 relative to no vitamin D3, 0.98 (95% CI, 0.84-1.14; P = .37 for interaction) with calcium relative to no calcium, and 1.09 (0.88-1.36; P = .03 for interaction) with both agents relative to neither agent. Among DBP2 homozygotes (rs4588*AA), the RR for adenoma recurrence was 0.57 (95% CI, 0.31-1.08) with both agents relative to neither agent. Conclusions and Relevance: The findings of this secondary analysis of a randomized clinical trial suggest that individuals with the DBP2 isoform-encoding rs4588*A allele may particularly benefit from vitamin D3 and/or calcium supplementation for colorectal adenoma prevention. Trial Registration: ClinicalTrials.gov Identifier: NCT00153816.

Effects of Supplemental Calcium and Vitamin D on Circulating Biomarkers of Gut Barrier Function in Patients with Colon Adenoma: A Randomized Clinical Trial.

Gut barrier dysfunction promotes chronic inflammation, contributing to several gastrointestinal diseases, including colorectal cancer. Preliminary evidence suggests that vitamin D and calcium could prevent colorectal carcinogenesis, in part, by influencing gut barrier function. However, relevant human data are scarce. We tested the effects of supplemental calcium (1,200 mg/day) and/or vitamin D3 (1,000 IU/day) on circulating concentrations of biomarkers of gut permeability (anti-flagellin and anti-lipopolysaccharide IgA and IgG, measured via ELISA) from baseline to 1 and 3 or 5 years postbaseline among 175 patients with colorectal adenoma in a randomized, double-blinded, placebo-controlled clinical trial. We also assessed factors associated with baseline concentrations of these biomarkers. We found no appreciable effects of supplemental vitamin D3 and/or calcium on individual or aggregate biomarkers of gut permeability. At baseline, a combined permeability score (the summed concentrations of all four biomarkers) was 14% lower among women (P = 0.01) and 10% higher among those who consumed >1 serving per day of red or processed meats relative to those who consumed none (P trend = 0.03). The permeability score was estimated to be 49% higher among participants with a body mass index (BMI) > 35 kg/m2 relative to those with a BMI < 22.5 kg/m2 (P trend = 0.17). Our results suggest that daily supplemental vitamin D3 and/or calcium may not modify circulating concentrations of gut permeability biomarkers within 1 or 3-5 years, but support continued investigation of modifiable factors, such as diet and excess adiposity, that could affect gut permeability. PREVENTION RELEVANCE: Calcium and vitamin D may be involved in regulating and maintaining the integrity of the intestinal mucosal barrier, the dysfunction of which results in exposure of the host to luminal bacteria, endotoxins, and antigens leading to potentially cancer-promoting endotoxemia and chronic colon inflammation. While our results suggest that daily supplementation with these chemopreventive agents does not modify circulating concentrations of gut permeability biomarkers, they support continued investigation of other potential modifiable factors, such as diet and excess adiposity, that could alter gut barrier function, to inform the development of treatable biomarkers of risk for colorectal neoplasms and effective colon cancer preventive strategies.

Inflammation Modulation by Vitamin D and Calcium in the Morphologically Normal Colorectal Mucosa of Patients with Colorectal Adenoma in a Clinical Trial.

Increased COX-2 and decreased 15-hydroxyprostaglandin dehydrogenase (15-HPGD) expression promote prostaglandin-mediated inflammation and colorectal carcinogenesis. Experimental studies suggest that vitamin D and calcium may inhibit these pathways, but their effects on colorectal tissue COX-2 and 15-HPGD expression in humans are unknown. We tested the effects of supplemental vitamin D (1,000 IU/day) and/or calcium (1,200 mg/day) on COX-2 and 15-HPGD expression in the morphologically normal rectal mucosa from 62 paients with colorectal adenoma in a placebo-controlled chemoprevention trial. We measured biomarker expression using automated IHC and quantitative image analysis at baseline and 1-year follow-up, and assessed treatment effects using mixed linear models. The primary outcome was the COX-2/15-HPGD expression ratio, because these enzymes function as physiologic antagonists. After 1 year of treatment, the mean COX-2/15-HPGD expression ratio in full-length crypts proportionately decreased 47% in the vitamin D group (P = 0.001), 46% in the calcium group (P = 0.002), and 34% in the calcium + vitamin D group (P = 0.03), relative to the placebo group. Among individuals with the functional vitamin D-binding protein isoform DBP2 (GC rs4588*A), the COX-2/15-HPDG ratio decreased 70% (P = 0.0006), 75% (P = 0.0002), and 60% (P = 0.006) in the vitamin D, calcium, and combined supplementation groups, respectively, relative to placebo. These results show that vitamin D and calcium favorably modulate the balance of expression of COX-2 and 15-HPGD-biomarkers of inflammation that are strongly linked to colorectal carcinogenesis-in the normal-appearing colorectal mucosa of patients with colorectal adenoma (perhaps especially those with the DBP2 isoform). PREVENTION RELEVANCE: Supplemental calcium and vitamin D reduce indicators of cancer-promoting inflammation in normal colorectal tissue in humans, thus furthering our understanding of how they may help prevent colorectal cancer.

Effects of supplemental calcium and vitamin D on tight-junction proteins and mucin-12 expression in the normal rectal mucosa of colorectal adenoma patients.

The physical gut barrier, comprised of a thick mucus layer and the epithelium, plays an important role in defense against microbes and foreign antigens. Calcium and vitamin D may be involved in maintaining the integrity of the intestinal mucosal barrier, the dysfunction of which may lead to endotoxemia and inflammation, and contribute to colorectal carcinogenesis. We investigated supplemental calcium (1200 mg, daily) and/or vitamin D3 (1000 IU daily) effects on intestinal barrier function-related biomarkers in a subset of 105 participants from a large colorectal adenoma recurrence chemoprevention clinical trial. We assessed expression of the tight junction proteins claudin-1 (CLDN1), occludin (OCLD), and mucin-12 (MUC12) in the normal-appearing colorectal mucosa using standardized, automated immunohistochemistry and quantitative image analysis. Following 1 year of treatment, in the calcium relative to the no calcium group, the CLDN1, OCLD, and MUC12 expression increased by 14% (P = 0.17), 23% (P = 0.11), and 22% (P = 0.07), respectively. In secondary analyses, the estimated calcium treatment effects were greater among participants with baseline serum 25-OH-vitamin D concentrations below the median value of 22.69 ng/mL (CLDN1: 29%, P = 0.04; OCLD: 36%, P = 0.06; MUC12: 35%, P = 0.05). There were no biomarker expression changes in the vitamin D3 alone group; however, modest increases were found in the combined calcium/vitamin D3 group. At baseline, obesity, history of a sessile-serrated adenoma, colorectal MIB-1/Ki-67 expression, and a family history of colorectal cancer were associated with CLDN1, OCLD, and MUC12 expression. Our study supports continued investigation of factors that could affect intestinal mucosal barrier integrity relevant to colorectal carcinogenesis.

Associations of calcium and dairy product intakes with all-cause, all-cancer, colorectal cancer and CHD mortality among older women in the Iowa Women's Health Study.

Ca and dairy product intakes may be inversely associated with all-cause and cause-specific mortality, and non-Ca components of dairy products, such as insulin-like growth factor-1, may be independently associated with mortality. We investigated associations of Ca and dairy product intakes with all-cause, all-cancer, colorectal cancer (CRC) and CHD mortality among 35 221 55- to 69-year-old women in the prospective Iowa Women's Health Study, who were cancer-free in 1986. We assessed diet using a Willett FFQ, and associations using multivariable Cox proportional hazards regression. We estimated residuals from linear regression models of dairy products with dietary Ca to investigate total and specific dairy products independent of their Ca content. Through 2012, 18 687 participants died, including 4665 from cancer (including 574 from CRC) and 3603 from CHD. For those in the highest relative to the lowest quintiles of intake, the multivariable-adjusted hazard ratios (HR) and 95 % CI for total Ca (dietary plus supplemental) were 0·88 (0·83, 0·93; P trend=0·001) for all-cause mortality, 0·91 (0·81, 1·02; P trend=0·34) for all-cancer mortality, 0·60 (0·43, 0·83; P trend=0·002) for CRC mortality and 0·73 (0·64, 0·83; P trend <0·0001) for CHD mortality. The corresponding HR for associations of whole milk, whole milk residuals, and low-/non-fat milk residuals with all-cause mortality were 1·20 (95 % CI 1·13, 1·27), 1·20 (95 % CI 1·13, 1·28) and 0·91 (95 % CI 0·86, 0·96), respectively. These results suggest that Ca may be associated with lower risk of all-cause, CRC and CHD mortality, and that non-Ca components of milk may be independently associated with mortality.

No Evidence for Posttreatment Effects of Vitamin D and Calcium Supplementation on Risk of Colorectal Adenomas in a Randomized Trial.

Vitamin D and calcium supplementation are postulated to have chemopreventive effects against colorectal neoplasia, yet in our previously reported randomized trial, there was no overall efficacy of calcium and/or vitamin D3 against colorectal adenoma recurrence. It is possible vitamin D3 and calcium chemopreventive effects are not detectable until beyond the 3- to 5-year follow-up captured in that trial. Accordingly, we explored possible vitamin D and calcium effects on posttreatment (observational) adenoma occurrence. In this secondary analysis of the observational follow-up phase of the Vitamin D/Calcium Polyp Prevention Study, participants who completed the treatment phase were invited to be followed for one additional surveillance colonoscopy cycle. We evaluated adenoma occurrence risk at surveillance colonoscopy, with a mean of 55 ± 15 months after treatment follow-up, according to randomized treatment with vitamin D versus no vitamin D, calcium versus no calcium, and calcium plus vitamin D versus calcium alone. Secondary outcomes included advanced and multiple adenomas. Among the 1,121 participants with observational follow-up, the relative risk (95% confidence interval, CI) of any adenoma was 1.04 (0.93-1.17) for vitamin D versus no vitamin D; 0.95 (0.84-1.08) for calcium versus no calcium; 1.07 (0.91-1.25) for calcium plus vitamin D versus calcium; and 0.96 (0.81-1.15) for calcium plus vitamin D versus neither. Risks of advanced or multiple adenomas also did not differ by treatment. Our results do not support an association between supplemental calcium and/or vitamin D3 for 3 to 5 years and risk of recurrent colorectal adenoma at an average of 4.6 years after treatment.

Combined Mineral Intakes and Risk of Colorectal Cancer in Postmenopausal Women.

BACKGROUND: Despite considerable biological plausibility, other than for calcium, there are few reported epidemiologic studies on mineral intake-colorectal cancer associations, none of which investigated multiple minerals in aggregate. METHODS: Accordingly, we incorporated 11 minerals into a mineral score and investigated its association with incident colorectal cancer in the Iowa Women's Health Study, a prospective cohort study of 55- to 69-year-old women who completed a food frequency questionnaire in 1986. In the analytic cohort (n = 35, 221), 1,731 incident colorectal cancer cases were identified via the State Health Registry of Iowa. Participants' calcium, magnesium, manganese, zinc, selenium, potassium, and iodine intakes were ranked 1 to 5, with higher ranks indicating higher, potentially anticarcinogenic, intakes, whereas for iron, copper, phosphorus, and sodium intakes, the rankings were reversed to account for their possible procarcinogenic properties. The rankings were summed to create each woman's mineral score. The mineral score-incident colorectal cancer association was estimated using multivariable Cox proportional hazards regression. RESULTS: There was decreasing risk with an increasing score (P trend = 0.001). The hazard ratios and 95% confidence intervals (CI) for those in mineral score quintiles 2 to 5 relative to those in the lowest were 0.91 (CI, 0.88-1.08), 0.85 (CI, 0.75-0.95), 0.86 (CI, 0.75-0.97), and 0.75 (CI, 0.71-0.95), respectively. CONCLUSIONS: Our findings suggest that a predominance of putative anti- relative to pro-colorectal carcinogenic mineral intakes may be inversely associated with colorectal cancer risk. IMPACT: These results support further investigation of colorectal cancer etiology using composite mineral intake scores.

Effects of vitamin D and calcium on expression of MSH2 and transforming growth factors in normal-appearing colorectal mucosa of sporadic colorectal adenoma patients: A randomized clinical trial.

Abnormal expression of the DNA mismatch repair protein MSH2 and autocrine/paracrine transforming growth factors TGFα (growth promoter) and TGFß1 (growth inhibitor) is common during colorectal carcinogenesis. To estimate vitamin D and calcium effects on these biomarkers in the normal-appearing colorectal mucosa of sporadic colorectal adenoma patients, we conducted a pilot, randomized, double-blinded, placebo-controlled, modified 2 × 2 factorial chemoprevention clinical trial (N = 104) of supplemental vitamin D3 (1000 IU daily) and calcium (1200 mg daily), alone and in combination, versus placebo over 1 year. The expression of the three biomarkers and Ki-67/mib-1 in colorectal crypts in biopsies of normal-appearing rectal mucosa were detected using automated immunohistochemistry and quantified using image analysis. In the vitamin D3 and vitamin D3 plus calcium groups, relative to their reference groups, in the upper 40% (differentiation zone) of crypts, it was estimated that, respectively, the MSH2/mib-1 ratio increased by 47% (P = 0.14) and 62% (P = 0.08), TGFß1 expression increased by 41% (P = 0.25) and 78% (P = 0.14), and the TGFα/TGFß1 ratio decreased by 25% (P = 0.31) and 44% (P = 0.13). Although not statistically significant, these results support further research into (i) whether supplemental vitamin D3 , alone or in combination with calcium, may increase DNA mismatch repair relative to proliferation, increase TGFß1 expression, and decrease autocrine/paracrine growth promotion relative to growth inhibition in the colorectal epithelium, all hypothesized to reduce risk for colorectal carcinogenesis; and (ii) the expression of MSH2 relative to mib-1, TGFß1 alone, and TGFα relative to TGFß1 in the normal-appearing rectal mucosa as potential modifiable, pre-neoplastic markers of risk for colorectal neoplasms.

Body mass index, calcium supplementation and risk of colorectal adenomas.

Calcium supplementation (1,200 mg/day) did not significantly reduce colorectal adenomas in our recent randomized, controlled trial (Vitamin D/Calcium Polyp Prevention Study, VCPPS, 2004-2013) in contrast to our previous trial (Calcium Polyp Prevention Study, CPPS, 1988-1996). To reconcile these findings, we identified participant characteristics that differed between the study populations and modified the effect of calcium supplementation on adenomas or high-risk findings (advanced or multiple adenomas). Compared to the CPPS, more participants in the VCPPS were obese (body mass index (BMI) ≥30 kg/m2 ; 37.5% vs. 24.4%) and fewer had normal BMI (BMI <25 kg/m2 ; 18.5% vs. 31%). BMI appeared to modify the effect of calcium supplementation on adenomas and especially on high risk-findings: in the VCPPS, there was a 44% reduction in high-risk findings among individuals whose BMI was normal (RR = 0.56, 95% CI = 0.26-1.23), but not among overweight (RR = 1.09, 95% CI = 0.62-1.91) or obese (RR = 1.54, 95% CI = 0.92-2.57) individuals (pinteraction = 0.03). Similarly, in the CPPS, there was a 56% reduction in high-risk findings among individuals whose BMI was normal (RR = 0.44, 95% CI = 0.26-0.74), but not among overweight (RR = 0.87, 95% CI = 0.55-1.39) or obese (RR = 1.02, 95% CI = 0.57-1.82) individuals (pinteraction = 0.02). Standardization of each trial's findings to the BMI distribution in the other attenuated calcium's protective effect on adenomas in the CPPS but enhanced it in the VCPPS. In conclusion, 1,200 mg/day calcium supplementation may reduce risk of colorectal adenomas among those with normal BMI but not in overweight or obese individuals; and differences in BMI distribution partially account for the apparent difference in calcium efficacy between the two trials.

Effects of supplemental vitamin D and calcium on markers of proliferation, differentiation, and apoptosis in the normal colorectal mucosa of colorectal adenoma patients.

To clarify the roles of vitamin D and calcium as potential chemopreventive agents against colorectal cancer in humans, and to develop "treatable", pre-neoplastic, phenotypic biomarkers of risk for colorectal neoplasms, we estimated the effects of supplemental vitamin D3 (1,000 IU/day [25 µg/day]) and calcium (1,200 mg/day), alone and in combination, on biomarkers of proliferation (mib-1), differentiation (p21), and apoptosis (bax [apoptosis-promoting] and bcl-2 [apoptosis-inhibiting]), in the normal-appearing rectal mucosa in a subsample of participants (n = 104) in a larger randomized, double-blind, placebo-controlled clinical trial among colorectal adenoma patients. The biomarkers were measured in rectal biopsies at baseline and after one year of follow up, using automated immunohistochemistry and quantitative image analysis. In the vitamin D plus calcium group relative to control, in the crypt differentiation zone (upper 40% of crypts), mib-1 expression decreased 24% (P = 0.28); p21 expression alone and relative to mib-1 expression increased 29% (P = 0.06) and 73% (P = 0.06), respectively; and bax expression relative to mib-1 expression increased 58% (P = 0.21). The estimated vitamin D alone treatment effects were similar but of lesser magnitudes, and those for calcium alone were mixed. All estimated treatment effects on bcl-2 expression were close to the null. These pilot study results support further investigation of whether 1) vitamin D and calcium promote colorectal epithelial cell differentiation, reduce proliferation, and promote apoptosis in the normal-appearing human colorectal mucosa, 2) vitamin D and calcium act as chemopreventive agents against colorectal neoplasms, and 3) mib-1, p21, and bax are potential "treatable", pre-neoplastic, biomarkers of risk for colorectal neoplasms.

Effects of Supplemental Calcium and Vitamin D on Expression of Toll-Like Receptors and Phospho-IKKα/ß in the Normal Rectal Mucosa of Colorectal Adenoma Patients.

Chronic inflammation in the colorectum, a significant contributor to colorectal carcinogenesis, can be triggered by the activation of proinflammatory signaling pathways such as those initiated by Toll-like receptors (TLR) and nuclear factor κB (NF-κB). Although experimental evidence supports calcium and vitamin D potentially modifying these proinflammatory pathways in the colorectum, human data in these regards are scarce. We investigated supplemental calcium (1,200 mg daily) and/or vitamin D3 (1,000 IU daily) effects on inflammatory signaling pathway-related biomarkers in a subset of 105 participants from a colorectal adenoma recurrence chemoprevention clinical trial. We assessed expression of TLR4 and TLR5, which recognize the bacterial components lipopolysaccharides and flagellin, respectively, and phospho-IKKα/ß (pIKKα/ß), a biomarker of inflammation, in the normal-appearing rectal crypt epithelium and stroma using standardized, automated immunohistochemistry and quantitative image analysis. Following 1 year of treatment, TLR4, TLR5, and pIKKα/ß expression in the rectal mucosa did not statistically significantly change with vitamin D or calcium supplementation, taken alone or in combination. Several baseline participant characteristics, including body mass index, history of sessile serrated adenomas, high red/processed meat intake, and high levels of rectal epithelial cell proliferation (as measured by MIB-1/Ki-67), were associated with higher baseline expression of TLRs or pIKKα/ß. Our findings suggest that vitamin D and calcium may have no substantial effect on the investigated biomarkers. However, several modifiable lifestyle factors may be associated with TLRs and pIKKα/ß expression in the normal rectal mucosa, supporting their future investigation as potentially treatable, preneoplastic risk factors for colorectal neoplasms. Cancer Prev Res; 11(11); 707-16. ©2018 AACR.

Associations of Calcium and Dairy Products with All-Cause and Cause-Specific Mortality in the REasons for Geographic and Racial Differences in Stroke (REGARDS) Prospective Cohort Study.

Associations of calcium and dairy product intakes with cardiovascular disease risk and cancer mortality are controversial. We investigated associations of calcium and dairy product intakes with mortality in the prospective REasons for Geographic and Racial Differences in Stroke study (n = 30,239). Of 2,966 total deaths, 32.3% were from CVD and 28.8% from cancer. For those in the upper relative to the lowest quintile of intakes, from Cox proportional hazards regression models, the multivariable-adjusted hazard ratios (HRs) for all-cause mortality were 1.13 (95% confidence intervals [CI] 0.95-1.35; P-trend 0.004) for whole milk, and 0.75 (CI 0.61-0.93; P-trend 0.001) for nonfat milk; for CVD mortality the corresponding HRs were 0.80 (CI 0.55-1.16; P-trend 0.80) and 0.72 (CI 0.49-1.05; P-trend 0.06); and for cancer mortality they were 1.56 (CI 1.17-2.08; P-trend 0.006) and 0.89 (CI 0.62-1.28; P-trend 0.86). Calcium (total, dietary, supplemental) and total dairy product intakes were not associated with all-cause, cardiovascular, or cancer mortality. These results suggest that whole milk consumption may be directly associated with cancer mortality; non-fat milk consumption may be inversely associated with all-cause and cardiovascular- and cancer-specific mortality; and calcium intake independent of milk product intakes may not be associated with mortality.

Circulating insulin-like growth factor-related biomarkers: Correlates and responses to calcium supplementation in colorectal adenoma patients.

Circulating insulin-like growth factor 1 (IGF-1) may be directly associated with colorectal cancer risk, and IGF binding protein 3 (IGFBP-3) is one of the most abundantly expressed binding proteins in various cancers. Calcium intakes, primarily from food, have been directly associated with circulating IGF-1, but whether supplemental calcium affects IGF-1 and IGFBP-3 is unknown. We tested the effects of 1.0 and 2.0 g of supplemental elemental calcium daily on circulating IGF-1 and IGFBP-3 concentrations in colorectal adenoma patients in a randomized, double-blinded, placebo-controlled clinical trial (n = 193). IGF-1 and IGFBP-3 were quantified using enzyme-linked immunoassay and quantitative Western ligand blot, respectively. We also assessed cross-sectional associations of these biomarkers with participants' baseline characteristics. We found no appreciable effect of calcium relative to placebo on circulating IGF-1, IGFBP-3, or the IGF-1:IGFBP-3 molar ratio. Mean IGF-1 concentrations were 11.1% higher in those with greater milk intakes (P = 0.05). Mean IGF-1 and IGFBP-3 concentrations were, respectively, 18.0% (P = 0.003) and 16.5% (P = 0.01) higher in men and were monotonically lower with increasing age (both P = 0.01). IGFBP-3 was 17.7% higher among those with higher relative to no alcohol consumption (P = 0.04). While these results support previous findings that IGF-1 concentrations are higher with greater milk intakes, and IGF-1 and IGFBP-3 concentrations differ according to sex and age, they provide no evidence to suggest that supplemental calcium appreciably affects circulating IGF-1, IGFBP-3, or the IGF-1:IGFBP-3 molar ratio in sporadic colorectal adenoma patients.

Factors Associated With Shorter Colonoscopy Surveillance Intervals for Patients With Low-Risk Colorectal Adenomas and Effects on Outcome.

BACKGROUND & AIMS: Endoscopists do not routinely follow guidelines to survey individuals with low-risk adenomas (LRAs; 1-2 small tubular adenomas, < 1 cm) every 5-10 years for colorectal cancer; many recommend shorter surveillance intervals for these individuals. We aimed to identify the reasons that endoscopists recommend shorter surveillance intervals for some individuals with LRAs and determine whether timing affects outcomes at follow-up examinations. METHODS: We collected data from 1560 individuals (45-75 years old) who participated in a prospective chemoprevention trial (of vitamin D and calcium) from 2004 through 2008. Participants in the trial had at least 1 adenoma, detected at their index colonoscopy, and were recommended to receive follow-up colonoscopy examinations at 3 or 5 years after adenoma identification, as recommended by the endoscopist. For this analysis we collected data from only participants with LRAs. These data included characteristics of participants and endoscopists and findings from index and follow-up colonoscopies. Primary endpoints were frequency of recommending shorter (3-year) vs longer (5-year) surveillance intervals, factors associated with these recommendations, and effect on outcome, determined at the follow-up colonoscopy. RESULTS: A 3-year surveillance interval was recommended for 594 of the subjects (38.1%). Factors most significantly associated with recommendation of 3-year vs a 5-year surveillance interval included African American race (relative risk [RR] to white, 1.41; 95% confidence interval [CI], 1.14-1.75), Asian/Pacific Islander ethnicity (RR to white, 1.7; 95% CI, 1.22-2.43), detection of 2 adenomas at the index examination (RR vs 1 adenoma, 1.47; 95% CI, 1.27-1.71), more than 3 serrated polyps at the index examination (RR=2.16, 95% CI, 1.59-2.93), or index examination with fair or poor quality bowel preparation (RR vs excellent quality, 2.16; 95% CI, 1.66-2.83). Other factors that had a significant association with recommendation for a 3-year surveillance interval included family history of colorectal cancer and detection of 1-2 serrated polyps at the index examination. In comparisons of outcomes, we found no significant differences between the 3-year vs 5-year recommendation groups in proportions of subjects found to have 1 or more adenomas (38.8% vs 41.7% respectively; P = .27), advanced adenomas (7.7% vs 8.2%; P = .73) or clinically significant serrated polyps (10.0% vs 10.3%; P = .82) at the follow-up colonoscopy. CONCLUSIONS: Possibly influenced by patients' family history, race, quality of bowel preparation, or number or size of polyps, endoscopists frequently recommend 3-year surveillance intervals instead of guideline-recommended intervals of 5 years or longer for individuals with LRAs. However, at the follow-up colonoscopy, similar proportions of participants have 1 or more adenomas, advanced adenomas, or serrated polyps. These findings support the current guideline recommendations of performing follow-up examinations of individuals with LRAs at least 5 years after the index colonoscopy.

Associations of Calcium and Milk Product Intakes with Incident, Sporadic Colorectal Adenomas.

Calcium intake has been consistently, modestly inversely associated with colorectal neoplasms, and supplemental calcium reduced adenoma recurrence in clinical trials. Milk products are the major source of dietary calcium in the United States, but their associations with colorectal neoplasms are unclear. Data pooled from three colonoscopy-based case-control studies of incident, sporadic colorectal adenoma (n = 807 cases, 2,185 controls) were analyzed using multivariable unconditional logistic regression. Residuals from linear regression models of milk with dietary calcium were estimated as the noncalcium, insulin-like growth factor 1-containing component of milk. For total, dietary, and supplemental calcium intakes, the adjusted odds ratios (ORs) comparing the highest to the lowest intake quintiles were 0.94 (95% confidence interval [CI] 0.69-1.30), 0.86 (CI 0.62-1.20), and 0.99 (CI 0.77-1.27), respectively. The corresponding ORs for consumption of total milk products, total milk, nonfat milk, total milk product residuals, and nonfat milk residuals were, respectively, 0.99, 0.90, 0.92, 0.94, and 0.95; all CIs included 1.0. For those who consumed any whole milk relative to those who consumed none, the OR was 1.15 (CI 0.89-1.49). These results are consistent with previous findings of modest inverse associations of calcium intakes with colorectal adenoma, but suggest that milk products may not be associated with adenoma.

Effects of supplemental calcium and vitamin D on the APC/ß-catenin pathway in the normal colorectal mucosa of colorectal adenoma patients.

APC/ß-catenin pathway malfunction is a common and early event in colorectal carcinogenesis. To assess calcium and vitamin D effects on the APC/ß-catenin pathway in the normal-appearing colorectal mucosa of sporadic colorectal adenoma patients, nested within a larger randomized, double-blind, placebo-controlled, partial 2 × 2 factorial chemoprevention clinical trial of supplemental calcium (1200 mg daily) and vitamin D (1000 IU daily), alone and in combination versus placebo, we assessed APC, ß-catenin, and E-cadherin expression in colon crypts in normal-appearing rectal mucosa biopsies from 104 participants at baseline and 1-yr follow up using standardized, automated immunohistochemistry and quantitative image analysis. For vitamin D versus no vitamin D, the ratio of APC expression to ß-catenin expression in the upper 40% (differentiation zone) of crypts (APC/ß-catenin score) increased by 28% (P = 0.02), for calcium versus no calcium it increased by 1% (P = 0.88), and for vitamin D + calcium versus calcium by 35% (P = 0.01). Total E-cadherin expression increased by 7% (P = 0.35) for vitamin D versus no vitamin D, 8% (P = 0.31) for calcium versus no calcium, and 12% (P = 0.21) for vitamin D + calcium versus calcium. These results support (i) that vitamin D, alone or in combination with calcium, may modify APC, ß-catenin, and E-cadherin expression in humans in directions hypothesized to reduce risk for colorectal neoplasms; (ii) vitamin D as a potential chemopreventive agent against colorectal neoplasms; and (iii) the potential of APC, ß-catenin, and E-cadherin expression as treatable, pre-neoplastic risk biomarkers for colorectal neoplasms. © 2016 Wiley Periodicals, Inc.

Vitamin D Receptor Genotype, Vitamin D3 Supplementation, and Risk of Colorectal Adenomas: A Randomized Clinical Trial.

IMPORTANCE: Despite epidemiological and preclinical evidence suggesting that vitamin D and calcium inhibit colorectal carcinogenesis, daily supplementation with these nutrients for 3 to 5 years was not found to significantly reduce the risk of recurrent colorectal adenomas in a recent randomized clinical trial. OBJECTIVE: To investigate whether common variants in 7 vitamin D and calcium pathway genes (VDR, GC, DHCR7, CYP2R1, CYP27B1, CYP24A1, and CASR) modify the effects of vitamin D3 or calcium supplementation on colorectal adenoma recurrence. DESIGN, SETTING, AND PARTICIPANTS: We examined 41 candidate single-nucleotide polymorphisms (SNPs) in 2259 participants in a randomized, double-blind, placebo-controlled trial conducted at 11 clinical centers in the United States. Eligibility criteria included a recently diagnosed adenoma and no remaining colorectal polyps after complete colonoscopy. The study's treatment phase ended on August 31, 2013, and the analysis for the present study took place from July 28, 2014, to October 19, 2016. INTERVENTIONS: Daily oral supplementation with vitamin D3 (1000 IU) or calcium carbonate (1200 mg elemental calcium) or both or neither. MAIN OUTCOMES AND MEASURES: The outcomes assessed were the occurrence of 1 or more adenomas or advanced adenomas (estimated diameter, ≥1 cm; or with villous histologic findings, high-grade dysplasia, or cancer) during follow-up. Treatment effects and genotype associations and interactions were estimated as adjusted risk ratios (RRs) and 95% confidence intervals (CIs). The effective number of independent SNPs was calculated to correct for multiple testing. RESULTS: Among the 2259 participants randomized, 1702 were non-Hispanic whites who completed the trial and had genotype data for analysis (1101 men; mean [SD] age 58.1 [6.8] years). The effect of vitamin D3 supplementation on advanced adenomas, but not on adenoma risk overall, significantly varied according to genotype at 2 VDR SNPs (rs7968585 and rs731236) in linkage disequilibrium (D' = 0.98; r2 = 0.6). For rs7968585, among individuals with the AA genotype (26%), vitamin D3 supplementation reduced risk by 64% (RR, 0.36; 95% CI, 0.19-0.69; P = .002; absolute risk decreased from 14.4% to 5.1%). Among individuals with 1 or 2 G alleles (74%), vitamin D3 supplementation increased risk by 41% (RR, 1.41; 95% CI, 0.99-2.00; P = .05; absolute risk increased from 7.7% to 11.1%; P < .001 for interaction). There were no significant interactions of genotypes with calcium supplementation. CONCLUSIONS AND RELEVANCE: Our findings suggest that benefits from vitamin D3 supplementation for the prevention of advanced colorectal adenomas may vary according to vitamin D receptor genotype. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00153816.

Lifestyle and Other Factors Explain One-Half of the Variability in the Serum 25-Hydroxyvitamin D Response to Cholecalciferol Supplementation in Healthy Adults.

BACKGROUND: Many factors have been associated with serum 25-hydroxyvitamin D [25(OH)D] concentrations in observational studies, with variable consistency. However, less information is available on factors affecting the magnitude of changes in serum 25(OH)D resulting from vitamin D supplementation. OBJECTIVE: This study aimed to identify factors associated with the serum 25(OH)D response to supplementation with 1000 IU cholecalciferol/d during the first year of a large, multicenter, randomized, placebo-controlled colorectal adenoma chemoprevention trial. METHODS: Eligible older adults who were not vitamin D-deficient [serum 25(OH)D ≥12 ng/mL] were randomly assigned in a modified 2 × 2 factorial design to 1 of 4 groups: daily 1000 IU cholecalciferol, 1200 mg Ca as carbonate, both, or placebo. Women could elect 2-group (calcium ± cholecalciferol) random assignment. In secondary analyses, we used multivariable models to assess factors associated with serum 25(OH)D concentrations in all enrollees (n = 2753) and with relative changes in serum 25(OH)D after 1 y cholecalciferol supplementation among those randomly assigned (n = 2187). RESULTS: In multivariable models, 8 factors accounted for 50% of the variability of proportional change in serum 25(OH)D after cholecalciferol supplementation. Larger increases were associated with being female (34.5% compared with 20.5%; P < 0.001) and with lower baseline serum 25(OH)D (P < 0.0001), optimal adherence to study pill intake (P = 0.0002), wearing long pants and sleeves during sun exposure (P = 0.0002), moderate activity level (P = 0.01), use of extra vitamin D-containing supplements during the trial (P = 0.03), and seasons of blood draw (P ≤ 0.002). Several genetic polymorphisms were associated with baseline serum 25(OH)D and/or serum response, but these did not substantially increase the models' R2 values. Other factors, including body mass index, were associated with serum 25(OH)D at baseline but not with its response to supplemental cholecalciferol. CONCLUSIONS: The factors that most affected changes in serum 25(OH)D concentrations in response to cholecalciferol supplementation included sex, baseline serum 25(OH)D, supplement intake adherence, skin-covering clothes, physical activity, and season. Genetic factors did not play a major role. This trial was registered at www.clinicaltrials.gov as NCT00153816.

Calcium intake and mortality from all causes, cancer, and cardiovascular disease: the Cancer Prevention Study II Nutrition Cohort.

BACKGROUND: Calcium intake may be important for bone health, but its effects on other outcomes, including cardiovascular disease (CVD) and cancer, remain unclear. Recent reports of adverse cardiovascular effects of supplemental calcium have raised concerns. OBJECTIVE: We investigated associations of supplemental, dietary, and total calcium intakes with all-cause, CVD-specific, and cancer-specific mortality in a large, prospective cohort. DESIGN: A total of 132,823 participants in the Cancer Prevention Study II Nutrition Cohort, who were followed from baseline (1992 or 1993) through 2012 for mortality outcomes, were included in the analysis. Dietary and supplemental calcium information was first collected at baseline and updated in 1999 and 2003. Multivariable-adjusted Cox proportional hazards models with cumulative updating of exposures were used to calculate RRs and 95% CIs for associations between calcium intake and mortality. RESULTS: During a mean follow-up of 17.5 y, 43,186 deaths occurred. For men, supplemental calcium intake was overall not associated with mortality outcomes (P-trend > 0.05 for all), but men who were taking ≥1000 mg supplemental calcium/d had a higher risk of all-cause mortality (RR: 1.17; 95% CI: 1.03, 1.33), which was primarily attributed to borderline statistically significant higher risk of CVD-specific mortality (RR: 1.22; 95% CI: 0.99, 1.51). For women, supplemental calcium was inversely associated with mortality from all causes [RR (95% CI): 0.90 (0.87, 0.94), 0.84 (0.80, 0.88), and 0.93 (0.87, 0.99) for intakes of 0.1 to <500, 500 to <1000, and ≥1000 mg/d, respectively; P-trend < 0.01]. Total calcium intake was inversely associated with mortality in women (P-trend < 0.01) but not in men; dietary calcium was not associated with all-cause mortality in either sex. CONCLUSIONS: In this cohort, associations of calcium intake and mortality varied by sex. For women, total and supplemental calcium intakes are associated with lower mortality, whereas for men, supplemental calcium intake ≥1000 mg/d may be associated with higher all-cause and CVD-specific mortality.

Circulating Biomarkers of Gut Barrier Function: Correlates and Nonresponse to Calcium Supplementation among Colon Adenoma Patients.

BACKGROUND: Gut barrier dysfunction contributes to several gastrointestinal disorders, including colorectal cancer, but factors associated with intestinal hyperpermeability have been minimally studied in humans. METHODS: We tested the effects of two doses of calcium (1.0 or 2.0 g/d) on circulating biomarkers of gut permeability [anti-flagellin and anti-lipopolysaccharide (LPS) Ig, measured via ELISA] over a 4-month treatment period among colorectal adenoma patients in a randomized, double-blinded, placebo-controlled clinical trial (n = 193), and evaluated the factors associated with baseline levels of these biomarkers. RESULTS: Baseline concentrations of anti-flagellin IgA and anti-LPS IgA were, respectively, statistically significantly proportionately higher by 11.8% and 14.1% among men, 31.3% and 39.8% among those with a body mass index ≥ 35 kg/m(2), and 19.9% and 22.0% among those in the upper relative to the lowest sex-specific tertile of waist circumference. A combined permeability score (the summed optical densities of all four biomarkers) was 24.3% higher among women in the upper tertile of plasma C-reactive protein (Ptrend < 0.01). We found no appreciable effects of supplemental calcium on anti-flagellin or anti-LPS Igs. CONCLUSIONS: Our results suggest that (i) men and those with higher adiposity may have greater gut permeability, (ii) gut permeability and systemic inflammation may be directly associated with one another, and (iii) supplemental calcium may not modify circulating levels of gut permeability biomarkers within 4 months. IMPACT: Our findings may improve the understanding of the factors that influence gut permeability to inform development of treatable biomarkers of risk for colorectal cancer and other health outcomes.