Calcium Supplementation Increases Blood Creatinine Concentration in a Randomized Controlled Trial

Background: Calcium supplements are widely used among older adults for osteoporosis prevention and treatment. However, their effect on creatinine levels and kidney function has not been well studied. Methods: We investigated the effect of calcium supplementation on blood creatinine concentration in a randomized controlled trial of colorectal adenoma chemoprevention conducted between 2004–2013 at 11 clinical centers in the United States. Healthy participants (N=1,675) aged 45–75 with a history of colorectal adenoma were assigned to daily supplementation with calcium (1200 mg, as carbonate), vitamin D3 (1000 IU), both, or placebo for three or five years. Changes in blood creatinine and total calcium concentration were measured after one year of treatment and multiple linear regression was used to estimate effects on creatinine concentrations. Results: After one year of treatment, blood creatinine was 0.01360.006 mg/dL higher on average among participants randomized to calcium compared to placebo after adjustment for other determinants of creatinine (P = 0.03). However, the effect of calcium treatment appeared to be larger among participants who consumed the most alcohol (2–6 drinks/day) or whose estimated glomerular filtration rate (eGFR) was less than 60 ml/min/1.73 m2 at baseline. The effect of calcium treatment on creatinine was only partially mediated by a concomitant increase in blood total calcium concentration and was independent of randomized vitamin D treatment. There did not appear to be further increases in creatinine after the first year of calcium treatment. Conclusions: Among healthy adults participating in a randomized clinical trial, daily supplementation with 1200 mg of elemental calcium caused a small increase in blood creatinine. If confirmed, this finding may have implications for clinical and public health recommendations for calcium supplementation

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

The Family Health Promotion Project (FHPP): Design and baseline data from a randomized trial to increase colonoscopy screening in high risk families

Colorectal cancer (CRC) is a significant cause of mortality and morbidity in the United States, much of which could be prevented through adequate screening. Consensus guidelines recommend that high-risk groups initiate screening earlier with colonoscopy and more frequently than average risk persons. However, a large proportion of high risk individuals do not receive regular colonoscopic screening. The Family Health Promotion Project (FHPP) is a randomized-controlled trial to test the effectiveness of a telephone-based counseling intervention to increase adherence to risk-appropriate colonoscopy screening in high risk individuals. Unaffected members of CRC families from two national cancer family registries were enrolled (n=632) and randomized to receive either a single session telephone counseling intervention using Motivational Interviewing techniques or a minimal mail-out intervention. The primary endpoint, rate of colonoscopy screening, was assessed at 6, 12 and 24 months post-enrollment. In this paper, we describe the research design and telephone counseling intervention of the FHPP trial, and report baseline data obtained from the two high risk cohorts recruited into this trial. Results obtained at baseline confirm the need for interventions to promote colonoscopy screening among these high risk individuals, as well as highlighting several key opportunities for intervention, including increasing knowledge about risk-appropriate screening guidelines, and providing both tailored risk information and barriers counseling

CYP2C9 variants increase risk of colorectal adenoma recurrence and modify associations with smoking but not aspirin treatment

The cytochrome P450 2C9 enzyme (CYP2C9) is involved in metabolism of endogenous compounds, drugs and procarcinogens. Two common nonsynonymous polymorphisms in CYP2C9 are associated with reduced enzyme activity: CYP2C9*2 (rs1799853, R144C) and CYP2C9*3 (rs1057910, I359L)

A Randomized Trial to Increase Colonoscopy Screening in Members of High-Risk Families in the Colorectal Cancer Family Registry and Cancer Genetics Network

Individuals with a strong family history of colorectal cancer (CRC) have significant risk for CRC, though adherence to colonoscopy screening in these groups remains low. This study assessed whether a tailored, telephone counseling intervention can increase adherence to colonoscopy in members of high risk families in a randomized, controlled trial

Vitamins B2, B6, and B12 and Risk of New Colorectal Adenomas in a Randomized Trial of Aspirin Use and Folic Acid Supplementation

Folate, other vitamin B cofactors, and genes involved in folate-mediated one-carbon metabolism (FOCM) all may play important roles in colorectal neoplasia. In this study, we examined the associations between dietary and circulating plasma levels of vitamins B2, B6 and B12 and risk colorectal adenomas

Smoking-associated risks of conventional adenomas and serrated polyps in the colorectum

PurposePrior studies suggest cigarette smoking is associated with 1.5- to twofold increased risk of colorectal adenomas and possibly a higher risk of serrated polyps. Further clarification of risk differences between adenomas and serrated polyps is needed with regard to co-occurrence and polyp location.Methods We conducted a combined analysis of conventional adenoma and serrated polyp occurrence using individual-level data from 2,915 patients participating in three colonoscopy-based clinical trials. All participants had ≥1 adenomas removed at baseline and were followed for up to 4years. Smoking habits and other lifestyle factors were collected at baseline using questionnaires. We used generalized linear regression to estimate risk ratios and 95% confidence intervals.ResultsSmokers were at slightly increased risk of adenomas compared to never smokers [current: RR 1.29 (95% CI 1.11–1.49) and former: RR 1.18 (1.05–1.32)]. Smoking was associated with greater risk of serrated polyps [current: RR 2.01 (1.66–2.44); former: RR 1.42 (1.20–1.68)], particularly in the left colorectum. Associations between current smoking and occurrence of serrated polyps only [RR 2.33 (1.76–3.07)] and both adenomas and serrated polyps [RR 2.27 (1.68–3.06)] were more pronounced than for adenomas only [RR 1.31 (1.08–1.58)]. Results were similar for other smoking variables and did not differ by gender or for advanced adenomas.ConclusionsCigarette smoking has only a weak association with adenomas, but is associated with a significantly increased risk of serrated polyps, particularly in the left colorectum. Since a minority of left-sided serrated polyps is thought to have malignant potential, the role of smoking in initiation phases of carcinogenesis is uncertain

Smoking-associated risks of conventional adenomas and serrated polyps in the colorectum

PurposePrior studies suggest cigarette smoking is associated with 1.5- to twofold increased risk of colorectal adenomas and possibly a higher risk of serrated polyps. Further clarification of risk differences between adenomas and serrated polyps is needed with regard to co-occurrence and polyp location.Methods We conducted a combined analysis of conventional adenoma and serrated polyp occurrence using individual-level data from 2,915 patients participating in three colonoscopy-based clinical trials. All participants had ≥1 adenomas removed at baseline and were followed for up to 4years. Smoking habits and other lifestyle factors were collected at baseline using questionnaires. We used generalized linear regression to estimate risk ratios and 95% confidence intervals.ResultsSmokers were at slightly increased risk of adenomas compared to never smokers [current: RR 1.29 (95% CI 1.11–1.49) and former: RR 1.18 (1.05–1.32)]. Smoking was associated with greater risk of serrated polyps [current: RR 2.01 (1.66–2.44); former: RR 1.42 (1.20–1.68)], particularly in the left colorectum. Associations between current smoking and occurrence of serrated polyps only [RR 2.33 (1.76–3.07)] and both adenomas and serrated polyps [RR 2.27 (1.68–3.06)] were more pronounced than for adenomas only [RR 1.31 (1.08–1.58)]. Results were similar for other smoking variables and did not differ by gender or for advanced adenomas.ConclusionsCigarette smoking has only a weak association with adenomas, but is associated with a significantly increased risk of serrated polyps, particularly in the left colorectum. Since a minority of left-sided serrated polyps is thought to have malignant potential, the role of smoking in initiation phases of carcinogenesis is uncertain

Colorectal Adenomas in a Randomized Folate Trial: The Role of Baseline Dietary and Circulating Folate Levels

The Aspirin/Folate Polyp Prevention Study is a randomized, placebo-controlled trial of aspirin use and folic acid supplementation and incidence of colorectal adenomas in individuals with a history of these lesions. The trial showed that folic acid supplementation does not prevent the occurrence of new adenomas and may increase risk. We extend these results by investigating whether the effect of folic acid treatment differed by baseline dietary and circulating folate levels. Diet and supplement use were ascertained at baseline through a food-frequency questionnaire; a blood sample was used to determine plasma and red blood cell (RBC) folate levels. Individuals were followed for 3 years (1st follow up) and subsequently for an additional 3-5 years (2nd follow up). We used generalized linear regression to estimate risk ratios and 95% confidence limits as measures of association. There was little evidence that baseline dietary and total folate intake, and plasma and RBC folate modified the association between folic acid treatment and risk of any adenomas or advanced lesions. However, there was a protective association of the highest tertile of dietary and total intake as well as circulating folate with risk of any adenomas among those in the placebo group, but no association among individuals in the folic acid group. Our findings support the idea that while moderate doses of folate may be protective compared to deficiency, at some point of sufficiency supplementation provides no additional benefit