Low-Carbohydrate Diet Score and the Risk of Colorectal Cancer: Findings from the Singapore Chinese Health Study.

BACKGROUND: Colorectal cancer is common cancer with a high mortality rate. Low-carbohydrate diet (LCD) score holistically evaluates the LCD pattern from carbohydrate, protein, and fat intake. Epidemiologic data of LCD-colorectal cancer association are sparse. METHODS: We evaluated the associations between LCD (i.e., total, animal- and plant-based) and colorectal cancer risk in the Singapore Chinese Health Study, a population-based prospective cohort study including 61,321 Chinese in Singapore who were 45 to 74 years old at baseline. Cox proportional hazard regression model was used to determine the HRs and respective 95% confidence intervals (CI) for colorectal cancer associated with LCD after adjusting for potential confounders, including age, sex, BMI, physical activity, family history of colorectal cancer, etc. RESULTS: After an average of 19.5 years of follow-up, 2,520 participants developed colorectal cancer (1,608 colon cancer and 912 rectal cancer). Overall, the association between total or plant-based LCD scores with the risk of colorectal, colon, or rectal cancer was null (all Ptrend ≥ 0.28). The animal-based LCD was modestly associated with colon cancer risk (Ptrend = 0.02), but not with rectal cancer. Compared with the lowest quartile, HRs (95% CIs) of colon cancer for quartiles 2, 3, and 4 of animal-based LCD were 1.12 (0.98-1.29), 1.27 (1.10-1.46), and 1.14 (0.99-1.31), respectively. CONCLUSIONS: A low-level carbohydrate diet with a high level of animal protein and fat was associated with a moderate increase in the risk of colon cancer among Chinese Singaporeans. IMPACT: High consumption of animal protein/fat and low consumption of carbohydrates may increase colon cancer risk.

Association of Vitamin D Level With Clinical Status in Inflammatory Bowel Disease: A 5-Year Longitudinal Study.

OBJECTIVES: Emerging data suggest that vitamin D has a significant role in inflammatory bowel disease (IBD). Prospective data evaluating the association of vitamin D serum status and disease course are lacking. We sought to determine the relationship between vitamin D status and clinical course of IBD over a multiyear time period. METHODS: IBD patients with up to 5-year follow-up from a longitudinal IBD natural history registry were included. Patients were categorized according to their mean serum 25-OH vitamin D level. IBD clinical status was approximated with patterns of medication use, health-care utilization, biochemical markers of inflammation (C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR)), pain and clinical disease activity scores, and health-related quality of life. RESULTS: A total of 965 IBD patients (61.9% Crohn's disease, 38.1% ulcerative colitis) formed the study population (mean age 44 years, 52.3% female). Among them, 29.9% had low mean vitamin D levels. Over the 5-year study period, subjects with low mean vitamin D required significantly more steroids, biologics, narcotics, computed tomography scans, emergency department visits, hospital admissions, and surgery compared with subjects with normal mean vitamin D levels (P<0.05). Moreover, subjects with low vitamin D levels had worse pain, disease activity scores, and quality of life (P<0.05). Finally, subjects who received vitamin D supplements had a significant reduction in their health-care utilization. CONCLUSIONS: Low vitamin D levels are common in IBD patients and are associated with higher morbidity and disease severity, signifying the potential importance of vitamin D monitoring and treatment.

No evidence of gene-calcium interactions from genome-wide analysis of colorectal cancer risk.

BACKGROUND: Calcium intake may reduce risk of colorectal cancer, but the mechanisms remain unclear. Studies of interaction between calcium intake and SNPs in calcium-related pathways have yielded inconsistent results. METHODS: To identify gene-calcium interactions, we tested interactions between approximately 2.7 million SNPs across the genome with self-reported calcium intake (from dietary or supplemental sources) in 9,006 colorectal cancer cases and 9,503 controls of European ancestry. To test for multiplicative interactions, we used multivariable logistic regression and defined statistical significance using the conventional genome-wide α = 5E-08. RESULTS: After accounting for multiple comparisons, there were no statistically significant SNP interactions with total, dietary, or supplemental calcium intake. CONCLUSIONS: We found no evidence of SNP interactions with calcium intake for colorectal cancer risk in a large population of 18,509 individuals. IMPACT: These results suggest that in genome-wide analysis common genetic variants do not strongly modify the association between calcium intake and colorectal cancer in European populations.

Supplementation with oral vs. intravenous iron for anemia with IBD or gastrointestinal bleeding: is oral iron getting a bad rap?

Although iron supplementation is commonly prescribed, the amount of elemental iron needed to achieve clinical efficacy, and the optimal method of supplementation, are under debate. Use of intravenous (IV) iron replacement is increasingly being advocated. We explore the physiology of iron supplementation, review clinical data suggesting that the typical oral dosing of iron may be excessive, and compare IV and oral methods of iron supplementation with a focus on inflammatory bowel disease (IBD). Both IV and oral iron can effectively raise hemoglobin levels in iron-deficiency anemia. There is no evidence that IV iron can raise hemoglobin at a faster pace. Side effects of oral iron are probably related to the relatively high doses of elemental iron that are typically prescribed. Emerging data suggest that low-dose iron has comparable efficacy, with fewer side effects. In IBD, both oral and IV iron are effective, and there is no convincing evidence that oral iron activates or exacerbates clinical symptoms. The use of a low starting dose of oral iron, such as one ferrous sulfate tablet per day, for treatment of iron deficiency is worth considering.

Variation in the selenoenzyme genes and risk of advanced distal colorectal adenoma.

BACKGROUND: Epidemiologic and animal studies provide evidence for a chemopreventive effect of selenium on colorectal cancer, which may be mediated by the antioxidative and anti-inflammatory properties of selenoenzymes. We therefore investigated whether genetic variants in selenoenzymes abundantly expressed in the colon are associated with advanced colorectal adenoma, a cancer precursor. METHODS: Cases with a left-sided advanced adenoma (n = 772) and matched controls (n = 777) screen negative for polyps based on sigmoidoscopy examination were randomly selected from participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. The underlying genetic variation was determined by resequencing. We genotyped 44 tagging single nucleotide polymorphisms (SNP) in six genes [glutathione peroxidase 1-4 (GPX1, GPX2, GPX3, and GPX4), selenoprotein P (SEPP1), and thioredoxin reductase 1 (TXNRD1)] to efficiently predict common variation across these genes. RESULTS: Four variants in SEPP1 were significantly associated with advanced adenoma risk. A rare variant in the 5' region of SEPP1 (-4166C>G) was present in nine cases but in none of the controls (exact P = 0.002). Three SNPs located in the 3' region of SEPP1, which is overlapping with the promoter region of an antisense transcript, were significantly associated with adenoma risk: homozygotes at two SEPP1 loci (31,174 bp 3' of STP A>G and 43,881 bp 3' of STP G>A) were associated with increased adenoma risk [odds ratio (OR), 1.48; 95% confidence interval (95% CI), 1.00-2.19 and OR, 1.53; 95% CI, 1.05-2.22, respectively] and the variant SEPP1 44,321 bp 3' of STP C>T was associated with a reduced adenoma risk (CT versus CC OR, 0.85; 95% CI, 0.63-1.15). Furthermore, we observed a significant 80% reduction for advanced colorectal adenoma risk for carriers of the variant allele at TXNRD1 IVS1-181C>G (OR, 0.20; 95% CI, 0.07-0.55; P trend = 0.004). Consistent with the individual SNP results, we observed a significant overall association with adenoma risk for SEPP1 and TXNRD1 (global P = 0.02 and 0.008, respectively) but not for the four GPX genes. CONCLUSION: Our study suggests that genetic variants at or near the SEPP1 and TXNRD1 loci may be associated with advanced colorectal adenoma. As this is the first study to comprehensively investigate this hypothesis, confirmation in independent study populations is needed.

No immunological benefit of selenium in consecutive patients with autoimmune thyroiditis.

BACKGROUND: Recently it has been demonstrated that after selenium (Se) supplementation in autoimmune thyroiditis (AIT) patients, there was a significant decrease of thyroid peroxidase (TPO) autoantibody (TPOAb) levels. The aim of our study was to evaluate the immunological benefit of Se administration in unselected AIT patients and thus address the question whether Se administration should generally be recommended for AIT patients. METHODS: Thirty-six consecutive AIT patients (aged 19-85 years) were included in the present study. In addition to their levothyroxine (LT(4)) treatment, 18 patients received 200 microg (2.53 micromol) sodium selenite per day orally for the time span of 3 months, whereas 18 patients received placebo. All patients had measurement of thyroid hormones, thyrotropin (TSH), autoantibodies (thyroglobulin antibodies [TgAb] and TPOAb), Se levels, and intracellular cytokine detection in CD4(+) and CD8(+) T cells of peripheral blood mononuclear cells (PBMC) by flow cytometry before and after Se or placebo administration. RESULTS: No significant difference in the TPOAb levels was found after Se administration (524 +/- 452 vs. 505 +/- 464 IU/mL; p > 0.05). Furthermore, we found no significant differences in the CD4(+) or CD8(+) cytokine pattern (IFN-gamma, IL-2, IL-4, IL-5, IL-6, IL-10, IL-13, TNF-alpha, TNF-beta) in patients before and after Se administration, in patients before and after placebo administration and between Se group and placebo group before and after Se vs. placebo administration. CONCLUSION: We demonstrate that Se administration in our AIT patient's cohort does not induce significant immunological changes, either in terms of cytokine production patterns of peripheral T lymphocytes or of TPOAb levels. Our data suggest that AIT patients with moderate disease activity (in terms of TPOAb and cytokine production patterns) may not (equally) benefit as patients with high disease activity.

Calcium intake and colorectal adenoma in a US colorectal cancer early detection program.

BACKGROUND: Calcium can reduce the risk of colorectal tumors by binding secondary bile and fatty acids, which leads to antiproliferative effects in the bowel, or by acting directly on the colonic epithelium, which affects differentiation and apoptosis. OBJECTIVE: We investigated calcium intake and risk of colon adenoma to evaluate the association of calcium intake with early stages of colorectal tumor development. DESIGN: We compared the supplemental and dietary calcium intakes of 3696 participants with histologically verified adenoma of the distal colon (ie, descending colon, sigmoid colon, or rectum) with the calcium intakes of 34 817 sigmoidoscopy-negative control participants in the Prostate, Lung, Colorectal, and Ovarian Cancer Screening Trial. Calcium intake was assessed at study entry with a 137-item food-frequency questionnaire and additional questions on the amount and duration of calcium supplement use. RESULTS: After adjustment for known risk factors, adenoma risk was lower by 12% for participants in the highest quintile of total calcium intake (>1767 mg/d) than for participants in the lowest quintile (<731 mg/d) (odds ratio: 0.88; 95% CI: 0.76, 1.02; P for trend = 0.04). The protective association between total calcium and colorectal adenoma was largely due to calcium supplement use, with a 27% decrease in adenoma risk for participants taking >1200 mg/d than for nonusers of supplements (odds ratio: 0.73; 95% CI: 0.56, 0.91; P for trend = 0.005). The protective associations of total and supplemental calcium were strongest for colon adenoma (descending and sigmoid colon). CONCLUSION: High calcium intake, particularly from supplements, is associated with a reduced risk of distal colorectal adenoma.

A population-based, community estimate of total colon examination: the impact on compliance with screening for colorectal cancer.

OBJECTIVE: Colorectal cancer screening is underutilized. Total colon examination (TCE), such as with colonoscopy, can have a significant effect on the measured compliance with screening, as colonoscopy may be able to be performed as infrequently as once every 10 yr. In a population-based survey we determined the prevalence and validated the self-reporting of TCE and assessed its impact on compliance with screening. METHODS: We interviewed an age- and sex-stratified random sample of 50- to 79-yr-old residents in two communities in southwestern Pennsylvania. Subjects reported ever having had and duration since last use of fecal occult blood testing (FOBT), flexible sigmoidoscopy (FS), rigid proctoscopy, barium enema, and colonoscopy. Self-reports of colorectal testing were validated via retrieval of procedure reports. RESULTS: Out of 1223 individuals sampled, 496 completed a telephone interview (40.6% overall and 58.3% of eligible contacts). In those without personal or family histories of colorectal cancer or personal histories of polyps (n = 377), 50%, 19.6%, 39.8%, and 17.5% reported ever having had FOBT, FS, barium enema, and colonoscopy, respectively. Thirty-one percent reported having FOBT within the previous year or FS within the previous 5 yr. Including TCE within the previous 5 yr increased the measured compliance to 39.7%. Compliance was significantly greater among subjects with family histories of colorectal cancer (62.9% vs 39.7%, odds ratio = 2.6, 95% CI = 1.3-5.2). Self-reports of recent colonoscopy were verified in 29 of 35 instances (83%). CONCLUSION: The prevalence of TCE in this population was significant, and including TCE substantially increased measured compliance with colorectal cancer screening. Self-reported use of colonoscopy was validated as accurate.