Prospective study of predictors of vitamin D status and cancer incidence and mortality in men

Serum vitamin D concentration and prostate cancer risk: a nested case-control study

BACKGROUND

Epidemiological studies have yielded inconsistent associations between vitamin D status and prostate cancer risk, and few studies have evaluated whether the associations vary by disease aggressiveness. We investigated the association between vitamin D status, as determined by serum 25-hydroxyvitamin D [25(OH)D] level, and risk of prostate cancer in a case-control study nested within the Prostate, Lung, Colorectal, and Ovarian (PLCO) Cancer Screening Trial.

METHODS

The study included 749 case patients with incident prostate cancer who were diagnosed 1-8 years after blood draw and 781 control subjects who were frequency matched by age at cohort entry, time since initial screening, and calendar year of cohort entry. All study participants were selected from the trial screening arm (which includes annual standardized prostate cancer screening). Conditional logistic regression was used to estimate adjusted odds ratios (ORs) with 95% confidence intervals (CIs) by quintile of season-standardized serum 25(OH)D concentration. Statistical tests were two-sided.

RESULTS

No statistically significant trend in overall prostate cancer risk was observed with increasing season-standardized serum 25(OH)D level. However, serum 25(OH)D concentrations greater than the lowest quintile (Q1) were associated with increased risk of aggressive (Gleason sum > or = 7 or clinical stage III or IV) disease (in a model adjusting for matching factors, study center, and history of diabetes, ORs for Q2 vs Q1 = 1.20, 95% CI = 0.80 to 1.81, for Q3 vs Q1 =1.96, 95% CI = 1.34 to 2.87, for Q4 vs Q1 = 1.61, 95% CI = 1.09 to 2.38, and for Q5 vs Q1 = 1.37, 95% CI = 0.92 to 2.05; P(trend) = .05). The rates of aggressive prostate cancer for increasing quintiles of serum 25(OH)D were 406, 479, 780, 633, and 544 per 100 000 person-years. In exploratory analyses, these associations with aggressive disease were consistent across subgroups defined by age, family history of prostate cancer, diabetes, body mass index, vigorous physical activity, calcium intake, study center, season of blood collection, and assay batch.

CONCLUSION

The findings of this large prospective study do not support the hypothesis that vitamin D is associated with decreased risk of prostate cancer; indeed, higher circulating 25(OH)D concentrations may be associated with increased risk of aggressive disease.

Periodontal disease, tooth loss, and cancer risk in male health professionals: a prospective cohort study

BACKGROUND

Studies suggest that tooth loss and periodontal disease might increase the risk of developing various cancers; however, smoking might have confounded the reported associations. We aimed to assess whether periodontal disease or tooth loss is associated with cancer risk.

METHODS

The analysis was done in a prospective study (the Health Professionals Follow-Up Study [HPFS]), which was initiated in 1986 when US male health professionals aged 40-75 years responded to questionnaires posted by the Department of Nutrition, Harvard University School of Public Health, Boston, MA, USA. In addition to the baseline questionnaires, follow-up questionnaires were posted to all living participants every 2 years and dietary questionnaires every 4 years. At baseline, participants were asked whether they had a history of periodontal disease with bone loss. Participants also reported number of natural teeth at baseline and any tooth loss during the previous 2 years was reported on the follow-up questionnaires. Smoking status and history of smoking were obtained at baseline and in all subsequent questionnaires. Additionally at baseline, participants reported their mean frequency of food intake over the previous year on a 131-item semiquantitative food-frequency questionnaire. Participants reported any new cancer diagnosis on the follow-up questionnaires. Endpoints for this study were risk of total cancer and individual cancers with more than 100 cases. Multivariate hazard ratios (HRs) and 95% CIs were calculated by use of Cox proportional hazard models according to periodontal disease status and number of teeth at baseline.

FINDINGS

In the main analyses, 48 375 men with median follow-up of 17.7 years (1986 to Jan 31, 2004) were eligible after excluding participants diagnosed with cancer before 1986 (other than non-melanoma skin cancer, n=2076) and those with missing data on periodontal disease (n=1078). 5720 incident cancer cases were documented (excluding non-melanoma skin cancer and non-aggressive prostate cancer). The five most common cancers were colorectal (n=1043), melanoma of the skin (n=698), lung (n=678), bladder (n=543), and advanced prostate (n=541). After adjusting for known risk factors, including detailed smoking history and dietary factors, participants with a history of periodontal disease had an increased risk of total cancer (HR 1.14 [95% CI 1.07-1.22]) compared with those with no history of periodontal disease. By cancer site, significant associations for those with a history of periodontal disease were noted for lung (1.36 [1.15-1.60]), kidney (1.49 [1.12-1.97]), pancreas (1.54 [1.16-2.04]; findings previously published), and haematological cancers (1.30 [1.11-1.53]). Fewer teeth at baseline (0-16) was associated with an increase in risk of lung cancer (1.70 [1.37-2.11]) for those with 0-16 teeth versus those with 25-32 teeth. In never-smokers, periodontal disease was associated with significant increases in total (1.21 [1.06-1.39]) and haematological cancers (1.35 [1.01-1.81]). By contrast, no association was noted for lung cancer (0.96 [0.46-1.98]).

INTERPRETATION

Periodontal disease was associated with a small, but significant, increase in overall cancer risk, which persisted in never-smokers. The associations recorded for lung cancer are probably because of residual confounding by smoking. The increased risks noted for haematological, kidney, and pancreatic cancers need confirmation, but suggest that periodontal disease might be a marker of a susceptible immune system or might directly affect cancer risk.

Serum metabolite profiles and target tissue gene expression define the effect of cholecalciferol intake on calcium metabolism in rats and mice

We studied the effect of cholecalciferol (VD3) intake on VD3 status and markers of calcium (Ca) homeostasis in mice and rats. Serum 25 hydroxycholecalciferol (25OH-VD3) concentrations were increased in animals fed diets containing 400-20,000 international units (IU) VD3/kg (37 nmol.L(-1).1000 IU VD3(-1)), but body weight, serum Ca, and duodenal gene expression were not altered. High-VD3 intake decreased serum 1, 25-dihydroxycholecalciferol [1,25(OH)2-VD3] and renal 25 hydroxycholecalciferol-1alphahydroxylase (CYP27B1) mRNA, suggesting that rodents tolerate high-VD3 intake by suppressing the activity of the VD3 endocrine system. Serum 25OH-VD3 declined when animals were fed diets containing 1000 to 25 IU VD3/kg (9-11 wk, inflection at 200 IU/kg, 4-fold steeper slope below this). Neither body weight nor serum Ca were influenced by low-VD3 intake. However, mice fed the 25-IU/kg diet had lower serum 1,25(OH)2-VD3, duodenal calbindin D9k mRNA, bone mineral density, and renal 25 hydroxycholecalciferol-24 hydroxylase mRNA, whereas renal CYP27B1 mRNA was elevated when rodents were fed < 200 IU VD3/kg. These data reveal a stress on VD3 and Ca metabolism at low dietary VD3 intake. Dietary Ca restriction (0.25 vs. 0.5%, 9 wk) increased serum 1,25(OH)2-VD3 and was 30% greater in rats fed a 10,000-IU VD3/kg diet. High-VD3 intake did not prevent Ca restriction-induced bone loss. Our data show that modeling human VD3 status requires lower intake than the current NRC rodent requirement (1000-IU/kg diet). Also, although rodents are very tolerant of high-VD3 intake, it cannot compensate for moderate Ca restriction.

Association of the polymorphisms of MTHFR C677T, VDR C352T, and MPO G463A with risk for esophageal squamous cell dysplasia and carcinoma

BACKGROUND

From January 2004 to December 2006 a program of endoscopic screening for esophageal lesions was carried out in the high incidence area of esophageal cancer in Feicheng County, China. It provided the samples to evaluate the association of polymorphisms of methylenetetrahydrofolate reductase (MTHFR) C677T, vitamin D receptor (VDR) C352T, and myeloperoxidase (MPO) G463A genotypes with esophageal squamous cell dysplasia and carcinoma.

METHODS

The subjects in the study were divided into 127 dysplasia cases, 126 squamous cell carcinoma cases, and 169 normal controls. Analyses of the MTHFR C677T, VDR C352T, and MPO G463A genotypes were performed using the PCR-restriction fragment length polymorphism (RFLP) method, whereas the multinomial logistic regression model was used in the data analysis to assess the odds ratios (ORs) related to dysplasia and carcinoma.

RESULTS

Compared with the CC genotype of MTHFR C677T, the TT/TC of the genotype significantly increased the risk of the esophageal squamous cells dysplasia [OR, 2.25; 95% confidence interval (CI), 1.18-4.31]; the OR of esophageal squamous cancer was 1.58 (95% CI, 0.85-2.97) after adjustments for age, sex, and years of education. There was an interaction between the TT/TC genotype and alcohol drinking, smoking, and family history of esophageal cancer in the risk of esophageal dysplasia and carcinoma.

CONCLUSIONS

Neither the VDR C352T nor the MPO G463A genotype had manifested association with the dysplasia and carcinoma of the disease, whereas the MTHFR 677TT genotype may be a genetic risk factor for esophageal dysplasia and carcinoma.

Shedding light on vitamin D and integrative oncology

Studies show an important relationship between vitamin D and malignancies, both in prevention and treatment. The extraskeletal actions of vitamin D relevant to oncology include being proapoptotic, antimetastatic, antiangiogenic, antiinflammatory, prodifferentiating, and immunomodulating. Widespread and severe vitamin D deficiencies exist worldwide. Decreased sun exposure, caused by lifestyle changes, as well as fear of skin cancers, is the main cause of these deficiencies. Recommended daily oral intakes, as well as suggested blood levels, are below optimal levels suggested by studies. Improvement in vitamin D status, through lifestyle changes and supplementation, can be of profound benefit regarding the occurrence and mortality of malignancies.

Interaction of estrogen therapy with calcium and vitamin D supplementation on colorectal cancer risk: reanalysis of Women's Health Initiative randomized trial

Although calcium and vitamin-D intake were consistently shown to be inversely associated with colorectal cancer risk in several large prospective studies and protective against adenoma and cancer in multiple randomized trials, the Women's Health Initiative (WHI) of calcium and low-dose vitamin-D supplementation trial found no overall effects on colorectal cancer. However, the previous report did not recognize an important biologic interaction with estrogen therapy. We investigated the treatment interaction of estrogen with calcium and vitamin-D on risk of colorectal cancer via a reanalysis of primary data results from the WHI calcium and vitamin-D supplementation trial (1,000 mg elemental calcium, 400 IU of vitamin-D3, or placebo), reanalyzing results from women concurrently randomized to estrogen interventions and placebo. Results indicate that concurrent estrogen therapy was a strong effect modifier of calcium and vitamin-D supplementation on colorectal cancer risk. While calcium plus vitamin-D supplementation among women concurrently assigned to estrogen therapies suggested increased risk (Hazard Ratio = 1.50, 95% CI: 0.96-2.33), among women concurrently assigned to placebos arms of the estrogen trials, calcium plus vitamin-D indicated suggestive benefits (HR = 0.71, 95% CI: 0.46-1.09) (p-for-estrogen-interaction = 0.018). Consistent interaction was also found by reported estrogen use (p interaction = 0.037). Results indicate contrasting effects of calcium and vitamin-D by concurrent estrogen therapy on colorectal cancer risk. Although further clinical and mechanistic studies are warranted, the potential clinical implications of the apparent interaction of estrogen therapy with calcium and vitamin-D supplementation should be recognized. Important biological mechanisms related to the key membrane receptor megalin and estrogen-dependent protein calbindin are discussed.

Vitamin D and calcium intake in relation to risk of endometrial cancer: a systematic review of the literature

OBJECTIVE

In response to a recent ecologic study of UV exposure and endometrial cancer incidence, we present the epidemiologic evidence on the relation between intake of vitamin D and its metabolically related nutrient, calcium, and the occurrence of endometrial cancer.

METHODS

We conducted a systematic literature review and meta-analysis of vitamin D and calcium in relation to endometrial cancer, including peer-reviewed manuscripts published up to May 2007. Random and fixed effects summary estimates were computed.

RESULTS

Pooled analyses of the three case-control studies of dietary vitamin D and endometrial cancer uncovered heterogeneous results that were not significant in random or fixed effects analyses. Cut-points for the highest vitamin D intakes ranged from >244 to >476 IU/day. Qualitatively similar findings were observed for dietary calcium. Only two studies provided estimates for calcium supplements (random effects OR=0.62, 95% CI 0.39-0.99; fixed effects OR=0.62, 95% CI 0.42-0.93, for top vs. bottom category, p for heterogeneity=0.25).

CONCLUSIONS

The limited epidemiological evidence suggests no relation between endometrial cancer in the ranges of dietary vitamin D examined, and suggests a possible inverse association for calcium from supplements. Prospective studies, ideally including plasma 25(OH) D to estimate vitamin D input from diet and sun exposure, are needed to further explore these hypotheses.

Vitamin D assessment in population-based studies: a review of the issues

In the past decade, research on the relation between vitamin D exposure and disease in population-based studies has increased exponentially. These studies have involved measurement of vitamin D exposure by means of several methods: blood assays, self-reported dietary and supplemental intakes, and sunlight exposure questionnaires or diaries. As with all exposure measurements, researchers must consider the validity of their assessment tools for capturing vitamin D exposure. The purpose of this article is to summarize our current understanding of the various approaches to measuring vitamin D status within populations as reviewed at the 2007 Experimental Biology symposium, "Assessment of Vitamin D in Population-Based Studies." In summary, serum 25-hydroxyvitamin D is the accepted biomarker for short-term vitamin D status, but estimates of long-term dietary and supplemental intakes of vitamin D and long-term sunlight exposure may be the most logistically feasible indicators of lifetime vitamin D exposure in population-based studies. Also discussed are issues investigators should consider when analyzing relations between vitamin D exposure and disease outcomes in population-based studies as well as research avenues that need further exploration. The best method for assessing vitamin D status in population-based studies will depend primarily on the research question asked and the critical window of vitamin D exposure hypothesized to be most important.

Vitamin D deficiency: a worldwide problem with health consequences

Vitamin D deficiency is now recognized as a pandemic. The major cause of vitamin D deficiency is the lack of appreciation that sun exposure in moderation is the major source of vitamin D for most humans. Very few foods naturally contain vitamin D, and foods that are fortified with vitamin D are often inadequate to satisfy either a child's or an adult's vitamin D requirement. Vitamin D deficiency causes rickets in children and will precipitate and exacerbate osteopenia, osteoporosis, and fractures in adults. Vitamin D deficiency has been associated with increased risk of common cancers, autoimmune diseases, hypertension, and infectious diseases. A circulating level of 25-hydroxyvitamin D of >75 nmol/L, or 30 ng/mL, is required to maximize vitamin D's beneficial effects for health. In the absence of adequate sun exposure, at least 800-1000 IU vitamin D3/d may be needed to achieve this in children and adults. Vitamin D2 may be equally effective for maintaining circulating concentrations of 25-hydroxyvitamin D when given in physiologic concentrations.

Vitamin D and cancer incidence in the Harvard cohorts

Since the hypothesis that vitamin D reduces the risk of some cancers was initiated in 1980, this hypothesis has been studied in the Harvard cohort studies, including the Nurses' Health Study (NHS), the Health Professionals Follow-Up Study (HPFS), and the Physicians' Health Study (PHS). Three approaches have been used, the study of circulating 25(OH)vitamin D (25(OH)D) level, of dietary and supplementary intake, and of predicted 25(OH)D. These cohorts strongly support an inverse association with colorectal cancer, because this association has been viewed in both the NHS and HPFS cohorts, for cancers and adenomas, and for plasma, diet, and predicted 25(OH)D analyses. In the NHS, about a 30% reduction in risk was observed for breast cancer comparing the highest with lowest quintiles of 25(OH)D levels. Vitamin D intake also was associated with a lower risk of pancreatic cancer in both men and women, but studies of plasma or predicted 25(OH)D level or dietary intake have generally not been supportive of a major role of vitamin D status in middle-age or elderly men on prostate cancer risk. Results from the HPFS also suggest that the poor vitamin D status generally in African-Americans contributes to their higher incidence and mortality from various malignancies.

Vitamin D insufficiency in southern Arizona

BACKGROUND

Vitamin D deficiency or insufficiency has been observed among populations in the northern United States. However, data on the prevalence of vitamin D deficiency in areas of high sun exposure, such as Arizona, are limited.

OBJECTIVE

The purpose of this study was to analyze serum 25-hydroxyvitamin D [25(OH)D] concentrations in residents of southern Arizona and to evaluate predictors of 25(OH)D in this population.

DESIGN

Cross-sectional analyses of serum from participants in a colorectal adenoma prevention study were conducted to determine rates of vitamin D deficiency. Participants were categorized into 4 groups on the basis of serum 25(OH)D concentrations: <10.0 ng/mL, > or =10.0 ng/mL and <20.0 ng/mL, > or =20.0 ng/mL and <30.0 ng/mL, and > or =30.0 ng/mL.

RESULTS

The mean serum 25(OH)D concentration for the total population was 26.1 +/- 9.1 ng/mL. Of 637 participants, 22.3% had 25(OH)D concentrations >30 ng/mL, 25.4% had concentrations <20 ng/mL, and 2.0% had concentrations <10 ng/mL. Blacks (55.5%) and Hispanics (37.6%) were more likely to have deficient 25(OH)D concentrations (<20 ng/mL) than were non-Hispanic whites (22.7%). Sun exposure had a greater effect on 25(OH)D in whites than in blacks and Hispanics, whereas BMI appeared to be more important in the latter groups.

CONCLUSION

Despite residing in a region with high chronic sun exposure, adults in southern Arizona are commonly deficient in vitamin D deficiency, particularly blacks and Hispanics.

Unequal burden of head and neck cancer in the United States

BACKGROUND

Black Americans are adversely affected by many types of malignancies.

METHODS

We reviewed data from the National Cancer Institute's Surveillance, Epidemiology, and End Results (SEER) program to evaluate racial disparities in head and neck cancer incidence, mortality, and survival.

RESULTS

Head and neck cancer incidence is greater in the black population and peaks at a younger age. The incidence disparity is decreasing over time and is less for cancers of the oral cavity/pharynx (OCP) than for cancers of the larynx. The disparity in survival after diagnosis is substantial for both sites and is increasing over time because of improvement in survival for the white population, but not for the black population. Some, but not all, of the survival disparity is due to more advanced stage at the time of diagnosis within the black population. The age-adjusted mortality rate for black men is approximately twice the rate for white men.

CONCLUSION

Black Americans clearly bear a greater burden from head and neck cancer. The underlying causes are largely unknown, but are most likely due to a complex interplay of differences in access to health care, quality of medical care, biologic/genetic factors, incidence of comorbid conditions, exposure to carcinogens, diet, and cultural beliefs. Prospective studies are needed to define the relative importance of these factors and to inform intervention strategies.

CpG island methylator phenotype-low (CIMP-low) colorectal cancer shows not only few methylated CIMP-high-specific CpG islands, but also low-level methylation at individual loci

The CpG island methylator phenotype (CIMP or CIMP-high) with widespread promoter methylation is a distinct phenotype in colorectal cancer. However, the concept of CIMP-low with less extensive CpG island methylation is still evolving. Our aim is to examine whether density of methylation in individual CpG islands was different between CIMP-low and CIMP-high tumors. Utilizing MethyLight technology and 889 population-based colorectal cancers, we quantified DNA methylation (methylation index, percentage of methylated reference) at 14 CpG islands, including 8 CIMP-high-specific loci (CACNA1G, CDKN2A (p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1). Methylation positivity in each locus was defined as methylation index>4. Low-level methylation (methylation index>0, <20) in each CIMP-high-specific locus was significantly more common in 340 CIMP-low tumors (1/8-5/8 methylation-positive loci) than 133 CIMP-high tumors (> or =6/8 methylation-positive loci) and 416 CIMP-0 tumors (0/8 methylation-positive loci) (P< or =0.002). In the other six loci (CHFR, HIC1, IGFBP3, MGMT, MINT31 and WRN), which were not highly specific for CIMP-high, low-level methylation, was not persistently more prevalent in CIMP-low tumors. In conclusion, compared to CIMP-high and CIMP-0 tumors, CIMP-low colorectal cancers show not only few methylated CIMP-high-specific CpG islands, but also more frequent low-level methylation at individual loci. Our data may provide supporting evidence for a difference in pathogenesis of DNA methylation between CIMP-low and CIMP-high tumors.

IGFBP3 promoter methylation in colorectal cancer: relationship with microsatellite instability, CpG island methylator phenotype, and p53

Insulin-like growth factor binding protein 3 (IGFBP3), which is induced by wild-type p53, regulates IGF and interacts with the TGF-beta pathway. IGFBP3 promoter methylation may occur in colorectal cancer with or without the CpG island methylator phenotype (CIMP), which is associated with microsatellite instability (MSI) and TGFBR2 mutation. We examined the relationship between IGFBP3 methylation, p53 expression, CIMP and MSI in 902 population-based colorectal cancers. Utilizing real-time PCR (MethyLight), we quantified promoter methylation in IGFBP3 and eight other CIMP-high-specific promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1). IGFBP3 methylation was far more frequent in non-MSI-high CIMP-high tumors (85% = 35/41) than in MSI-high CIMP-high (49% = 44/90, P < .0001), MSI-high non-CIMP-high (17% = 6/36, P < .0001), and non-MSI-high non-CIMP-high tumors (22% = 152/680, P < .0001). Among CIMP-high tumors, the inverse relationship between MSI and IGFBP3 methylation persisted in p53-negative tumors (P < .0001), but not in p53-positive tumors. IGFBP3 methylation was associated inversely with TGFBR2 mutation in MSI-high non-CIMP-high tumors (P = .02). In conclusion, IGFBP3 methylation is inversely associated with MSI in CIMP-high colorectal cancers, and this relationship is limited to p53-negative tumors. Our data suggest complex relationship between global genomic/epigenomic phenomena (such as MSI/CIMP), single molecular events (e.g., IGFBP3 methylation, TP53 mutation, and TGFBR2 mutation), and the related pathways.

Prevalence of 25(OH) vitamin D (calcidiol) deficiency at time of renal transplantation: a prospective study

25(OH) Vitamin D (calcidiol) is the major circulating form of vitamin D and is considered the most reliable measure of vitamin D status. Adequate vitamin D status is important for bone health but there is increasing evidence that low serum concentrations of calcidiol (<30 ng/mL) are associated with many adverse health outcomes in the general population. Little is known about calcidiol status at the time of renal transplantation, a period when bone loss is greatest and immunosuppression is highest. We prospectively measured serum calcidiol and parathyroid hormone immediately after transplant from March 2005 onwards. Of 112 patients studied, 29% had calcidiol deficiency (<10 ng/mL), 59% had calcidiol insufficiency (10-29 ng/mL) and only 12% of patients had a normal calcidiol concentration (>30 ng/mL). The prevalence of calcidiol deficiency in black recipients was extremely high at 41%. Serum calcidiol tended to be lower in winter than other seasons. In conclusion, the prevalence of 25(OH) vitamin D (calcidiol) deficiency/insufficiency at the time of renal transplant is very high. The clinical effects of this deficiency/insufficiency deserve further study.

WRN promoter methylation possibly connects mucinous differentiation, microsatellite instability and CpG island methylator phenotype in colorectal cancer

Werner syndrome is a premature aging syndrome characterized by early onset of cancer and abnormal cellular metabolism of glycosaminoglycan. The WRN helicase plays an important role in the maintenance of telomere function. WRN promoter methylation and gene silencing are common in colorectal cancer with the CpG island methylator phenotype (CIMP), which is associated with microsatellite instability (MSI) and mucinous tumors. However, no study has examined the relationship between mucinous differentiation, WRN methylation, CIMP and MSI in colorectal cancer. Utilizing 903 population-based colorectal cancers and real-time PCR (MethyLight), we quantified DNA methylation in WRN and eight other promoters (CACNA1G, CDKN2A, CRABP1, IGF2, MLH1, NEUROG1, RUNX3 and SOCS1) known to be specific for CIMP. Supporting WRN as a good CIMP marker, WRN methylation was correlated well with CIMP-high diagnosis (> or =6/8 methylated promoters), demonstrating 89% sensitivity and 81% specificity. WRN methylation was associated with the presence of any mucinous component and > or =50% mucinous component (P<0.0001). Because both MSI and CIMP were associated with mucinous tumors and WRN methylation, we stratified tumors into 9 MSI/CIMP subtypes, to examine whether the relationship between WRN methylation and mucin still persisted. In each MSI/CIMP subtype, tumors with mucinous component were persistently more common in WRN-methylated tumors than WRN-unmethylated tumors (P=0.004). No relations of WRN methylation with other variables (age, sex, tumor location, poor differentiation, signet ring cells, lymphocytic reactions, KRAS, BRAF, p53, p21 or 18q loss of heterozygosity) persisted after tumors were stratified by CIMP status. In conclusion, WRN methylation is associated with mucinous differentiation independent of CIMP and MSI status. Our data suggest a possible role of WRN methylation in mucinous differentiation, and may provide explanation to the enigmatic association between mucin and MSI/CIMP.

Unexpected actions of vitamin D: new perspectives on the regulation of innate and adaptive immunity

Knowledge about the ability of vitamin D to function outside its established role in skeletal homeostasis is not a new phenomenon. Nonclassical immunomodulatory and antiproliferative responses triggered by active 1,25-dihydroxyvitamin D were first reported more than a quarter of a century ago. It is only in recent years, however, that there has been a significant improvement in our understanding of how these nonclassical effects of vitamin D can influence the pathophysiology and possible prevention of human disease. Three particular strands of evidence have been prominent: firstly, population studies have revised our interpretation of normal vitamin D status in humans, suggesting, in turn, that vitamin D insufficiency is a clinical problem of global proportions; secondly, epidemiology has linked vitamin D status with disease susceptibility and/or mortality; and, thirdly, expression of the machinery required to synthesize 1,25-dihydroxyvitamin D in normal human tissue seems to be much more widespread than originally thought. Collectively, these observations suggest that nonclassical metabolism and response to vitamin D might have a significant role in human physiology beyond skeletal and calcium homeostasis. Specific examples of this will be detailed in the current Review, with particular emphasis on the immunomodulatory properties of vitamin D.

[Hypovitaminosis D associated to low sun exposure in the population over 64 years old]

BACKGROUND AND OBJECTIVE

To identify the factors related to hypovitaminosis D in the population over 64 years of age without known risk factors of hypovitaminosis D.

SUBJECTS AND METHOD

It was a cross-sectional population study in individuals over 64 year-old attending basic healthcare areas in our hospital's area of reference. A survey was conducted to assess various items (functional capacity, exposure to sun, walks, eating habits). Blood samples taken from each participant were analyzed.

RESULTS

A total of 239 individuals -mean age (standard deviation): 72 (5.4) years- were evaluated. 95% of the participants scored > 90 on the Barthel index. Mean serum 25-hydroxyvitamin D3 -25(OH)D3- concentration was 17 (7.5) ng/ml and intact parathormone was 60 (26 pg/ml). The prevalence of hypovitaminosis D was 87%, including 70.3% with insufficiency (25(OH)D3 between 11 and 25 ng/ml) and 16.7% with deficiency (25(OH)D3 < or = 10 ng/ml). The intake of vitamin D and calcium were below recommended levels. The principal source of vitamin D was oily fish. Participants with deficiency scored lower on the Barthel index, had a higher mean age, lived in flats, had less exposure to sun, and used to walk less in sun-hours. Higher levels of alkaline phosphatase and intact parathormone were found in participants with deficiency. The variables independently and significantly associated with vitamin D deficiency were a Barthel score < or = 90, scant exposure to sun and living in a flat.

CONCLUSIONS

There is a high prevalence of hypovitaminosis D in the population aged over 64 years in our area, which is associated with lower functional capacity, scant exposure to sun and living in flats.

Vitamin D insufficiency among African-Americans in the southeastern United States: implications for cancer disparities (United States)

OBJECTIVE

To determine the prevalence and predictors of vitamin D insufficiency among black and white adult residents of the southern US.

METHODS

A cross-sectional analysis of serum 25(OH)D levels using baseline blood samples from 395 Southern Community Cohort Study (SCCS) participants. Participants were African-American and white adults aged 40-79 who enrolled in the study from 2002-2004. We defined hypovitaminosis D as serum 25(OH)D levels < or = 15 ng/ml.

RESULTS

Hypovitaminosis D prevalence was 45% among blacks and 11% among whites. Vitamin D intake from diet and supplements was associated with modest increases in circulating 25(OH)D (0.5-0.7 ng/ml per 100 IU increment), but hypovitaminosis D was found for 32% of blacks with intake > or = 400 IU/day. Body mass index (BMI) was a strong predictor of risk for hypovitaminosis D among black women (OR = 6.5, 95% CI 1.7-25.1 for BMI > or = 30 kg/m(2) vs. 18-24.9 kg/m(2)). UVR exposure estimated by residential location was positively associated with 25(OH)D levels among all groups except white women.

CONCLUSIONS

Hypovitaminosis D was present in a substantial proportion of the African-American population studied, even in the South and among those meeting recommended dietary guidelines. Vitamin D should continue to be a studied target for ameliorating racial cancer disparities in the US.

Addressing the health benefits and risks, involving vitamin D or skin cancer, of increased sun exposure

Solar radiation is the main cause of skin cancers. However, it also is a main source of vitamin D for humans. Because the optimal status of vitamin D protects against internal cancers and a number of other diseases, a controversy exists: Will increased sun exposure lead to net health benefits or risks? We calculated the relative yield of vitamin D photosynthesis as a function of latitude with a radiative transfer model and cylinder geometry for the human skin surface. The annual yield of vitamin D is 3.4 and 4.8 times larger below the equator than in the U.K. and Scandinavia, respectively. In populations with similar skin types, there are clear latitude gradients of all major forms of skin cancer, indicating a north-south gradient in real sun exposure. Surprisingly, the incidence rates of major internal cancers also increase from north to south. However, the survival prognosis also improves significantly from north to south. Reasons for these findings are discussed in view of the role of vitamin D. In Norway, melanoma rates increased by a factor of 6 from 1960 to 1990, while the prognosis improved in the same period. After 1990, melanoma rates have remained constant or even decreased in age groups <50 years, whereas the prognosis has not improved further. These data, together with those for internal cancers and the beneficial effects of an optimal vitamin D status, indicate that increased sun exposure may lead to improved cancer prognosis and, possibly, give more positive than adverse health effects.

Hypothesis--ultraviolet-B irradiance and vitamin D reduce the risk of viral infections and thus their sequelae, including autoimmune diseases and some cancers

Many viral infections reach clinical significance in winter, when it is cold, relative humidity is lowest and vitamin D production from solar ultraviolet-B irradiation is at its nadir. Several autoimmune diseases, such as multiple sclerosis, type 1 diabetes mellitus and asthma, are linked to viral infections. Vitamin D, through induction of cathelicidin, which effectively combats both bacterial and viral infections, may reduce the risk of several autoimmune diseases and cancers by reducing the development of viral infections. Some types of cancer are also linked to viral infections. The cancers with seemingly important risk from viral infections important in winter, based on correlations with increasing latitude in the United States, an index of wintertime solar ultraviolet-B dose and vitamin D, are bladder, prostate, testicular and thyroid cancer, Hodgkin's and non-Hodgkin's lymphoma, and, perhaps, gastric cancer. The evidence examined includes the role of viruses in the etiology of these diseases, the geographic and seasonal variation of these diseases, and the time of life when vitamin D is effective in reducing the risk of disease. In general, the evidence supports the hypothesis. However, further work is required to evaluate this hypothesis.

Personal sun exposure and risk of non Hodgkin lymphoma: a pooled analysis from the Interlymph Consortium

In 2004-2007 4 independent case-control studies reported evidence that sun exposure might protect against NHL; a fifth, in women only, found increased risks of NHL associated with a range of sun exposure measurements. These 5 studies are the first to examine the association between personal sun exposure and NHL. We report here on the relationship between sun exposure and NHL in a pooled analysis of 10 studies participating in the International Lymphoma Epidemiology Consortium (InterLymph), including the 5 published studies. Ten case-control studies covering 8,243 cases and 9,697 controls in the USA, Europe and Australia contributed original data for participants of European origin to the pooled analysis. Four kinds of measures of self-reported personal sun exposure were assessed at interview. A two-stage estimation method was used in which study-specific odds ratios (ORs) and 95% confidence intervals (CIs), adjusted for potential confounders including smoking and alcohol use, were obtained from unconditional logistic regression models and combined in random-effects models to obtain the pooled estimates. Risk of NHL fell significantly with the composite measure of increasing recreational sun exposure, pooled OR = 0.76 (95% CI 0.63-0.91) for the highest exposure category (p for trend 0.01). A downtrend in risk with increasing total sun exposure was not statistically significant. The protective effect of recreational sun exposure was statistically significant at 18-40 years of age and in the 10 years before diagnosis, and for B cell, but not T cell, lymphomas. Increased recreational sun exposure may protect against NHL.

Alcohol, tobacco, and diet in relation to esophageal cancer: the Shanghai Cohort Study

Prospective data on environmental exposures, especially with respect to alcohol, tobacco, and diet, in relation to the risk of esophageal cancer in high-risk populations are sparse. We analyzed data from a population-based cohort of 18,244 middle-aged and older men in Shanghai to identify risk factors for esophageal cancer in this high-risk population. The cohort was followed through 2006, and 101 incident esophageal cancer cases were identified. Cox proportional hazards models were used to estimate hazard ratios (HR) and their corresponding 95% confidence intervals (CI) for associations between exposures and esophageal cancer risk. With adjustment for tobacco use and other potential confounders, regular drinkers vs. nondrinkers of alcoholic beverages had a twofold risk of developing esophageal cancer (HR=2.02, 95% CI=1.31-3.12). With adjustment for alcohol and other potential confounders, long-term smokers (40+ yr) vs. nonsmokers of cigarettes showed a twofold risk of developing esophageal cancer (HR=2.06, 95% CI=1.11-3.82). Increased consumption of fruits (including oranges/tangerines), seafood, and milk were found to be protective against the development of esophageal cancer; HRs were decreased by 40-60% for high vs. low consumers after adjustment for cigarette smoking, alcohol drinking, and other confounders.

Androgenic alopecia may have evolved to protect men from prostate cancer by increasing skin exposure to ultraviolet radiation

Androgenic alopecia affects populations adapted to colder climate, and individuals at an age and hormonal status susceptible to prostate cancer. Male pattern baldness enhances absorption of UV radiation on the top of the head, an area directly exposed to sunlight during everyday activities. Ultraviolet radiation is reported to reduce the risk of advanced prostate cancer. Here I propose that progression of androgenic alopecia rather than being a risk factor is a finely tuned mechanism evolved to protect against prostate cancer.

Serum 25(OH)-vitamin D concentration and risk of esophageal squamous dysplasia

BACKGROUND

Squamous dysplasia is the precursor lesion for esophageal squamous cell carcinoma, and nutritional factors play an important role in the etiology of this cancer. Previous studies using a variety of measures for vitamin D exposure have reached different conclusions about the association between vitamin D and the risk of developing esophageal cancer.

METHODS

We measured serum 25-hydroxyvitamin D [25(OH)D] concentrations in a cross-sectional analysis of 720 subjects from Linxian, China, a population at high risk for developing esophageal squamous cell carcinoma. All subjects underwent endoscopy and biopsy and were categorized by the presence or absence of histologic squamous dysplasia. We used crude and multivariate-adjusted generalized linear models to estimate the relative risks (RR) and 95% confidence intervals (95% CI) for the association between squamous dysplasia and sex-specific quartiles of serum 25(OH)D concentration.

RESULTS

Two-hundred and thirty of 720 subjects (32%) had squamous dysplasia. Subjects with dysplasia had significantly higher median serum 25(OH)D concentrations than subjects without dysplasia, 36.5 and 31.5 nmol/L, respectively (Wilcoxon two-sample test, P = 0.0004). In multivariate-adjusted models, subjects in the highest compared with the lowest quartiles were at a significantly increased risk of squamous dysplasia (RR, 1.86; 95% CI, 1.35-2.62). Increased risks were similar when examined in men and women separately: men (RR, 1.74; 95% CI, 1.08-2.93); women (RR, 1.96; 95% CI, 1.28-3.18).

CONCLUSIONS

Higher serum 25(OH)D concentrations were associated with significantly increased risk of squamous dysplasia. No obvious source of measured or unmeasured confounding explains this finding.

Is there convincing biological or behavioral evidence linking vitamin D deficiency to brain dysfunction?

Vitamin D insufficiency is common in the United States; the elderly and African-Americans are at particularly high risk of deficiency. This review, written for a broad scientific readership, presents a critical overview of scientific evidence relevant to a possible causal relationship between vitamin D deficiency and adverse cognitive or behavioral effects. Topics discussed are 1) biological functions of vitamin D relevant to cognition and behavior; 2) studies in humans and rodents that directly examine effects of vitamin D inadequacy on cognition or behavior; and 3) immunomodulatory activity of vitamin D relative to the proinflammatory cytokine theory of cognitive/behavioral dysfunction. We conclude there is ample biological evidence to suggest an important role for vitamin D in brain development and function. However, direct effects of vitamin D inadequacy on cognition/behavior in human or rodent systems appear to be subtle, and in our opinion, the current experimental evidence base does not yet fully satisfy causal criteria. Possible explanations for the apparent inconsistency between results of biological and cognitive/behavioral experiments, as well as suggested areas for further research are discussed. Despite residual uncertainty, recommendations for vitamin D supplementation of at-risk groups, including nursing infants, the elderly, and African-Americans appear warranted to ensure adequacy.

Epidemiological evidence for vitamin D and colorectal cancer

Since Garland and Garland formulated the hypothesis that vitamin D may protect against colorectal cancer in 1980, various epidemiological approaches have been undertaken to evaluate this hypothesis. These approaches include studies based on regional solar UVB radiation, plasma- or serum-based studies, dietary studies, and those examining multiple factors that influence vitamin D status. Studies over the past several decades have tended to support that higher levels of vitamin D may decrease risk of colorectal cancer. An important implication is that current recommended dietary intakes such as 200-400 IU/d may be too low to exert appreciable benefits. To substantially reduce risk, higher levels of vitamin D associated with sunshine exposure or considerably higher intakes may be required. Recent studies also suggest a potential benefit of vitamin D on other digestive system cancers. One study suggested that a better vitamin D status at the time of diagnosis and treatment, as indicated by season of diagnosis, may improve survival from colorectal cancer. Darker-skinned individuals who tend to make less vitamin D may be at particularly high risk for digestive system cancer. The strong biological evidence for a protective role of vitamin D supports the epidemiological data. More study is needed to determine the optimal levels and intakes of this vitamin to optimally reduce colorectal cancer risk.

Prospective study of serum vitamin D and cancer mortality in the United States

BACKGROUND

Vitamin D has been hypothesized to reduce cancer mortality through its effects on incidence and/or survival. Epidemiologic studies of the association of 25-hydroxyvitamin D [25(OH)D] and the risk of cancer, however, have been largely limited to incident cancers at a few sites.

METHODS

A total of 16,818 participants in the Third National Health and Nutrition Examination Survey who were 17 years or older at enrollment were followed from 1988-1994 through 2000. Levels of serum 25(OH)D were measured at baseline by radioimmunoassay. Cox proportional hazards regression models were used to examine the relationship between serum 25(OH)D levels and total cancer mortality (in the entire population or according to race/ethnicity, sex, age, and retinol status) and mortality from specific cancers. Because serum was collected in the south in cooler months and the north in warmer months, we examined associations by collection season. All statistical tests were two-sided.

RESULTS

We identified 536 cancer deaths in 146,578 person-years. Total cancer mortality was unrelated to baseline vitamin D status in the entire population, men, women, non-Hispanic whites, non-Hispanic blacks, Mexican Americans, and in persons younger than 70 or 70 years or older. We found no interaction between vitamin D and season or vitamin D and serum retinol. Colorectal cancer mortality was inversely related to serum 25(OH)D level, with levels 80 nmol/L or higher associated with a 72% risk reduction (95% confidence interval = 32% to 89%) compared with lower than 50 nmol/L, P(trend) = .02.

CONCLUSIONS

Our results do not support an association between 25(OH)D and total cancer mortality, although there was an inverse relationship between 25(OH)D levels and colorectal cancer mortality.

The effect of solar UVB doses and vitamin D production, skin cancer action spectra, and smoking in explaining links between skin cancers and solid tumours

The report of differences between skin cancer rates and solid tumours in sunny versus less sunny countries [Tuohimaa P, Pukkala E, Scelo G, et al. Does solar exposure, as indicated by the non-melanoma skin cancers, protect from solid cancers: Vitamin D as a possible explanation. Eur J Cancer 2007; 43: 1701-12] raised some important questions regarding the roles of solar ultraviolet (UV) irradiance and cancer risk. The findings can likely be explained based on the effects of UVB dose on cancer risk, the action spectra of different skin cancers, the amount of skin exposed, and the differential effects of smoking on cancer risk. Solar UVB has been found inversely correlated with about 20 types of cancer in ecological and cohort studies in sunny countries. Vitamin D and calcium were recently found to greatly reduce cancer incidence in a prospective double-blind study. Epidemiological studies suggest that the action spectra for skin cancers vary, with solar UVB most important for squamous cell carcinoma, UVA most important for melanoma, and both important for basal cell carcinoma. These differences may explain the different standardised incidence ratios for solid tumours with respect to the different skin cancers in sunny countries. Smoking has been reported as a risk factor for non-melanoma skin cancers, but has been found inversely correlated with melanoma, which may explain some of the differences in standardised incidence ratios for solid tumours linked to smoking with respect to type of skin cancer. In Nordic countries, less skin is generally exposed (in head and neck regions, the most frequent sites of squamous cell carcinoma) resulting in reduced vitamin D production.

Correlation of beta-catenin localization with cyclooxygenase-2 expression and CpG island methylator phenotype (CIMP) in colorectal cancer

The WNT/beta-catenin (CTNNB1) pathway is commonly activated in the carcinogenic process. Cross-talks between the WNT and cyclooxygenase-2 (COX-2 or PTGS2)/prostaglandin pathways have been suggested. The relationship between beta-catenin activation and microsatellite instability (MSI) in colorectal cancer has been controversial. The CpG island methylator phenotype (CIMP or CIMP-high) with widespread promoter methylation is a distinct epigenetic phenotype in colorectal cancer, which is associated with MSI-high. However, no study has examined the relationship between beta-catenin activation and CIMP status. Using 832 population-based colorectal cancer specimens, we assessed beta-catenin localization by immunohistochemistry. We quantified DNA methylation in eight CIMP-specific promoters [CACNA1G, CDKN2A(p16), CRABP1, IGF2, MLH1, NEUROG1, RUNX3, and SOCS1] by real-time polymerase chain reaction (MethyLight). MSI-high, CIMP-high, and BRAF mutation were associated inversely with cytoplasmic and nuclear beta-catenin expressions (i.e., beta-catenin activation) and associated positively with membrane expression. The inverse relation between beta-catenin activation and CIMP was independent of MSI. COX-2 overexpression correlated with cytoplasmic beta-catenin expression (even after tumors were stratified by CIMP status), but did not correlate significantly with nuclear or membrane expression. In conclusion, beta-catenin activation is inversely associated with CIMP-high independent of MSI status. Cytoplasmic beta-catenin is associated with COX-2 overexpression, supporting the role of cytoplasmic beta-catenin in stabilizing PTGS2 (COX-2) mRNA.

Colon cancer: prognosis for different latitudes, age groups and seasons in Norway

The survival of colon cancer patients in Norway, as determined three years after diagnosis, is dependent on the season of diagnosis. This has been attributed to seasonal variations of the vitamin D status. Since solar radiation and food are the human sources of vitamin D, we divided Norway in three regions: The southeast region with a high annual dose of ultraviolet (UV) to the population, as evidenced by a high incidence rate of squamous cell carcinoma of the skin (SCC), the midwest region and the north region with low annual UV doses. The latter region is characterized by a high consumption of vitamin D, mainly through fish intake. Vacations to southern latitudes were equally frequent for all the three geographical regions. Two age groups were analyzed separately (< or =65 years and >65 years), since the photosynthesis of vitamin D(3) in skin decreases with age. In all three regions, and in both age groups, the survival was highest for summer and autumn diagnosis. The seasonal effect was slightly, but not significantly, better for the younger than for the older age group. The effect was similar for all three geographical regions, irrespective of SCC incidence.

Combination of physical activity, nutrition, or other metabolic factors and vaccine response

A number of lifestyle factors that reduce cancer risk in the primary prevention setting may be potential new targets for use in combination with cancer vaccines. This review discusses the modulation of energy balance (physical activity, calorie restriction, and obesity prevention), and the supplementation with natural and synthetic analogs of vitamins A and E, as potential interventions for use in combination with cancer vaccines. Additionally, the pharmacologic manipulation of nutrient metabolism in the tumor microenvironment (e.g., arachidonic acid, arginine, tryptophan, and glucose metabolism) is discussed. This review includes a brief overview of the role of each agent in primary cancer prevention; outlines the effects of these agents on immune function, specifically adaptive and/or anti-tumor immune mechanisms, when known; and discusses the potential use of these interventions in combination with therapeutic cancer vaccines. Modulation of energy balance through exercise and strategies targeting nutrient metabolism in the tumor microenvironment represent the most promising interventions to partner with therapeutic cancer vaccines. Additionally, the use of vitamin E succinate and the retinoid X receptor-directed rexinoids in combination with cancer vaccines offer promise. In summary, a number of energy balance- and nutrition-related interventions are viable candidates for further study in combination with cancer vaccines.

Vitamin D signalling pathways in cancer: potential for anticancer therapeutics

Epidemiological studies indicate that vitamin D insufficiency could have an aetiological role in various human cancers. Preclinical research indicates that the active metabolite of vitamin D, 1alpha,25(OH)2D3, also known as calcitriol, or vitamin D analogues might have potential as anticancer agents because their administration has antiproliferative effects, can activate apoptotic pathways and inhibit angiogenesis. In addition, 1alpha,25(OH)2D3 potentiates the anticancer effects of many cytotoxic and antiproliferative anticancer agents. Here, we outline the epidemiological, preclinical and clinical studies that support the development of 1alpha,25(OH)2D3 and vitamin D analogues as preventative and therapeutic anticancer agents.

Prostate cancer survival is dependent on season of diagnosis

BACKGROUND

We have earlier found that the prognosis for several cancers is dependent on season of diagnosis. More recently, both prostate cancer incidence and mortality have been shown to increase with increasing latitude, which probably relates to photosynthesis of vitamin D.

METHODS

The 3 year survival of prostate cancer patients has been analyzed with the Cox regression method for two age groups at different latitudes in Norway.

RESULTS

Patients diagnosed during the summer and autumn had the best prognosis (Ralative risk (RR) death 0.8; 95% CI 0.75-0.85). Similar results were observed in three regions of the country that differ with respect to annual fluences of solar UV radiation, incidence rates of squamous cell carcinoma (SCC) and intake of fish. Furthermore, similar relationship between the season and survival was seen among patients </=65 years and >65 years old, although the younger group had a slightly larger advantage of summer and autumn diagnosis.

CONCLUSIONS

The seasonal effect on prognosis may be related to the seasonal variations of calcidiol (the marker of vitamin D status). The lack of latitude effect and the similarity of prognosis for different age groups may be related to higher consumption of vitamin D in food in the north region and to increase of such consumption with age.

Serum 25(OH)-vitamin D concentration and risk of esophageal squamous dysplasia

BACKGROUND

Squamous dysplasia is the precursor lesion for esophageal squamous cell carcinoma, and nutritional factors play an important role in the etiology of this cancer. Previous studies using a variety of measures for vitamin D exposure have reached different conclusions about the association between vitamin D and the risk of developing esophageal cancer.

METHODS

We measured serum 25-hydroxyvitamin D [25(OH)D] concentrations in a cross-sectional analysis of 720 subjects from Linxian, China, a population at high risk for developing esophageal squamous cell carcinoma. All subjects underwent endoscopy and biopsy and were categorized by the presence or absence of histologic squamous dysplasia. We used crude and multivariate-adjusted generalized linear models to estimate the relative risks (RR) and 95% confidence intervals (95% CI) for the association between squamous dysplasia and sex-specific quartiles of serum 25(OH)D concentration.

RESULTS

Two-hundred and thirty of 720 subjects (32%) had squamous dysplasia. Subjects with dysplasia had significantly higher median serum 25(OH)D concentrations than subjects without dysplasia, 36.5 and 31.5 nmol/L, respectively (Wilcoxon two-sample test, P = 0.0004). In multivariate-adjusted models, subjects in the highest compared with the lowest quartiles were at a significantly increased risk of squamous dysplasia (RR, 1.86; 95% CI, 1.35-2.62). Increased risks were similar when examined in men and women separately: men (RR, 1.74; 95% CI, 1.08-2.93); women (RR, 1.96; 95% CI, 1.28-3.18).

CONCLUSIONS

Higher serum 25(OH)D concentrations were associated with significantly increased risk of squamous dysplasia. No obvious source of measured or unmeasured confounding explains this finding.

Vitamin D levels and early mortality among incident hemodialysis patients

Vitamin D deficiency is associated with cardiovascular disease, the most common cause of mortality in hemodialysis patients. To investigate the relation between blood levels of 25-hydroxyvitamin D (25D) and 1,25-dihydroxyvitamin D (1,25D) with hemodialysis outcomes, we measured baseline vitamin D levels in a cross-sectional analysis of 825 consecutive patients from within a prospective cohort of incident US hemodialysis patients. Of these patients, 78% were considered vitamin D deficient with 18% considered severely deficient. Calcium, phosphorus, and parathyroid hormone levels correlated poorly with 25D and 1,25D concentrations. To test the association between baseline vitamin D levels and 90-day mortality, we selected the next 175 consecutive participants who died within 90 days and compared them to the 750 patients who survived in a nested case-control analysis. While low vitamin D levels were associated with increased mortality, significant interaction was noted between vitamin D levels, subsequent active vitamin D therapy, and survival. Compared to patients with the highest 25D or 1,25D levels who received therapy, untreated deficient patients were at significantly increased risk for early mortality. Our study shows that among incident hemodialysis patients, vitamin D deficiency is common, correlates poorly with other components of mineral metabolism and is associated with increased early mortality.

Age-, gender-, and weight-related effects on levels of 25-hydroxyvitamin D are not mediated by vitamin D binding protein

OBJECTIVE

25-hydroxyvitamin D (25OHD) levels are inversely related to body weight, and have been reported to decline with age and be lower in women than men. We hypothesized that these findings might be explained by effects of these variables on vitamin D binding protein (DBP) levels. We set out to determine the relationships between DBP and gender, 25OHD, body weight and body composition.

DESIGN

Cross-sectional analysis.

PATIENTS

One hundred healthy, middle-aged and older, community-dwelling men and women.

MEASUREMENTS

All participants were measured for 25OHD, DBP, body weight, bone mineral density and body composition.

RESULTS

Women had higher mean DBP levels than men but lower total 25OHD levels [DBP: women, mean (SD) 339 (36) mg/l, men 307 (71) mg/l, P = 0.005; 25OHD: women 67 (23) nmol/l, men 91 (39) nmol/l, P < 0.001]. In women, there were significant positive relationships between DBP and albumin (r = 0.33) and 25OHD (r = 0.34) whereas in men there were no significant relationships between DBP and any measured variables. There was no significant relationship between DBP and age, body weight, body mass index, fat mass or percentage fat in men or women.

CONCLUSION

We found no evidence to support the hypothesis that DBP levels are related to age, or adiposity. The changes in 25OHD levels with age, gender, or fat mass are not due to underlying relationships between DBP and these variables. This suggests that the relationships consistently observed between 25OHD and body composition and gender are of biological origin and not due to adaptation to changes in transport proteins.

Mechanistic and pharmacodynamic studies of a 25-hydroxyvitamin D3 derivative in prostate cancer cells

1,25-Dihydroxyvitamin D(3) (1,25(OH)(2)D(3)), the biologically active form of vitamin D has strong antiproliferative effects in cancer cells. But it is highly toxic at therapeutic doses. We have observed that 25-hydroxyvitamin D(3)-3-bromoacetate (25-OH-D(3)-3-BE), a derivative of 25-hydroxyvitamin D(3), the pro-hormonal form of 1,25(OH)(2)D(3) has strong growth-inhibitory and proapoptotic properties in hormone-sensitive and hormone-refractory prostate cancer cells. In the present investigation we demonstrate that the antiproliferative effect of 25-OH-D(3)-3-BE is predominantly mediated by VDR in ALVA-31 prostate cancer cells. In other mechanistic studies we show that the proapoptotic property of 25-OH-D(3)-3-BE is related to the inhibition of phosphorylation of Akt, a pro-survival protein. Furthermore, we carried out cellular uptake and serum stability studies of 25-OH-D(3)-3-BE to demonstrate potential therapeutic applicability of 25-OH-D(3)-3-BE in hormone-sensitive and hormone-insensitive prostate cancer.