Plasma vitamin D and risk of colorectal cancer: the Japan Public Health Center-Based Prospective Study

Importance of circulating leptin and adiponectin in the causal pathways between obesity and the development of colorectal cancer in Japanese men

BACKGROUND

The mechanistic associations between obesity and risk of colorectal cancer (CRC) remain unclear. Here, using body mass index (BMI) as an obesity indicator, we decomposed the total effects of obesity on the risk of CRC into: (1) direct effects, which are possibly mediated by unmeasured or currently unknown factors; (2) indirect effects mediated by circulating leptin and adiponectin; and (3) indirect effects that are not mediated by circulating leptin and adiponectin but by hyperinsulinemia and chronic inflammation (assessed via circulating connecting peptide and C-reactive protein, respectively).

METHODS

We adopted a causal mediation framework, using data from a large prospective cohort study of 44,271 Japanese men.

RESULTS

BMI was not associated with the risk of CRC due to direct and indirect effects that were not mediated by circulating leptin and adiponectin. By contrast, individuals with BMIs of 25.0-27.4 kg/m2 (risk ratio, 1.29; 95% confidence interval, 0.98-1.69) and ≥27.5 kg/m2 (risk ratio, 1.28; 95% confidence interval, 0.98-1.68) had a higher risk of CRC due to indirect effects of circulating leptin and adiponectin.

CONCLUSIONS

Our mediation analyses suggest that the association between BMI and CRC risk may be largely mediated by a pathway involving circulating leptin and adiponectin.

Serum 25-hydroxyvitamin D concentrations and colorectal cancer incidence in adults with type 2 diabetes

BACKGROUND

To examine the association of serum 25-hydroxyvitamin D (25[OH]D) with colorectal cancer (CRC) risk in adults with type 2 diabetes (T2D).

METHODS

Using UK Biobank data, this study included 18,453 adults with T2D. Serum 25(OH)D concentrations were determined by the chemiluminescent immunoassay method. A Cox proportional hazards model was used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for CRC outcomes.

RESULTS

During a median follow-up of 8.8 years, there were 284 incident CRC cases. Compared with adults with serum 25(OH)D concentrations <25.0 nmol/L, the adjusted HRs (95% CIs) for lower to higher serum 25(OH)D concentrations (25.0 to <50.0, 50.0 to <75.0, and ≥75.0 nmol/L) were 0.61 (0.46-0.82), 0.50 (0.34-0.74), and 0.53 (0.30-0.94), respectively (Ptrend = 0.001). The risk of CRC decreased by 19.0% for per 1-SD increment in serum 25(OH)D concentrations. A nonlinear association of serum 25(OH)D concentrations with CRC risk was observed using a restricted cubic spline analysis (P nonlinearity = 0.002).

CONCLUSIONS

Higher serum 25(OH)D concentrations were significantly and nonlinearly associated with a lower risk of CRC. These findings highlight the potential benefits of maintaining adequate vitamin D levels in CRC prevention among adults with T2D.

Prediagnostic Vitamin D Status and Colorectal Cancer Survival by Vitamin D Binding Protein Isoforms in US Cohorts

CONTEXT

Lower 25-hydroxyvitamin D (25(OH)D) levels have consistently been associated with higher mortality among participants with colorectal cancer (CRC).

OBJECTIVE

To investigate whether the association between 25(OH)D and CRC mortality differs according to vitamin D binding protein (also known as Gc) isoforms.

METHODS

We examined the association between prediagnostic 25(OH)D levels and overall and CRC-specific mortality among participants with CRC within 2 prospective US cohorts. Cox proportional hazards regression was used to estimate the hazard ratios (HRs) and 95% CIs.

RESULTS

588 participants with CRC were observed until the date of death or last follow-up (2018), whichever came first. Deficient vs sufficient 25(OH)D concentrations (<30 vs ≥50 nmol/L) were associated with higher overall mortality (HR 2.06; 95% CI 1.34-3.18) but not with CRC-specific mortality (HR 1.51; 95% CI 0.75-3.07). The HRs for overall mortality comparing deficient vs sufficient concentrations were 2.43 (95% CI 1.26-4.70) for those with the Gc1-1 isoform (rs4588 CC) and 1.63 (95% CI 0.88-3.02) for those with the Gc1-2 or Gc2-2 (rs4588 CA or AA) isoform (P for interaction = .54). The HRs for CRC-specific mortality were 1.18 (95% CI 0.27-5.14) for those with the Gc1-1 isoform and 1.41 (95% CI 0.62-3.24) for those with the Gc1-2 or Gc2-2 isoform (P for interaction = .94).

CONCLUSION

In these 2 US cohorts, we found that lower 25(OH)D levels were associated with higher overall mortality, but this association did not differ by Gc isoforms.

Circulating vitamin D levels and colorectal cancer risk: A meta-analysis and systematic review of case-control and prospective cohort studies

The associations between circulating vitamin D concentrations and total and site-specific colorectal cancer (CRC) incidence have been examined in several epidemiological studies with overall inconclusive findings. The aim of this systematic review and meta-analysis of both case-control and prospective cohort studies was to evaluate the association between CRC and circulating levels of vitamin D. The main exposure and outcome were circulating total 25(OH)D and CRC, respectively, in the overall population (i.e., all subjects). Two reviewers, working independently, screened all the literature available to identify studies that met the inclusion criteria (e.g., case-control or prospective cohort studies, published in English, and excluding non-original papers). Data were pooled by the generic inverse variance method using a random or fixed effect model, as approriate. Heterogeneity was identified using the Cochran's Q-test and quantified by the I² statistic. Results were stratified by study design, sex, and metabolite of vitamin D. Sensitivity and subgroup analyses were also performed. A total of 28 original studies were included for the quantitative meta-analysis. Meta-analyses comparing the highest vs lowest categories, showed a 39% lower risk between levels of total 25(OH)D and CRC risk (OR (95% CI): 0.61 (0.52; 0.71); 11 studies) in case-control studies; whereas a 20% reduced CRC risk in prospective cohort studies (HR (95% CI): 0.80 (0.66; 0.97); 6 studies). Results in women mirrored main results, whereas results in men were non-significant in both analyses. Our findings support an inverse association between circulating vitamin D levels and CRC risk.

Low Vitamin D Status Is Associated with Increased Risk of Mortality in Korean Men and Adults with Hypertension: A Population-Based Cohort Study

Background Recent randomized controlled trials (RCTs) have shown no effect of vitamin D supplementation on cardiovascular disease, cancer events and mortality or all-cause mortality in Western populations. However, there has been a lack of research on populations with low vitamin D status, including Asians. In addition, there have been indications that an individual’s sex or hypertension status may affect the relationship between vitamin D status and mortality. In this study, we retrospectively assessed the association between vitamin D status and all-cause, cardiovascular, and cancer mortality in Koreans using a national database, and stratified participants according to sex and hypertension status. Methods Participants in the Korean Health and Nutrition Examination Survey 2008−2014, who consented to their data being synthesized with mortality data (up to December 2019), were included (n = 22,742; mean follow-up: 8.9 years). Participants’ level of serum 25-hydroxyvitamin D (25(OH)D) was measured by radioimmunoassay and categorized as <12, 12−19.9, and ≥20 ng/mL. A Cox proportional hazard model was used to assess the risk of mortality. Results In the total sample, risk of all-cause, cancer, and cardiovascular mortality was greater in adults with a serum 25(OH)D level below 12 and 12−19.9 ng/mL than those with ≥20 ng/mL. Men and adults with hypertension, who had low vitamin D status, had a higher risk of cancer and cardiovascular mortality, but not women or adults without hypertension. Similar results were observed when various cutoffs for 25(OH)D were employed, or extrinsic deaths were excluded. Conclusions Vitamin D status below 20 ng/mL is associated with a higher risk of mortality in Korean adults, especially in men and those with hypertension, on the basis of data from a nationally representative sample. Further RCTs on Asian adults with low vitamin D status are warranted.

Vitamin D and Cancer: An Historical Overview of the Epidemiology and Mechanisms

This is a narrative review of the evidence supporting vitamin D’s anticancer actions. The first section reviews the findings from ecological studies of cancer with respect to indices of solar radiation, which found a reduced risk of incidence and mortality for approximately 23 types of cancer. Meta-analyses of observational studies reported the inverse correlations of serum 25-hydroxyvitamin D [25(OH)D] with the incidence of 12 types of cancer. Case-control studies with a 25(OH)D concentration measured near the time of cancer diagnosis are stronger than nested case-control and cohort studies as long follow-up times reduce the correlations due to changes in 25(OH)D with time. There is no evidence that undiagnosed cancer reduces 25(OH)D concentrations unless the cancer is at a very advanced stage. Meta-analyses of cancer incidence with respect to dietary intake have had limited success due to the low amount of vitamin D in most diets. An analysis of 25(OH)D-cancer incidence rates suggests that achieving 80 ng/mL vs. 10 ng/mL would reduce cancer incidence rates by 70 ± 10%. Clinical trials have provided limited support for the UVB-vitamin D-cancer hypothesis due to poor design and execution. In recent decades, many experimental studies in cultured cells and animal models have described a wide range of anticancer effects of vitamin D compounds. This paper will review studies showing the inhibition of tumor cell proliferation, dedifferentiation, and invasion together with the sensitization to proapoptotic agents. Moreover, 1,25-(OH)₂D₃ and other vitamin D receptor agonists modulate the biology of several types of stromal cells such as fibroblasts, endothelial and immune cells in a way that interferes the apparition of metastases. In sum, the available mechanistic data support the global protective action of vitamin D against several important types of cancer.

Predicted Vitamin D Status and Colorectal Cancer Incidence in the Black Women's Health Study

BACKGROUND

Observational studies, mostly among White populations, suggest that low vitamin D levels increase colorectal cancer risk. African Americans, who are disproportionately burdened by colorectal cancer, often have lower vitamin D levels compared with other populations.

METHODS

We assessed predicted vitamin D score in relation to colorectal cancer among 49,534 participants in the Black Women's Health Study, a cohort of African American women followed from 1995 to 2017 through biennial questionnaires. We derived predicted vitamin D scores at each questionnaire cycle for all participants using a previously validated prediction model based on actual 25-hydroxyvitamin D values from a subset of participants. We calculated cumulative average predicted vitamin D score at every cycle by averaging scores from cycles up to and including that cycle. Using Cox proportional hazards regression, we estimated hazard ratios (HR) and 95% confidence intervals (CI) for colorectal cancer incidence according to predicted score quartiles.

RESULTS

Over follow-up, 488 incident colorectal cancers occurred. Compared with women in the highest quartile of predicted vitamin D score, those in the lowest had an estimated 41% (HR = 1.41; 95% CI, 1.05-1.90) higher colorectal cancer risk. Comparable HRs were 1.44 (95% CI, 1.02-2.01) for colon and 1.34 (95% CI, 0.70-2.56) for rectal cancer.

CONCLUSIONS

Low vitamin D status may lead to elevated colorectal cancer risk in African American women.

IMPACT

Our findings, taken together with established evidence that vitamin D levels are generally lower in African Americans than other U.S. groups, suggest that low vitamin D status may contribute to the disproportionately high colorectal cancer incidence among African Americans.

Total Vitamin D Intake and Risks of Early-Onset Colorectal Cancer and Precursors

BACKGROUND & AIMS

Vitamin D has been implicated in colorectal cancer (CRC) pathogenesis, but it remains unknown whether total vitamin D intake is associated with early-onset CRC and precursors diagnosed before age 50.

METHODS

We prospectively examined the association between total vitamin D intake and risks of early-onset CRC and precursors among women enrolled in the Nurses' Health Study II. Multivariable-adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for early-onset CRC were estimated with Cox proportional hazards model. Multivariable-adjusted odds ratios (ORs) and 95% CIs for early-onset conventional adenoma and serrated polyp were estimated with logistic regression model.

RESULTS

We documented 111 incident cases of early-onset CRC during 1,250,560 person-years of follow-up (1991 to 2015). Higher total vitamin D intake was significantly associated with a reduced risk of early-onset CRC (HR for ≥450 IU/day vs <300 IU/day, 0.49; 95% CI, 0.26-0.93; P for trend = .01). The HR per 400 IU/day increase was 0.46 (95% CI, 0.26-0.83). The inverse association was significant and appeared more evident for dietary sources of vitamin D (HR per 400 IU/day increase, 0.34; 95% CI, 0.15-0.79) than supplemental vitamin D (HR per 400 IU/day increase, 0.77; 95% CI, 0.37-1.62). For CRC precursors, the ORs per 400 IU/day increase were 0.76 (95% CI, 0.65-0.88) for conventional adenoma (n = 1,439) and 0.85 (95% CI, 0.75-0.97) for serrated polyp (n = 1,878).

CONCLUSIONS

In a cohort of younger women, higher total vitamin D intake was associated with decreased risks of early-onset CRC and precursors.

Associations of vitamin D status with colorectal cancer risk and survival

Biological evidence suggests that vitamin D has numerous anticancer functions, but the associations between vitamin D status and colorectal cancer (CRC) risk and survival remain inconclusive. Based on UK Biobank, we prospectively evaluated the associations of season-standardized 25-hydroxyvitamin D (25(OH)D) concentrations with CRC risk among 360 061 participants, and with survival among 2509 CRC cases. We observed an inverse linear relationship between 25(OH)D concentrations and CRC risk (P for linearity = .01; HR per 1-SD increment, 0.95; 95% CI, 0.91-0.99). Compared to the lowest quartile of 25(OH)D, the highest quartile was associated with a 13% (HR, 0.87; 95% CI, 0.77-0.98) lower risk of CRC. For CRC survival, compared to those in the lowest quartile of 25(OH)D, cases in the highest quartile had a 20% (HR, 0.80; 95% CI, 0.65-0.99) lower risk for overall death. Our findings indicate that higher concentrations of serum 25(OH)D are associated with lower incidence and improved survival of CRC, suggesting a role of vitamin D in the pathogenesis of CRC.

Reproductive Factors and Breast Cancer Risk in Lithuanian Women: A Population-Based Cohort Study

Abstract. Background.

Although the relationship between reproductive factors and breast cancer is internationally proved, reliable data on former USSR countries are scarce. This study examines the association of parity, age at the first childbirth, number of children, and breast cancer risk in Lithuanian women.

Methods.

The study that included women from 40 to 79 years old was based on a dataset that was made up linking all records from the 2001 census, all cancer incidence records from the Lithuanian Cancer Registry and all death records from Statistics Lithuania between 6th April 2001 and 31st December 2009. Cox’s proportional hazards regression models were used to estimate the hazard ratios (HRs) for parity, age at the first childbirth, and number of children.

Results.

If compared to nulliparous women, parous women had a lower risk of breast cancer (HR=0.84, 95% CI 0.78–0.89) and this risk further decreased with an increasing number of children. Women who gave birth after the age of 25 had a significantly higher risk of breast cancer. This disadvantage became statistically insignificant or decreased after controlling for total number of children.

Conclusions.

Parity and age at the first childbirth are strong predictors of breast cancer risk among Lithu-anian women.

Association between blood circulating vitamin D and colorectal cancer risk in Asian countries: a systematic review and dose-response meta-analysis

OBJECTIVES

To assess the association between blood circulating vitamin D levels and colorectal cancer risk in the Asian population.

DESIGN

This is a systematic review and dose-response meta-analysis of observational studies that investigated the relationship between blood circulating vitamin D levels and colorectal cancer risk in the Asian population.

DATA SOURCES

Relevant studies were identified through a literature search in Medline, Embase and Web of Science from 1st January 1980 to 31st January 2019. Eligibility criteria: original studies published in peer-reviewed journals investigating the association between blood circulating vitamin D levels and the risk of colorectal cancer and/or adenoma in Asian countries.

DATA EXTRACTION AND SYNTHESIS

Two authors independently extracted data and assessed the quality of included studies. Study-specific ORs were pooled using a random-effects model. A dose-response meta-analysis was performed with generalised least squares regression. We applied the Newcastle-Ottawa Scale quality assessment to evaluate the quality of the selected studies.

RESULTS

The eight included studies encompassed a total of 2916 cases and 6678 controls. The pooled ORs of colorectal cancer for the highest versus lowest categories of blood circulating vitamin D levels was 0.75 (95% CI 0.58 to 0.97) up to 36.5 ng/mL in the Asian population. There was heterogeneity among the studies (I²=53.9%, P_{heterogeneity}=0.034). The dose-response meta-analysis indicated a significant linear relationship (P_{non-linearity}=0.11). An increment of 16 ng/mL in blood circulating vitamin D level corresponded to an OR of 0.79 (95% CI 0.64 to 0.97).

CONCLUSIONS

The results of this meta-analysis indicate that blood circulating vitamin D level is associated with decreased risk of colorectal cancer in Asian countries. The dose-response meta-analysis shows that the strength of this association among the Asian population is similar to that among the Western population. Our study suggests that the Asian population should improve nutritional status and maintain a higher level of blood circulating vitamin D.

Additively protective effects of vitamin D and calcium against colorectal adenoma incidence, malignant transformation and progression: A systematic review and meta-analysis

BACKGROUND

Colorectal cancer (CRC) exhibits a linear progression from normal colonic epithelium, adenoma initiation, carcinoma transformation and even to metastasis. Diet changes might influence carcinogenesis and prognosis. We aimed to determine the effects of vitamin D and calcium on colorectal adenoma incidence, malignancy development and prognosis.

METHODS

Systematic literature searches (PubMed, Embase, and Cochrane Library databases) and hand searches were performed by September 30, 2019. A random-effects model was adopted to pool relative ratios (RRs) for colorectal tumour incidence or hazard ratios (HRs) for CRC mortality. Stratified analyses were performed by gender, tumour location, calcium intake level and ethnic group.

RESULTS

Total 854,195 cases from 166 studies were included. The colorectal adenoma incidence was inversely correlated with the circulating 25-hydroxyvitamin D [25(OH)D] level (RR: 0.80, 95% CI: 0.71-0.89), vitamin D intake (RR: 0.87, 95% CI: 0.82-0.92) and calcium intake (RR: 0.86, 95% CI: 0.81-0.91). The CRC incidence was decreased by circulating 25(OH)D (RR: 0.67, 95% CI: 0.59-0.77), vitamin D intake (RR: 0.85, 95% CI: 0.78-0.93) and calcium intake (RR: 0.75, 95% CI: 0.70-0.79). High-level circulating 25(OH)D triggered better overall survival (HR: 0.67, 95% CI: 0.57-0.79) and CRC-specific survival (HR: 0.63, 95% CI: 0.53-0.74). Stratified analyses showed that vitamin D and calcium significantly suppressed colorectal tumour incidence among women. Left-sided CRC risk was reversely related to circulating 25(OH)D (RR: 0.60, 95% CI: 0.41-0.88) and vitamin D intake (RR: 0.73, 95% CI: 0.57-0.93). Circulating 25(OH)D decreased colorectal adenoma (RR: 0.63, 95% CI: 0.48-0.82) and CRC (RR: 0.69, 95% CI: 0.56-0.86) risk in populations with higher calcium intake. European and American populations benefited more from vitamin D intake against colorectal tumour. A significant dose-response relationship was observed between intake of vitamin D or calcium and colorectal tumour incidence.

CONCLUSIONS

Vitamin D and calcium play additively chemopreventive roles in colorectal adenoma incidence, malignant transformation and progression, especially for women and left-sided CRC patients.

The Association of Dietary Intake of Calcium and Vitamin D to Colorectal Cancer Risk among Iranian Population

Background:

Vitamin D and Calcium have a possible protective impact versus rectal neoplasm. Vitamin D, an important nutrient, is vital to regulate the absorption of calcium and bone mineralization; nevertheless, in a case-control study in Iran, we investigated the relationship among the dietary intake of vitamin D and calcium with the hazard of rectal neoplasm.

Methods:

363 subjects (162 cases and 201 controls) participated in the case- control Study from March 2017 to November 2018. Dietary intake of Calcium and Vitamin D was calculated using a 148-items food-frequency questionnaire.

Results:

Since altering the strong confounding agents, the multivariate risk proportion within the dietary vitamin D intake was OR=0.2, 95%CI 0.1-0.5, P-value <0.001 among cases. There was no association in case of calcium and rectal cancer.

Conclusions:

Taken together, a possible reduction in the hazard of rectal neoplasm with dietary intake of Vitamin D within Iranian patients was observed.

Circulating Vitamin D and Colorectal Cancer Risk: An International Pooling Project of 17 Cohorts

BACKGROUND

Experimental and epidemiological studies suggest a protective role for vitamin D in colorectal carcinogenesis, but evidence is inconclusive. Circulating 25-hydroxyvitamin D (25(OH)D) concentrations that minimize risk are unknown. Current Institute of Medicine (IOM) vitamin D guidance is based solely on bone health.

METHODS

We pooled participant-level data from 17 cohorts, comprising 5706 colorectal cancer case participants and 7107 control participants with a wide range of circulating 25(OH)D concentrations. For 30.1% of participants, 25(OH)D was newly measured. Previously measured 25(OH)D was calibrated to the same assay to permit estimating risk by absolute concentrations. Study-specific relative risks (RRs) for prediagnostic season-standardized 25(OH)D concentrations were calculated using conditional logistic regression and pooled using random effects models.

RESULTS

Compared with the lower range of sufficiency for bone health (50-<62.5 nmol/L), deficient 25(OH)D (<30 nmol/L) was associated with 31% higher colorectal cancer risk (RR = 1.31, 95% confidence interval [CI] = 1.05 to 1.62); 25(OH)D above sufficiency (75-<87.5 and 87.5-<100 nmol/L) was associated with 19% (RR = 0.81, 95% CI = 0.67 to 0.99) and 27% (RR = 0.73, 95% CI = 0.59 to 0.91) lower risk, respectively. At 25(OH)D of 100 nmol/L or greater, risk did not continue to decline and was not statistically significantly reduced (RR = 0.91, 95% CI = 0.67 to 1.24, 3.5% of control participants). Associations were minimally affected when adjusting for body mass index, physical activity, or other risk factors. For each 25 nmol/L increment in circulating 25(OH)D, colorectal cancer risk was 19% lower in women (RR = 0.81, 95% CI = 0.75 to 0.87) and 7% lower in men (RR = 0.93, 95% CI = 0.86 to 1.00) (two-sided Pheterogeneity by sex = .008). Associations were inverse in all subgroups, including colorectal subsite, geographic region, and season of blood collection.

CONCLUSIONS

Higher circulating 25(OH)D was related to a statistically significant, substantially lower colorectal cancer risk in women and non-statistically significant lower risk in men. Optimal 25(OH)D concentrations for colorectal cancer risk reduction, 75-100 nmol/L, appear higher than current IOM recommendations.

The Effects of UVB and Vitamin D on Decreasing Risk of Colorectal Cancer Incidence and Mortality: A Review of the Epidemiology, Clinical Trials, and Mechanisms

The solar ultraviolet B-vitamin D-cancer hypothesis was first suggested in 1980 based on a geographical ecological study. Since then, several ecological and observational studies, as well as researches of mechanisms have supported the hypothesis. Also, the association between vitamin D condition and cancer risk has been assessed in a number of epidemiologic studies, while data from interventional studies remain scant. In regard of cancer locations, the body of evidence is most substantial for colorectal cancer, for which support comes from studies of 25(OH)D, vitamin D intake, and region of residence in a sunny weather. Collectively evidence demonstrates that vitamin D has a potent and beneficial effect at antagonizing and blocking several mitogenic mechanisms related to tumorigenesis. Taken together with the epidemiological studies and limited clinical trials, individuals may need to consider elevating 25(OH)D levels via sun exposure and/or vitamin D supplementation to decrease risk of colorectal cancer, in addition to standard care, treat cancer.

Cruciferous vegetable intake and colorectal cancer risk: Japan public health center-based prospective study

We aimed to assess the association between cruciferous vegetable intake and colorectal cancer (CRC) development among Japanese adults aged between 45 and 74 years in the Japan Public Health Center-based Prospective Study. During 1 325 853 person-years of follow-up, 2612 CRC cases were identified. The association of cruciferous vegetable intake with CRC risk was assessed using a Cox proportional hazard regression model to compute hazard ratios (HRs) and 95% confidence intervals (CIs), adjusted for potential confounders. No significant association was observed between the highest cruciferous vegetable intake quartile (compared with the lowest) and CRC risk in men (multivariate HRs: 1.08; 95% CI: 0.91, 1.29) and women (multivariate HRs: 0.99; 95% CI: 0.80, 1.22) and its subsites. Women showed a marginal negative association between cruciferous vegetable intake and the risk of colon cancer (CC) after excluding participants who developed CC in the first 3 years of follow-up (P for trend = 0.08); a positive association was found with proximal CC in men. Cruciferous vegetable intake does not have a significant association with CRC risk in the Japanese general population.

Circulating 25-hydroxyvitamin D up to 3 decades prior to diagnosis in relation to overall and organ-specific cancer survival

While vitamin D has been associated with improved overall cancer survival in some investigations, few have prospectively evaluated organ-specific survival. We examined the accepted biomarker of vitamin D status, serum 25-hydroxyvitamin D [25(OH)D], and cancer survival in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. Of 4616 cancer cases with measured serum 25(OH)D, 2884 died of their cancer during 28 years of follow-up and 1732 survived or died of other causes. Proportional hazards regression estimated hazard ratios (HR) and 95% confidence intervals (CI) for the association between pre-diagnostic 25(OH)D and overall and site-specific survival. Serum 25(OH)D was significantly lower among cases who subsequently died from their malignancy compared with those who did not (medians 34.7 vs. 36.5 nmol/L, respectively; p = 0.01). Higher 25(OH)D was associated with lower overall cancer mortality (HR = 0.76, 95% CI 0.67-0.85 for highest vs. lowest quintile, p-trend < 0.0001). Higher 25(OH)D was related to lower mortality from the following site-specific malignancies: prostate (HR = 0.74, 95% CI 0.55-1.01, p-trend = 0.005), kidney (HR = 0.59, 95% CI 0.35-0.98, p-trend = 0.28), and melanoma (HR = 0.39, 95% CI 0.20-0.78, p-trend = 0.01), but increased mortality from lung cancer (HR = 1.28, 95% CI 1.02-1.61, p-trend = 0.19). Improved survival was also suggested for head and neck, gastric, pancreatic, and liver cancers, though not statistically significantly, and case numbers for the latter two organ sites were small. Higher 25(OH)D status years prior to diagnosis was related to improved survival for overall and some site-specific cancers, associations that should be examined in other prospective populations that include women and other racial-ethnic groups.

Plasma 25-hydroxyvitamin D concentration and subsequent risk of total and site specific cancers in Japanese population: large case-cohort study within Japan Public Health Center-based Prospective Study cohort

OBJECTIVE

To evaluate the association between pre-diagnostic circulating vitamin D concentration and the subsequent risk of overall and site specific cancer in a large cohort study.

DESIGN

Nested case-cohort study within the Japan Public Health Center-based Prospective Study cohort.

SETTING

Nine public health centre areas across Japan.

PARTICIPANTS

3301 incident cases of cancer and 4044 randomly selected subcohort participants.

EXPOSURE

Plasma concentration of 25-hydroxyvitamin D measured by enzyme immunoassay. Participants were divided into quarters based on the sex and season specific distribution of 25-hydroxyvitamin D among subcohorts. Weighted Cox proportional hazard models were used to calculate the multivariable adjusted hazard ratios for overall and site specific cancer across categories of 25-hydroxyvitamin D concentration, with the lowest quarter as the reference.

MAIN OUTCOME MEASURE

Incidence of overall or site specific cancer.

RESULTS

Plasma 25-hydroxyvitamin D concentration was inversely associated with the risk of total cancer, with multivariable adjusted hazard ratios for the second to fourth quarters compared with the lowest quarter of 0.81 (95% confidence interval 0.70 to 0.94), 0.75 (0.65 to 0.87), and 0.78 (0.67 to 0.91), respectively (P for trend=0.001). Among the findings for cancers at specific sites, an inverse association was found for liver cancer, with corresponding hazard ratios of 0.70 (0.44 to 1.13), 0.65 (0.40 to 1.06), and 0.45 (0.26 to 0.79) (P for trend=0.006). A sensitivity analysis showed that alternately removing cases of cancer at one specific site from total cancer cases did not substantially change the overall hazard ratios.

CONCLUSIONS

In this large prospective study, higher vitamin D concentration was associated with lower risk of total cancer. These findings support the hypothesis that vitamin D has protective effects against cancers at many sites.

Vitamin D receptor and calcium-sensing receptor polymorphisms and colorectal cancer survival in the Newfoundland population

Background:

Increased serum levels of vitamin D and calcium have been associated with lower risks of colorectal cancer (CRC) incidence and mortality. These inverse associations may be mediated by the vitamin D receptor (VDR) and the calcium-sensing receptor (CASR). We investigated genetic variants in VDR and CASR for their relevance to CRC prognosis.

Methods:

A population-based cohort of 531 CRC patients diagnosed from 1999 to 2003 in Newfoundland and Labrador, Canada, was followed for mortality and cancer recurrence until April 2010. Germline DNA samples were genotyped with the Illumina Omni-Quad 1 Million chip. Multivariate Cox models assessed 41 tag single-nucleotide polymorphisms and relative haplotypes on VDR and CASR in relation to all-cause mortality (overall survival, OS) and disease-free survival (DFS).

Results:

Gene-level associations were observed between VDR and the DFS of rectal cancer patients (P=0.037) as well as between CASR and the OS of colon cancer patients (P=0.014). Haplotype analysis within linkage blocks of CASR revealed the G-G-G-G-G-A-C haplotype (rs10222633-rs10934578-rs3804592-rs17250717-A986S-R990G-rs1802757) to be associated with a decreased OS of colon cancer (HR, 3.15; 95% CI, 1.66–5.96). Potential interactions were seen among prediagnostic dietary calcium intake with the CASR R990G (P_int=0.040) and the CASR G-T-G-G-G-G-C haplotype for rs10222633-rs10934578-rs3804592-rs17250717-A986S-R990G-rs1802757 (P_int=0.017), with decreased OS time associated with these variants limited to patients consuming dietary calcium below the median, although the stratified results were not statistically significant after correction for multiple testing.

Conclusions:

Polymorphic variations in VDR and CASR may be associated with survival after a diagnosis of CRC.

Prevalence and predictors of hypovitaminosis D among the elderly in subtropical region

The prevalence of low vitamin D status in the elderly population of subtropical area and the potential risk/protective factors have not been addressed. This cross-sectional questionnaire-based study, which collected demographic/anthropometric data and information on diet habit and sun exposure, recruited 170 subjects with mean age 70.9±5.6 in rural areas of southern Taiwan. Serum 25-OH vitamin D, calcium, and intact parathyroid hormone were also measured. Using cut-off level of 30 ng/mL, subjects were divided into low (n = 95) and normal (n = 75) serum vitamin D groups. The results demonstrated a low vitamin D status in 30.6% of men and 57.7% of women. Dietary vitamin D intake was another factor associated with vitamin D status (p = 0.02). Logistic regression identified inadequate intake of vitamin D-rich food as the only risk factor for low vitamin D status in men (OR = 4.55, p = 0.01), whereas inadequate sun exposure was the only predictable risk with dose-response relationship in women (low vs. high sun exposure, OR = 6.84, p = 0.018; moderate vs. high sun exposure, OR = 6.67, p = 0.005). In conclusion, low vitamin D status was common in the elderly of subtropical rural areas. Low sun exposure and inadequate dietary vitamin D consumption were associated with a low vitamin D status in females and males, respectively.

Vitamin D and colorectal cancer: molecular, epidemiological and clinical evidence

In many cells throughout the body, vitamin D is converted into its active form calcitriol and binds to the vitamin D receptor (VDR), which functions as a transcription factor to regulate various biological processes including cellular differentiation and immune response. Vitamin D-metabolising enzymes (including CYP24A1 and CYP27B1) and VDR play major roles in exerting and regulating the effects of vitamin D. Preclinical and epidemiological studies have provided evidence for anti-cancer effects of vitamin D (particularly against colorectal cancer), although clinical trials have yet to prove its benefit. In addition, molecular pathological epidemiology research can provide insights into the interaction of vitamin D with tumour molecular and immunity status. Other future research directions include genome-wide research on VDR transcriptional targets, gene-environment interaction analyses and clinical trials on vitamin D efficacy in colorectal cancer patients. In this study, we review the literature on vitamin D and colorectal cancer from both mechanistic and population studies and discuss the links and controversies within and between the two parts of evidence.

Dose-response of serum 25-hydroxyvitamin D in association with risk of colorectal cancer: A meta-analysis

Fifteen nested case-control or cohort studies in 14 countries have examined the association between serum 25-hydroxyvitamin D [25(OH)D] and risk of colorectal cancer. A meta-analysis of these studies would provide a useful dose-response gradient curve based on pooling of the results of known studies to date. An up-to-date dose-response curve that combines the findings of these studies has not been reported, to our knowledge. This curve would help in designing interventions for future studies. A new meta-analysis would be more precise than any previous analysis due to its larger sample size. Therefore a search of PubMed and other resources was performed in May 2016 for all cohort or nested case-control observational studies that reported risk of colon or colorectal cancer by quantiles of 25(OH)D. All but two of the 15 studies found a trend toward lower risk of colorectal cancer associated with higher serum 25(OH)D. There was a linear reduction in the odds ratio (OR) with each 10ng/ml-increment in 25(OH)D concentration. The lowest quantile of the serum 25(OH)D concentration was generally<20ng/ml. The downward trend in ORs associated with higher serum 25(OH)D concentrations was statistically significant in 3 studies. The pooled OR from all studies comparing highest with lowest quantile of 25(OH)D was 0.67 (95% confidence interval [CI], 0.59-0.76), meaning there was a 33% lower risk associated with the highest compared with the lowest quantile of serum 25(OH)D. A dose-response analysis revealed that a serum 25(OH)D of 50ng/ml was associated with an OR of 0.4 (95% CI, 0.2-1.0) compared with a concentration of 5ng/ml. The formula for the linear relationship was OR=0.008x. For example, individuals with a 25(OH)D concentration of 50ng/ml had an approximately 60% lower risk of colorectal cancer than those with a concentration of 5ng/ml. Those with a 25(OH)D concentration of 30ng/ml had a 33% lower risk than those with a concentration of 5ng/ml. The inverse association between serum 25(OH)D and risk of colorectal cancer overall was strong and statistically significant. There also was a mostly linear dose response relationship between serum 25(OH)D and risk of colorectal cancer when all studies were combined. No study reported significant adverse effects, and there was no evidence of publication bias. Misclassification in some studies could have influenced the association, causing it to appear weaker than the true association.

25-Hydroxyvitamin D Status and Risk for Colorectal Cancer and Type 2 Diabetes Mellitus: A Systematic Review and Meta-Analysis of Epidemiological Studies

Epidemiological evidence suggests an association between low vitamin D status and risk for various outcomes including cardiovascular diseases, cancer, and type 2 diabetes mellitus (T2DM). Analyzing serum 25-hydroxyvitamin D [25(OH)D] is the most established means to evaluate an individual's vitamin D status. However, cutoff values for 25(OH)D insufficiency as well as for optimal 25(OH)D levels are controversial. This systematic review critically summarizes the epidemiological evidence regarding 25(OH)D levels and the risk for colorectal cancer and T2DM. The meta-analytical calculation revealed a pooled relative risk (RR) of 0.62 (CI 0.56-0.70; I² = 14.7%) for colorectal cancer and an RR of 0.66 (CI 0.61-0.73; I² = 38.6%) for T2DM when comparing individuals with the highest category of 25(OH)D with those in the lowest. A dose-response analysis showed an inverse association between 25(OH)D levels and RR for both outcomes up to concentrations of about 55 ng/mL for colorectal cancer and about 65 ng/mL for T2DM. At still higher 25(OH)D levels the RR increases slightly, consistent with a U-shaped association. In conclusion, a higher 25(OH)D status is associated with a lower risk for colorectal cancer and T2DM; however, this advantage is gradually lost as levels increase beyond 50-60 ng/mL.

Vitamin D Receptor Gene Polymorphism and the Risk of Colorectal Cancer: A Nested Case-Control Study

Epidemiological and experimental evidence suggest that vitamin D is protective against the risk of colorectal cancer. Polymorphisms in the gene encoding vitamin D receptor (VDR), which mediates most of the known cellular effects of vitamin D, have been suggested to alter this association. Here, using a tag SNP approach, we comprehensively evaluated the role of common genetic variants in VDR and their interaction with plasma vitamin D levels in relation to colorectal cancer risk in Japanese populations. A total of 356 colorectal cancer cases and 709 matched control subjects were selected from the participants of the Japan Public Health Center-based Prospective Cohort Study. Among these subjects, 29 VDR single nucleotide polymorphisms (SNPs) were selected and genotyped, and plasma vitamin D concentrations were measured. Conditional logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (CIs) of colorectal cancer, with adjustment for potential confounding factors. Among the results, eight VDR SNPs, namely rs2254210, rs1540339, rs2107301, rs11168267, rs11574113, rs731236, rs3847987 and rs11574143, the latter 5 of which were located in the 3′ region, were nominally associated with the risk of colorectal cancer (P = 0.01–0.048). Furthermore, of the above 5 3′ region SNPs, the inverse associations for 3 SNPs (rs11574113, rs3847987 and rs11574143) appeared to be evident only in those with high plasma vitamin D concentration. However, neither of these direct and suggestive interaction analysis associations was significant after multiple testing adjustment. Overall, the findings of this study provide only limited support for an association between common genetic variations in VDR and colorectal cancer risk in the Japanese population.

The Role of Aspirin, Vitamin D, Exercise, Diet, Statins, and Metformin in the Prevention and Treatment of Colorectal Cancer

Colorectal cancer (CRC) is a worldwide health problem leading to significant morbidity and mortality. Several strategies based on either lifestyle modifications or pharmacological interventions have been developed in an attempt to reduce the risk of CRC. In this review article, we discuss these interventions including aspirin (and other non-steroidal anti-inflammatory drugs), vitamin D, exercise, diet, statins, and metformin. Depending upon the risk of developing CRC, the current evidence supports the beneficial role of aspirin, vitamin D, diet, and exercise especially in high-risk individuals (advanced adenoma or CRC). However, even with these established interventions, there are significant knowledge gaps such as doses of aspirin and 25-hydroxy vitamin D are not well established. Similarly, there is no convincing data from randomized controlled trials that a high fiber diet or a low animal fat diet reduces the risk of CRC. Some potential interventions, such as statins and metformin, do not have convincing data for clinical use even in high-risk individuals. However, these may have emerging roles in the prevention and treatment of CRC. Greater understanding of molecular mechanisms and the application of genomic tools to risk stratify an individual and tailor the interventions based on that individual's risk will help further advance the field. Some of this work is already underway and is a focus of this article.

Vitamin D and Colorectal, Breast, and Prostate Cancers: A Review of the Epidemiological Evidence

Over the past two decades, the question of whether vitamin D has a role in cancer incidence, progression, and mortality has been studied in detail. Colorectal, breast, and prostate cancers have been a particular area of focus; together, these three malignancies account for approximately 35% of cancer cases and 20% of cancer deaths in the United States, and as such are a major public health concern. Herein, we review and synthesize the epidemiological research regarding vitamin D, as measured by the biomarker 25-hydroxycholecalciferol [25(OH)D], and the incidence, progression, and mortality of these cancers. Overall, the results of observational studies of the relationship between 25(OH)D and colorectal cancer have revealed a consistent inverse association for incidence and mortality; while for breast cancer, results have generally demonstrated a relationship between higher 25(OH)D and lower risk for progression and mortality. In contrast, randomized, double-blind clinical trials conducted to date have generally failed to support these findings. For prostate cancer, there is no convincing evidence of an association between 25(OH)D and incidence, and inconsistent data for progression and mortality, though results of one open label clinical trial suggest that supplementation with 4000 IU/d of vitamin D3 may inhibit progression of the disease. Nonetheless, until the results of additional ongoing randomized, double-blind clinical trials are reported, it will be difficult to ascertain if vitamin D itself is related to a reduction in risk for some cancer endpoints, or whether high concentrations of the vitamin D biomarker 25(OH)D may instead serve as a marker for an overall beneficial risk factor profile.

Nutrients, foods, and colorectal cancer prevention

Diet has an important role in the development of colorectal cancer. In the past few decades, findings from extensive epidemiologic and experimental investigations have linked consumption of several foods and nutrients to the risk of colorectal neoplasia. Calcium, fiber, milk, and whole grains have been associated with a lower risk of colorectal cancer, and red meat and processed meat have been associated with an increased risk. There is substantial evidence for the potential chemopreventive effects of vitamin D, folate, fruits, and vegetables. Nutrients and foods also may interact, as a dietary pattern, to influence colorectal cancer risk. Diet likely influences colorectal carcinogenesis through several interacting mechanisms. These include the direct effects on immune responsiveness and inflammation, and the indirect effects of overnutrition and obesity-risk factors for colorectal cancer. Emerging evidence also implicates the gut microbiota as an important effector in the relationship between diet and cancer. Dietary modification therefore has the promise of reducing colorectal cancer incidence.

Circulating Vitamin D Levels and Risk of Colorectal Cancer in Women

Observational data on the association between circulating 25(OH)D and colorectal cancer risk are limited in women. To determine whether prediagnostic levels of 25(OH)D were associated with risk of incident colorectal cancer in the Women's Health Study (WHS), we conducted a nested case-control study using 274 colorectal cases and 274 controls. Each case was matched to a control by age, ethnicity, fasting status at the time of blood collection, time of day when blood was drawn, and month of blood draw. Conditional logistic regression was used to estimate the OR and 95% confidence interval (CI) for colorectal cancer by 25(OH)D quartiles. Mean plasma 25(OH)D was lower in cases versus controls (21.9 vs. 23.9 ng/mL, P = 0.01). In multivariable-adjusted logistic regression models, plasma 25(OH)D was significantly and inversely associated with odds of colorectal cancer (quartile 4 [Q4] vs. quartile 1 [Q1]: OR, 0.45; 95% CI, 0.25-0.81; Ptrend 0.02). In addition, we observed a somewhat lower risk of colorectal cancer-related mortality after adjustment for matching variables, randomization treatment and other risk factors (Q4:Q1 OR, 0.40; 95% CI, 0.17-0.97; Ptrend 0.05). In this cohort of healthy women, we found a significant inverse association between prediagnostic 25(OH)D levels and risk of incident colorectal cancer, and a borderline significant inverse association between prediagnostic 25(OH)D levels and colorectal cancer-related mortality. These results support a possible association between plasma 25(OH)D and risk of colorectal cancer in women.

Serum 25-hydroxyvitamin D, vitamin D binding protein and risk of colorectal cancer in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial

The potential role of vitamin D in cancer prevention has generated substantial interest, and laboratory experiments indicate several anti-cancer properties for vitamin D compounds. Prospective studies of circulating 25-hydroxyvitamin D [25(OH)D], the accepted biomarker of vitamin D status, suggest an inverse association with colorectal cancer risk, but with some inconsistencies. Furthermore, the direct or indirect impact of the key transport protein, vitamin D binding protein (DBP), has not been examined. We conducted a prospective study of serum 25(OH)D and DBP concentrations and colorectal cancer risk in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial, based on 476 colorectal cancer cases and 476 controls, matched on age, sex, race and date of serum collection. All subjects underwent sigmoidoscopic screening at baseline and once during follow-up. Conditional logistic regression estimated odds ratios (ORs) and 95% confidence intervals (CIs). Circulating 25(OH)D was inversely associated with colorectal cancer (OR = 0.60, 95% CI 0.38-0.94 for highest versus lowest quintile, p trend 0.01). Adjusting for recognized colorectal cancer risk factors and accounting for seasonal vitamin D variation did not alter the findings. Neither circulating DBP nor the 25(OH)D:DBP molar ratio, a proxy for free circulating 25(OH)D, was associated with risk (OR = 0.82, 95% CI 0.54-1.26, and OR = 0.79, 95% CI 0.52-1.21, respectively), and DBP did not modify the 25(OH)D association. The current study eliminated confounding by colorectal cancer screening behavior, and supports an association between higher vitamin D status and substantially lower colorectal cancer risk, but does not indicate a direct or modifying role for DBP.

In older men, lower plasma 25-hydroxyvitamin D is associated with reduced incidence of prostate, but not colorectal or lung cancer

CONTEXT AND OBJECTIVE

Prostate, colorectal and lung cancers are common in men. In this study, we aimed to determine whether vitamin D status is associated with the incidence of these cancers in older men.

DESIGN

Prospective cohort study.

SETTING AND PARTICIPANTS

4208 older men aged 70-88 years in Perth, Western Australia.

MAIN OUTCOME MEASURES

Plasma 25-hydroxyvitamin D [25(OH)D] concentration was measured by immunoassay. New diagnoses of prostate, colorectal and lung cancers were determined via electronic record linkage.

RESULTS

During a mean follow-up of 6.7±1.8 years, there were 315, 117 and 101 new diagnoses of prostate, colorectal and lung cancer. In multivariate competing risks proportional hazards models, every 10 nmol/l decrease in 25(OH)D concentration was associated with a 4% reduction in prostate cancer incidence (sub-hazard ratio [SHR] 0.96, 95% confidence interval [CI] 0.92-1.00). Every halving of 25(OH)D concentration was associated with a 21% reduction in incident prostate cancer in multivariate analysis (SHR 0.79, 95% CI 0.63-0.99). Following exclusion of prostate cancer cases diagnosed within 3 years of blood sampling, low 25(OH)D <50 nmol/l was associated with lower incident prostate cancer, and higher 25(OH)D >75 nmol/l was associated with higher incidence, when compared to the reference range 50-75 nmol/l, respectively (p = 0.027). Significant associations were also observed when 25(OH)D was modeled as a quantitative variable. No associations were observed between plasma 25(OH)D concentration with incidence of colorectal or lung cancer.

CONCLUSION

Lower levels of vitamin D may reduce prostate cancer risk in older men. By contrast, levels of vitamin D did not predict incidence of colorectal or lung cancers. Further studies are needed to determine whether a causal relationship exists between vitamin D and prostate cancer in ageing men.

Role of Vitamin D Metabolism and Activity on Carcinogenesis

The vitamin D endocrine system regulates a broad variety of independent biological processes, and its deficiency is associated with rickets, bone diseases, diabetes, cardiovascular diseases, and tuberculosis. Cellular and molecular studies have also shown that it is implicated in the suppression of cancer cell invasion, angiogenesis, and metastasis. Sunlight exposure and consequent increased circulating levels of vitamin D are associated with reduced occurrence and a reduced mortality in different histological types of cancer, including those resident in the skin, prostate, breast, colon, ovary, kidney, and bladder. The vitamin D receptor (VDR) as a steroid hormone superfamily of nuclear receptors is highly expressed in epithelial cells at risk for carcinogenesis, providing a direct molecular link by which vitamin D status impacts on carcinogenesis. Because VDR expression is retained in many human tumors, vitamin D status may be an important modulator of cancer progression in persons living with cancer. The aim of this review is to highlight the relationship between vitamin D, VDR, and cancer, summarizing several mechanisms proposed to explain the potential protective effect of vitamin D against the development and progression of cancer.

Association between circulating concentrations of 25(OH)D and colorectal adenoma: a pooled analysis

The relationship between the biomarker of vitamin D status, 25(OH)D, and the risk for colorectal neoplasia is suggestive but equivocal. Questions remain regarding whether there are differential associations between 25(OH)D and colorectal adenoma by gender, colorectal subsite or features of baseline and recurrent adenomas. We sought to investigate the relationship between 25(OH)D and both baseline and recurrent adenoma characteristics. Our study was conducted among 2,074 participants in a pooled population of two clinical intervention trials of colorectal adenoma recurrence. A cross-sectional analysis of 25(OH)D and baseline adenoma characteristics and a prospective study of recurrent adenomas and their characteristics were conducted. There was a statistically significant inverse association between the concentrations of 25(OH)D and the presence of three or more adenomas at baseline. Compared to participants with 25(OH)D levels of <20 ng/mL, the adjusted odds ratios (ORs) (95% condifdence intervals [CIs]) were 0.99 (0.70-1.41) for those with concentrations of ≥20 and <30 ng/mL, and 0.73 (0.50-1.06) among participants with levels of ≥30 ng/mL (p-trend = 0.05). Baseline villous histology was also significantly inversely related to 25(OH)D levels (p-trend = 0.04). Conversely, 25(OH)D concentrations were not associated with overall colorectal adenoma recurrence, with ORs (95% CIs) of 0.91 (0.71-1.17) and 0.95 (0.73-1.24; p-trend = 0.85). These findings support the concept that the relationship between vitamin D and colorectal neoplasia may vary by stage of adenoma development.

Association of common gene variants in vitamin D modulating genes and colon cancer recurrence

PURPOSE

Low concentrations of 25-hydroxyvitamin D3 (25(OH)D) have been associated with increased risk and poor prognosis of various cancer types, including colon cancer. Common genetic variants in genes that influence circulating 25(OH)D levels may affect vitamin D concentrations and risk of vitamin D insufficiency. In the present study, we investigated the association of three functional gene variants in GC (rs2282679 T>G), DHCR7 (rs12785878 G>T) and CYP2R1 (rs10741657 A>G) with time to recurrence (TTR) in patients with stages II and III colon cancer.

METHODS

Two hundred and sixty-four patients were included in this retrospective study. Genomic DNA was genotyped for GC rs2282679 T>G, DHCR7 rs12785878 G>T and CYP2R1 rs10741657 A>G by 5'-exonuclease (TaqMan™) technology.

RESULTS

In the univariate analysis, GC rs2282679 GG was significantly associated with decreased TTR (HR = 3.30, 95 % CI 1.09-9.97, p = 0.034) in patients with surgery alone and remained significantly associated in multivariate analysis including lymph node involvement and clinical stage (HR = 3.64, 95 % CI 1.16-11.46, p = 0.027). In patients with adjuvant chemotherapy, GC rs2282679 T>G was not significantly associated with TTR (HR = 1.02, 95 % CI 0.44-2.37, p = 0.964). Furthermore, we observed a trend toward decreased TTR in patients harboring the CYP2R1 rs10741657 A>G gene variant including all patients (HR = 1.50, 95 % CI 0.98-2.28, p = 0.060). No association was found between DHCR7 rs12785878 G>T and TTR in our study cohort.

CONCLUSION

In conclusion, our results may indicate a prognostic effect of GC rs2282679 in stages II and III colon cancer patients with surgery alone. Larger studies have to be performed to validate our findings.

Antineoplastic effects of 1,25(OH)2D3 and its analogs in breast, prostate and colorectal cancer

The active form of vitamin D3, 1,25-dihydroxyvitamin D3 (1,25(OH)2D3), is mostly known for its importance in the maintenance of calcium and phosphate homeostasis. However, next to its classical effects on bone, kidney and intestine, 1,25(OH)2D3 also exerts antineoplastic effects on various types of cancer. The use of 1,25(OH)2D3 itself as treatment against neoplasia is hampered by its calcemic side effects. Therefore, 1,25(OH)2D3-derived analogs were developed that are characterized by lower calcemic side effects and stronger antineoplastic effects. This review mainly focuses on the role of 1,25(OH)2D3 in breast, prostate and colorectal cancer (CRC) and the underlying signaling pathways. 1,25(OH)2D3 and its analogs inhibit proliferation, angiogenesis, migration/invasion and induce differentiation and apoptosis in malignant cell lines. Moreover, prostaglandin synthesis and Wnt/b-catenin signaling are also influenced by 1,25(OH)2D3 and its analogs. Human studies indicate an inverse association between serum 25(OH)D3 values and the incidence of certain cancer types. Given the literature, it appears that the epidemiological link between vitamin D3 and cancer is the strongest for CRC, however more intervention studies and randomized placebo-controlled trials are needed to unravel the beneficial dose of 1,25(OH)2D3 and its analogs to induce antineoplastic effects.

Sunlight, vitamin D and the prevention of cancer: a systematic review of epidemiological studies

The number of studies reporting beneficial effects of sunlight and vitamin D on several types of cancer with a high mortality rate is growing rapidly. Present health recommendations on sun exposure are mainly based on the increased risks for skin cancer. We reviewed all published studies concerning cancer and sun exposure and vitamin D, respectively, excluding those about skin cancer. Most identified ecological, case-control and prospective studies on the incidence and mortality of colorectal, prostate, breast carcinoma and non-Hodgkin lymphoma reported a significantly inverse association with sun exposure. The results of the included studies on the association between cancer risk and vitamin D were much less consistent. Only those studies that prospectively examined the 25-hydroxyvitamin D serum levels in relation to risk of colorectal cancer are homogeneous: they all reported inverse associations, although not all reaching statistical significance. The results of the intervention studies are suggestive of a protective role of high doses of vitamin D in cancer, but they have been criticized in the literature. We, therefore, conclude that there is accumulating evidence for sunlight as a protective factor for several types of cancer. The same conclusion can be made concerning high vitamin D levels and the risk of colorectal cancer. This evidence, however, is not conclusive, because the number of (good quality) studies is still limited and publication biases cannot be excluded. The discrepancies between the epidemiological evidence for a possible preventive effect of sunlight and vitamin D and the question of how to apply the findings on the beneficial effects of sunlight to (public) health recommendations are discussed.

Common variants of the vitamin D binding protein gene and adverse health outcomes

The vitamin D binding protein (DBP) is the major plasma carrier for vitamin D and its metabolites, but it is also an actin scavenger, and is the precursor to the immunomodulatory protein, Gc-MAF. Two missense variants of the DBP gene - rs7041 encoding Asp432Glu and rs4588 encoding Thr436Lys - change the amino acid sequence and alter the protein function. They are common enough to generate population-wide constitutive differences in vitamin D status, based on assay of the serum metabolite, 25-hydroxyvitamin D (25OHD). Whether these variants also influence the role of vitamin D in an immunologic milieu is not known. However, the issue is relevant, given the immunomodulatory effects of DBP and the role of protracted innate immune-related inflammation in response to tissue injury or repeated infection. Indeed, DBP and vitamin D may jointly or independently contribute to a variety of adverse health outcomes unrelated to classical notions of their function in bone and mineral metabolism. This review summarizes the reports to date of associations between DBP variants, and various chronic and infectious diseases. The available information leads us to conclude that DBP variants are a significant and common genetic factor in some common disorders, and therefore, are worthy of closer attention. In view of the heightened interest in vitamin D as a public health target, well-designed studies that look simultaneously at vitamin D and its carrier in relation to genotypes and adverse health outcome should be encouraged.

Is prevention of cancer by sun exposure more than just the effect of vitamin D? A systematic review of epidemiological studies

The number of studies reporting on the association between sunlight exposure, vitamin D and cancer risk is steadily increasing. We reviewed all published case-control and cohort studies concerning colorectal-, prostate-, breast cancer, non-Hodgkin's lymphoma (NHL) and both sunlight and vitamin D to update our previous review and to verify if the epidemiological evidence is in line with the hypothesis that the possible preventive effect of sunlight on cancer might be mediated not only by vitamin D but also by other pathways. We found that almost all epidemiological studies suggest that chronic (not intermittent) sun exposure is associated with a reduced risk of colorectal-, breast-, prostate cancer and NHL. In colorectal- and to a lesser degree in breast cancer vitamin D levels were found to be inversely associated with cancer risk. In prostate cancer and NHL, however, no associations were found. These findings are discussed and it is concluded that the evidence that sunlight is a protective factor for colorectal-, prostate-, breast cancer and non-Hodgkin's lymphoma is still accumulating. The same conclusion can be drawn concerning high vitamin D levels and the risk of colorectal cancer and possibly breast cancer. Particularly in prostate cancer and NHL other sunlight potentiated and vitamin D independent pathways, such as modulation of the immune system and the circadian rhythm, and the degradation of folic acid might play a role in reduced cancer risk as well.

Widespread vitamin D deficiency among Indian health care professionals

Information on vitamin D status of Indian health care professionals is limited. Among 2,119 subjects studied, just 6 % were found to be sufficient in vitamin D status. There is urgent need of an integrated approach to detect and treat vitamin D deficiency among health care professionals to improve on-the-job productivity.

INTRODUCTION

Vitamin D deficiency is prevalent worldwide. India has been reported to be one of the worst affected countries. Several single-center studies from India have shown high prevalence of vitamin D deficiency. Little is known regarding the vitamin D status of Indian health care professionals.

AIM

This study aimed to determine prevalence of vitamin D deficiency among health care professionals in different regions of India.

METHOD

In this cross-sectional, multicenter study, we enrolled 2,119 medical and paramedical personnel from 18 Indian cities. Blood samples were collected from December 2010 to March 2011 and analyzed in a central laboratory by radioimmunoassay. Vitamin D deficiency was defined as 25-hydroxyvitamin D [25(OH)D] <20 ng/mL or <50 nmol/L, insufficiency as 25(OH)D = 20-30 ng/mL or 50-75 nmol/L, and sufficiency as 25(OH)D >30 ng/mL or >75 nmol/L.

RESULTS

Mean (±SD) age of subjects was 42.71 ± 6.8 years. Mean (±SD) 25(OH)D level was 14.35 ± 10.62 ng/mL (median 11.93 ng/mL). Seventy-nine percent of subjects were deficient, 15 % were insufficient, and just 6 % were sufficient in vitamin D status. No significant difference was found between vitamin D status in southern (25(OH)D = 13.3 ± 6.4 ng/mL) and northern (25(OH)D = 14.4 ± 8.5 ng/mL) parts of India.

CONCLUSION

Our study confirms the high prevalence of vitamin D deficiency all across India in apparently healthy, middle-aged health care professionals.

Response to an adequate dietary intake of vitamin D3 modulates the effect of estrogen therapy on bone density

INTRODUCTION

This study analyzed associations between plasma vitamin D(3) (25OHD(3)) and bone mineral density (BMD) and whether the effects of conjugated equine estrogens (CEE) on BMD are modulated by 25OHD(3).

METHODS

Fifty cynomolgus monkeys were fed a diet containing 25OHD(3) (providing a woman's equivalent of 1000 IU/day of 25OHD3). The monkeys underwent bilateral oophorectomy and were randomized to either CEE (equivalent of 0.45 mg/day) (n=25) or placebo (n=25) and continued receiving the same diet. 25OHD(3) and BMD were measured at randomization and after 6 months. BMD also was measured after 20 months (equivalent to 6 human years). Associations between 25OHD(3) and BMD were subsequently analyzed.

RESULTS

Baseline 25OHD(3) plasma concentrations varied from 26 to 95 ng/mL (mean±standard deviation [SD] 54 ± 15 ng/mL). Higher plasma concentrations of 25OHD(3) were associated with a significantly increased BMD. Monkeys on both CEE and placebo had increased BMD over 20 months; however, the increase was not significantly different (0.034 g/cm(2) vs. 0.020 g/cm(2), respectively; p=0.064). The 20-month BMD increased significantly with CEE treatment in those with higher vs. lower 25OHD(3) concentrations (p=0.027). The percent change in BMD over 20 months also increased significantly with CEE treatment in those with higher vs. lower 25OHD(3) concentrations (p=0.018). A higher 25OHD(3) concentration had no significant effect on BMD in those receiving placebo.

CONCLUSIONS

Monkeys fed a diet containing 1000 IU/day equivalent of 25OHD(3) have a wide range of plasma 25OHD(3) concentrations. Those receiving CEE with higher 25OHD(3) concentrations had higher BMDs, suggesting 25OHD(3) and CEE have synergistic effects on BMD.

Impact of vitamin D deficiency on the productivity of a health care workforce

OBJECTIVE

To define the relationship between vitamin D status and employee presenteeism in a large sample of health care employees.

METHODS

Prospective observation study of 10,646 employees of a Midwestern-integrated health care system who completed an on-line health risk appraisal questionnaire and were measured for 25-hydroxyvitamin D.

RESULTS

Measured differences in productivity due to presenteeism were 0.66, 0.91, and 0.75 when comparing employees above and below vitamin D levels of 20 ng/mL, 30 ng/mL, and 40 ng/mL, respectively. These productivity differences translate into potential productivity savings of 0.191%, 0.553%, and 0.625%, respectively, of total payroll costs.

CONCLUSIONS

Low vitamin D status is associated with reduced employee work productivity. Employee vitamin D assessment and replenishment may represent a low-cost, high-return program to mitigate risk factors and health conditions that drive total employer health care costs.

The nonskeletal effects of vitamin D: an Endocrine Society scientific statement

Significant controversy has emerged over the last decade concerning the effects of vitamin D on skeletal and nonskeletal tissues. The demonstration that the vitamin D receptor is expressed in virtually all cells of the body and the growing body of observational data supporting a relationship of serum 25-hydroxyvitamin D to chronic metabolic, cardiovascular, and neoplastic diseases have led to widespread utilization of vitamin D supplementation for the prevention and treatment of numerous disorders. In this paper, we review both the basic and clinical aspects of vitamin D in relation to nonskeletal organ systems. We begin by focusing on the molecular aspects of vitamin D, primarily by examining the structure and function of the vitamin D receptor. This is followed by a systematic review according to tissue type of the inherent biological plausibility, the strength of the observational data, and the levels of evidence that support or refute an association between vitamin D levels or supplementation and maternal/child health as well as various disease states. Although observational studies support a strong case for an association between vitamin D and musculoskeletal, cardiovascular, neoplastic, and metabolic disorders, there remains a paucity of large-scale and long-term randomized clinical trials. Thus, at this time, more studies are needed to definitively conclude that vitamin D can offer preventive and therapeutic benefits across a wide range of physiological states and chronic nonskeletal disorders.

Role of vitamin D metabolism in cutaneous tumour formation and progression

OBJECTIVES

Very limited information is available on the role of vitamin D in skin carcinogenesis. For most individuals, skin cancer can be readily managed with surgery; however, some patients may face life-threatening neoplasia. Sun exposure, specifically UV radiation, is a causative agent for development of skin cancer, though, somewhat ironically, sunlight through the production of vitamin D may have protective effect against some skin cancers. This review focuses on the development and progression of cutaneous carcinogenesis and the role of vitamin D in the prevention of the initiation and progression of lethal skin cancers.

KEY FINDINGS

Vitamin D is involved in regulation of multiple signalling pathways that have implications in carcinogenesis. Skin cancer metastasis depends on the tumour microenvironment, where vitamin D metabolites play a key role in prevention of certain molecular events involved in tumour progression. The vitamin D receptor (VDR) is a well-known potent regulator of cellular growth and differentiation.

SUMMARY

The VDR's possible involvement in cell death, tumour microenvironment and angiogenesis makes it a candidate agent for cancer regulation.

Dietary, endocrine, and metabolic factors in the development of colorectal cancer

INTRODUCTION

Colorectal cancer is the third cause of death in industrialized countries. Genetic susceptibility and diet are determinant of cancer risk and tumor behavior. Variation in cancer incidence among and within populations with similar dietary patterns suggests that an individual response may reflect interactions with genetic factors, which may modify gene, protein, and metabolite expression patterns. Nutrigenomics, defined as the interaction between nutrition and an individual genome, will likely provide important clues about responders and non-responders to nutritional intervention.

DISCUSSION

Epidemiological and experimental studies suggest a protective role of some normal components of daily diet (fish oil, milk, and vegetables), estrogens, and phytoestrogens in colorectal cancer. The effect of estrogen seems to be mediated by their binding to estrogen receptor beta (ER-β), one of the two estrogen receptors with high affinity for these hormones. Very recently, the demonstration of an involvement of ER-β in the development of adenomatous polyps of the colon has also been documented, suggesting the use of selective ER-β agonists in primary colorectal cancer prevention. Phytoestrogens are plant-derived compounds that structurally and functionally act as estrogen agonists in mammals. They are characterized by a higher binding affinity to ER-β as compared to estrogen receptor alpha (ER-α), the other estrogen receptor subtype. These biological characteristics explain why the administration of phytoestrogens does not produce the classical side effects associated to estrogen administration (cerebro- and cardiovascular accidents, higher incidence of endometrial and breast cancer) and makes these substances potential candidates for colorectal cancer prevention.

Association between plasma 25-hydroxyvitamin D and colorectal adenoma according to dietary calcium intake and vitamin D receptor polymorphism

The anticarcinogenic potential of vitamin D might be mediated by not only calcium metabolism but also other mechanisms initiated by vitamin D receptor (VDR). The authors measured plasma 25-hydroxyvitamin D in healthy volunteer examinees who underwent total colonoscopy in Tokyo, Japan, 2004-2005, and evaluated its influence on colorectal adenoma, both alone and in interaction with VDR polymorphisms, which correspond to the FokI and TaqI restriction sites. The main analysis of plasma 25-hydroxyvitamin D included 737 cases and 703 controls. Compared with the lowest quintile of plasma 25-hydroxyvitamin D, only the highest was related to a significantly decreased odds ratio of colorectal adenoma (odds ratio = 0.64, 95% confidence interval: 0.45, 0.92). In contrast, all but the lowest quintile of dietary calcium intake presented similarly reduced odds ratios (odds ratio for the highest = 0.67, 95% confidence interval: 0.47, 0.95). Of note, the association between plasma 25-hydroxyvitamin D levels and colorectal adenoma was modified by the TaqI polymorphism of the VDR gene (P(interaction) = 0.03) but not by dietary calcium intake (P(interaction) = 0.93). These observations highlight the importance of vitamin D in colorectal tumorigenesis. Vitamin D might protect against colorectal neoplasia, mainly through mechanisms other than the indirect mechanism via calcium metabolism.

Prediagnostic 25-hydroxyvitamin D, VDR and CASR polymorphisms, and survival in patients with colorectal cancer in western European ppulations

BACKGROUND

Individuals with higher blood 25-hydroxyvitamin D [25(OH)D] levels have a lower risk of developing colorectal cancer (CRC), but the influence of 25(OH)D on mortality after CRC diagnosis is unknown.

METHODS

The association between prediagnostic 25(OH)D levels and CRC-specific (N = 444) and overall mortality (N = 541) was prospectively examined among 1,202 participants diagnosed with CRC between 1992 and 2003 in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort. Multivariable Cox proportional hazards models were used to calculate HRs and corresponding 95% CIs according to 25(OH)D quintiles and genetic variation within the VDR and CASR genes. Potential dietary, lifestyle, and metabolic effect modifiers were also investigated.

RESULTS

There were 541 deaths, 444 (82%) due to CRC. Mean follow-up was 73 months. In multivariable analysis, higher 25(OH)D levels were associated with a statistically significant reduction in CRC-specific (P(trend) = 0.04) and overall mortality (P(trend) = 0.01). Participants with 25(OH)D levels in the highest quintile had an adjusted HR of 0.69 (95% CI: 0.50-0.93) for CRC-specific mortality and 0.67 (95% CI: 0.50-0.88) for overall mortality, compared with the lowest quintile. Except for a possible interaction by prediagnostic dietary calcium intake (P(interaction) = 0.01), no other potential modifying factors related to CRC survival were noted. The VDR (FokI and BsmI) and CASR (rs1801725) genotypes were not associated with survival.

CONCLUSIONS

High prediagnostic 25(OH)D levels are associated with improved survival of patients with CRC.

IMPACT

Our findings may stimulate further research directed at investigating the effects of blood vitamin D levels before, at, and after CRC diagnosis on outcomes in CRC patients.

Interactions between plasma levels of 25-hydroxyvitamin D, insulin-like growth factor (IGF)-1 and C-peptide with risk of colorectal cancer

Background

Vitamin D status and levels of insulin-like growth factor (IGF)-1 and C-peptide have been implicated in colorectal carcinogenesis. However, in contrast to vitamin D IGF-1 is not an easily modifiable risk factor.

Methods

Combining data from the Health Professionals Follow up Study (HPFS) and the Nurses' Health Study cohort (NHS) additive and multiplicative interactions were examined between plasma 25-hydroxyvitamin D (25(OH)D) and IGF-1, IGFBP-3 as well as C-peptide levels in 499 cases and 992 matched controls. For the various analytes, being high or low was based on being either above (or equal) or below the medians, respectively.

Results

Compared to participants with high 25(OH)D and low IGF-1/IGFBP-3 ratio (reference group), participants with a high IGF-1/IGFBP-3 ratio were at elevated risk of colorectal cancer when 25(OH)D was low (odds ratio (OR): 2.05 (95% CI: 1.43 to 2.92), but not when 25(OH)D was high (OR:1.20 (95% CI: 0.84 to 1.71, p(interaction): additive  = 0.06, multiplicative  = 0.25). Similarly, compared to participants with high 25(OH)D and low molar IGF-1/IGFBP-3 ratio and low C-peptide levels (reference group), participants with a combination of either high IGF-1/IGFBP-3 ratio or high C-peptide were at elevated risk for colorectal cancer when 25(OH)D was low (OR = 1.90, 95% CI: 1.22 to 2.94) but not when 25(OH)D was high (OR = 1.15, 95% CI: 0.74 to 1.77, p(interaction): additive = 0.004; multiplicative  = 0.04).

Conclusion

The results from this study suggest that improving vitamin D status may help lower risk of colorectal cancer associated with higher IGF-1/IGFBP-3 ratio or C-peptide levels.