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

Ecological studies of ultraviolet B, vitamin D and cancer since 2000

PURPOSE

The purpose of this review is to summarize ecological studies of solar ultraviolet B (UVB), vitamin D and cancer since 2000.

METHODS

The journal literature is surveyed and summarized.

RESULTS

The ecological approach has been the primary tool used during the past two decades to extend the applicability of the UVB-vitamin D-cancer theory to include at least 18 types of cancer. Many of these studies were conducted in the United States, which has the advantages of availability of reliable age-standardized cancer incidence and mortality rate data for geographic areas at various spatial resolutions, and an asymmetric solar UVB dose pattern, with higher UVB irradiance in the west and lower in the east, at any particular latitude. In addition, indices for other cancer risk-modifying factors are readily available including those for smoking, alcohol consumption, ethnic background, urban/rural residence, socioeconomic status, air pollution, and in limited fashion, diet. The ecological approach has also been used to identify latitudinal variations in cancer mortality rates in Australia, China, Japan, and Spain, and in multicountry studies. It has been used to investigate the relative roles of solar UVB and dietary factors on a global scale. The ecological approach has also been applied to cancer survival. Studies in Norway and England found that individuals diagnosed with cancer in summer or fall, when serum 25-hydroxyvitamin D levels are highest, had a milder clinical course and longer survival than those diagnosed in winter or spring.

CONCLUSION

These findings provide strong evidence that vitamin D status plays an important role in controlling the outcome of cancer. Support for the UVB-vitamin D-cancer theory is now scientifically strong enough to warrant use of vitamin D in cancer prevention, and as a component of treatment. More research studies would help to explore whether there are benefits beyond the substantial effects that have been observed.

Estimated benefit of increased vitamin D status in reducing the economic burden of disease in western Europe

Vitamin D has important benefits in reducing the risk of many conditions and diseases. Those diseases for which the benefits are well supported and that have large economic effects include many types of cancer, cardiovascular diseases, diabetes mellitus, several bacterial and viral infections, and autoimmune diseases such as multiple sclerosis. Europeans generally have low serum 25-hydroxyvitamin D [25(OH)D] levels owing to the high latitudes, largely indoor living, low natural dietary sources of vitamin D such as cold-water ocean fish, and lack of effective vitamin D fortification of food in most countries. Vitamin D dose-disease response relations were estimated from observational studies and randomized controlled trials. The reduction in direct plus indirect economic burden of disease was based on increasing the mean serum 25(OH)D level to 40 ng/mL, which could be achieved by a daily intake of 2000-3000 IU of vitamin D. For 2007, the reduction is estimated at euro187,000 million/year. The estimated cost of 2000-3000 IU of vitamin D3/day along with ancillary costs such as education and testing might be about euro10,000 million/year. Sources of vitamin D could include a combination of food fortification, supplements, and natural and artificial UVB irradiation, if properly acquired. Additional randomized controlled trials are warranted to evaluate the benefits and risks of vitamin D supplementation. However, steps to increase serum 25(OH)D levels can be implemented now based on what is already known.

Vitamin D and aging

Recent studies using genetically modified mice, such as FGF23-/- and Klotho-/- mice that exhibit altered mineral homeostasis due to a high vitamin D activity showed features of premature aging that include retarded growth, osteoporosis, atherosclerosis, ectopic calcification, immunological deficiency, skin and general organ atrophy, hypogonadism and short lifespan. The phenotype reversed by normalizing vitamin D and/or mineral homeostasis. Thus, hypervitaminosis D due to an increased 1alpha-hydroxylase activity seems to be a cause of the premature aging. In several studies, we have described that a complete or partial lack of vitamin D action (VDR-/- mice and CYP27B1-/-) show almost similar phenotype as FGF23-/- or Klotho-/- mice. VDR mutant mice have growth retardation, osteoporosis, kyphosis, skin thickening and wrinkling, alopecia, ectopic calcification, progressive loss of hearing and balance as well as short lifespan. CYP27B1-/- mice do not show alopecia nor balance deficit, which might be apoVDR-dependent or calcidiol-dependent. The features are typical to premature aging. The phenotype is resistant to a normalization of the mineral homeostasis by a rescue diet containing high calcium and phosphate. Taken together, aging shows a U-shaped dependency on hormonal forms of vitamin D suggesting that there is an optimal concentration of vitamin D in delaying aging phenomena. Our recent study shows that calcidiol is an active hormone. Since serum calcidiol but not calcitriol is fluctuating in physiological situations, calcidiol might determine the biological output of vitamin D action. Due to its high serum concentration and better uptake of calcidiol-DBP by the target cells through the cubilin-megalin system, calcidiol seems to be an important circulating hormone. Therefore, serum calcidiol might be associated with an increased risk of aging-related chronic diseases more directly than calcitriol. Aging and cancer seem to be tightly associated phenomena. Accumulation of damage on DNA and telomeres cause both aging and cancer, moreover the signalling pathways seem to converge on tumour suppressor protein, p53, which seems to be regulated by vitamin D. Also, the insulin-like growth factor signalling pathway (IGF-1, IGFBPs, IGFR) and fibroblast growth factor-23 (FGF-23) regulate growth, aging and cancer. Vitamin D can regulate these signalling pathways, too. Also NF-kappaB and telomerase reverse transcriptase (TERT) might be molecular mechanisms mediating vitamin D action in aging and cancer. Calcidiol serum concentrations show a U-shaped risk of prostate cancer suggesting an optimal serum concentration of 40-60 nmol/L for the lowest cancer risk. Therefore, it is necessary to study several common aging-associated diseases such as osteoporosis, hypertension and diabetes known to be vitamin D-dependent before any recommendations of an optimal serum concentration of calcidiol are given.

Plasma C-peptide is inversely associated with calcium intake in women and with plasma 25-hydroxy vitamin D in men

The consumption of calcium, vitamin D, and dairy products may be associated with a reduced risk of type 2 diabetes mellitus. However, whether this reduction is due to calcium, vitamin D, or other components of dairy products is not clear. We examined intakes of total calcium and vitamin D, and plasma concentrations of 25 hydroxyvitamin D [25(OH)D] in relation to fasting plasma concentrations of C-peptide in 2 cross-sectional studies among healthy men from the Health Professionals Follow-up Study and among healthy women from the Nurses' Health Study I. Intake of total calcium was modestly inversely associated with C-peptide concentration in women (P-trend = 0.05); however, the inverse association was not significant in men (P = 0.7). Concentrations of C-peptide were 20% lower among men who had plasma concentrations of 25(OH)D in the highest quartile compared with those in the lowest quartile (P-trend = 0.08); there was no association in women (P = 0.3). The inverse association between calcium intake and the plasma C-peptide concentration was stronger in hypertensive individuals of both sexes. The difference in the C-peptide concentrations between extreme quartiles of calcium intake was 17% in men and 20% in women. Plasma concentrations of C-peptide for the combination of the highest tertiles of calcium intake and plasma 25(OH)D compared with the opposite extreme were 35% lower (P = 0.03) in men and 12% lower (P = 0.01) in women. The results suggest that calcium intake or systemic vitamin D status, after adjustment for intake of dairy products, is associated with decreased insulin secretion.

The aryl hydrocarbon receptor activator benzo[a]pyrene enhances vitamin D3 catabolism in macrophages

Benzo[a]pyrene (BaP), a polycyclic aromatic hydrocarbon produced by cigarette combustion, is implicated as a causative agent in smoking-related cancer and atherosclerosis. 1,25-Dihydroxyvitamin D3 [1,25(OH)2D3], a potent ligand for the nuclear receptor vitamin D receptor (VDR), has been shown to decrease the risk of osteoporosis, some types of cancer and cardiovascular disease, suggesting an opposing effect of vitamin D3 to cigarette smoking. In this study, we investigated the effects of BaP on the vitamin D3 signaling pathway. BaP effectively enhanced the 1,25(OH)2D3-dependent induction of cytochrome P450 24A1 (CYP24A1) in human monocyte/macrophage-derived THP-1 cells and breast cancer MCF-7 cells. BaP combination was less or not effective on mRNA expression of CD14, arachidonate 5-lipoxygenase, and cathelicidin antimicrobial peptide in THP-1 cells. BaP also increased the expression of CYP24A1 induced by a non-vitamin D VDR ligand, lithocholic acid acetate. Another aryl hydrocarbon receptor (AhR) ligand, 2,3,7,8-tetrachlorodibenzo-p-dioxin, enhanced CYP24A1 expression by 1,25(OH)2D3 in THP-1 cells. Treatment of cells with an AhR antagonist and a protein synthesis inhibitor inhibited the enhancing effect of BaP on CYP24A1 induction, indicating that the effects of BaP are mediated by AhR activation and de novo protein synthesis. BaP pretreatment increased 1,25(OH)2D3-dependent recruitment of VDR and retinoid X receptor to the CYP24A1 promoter. Analysis of 1,25(OH)2D3 metabolism showed that BaP enhanced the hydroxylation of 1,25(OH)2D3 by CYP24A1 in THP-1 cells. Thus, AhR activation by BaP stimulates vitamin D3 catabolism. Modulation of vitamin D signaling by AhR may represent a mechanism underlying cigarette smoking-related diseases.

Dairy food, calcium, and risk of cancer in the NIH-AARP Diet and Health Study

BACKGROUND

Dairy food and calcium intakes have been hypothesized to play roles that differ among individual cancer sites, but the evidence has been limited and inconsistent. Moreover, their effect on cancer in total is unclear.

METHODS

Dairy food and calcium intakes in relation to total cancer as well as cancer at individual sites were examined in the National Institutes of Health (NIH)-AARP (formerly known as the American Association of Retired Persons) Diet and Health Study. Intakes of dairy food and calcium from foods and supplements were assessed with a food frequency questionnaire. Incident cancer cases were identified through linkage with state cancer registries. A Cox proportional hazard model was used to estimate relative risks and 2-sided 95% confidence intervals (CIs).

RESULTS

During an average of 7 years of follow-up, we identified 36 965 and 16 605 cancer cases in men and women, respectively. Calcium intake was not related to total cancer in men but was nonlinearly associated with total cancer in women: the risk decreased up to approximately 1300 mg/d, above which no further risk reduction was observed. In both men and women, dairy food and calcium intakes were inversely associated with cancers of the digestive system (multivariate relative risk for the highest quintile of total calcium vs the lowest, 0.84; 95% CI, 0.77-0.92 in men, and 0.77; 95% CI, 0.69-0.91 in women). Decreased risk was particularly pronounced with colorectal cancer. Supplemental calcium intake was also inversely associated with colorectal cancer risk.

CONCLUSION

Our study suggests that calcium intake is associated with a lower risk of total cancer and cancers of the digestive system, especially colorectal cancer.

Calcium plus vitamin D supplementation and mortality in postmenopausal women: the Women's Health Initiative calcium-vitamin D randomized controlled trial

BACKGROUND

Calcium and vitamin D (CaD) supplementation trials including the Women's Health Initiative (WHI) trial of CaD have shown nonsignificant reductions in total mortality. This report examines intervention effects on total and cause-specific mortality by age and adherence.

METHODS

The WHI CaD trial was a randomized, double-blind, placebo-controlled trial that enrolled 36,282 postmenopausal women aged 51-82 years from 40 U.S. clinical centers. Women were assigned to 1,000 mg of elemental calcium carbonate and 400 IU of vitamin D(3) daily or placebo with average follow-up of 7.0 years.

RESULTS

The hazard ratio (HR) for total mortality was 0.91 (95% confidence interval [CI], 0.83-1.01) with 744 deaths in women randomized to CaD versus 807 deaths in the placebo group. HRs were in the direction of reduced risk but nonsignificant for stroke and cancer mortality, but near unity for coronary heart disease and other causes of death. HRs for total mortality were 0.89 in the 29,942 women younger than 70 years (95% CI, 0.79-1.01) and 0.95 in the 6,340 women aged 70 and older (95% CI, 0.80-1.12; p value for age interaction = .10). No statistically significant interactions were observed for any baseline characteristics. Treatment effects did not vary significantly by season.

CONCLUSIONS

In the WHI CaD trial, supplementation did not have a statistically significant effect on mortality rates but the findings support the possibility that these supplements may reduce mortality rates in postmenopausal women. These data can neither support nor refute recommendations for higher dose vitamin D supplementation to reduce cancer or total mortality.

Serum vitamin D and risk of pancreatic cancer in the prostate, lung, colorectal, and ovarian screening trial

Experimental evidence suggests that vitamin D has anticarcinogenic properties; however, a nested case-control study conducted in a population of male Finnish smokers found that higher 25-hydroxyvitamin D [25(OH)D], the best indicator of vitamin D status as determined by the sun and diet, was associated with a significant 3-fold increased risk for pancreatic cancer. We conducted a nested case-control study in the Prostate, Lung, Colorectal, and Ovarian Screening Trial cohort of men and women 55 to 74 years of age at baseline to test whether prediagnostic serum 25(OH)D concentrations were associated with pancreatic cancer risk. Between 1994 and 2006, 184 incident cases of pancreatic adenocarcinoma occurred (follow-up to 11.7 years). Two controls (n = 368) who were alive at the time the case was diagnosed were selected for each case and matched by age, race, sex, and calendar date of blood draw (to control for seasonal variation). We calculated odds ratios (OR) and 95% confidence intervals (95% CI) using conditional logistic regression, adjusting for smoking and body mass index. Vitamin D concentrations were not associated with pancreatic cancer overall (highest versus lowest quintile, >82.3 versus <45.9 nmol/L: OR, 1.45; 95% CI, 0.66-3.15; P trend = 0.49). However, positive associations were observed among subjects with low estimated annual residential solar UBV exposure, but not among those with moderate to high annual exposure (P interaction = 0.015). We did not confirm the previous strong positive association between 25(OH)D and pancreatic cancer; however, the increased risk among participants with low residential UVB exposure is similar.

Vitamin D and prevention of colorectal adenoma: a meta-analysis

BACKGROUND

Vitamin D status is associated inversely with risk of colorectal cancer, but the association with adenoma risk is less clear. This meta-analysis examined the overall relationship between circulating (plasma or serum) 25-hydroxyvitamin D [25(OH)D], vitamin D intake (dietary, supplemental, or total), and colorectal adenoma incidence in published studies.

METHODS

A meta-analysis composed of 17 epidemiologic studies [1 cross-sectional, 9 case-control, and 7 cohort or nested case-control studies; 7 on 25(OH)D and 12 on vitamin D intake] published before December 2007 was done to examine the association between circulating 25(OH)D, vitamin D intake, and colorectal adenomas. Summary Peto odds ratios (OR) were computed for overall and stratified analyses.

RESULTS

Circulating 25(OH)D was inversely associated with risk of colorectal adenomas: the OR was 0.70 [95% confidence interval (95% CI), 0.56-0.87] for high versus low circulating 25(OH)D. The highest quintile of vitamin D intake was associated with an 11% marginally decreased risk of colorectal adenomas compared with low vitamin D intake (OR, 0.89; 95% CI, 0.78-1.02). For recurrent adenomas, there was a decreased risk of 12% (95% CI, 0.72-1.07) among individuals with high versus low vitamin D intake. The inverse associations appeared stronger for advanced adenoma [OR, 0.64; 95% CI, 0.45-0.90 for serum 25(OH)D and OR, 0.77; 95% CI, 0.63-0.95 for vitamin D intake], but the number of studies was small.

CONCLUSIONS

Both circulating 25(OH)D and vitamin D intake were inversely associated with colorectal adenoma incidence and recurrent adenomas. These results further support a role of vitamin D in prevention of colorectal adenoma incidence and recurrence.

Preventing cancer

Advancements in management protocols and chemotherapeutics have improved outcomes for patients diagnosed with cancer. Cancer, however, continues to claim many lives annually in the United States and around the world. There is a large body of evidence that is strong and consistent that through modification of diet and lifestyle habits, cancer can be a preventable disease. This article discusses these changes and highlights the evidence for and against implementing them.

Genetic polymorphisms of the vitamin D binding protein and plasma concentrations of 25-hydroxyvitamin D in premenopausal women

BACKGROUND

Vitamin D status, determined on the basis of 25-hydroxyvitamin D [25(OH)D] concentrations, is associated with the risk of several diseases. Vitamin D binding protein (DBP) is the major carrier of vitamin D and its metabolites, but the role of DBP single nucleotide polymorphisms (SNPs) on 25(OH)D concentrations is unclear.

OBJECTIVE

The objective was to evaluate the association of 2 DBP gene SNPs with 25(OH)D concentrations and explore whether such association varies according to the amount of vitamin D that needs to be transported.

DESIGN

This cross-sectional study included 741 premenopausal white women, mostly of French descent. Plasma 25(OH)D concentrations were measured by radioimmunoassay. DBP-1 (rs7041) and DBP-2 (rs4588) were genotyped with a Sequenom MassArray platform. Associations and interactions were modeled by using multivariate linear regression.

RESULTS

DBP-1 and DBP-2 SNPs were in strong linkage disequilibrium and were both associated with 25(OH)D concentrations. An additional copy of the rare allele of DBP-1 or DBP-2 was associated with lower 25(OH)D concentrations (beta = -3.29, P for trend = 0.0003; beta = -4.22, P for trend < 0.0001, respectively). These DBP polymorphisms explained as much of the variation in circulating 25(OH)D as did total vitamin D intake (r2 = 1.3% for DBP-1, r2 = 2.0% for DBP-2, and r2 < or = 1.2% for vitamin D intake).

CONCLUSION

Circulating 25(OH)D concentrations in premenopausal women are strongly related to DBP polymorphisms. Whether DBP rare allele carriers have a different risk of vitamin D-related diseases and whether such carriers can benefit more or less from dietary interventions, vitamin D supplementation, or sun exposure need to be clarified.

Vitamin D and pancreatic cancer

Sun exposure has been associated with lower death rates for pancreatic cancer in ecological studies. Skin exposure to solar ultraviolet B radiation induces cutaneous production of precursors to 25-hydroxy (OH) vitamin D (D) and is considered the primary contributor to vitamin D status in most populations. Pancreatic islet and duct cells express 25-(OH) D(3)-1alpha-hydroxylase that generates the biologically active 1,25-dihydroxy(OH)(2) D form. Thus, 25(OH)D concentrations could affect pancreatic function and possibly pancreatic cancer etiology. Serum 25-(OH)D is the major circulating vitamin D metabolite and is considered the best indicator of vitamin D status as determined by the sun and diet. Although recent prospective epidemiologic studies of higher predicted vitamin D status score and vitamin D intake and pancreatic cancer risk suggest protective associations, a nested case-control study showed a significant 3-fold increased risk for pancreatic cancer with higher vitamin D status. Limitations of these studies include the former do not measure vitamin D status on pancreatic cancer cases and the later was conducted in a male smoker population. More research is needed, particularly examination of pre-diagnostic vitamin D status and risk of pancreatic cancer, prior to conclusions for vitamin D's potential role in the etiology of this highly fatal cancer.

Vitamin D beyond bones in chronic obstructive pulmonary disease: time to act

The discovery that the vitamin D endocrine system regulates a very large number of genes and their associated biological processes improves our insight into the fundamental role of vitamin D and sun exposure for human health. Accumulating epidemiological data are linking a low vitamin D nutritional status to highly prevalent diseases such as cancer, autoimmune diseases, and chronic infections. Approximately half of the world's elderly, and to a lesser extent the adult population, have insufficient to deficient 25-hydroxyvitamin D (25-OHD) serum levels, and several intervention studies are being undertaken to study the impact of adequate vitamin D supplementation in chronic diseases. In this perspective we claim that chronic obstructive pulmonary disease (COPD) is a candidate disease for which vitamin D supplementation might be beneficial. Epidemiological studies revealed a dose-dependent association between serum 25-OHD levels and pulmonary function so that adequate vitamin D supplementation may extend beyond its protection against osteoporotic fractures. In line with the novel insights on its immune function, it is tempting to speculate that vitamin D may down-regulate the inflammatory immune response in the airways while boosting innate immune defense against different microorganisms. Apart from its affects on osteoporosis, vitamin D may also interfere with other comorbidities of COPD such as skeletal muscle weakness, cardiovascular disease, and cancer. Because respiratory treatments in COPD fail to reverse disease progression, interventional trials that may exploit the broader potential of vitamin D are warranted. A further challenge of such studies is to define optimal serum 25-OHD levels for such noncalcemic endpoints.

Sunlight, UV-radiation, vitamin D and skin cancer: how much sunlight do we need?

Vtamin D is the sunshine vitamin for good reason. During exposure to sunlight, the utraviolet B photons enter the skin and photolyze 7-dehydrocholesterol to previtamin D3 which in turn is isomerized by the body's temperature to vitamin D3. Most humans have depended on sun for their vitamin D requirement. Skin pigment, sunscreen use, aging, time of day, season and latitude dramatically affect previtamin D3 synthesis. Vitamin D deficiency was thought to have been conquered, but it is now recognized that more than 50% of the world's population is at risk for vitamin D deficiency. This deficiency is in part due to the inadequate fortification of foods with vitamin D and the misconception that a healthy diet contains an adequate amount of vitamin D. Vitamin D deficiency causes growth retardation and rickets in children and will precipitate and exacerbate osteopenia, osteoporosis and increase risk of fracture in adults. The vitamin D deficiency has been associated pandemic with other serious consequences including increased risk of common cancers, autoimmune diseases, infectious diseases and cardiovascular disease. There needs to be a renewed appreciation of the beneficial effect of moderate sunlight for providing all humans with their vitamin D requirement for health.

Solar ultraviolet irradiance and cancer incidence and mortality

Evidence supporting the UVB/vitamin D/cancer theory continues to mount with little detraction, although there are some inconsistent results, such as some from Nordic countries, with respect to serum calcidiol levels. Also, studies designed and conducted before it was realized that dietary sources are largely inadequate to have a pronounced effect on cancer risk were largely unable to confirm a beneficial role for vitamin D in reducing the risk of cancer. The analysis of the economic burden of solar UVB irradiance and vitamin D deficiencies compared to excess solar UV irradiance for the United States yielded interesting findings. One was that the US economic burden due to vitamin D insufficiency from inadequate exposure to solar UVB irradiance, diet and supplements was estimated at $40 billion to $56 billion in 2004, whereas the economic burden for excess UV irradiance was estimated at $6 billion to $7 billion. These findings are probably still approximately correct, if not on the low side, with respect to vitamin D because of the additional benefits found recently, such as protection against infectious diseases.

How strong is the evidence that solar ultraviolet B and vitamin D reduce the risk of cancer?: An examination using Hill's criteria for causality

The ultraviolet-B (UVB)-vitamin D-cancer hypothesis was proposed in 1980. Since then, several ecological and observational studies have examined the hypothesis, in addition to one good randomized, controlled trial. Also, the mechanisms whereby vitamin D reduces the risk of cancer have been elucidated. This report aims to examine the evidence to date with respect to the criteria for causality in a biological system first proposed by Robert Koch and later systematized by A. Bradford Hill. The criteria of most relevance are strength of association, consistency, biological gradient, plausibility/mechanisms and experimental verification. Results for several cancers generally satisfy these criteria. Results for breast and colorectal cancer satisfy the criteria best, but there is also good evidence that other cancers do as well, including bladder, esophageal, gallbladder, gastric, ovarian, rectal, renal and uterine corpus cancer, as well as Hodgkin's and non-Hodgkin's lymphoma. Several cancers have mixed findings with respect to UVB and/or vitamin D, including pancreatic and prostate cancer and melanoma. Even for these, the benefit of vitamin D seems reasonably strong. Although ecological and observational studies are not generally regarded as able to provide convincing evidence of causality, the fact that humanity has always existed with vitamin D from solar UVB irradiance means that there is a wealth of evidence to be harvested using the ecological and observational approaches. Nonetheless, additional randomized, controlled trials are warranted to further examine the link between vitamin D and cancer incidence, survival and mortality.

Vitamin D and differentiation in cancer

This paper reviews the current understanding of the vitamin D-induced differentiation of neoplastic cells, which results in the generation of cells that acquire near-normal, mature phenotype. Examples of the criteria by which differentiation is recognized in each cell type are provided, and only those effects of 1alpha,25-dihydroxyvitamin D(3) (1,25D) on cell proliferation and survival that are associated with the differentiation process are emphasized. The existing knowledge, often fragmentary, of the signaling pathways that lead to vitamin D-induced differentiation of colon, breast, prostate, squamous cell carcinoma, osteosarcoma, and myeloid leukemia cancer cells is outlined. The important distinctions between the different mechanisms of 1,25D-induced differentiation that are cell-type and cell-context specific are pointed out where known. There is a considerable body of evidence that the principal human cancer cells can be suitable candidates for chemoprevention or differentiation therapy with vitamin D. However, further studies are needed to fully understand the underlying mechanisms in order to improve the therapeutic approaches.

Solar ultraviolet-B irradiance and vitamin D may reduce the risk of septicemia

The primary features of the epidemiology of septicemia in the United States include highest rates in winter and the Northeast, lowest in fall and in the West; higher rates among African Americans than white Americans; a rapid increase in incidence with age; comorbidity with several chronic and infectious diseases; and a rapid increase in incidence rate starting in the early 1980s. This article reviews the literature on the epidemiology of septicemia in the United States, along with the roles of solar ultraviolet-B (UVB) and vitamin D3 related to the more important features. Solar UVB doses in summer are highest in the Southwest and lowest in the Northeast. Serum 25-hydroxyvitamin D [25(OH)D] levels are highest in summer, lowest in winter. African Americans have much lower 25(OH)D levels than those of white Americans. Serum 25(OH)D levels decline rapidly with advancing age. The risk of diseases comorbid with septicemia are generally inversely correlated with serum 25(OH)D levels. Sun-avoidance messages may have led to lower population levels of 25(OH)D, although prevalence of antibiotic-resistant bacteria may have increased. Previous reports have shown that 1,25-dihydroxyvitamin D upregulates human cathelicidin, LL-37, which has antimicrobial as well as antiendotoxin activity. The general agreement between the epidemiology of septicemia in the United States and the variations of solar UVB and the effects of vitamin D supports the hypothesis that both play important roles in reducing the risk of septicemia. Further study is warranted to evaluate this hypothesis.

A critical review of Vitamin D and Cancer: A report of the IARC Working Group

The International Agency for Research on Cancer (IARC) released a report, Vitamin D and Cancer, on November 25, 2008. The report focused on the current state of knowledge and level of evidence of a causal association between vitamin D status and cancer risk. Although presenting and evaluating evidence for the beneficial role of UVB and vitamin D in reducing the risk of cancer, it discounted or omitted important evidence in support of the efficacy of vitamin D. The report largely dismissed or ignored ecological studies on the grounds that confounding factors might have affected the findings. The report accepted a preventive role of vitamin D in colorectal cancer but not for breast cancer.The only randomized controlled trial (RCT) on cancer incidence that used a sufficiently high dose of vitamin D (1,100 IU/day) and calcium (1,400-1,500 mg/day) found a 77% reduction in the risk of all-cancer incidence in postmenopausal women who received both, of which approximately 35% reduction in risk was attributed to vitamin D alone. Unfairly, the report dismissed these findings on the basis of a flawed critique.The report called for RCTs of vitamin D supplementation to settle the issue. Although RCTs theoretically would be beneficial, development of sound and effective public health policies does not necessarily depend on them, and the field of vitamin D, calcium and chronic disease has reached the point where RCTs may not be ethical.The IARC report should therefore not form the basis for public health policy decisions.

RhoA-ROCK and p38MAPK-MSK1 mediate vitamin D effects on gene expression, phenotype, and Wnt pathway in colon cancer cells

The active vitamin D metabolite 1,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) inhibits proliferation and promotes differentiation of colon cancer cells through the activation of vitamin D receptor (VDR), a transcription factor of the nuclear receptor superfamily. Additionally, 1,25(OH)₂D₃ has several nongenomic effects of uncertain relevance. We show that 1,25(OH)₂D₃ induces a transcription-independent Ca²⁺ influx and activation of RhoA–Rho-associated coiled kinase (ROCK). This requires VDR and is followed by activation of the p38 mitogen-activated protein kinase (p38MAPK) and mitogen- and stress-activated kinase 1 (MSK1). As shown by the use of chemical inhibitors, dominant-negative mutants and small interfering RNA, RhoA–ROCK, and p38MAPK-MSK1 activation is necessary for the induction of CDH1/E-cadherin, CYP24, and other genes and of an adhesive phenotype by 1,25(OH)₂D₃. RhoA–ROCK and MSK1 are also required for the inhibition of Wnt–β-catenin pathway and cell proliferation. Thus, the action of 1,25(OH)₂D₃ on colon carcinoma cells depends on the dual action of VDR as a transcription factor and a nongenomic activator of RhoA–ROCK and p38MAPK-MSK1.

Assessment of vitamin D status and definition of a normal circulating range of 25-hydroxyvitamin D

PURPOSE OF REVIEW

The assessment of circulating 25-hydroxyvitamin D [25(OH)D] for clinical diagnosis has increased in an exponential fashion during the past 5 years. It is thus timely to review the reasons for this increase as well as the diverse analytical methods used to meet this need.

RECENT FINDINGS

Nutritional vitamin D status, as defined by circulating levels of 25(OH)D, has long been implicated in skeletal health. However, in the past decade circulating 25(OH)D has been strongly linked in humans to cancer rates, autoimmune disease, cardiovascular health and infectious disease. As a result, availability and rapid analytical turnaround of 25(OH)D assays have had to improve. Today these demands are largely met in the clinical laboratory by direct automated chemiluminescent platform analysis or high-throughput LC/MS procedures. These methods are diverse and often do not agree with respect to designated reference ranges.

SUMMARY

The assessment of circulating 25(OH)D levels has become an important clinical tool in the management and prevention of diverse disease states. For this reason, assay standardization as well as a uniform reference range for circulating 25(OH)D levels must be achieved.

Respiratory epithelial cells convert inactive vitamin D to its active form: potential effects on host defense

The role of vitamin D in innate immunity is increasingly recognized. Recent work has identified a number of tissues that express the enzyme 1alpha-hydroxylase and are able to activate vitamin D. This locally produced vitamin D is believed to have important immunomodulatory effects. In this paper, we show that primary lung epithelial cells express high baseline levels of activating 1alpha-hydroxylase and low levels of inactivating 24-hydroxylase. The result of this enzyme expression is that airway epithelial cells constitutively convert inactive 25-dihydroxyvitamin D(3) to the active 1,25-dihydroxyvitamin D(3). Active vitamin D that is generated by lung epithelium leads to increased expression of vitamin D-regulated genes with important innate immune functions. These include the cathelicidin antimicrobial peptide gene and the TLR coreceptor CD14. dsRNA increases the expression of 1alpha-hydroxylase, augments the production of active vitamin D, and synergizes with vitamin D to increase expression of cathelicidin. In contrast to induction of the antimicrobial peptide, vitamin D attenuates dsRNA-induced expression of the NF-kappaB-driven gene IL-8. We conclude that primary epithelial cells generate active vitamin D, which then influences the expression of vitamin D-driven genes that play a major role in host defense. Furthermore, the presence of vitamin D alters induction of antimicrobial peptides and inflammatory cytokines in response to viruses. These observations suggest a novel mechanism by which local conversion of inactive to active vitamin D alters immune function in the lung.

Plasma 25-hydroxyvitamin D levels and risk of incident hypertension among young women

Numerous cross-sectional studies demonstrate an inverse association between plasma 25-hydroxyvitamin D [25(OH)D] and blood pressure or hypertension. Prospective data, however, are limited. Among 1484 women aged 32 to 52 years who did not have hypertension at baseline, we prospectively analyzed the association between plasma levels of 25(OH)D and the odds of incident hypertension using a nested case-control study design. We matched cases and controls on age, race, and month of blood collection and further adjusted for body mass index, physical activity, family history of hypertension, oral contraceptive use, and plasma levels of parathyroid hormone, calcium, phosphorous, creatinine, and uric acid. Median plasma 25(OH)D levels were lower in the cases (25.6 ng/mL) than in the controls (27.3 ng/mL; P<0.001). Women in the lowest compared with highest quartile of plasma 25(OH)D had an adjusted odds ratio for incident hypertension of 1.66 (95% CI: 1.11 to 2.48; P for trend=0.01). Compared with women with sufficient levels, those with vitamin D deficiency (<30 ng/mL; 65.7% of the study population) had a multivariable odds ratio of 1.47 (95% CI: 1.10 to 1.97). Plasma 25(OH)D levels are inversely and independently associated with the risk of developing hypertension.

Abstract ED07-01: Vitamin D and the Cancer Connection: A D-Lightful Story

ED07-01

Abstract: ACCR

Vitamin D and the Cancer Connection: A D-Lightful Story

In the 1930’s, it was first appreciated that living at higher latitudes and having minimum exposure to sunlight increased risk of dying of cancer. This was followed by the observation by Apperley who reported that living at higher latitudes increased risk of dying of common cancers. He speculated that non-melanoma skin cancer, which is easy to detect and easy to treat, may be providing some immunity against more deadly cancers for people who live in southern United States. These data were followed by several epidemiologic studies suggesting that living at higher latitudes or being at risk of vitamin D deficiency increases risk of developing and dying of colon, prostate, and breast among other deadly cancers. Recently Iit’s has been recently reported that increased exposure to sunlight reduces risk of breast cancer in young women. Furthermore, women who ingested 1,500 milligrams of calcium and 1,100 IU of vitamin D3/d reduced their risk of developing all cancers by 60% in four years. It is now recognized that most tissues in the body not only have a vitamin D receptor but have the enzymatic machinery to produce the active form of vitamin D, 1,25-dihydroxyvitamin D3. 1,25(OH)2D3 is one of the most potent hormones for inhibiting cell growth and inducing terminal differentiation. It is believed that the local production of 1,25(OH)2D3 acts as a sentinel hormone to maintain cell growth and maturation. It’s has been estimated that more than 200 genes, many of which control cellular proliferation, differentiation, apoptosis and angiogenesis, are directly or indirectly influenced by 1,25(OH)2D3. Animal studies have revealed that vitamin D deficiency enhances colon tumor growth by as much as 40%. Novel vitamin D analogues with two side arms known as Gemini analogues have been tested in a mouse colon cancer model and have been shown to be up to 1,000 times more effective in not only reducing tumor growth and volume, but also tumor invasion when compared to 1,25(OH)2D3. In addition, these novel analogues have little calcemic activity when compared to 1,25(OH)2D3.

Studies have reported that by increasing intake of vitamin D to 1,000 IU/d could reduce risk of developing colorectal cancer by 50%. WIn women who had a blood level of 25(OH)D of at least 48 ng/ml reduced risk of developing breast cancer by 50%. Men with prostate cancer and metastatic disease who received 2,000 IU of vitamin D3/d for up to 18 months either had a significant reduction in their PSA levels or had less increase in their PSA doubling time.

The major source of vitamin D for most humans throughout evolution hasd been exposure to sunlight. However, for more than 40 years, there has been a campaign recommending that no one should be exposed to direct sunlight because it increases risk of skin cancer. Although it is true that chronic excessive exposure to sunlight increases risk of non-melanoma skin cancer, these cancers are often easy to detect and easy to treat with cure. Melanoma, however, is an aggressive deadly cancer. Because it originates in the skin, it is often included as one of the skin cancers that is caused by exposure to sunlight. However, when put into perspective, it is known that most melanomas occur on the least sun exposed areas, and, more importantly, two large studies have reported that occupational sun exposure reduces risk of malignant melanoma. Furthermore, children and young adults exposed to the most sunlight who develop melanoma are less likely to die of this deadly disease. The major risk factors for melanoma include bad genetics, red hair color and fair skin, the number of sun burning experiences especially as a child and young adult and those that have the largest number of moles on their body.

For every 100 IU of vitamin D that an adult ingests, the blood levels of the major circulating form of vitamin,[25(OH)D increases by 1 ng/ml. Most experts agree that a blood level of &gt; 30 ng/ml for 25(OH)D will provide health benefits including reducing risk of deadly cancers. It is essentially impossible to get a 1,000 IU of vitamin D/d from dietary sources. Thus, there needs to be a conscience effort to take a vitamin D supplement of at least 1,000 IU of vitamin D/d. An adult in a bathing suit exposed to 1 minimal erythemal dose of sunlight is equivalent to ingesting approximately 15,000 to 20,000 IU of vitamin D. Thus, sensible sun exposure is an excellent source of vitamin D. Indeed, even today most children and adults blood levels of 25(OH)D is seasonal in nature, with it peaking at the end of the summer and is at its nadir at the end of the winter. In the absence of any sun exposure, 2,000 IU of vitamin D/d is required for both children and adults to maintain a 25(OH)D of &gt; 30 ng/ml. Thus, all health care professionals should be vigilant about their patient’s’ vitamin D status. Either measurement of 25(OH)D once as year, preferably at the beginning of winter, with treatment for vitamin D deficiency or making certain that both children and adults are ingesting at least 1,000 IU of vitamin D/d, are two good methods to assure vitamin D sufficiency. For patients, I find that 50,000 IU vitamin D2 every two weeks for up to six years maintains their blood level of 25(OH)D at ~ 40-50 ng/ml with no toxicity.

Citation Information: Cancer Prev Res 2008;1(7 Suppl):ED07-01.

Prevention of rickets and vitamin D deficiency in infants, children, and adolescents

Rickets in infants attributable to inadequate vitamin D intake and decreased exposure to sunlight continues to be reported in the United States. There are also concerns for vitamin D deficiency in older children and adolescents. Because there are limited natural dietary sources of vitamin D and adequate sunshine exposure for the cutaneous synthesis of vitamin D is not easily determined for a given individual and may increase the risk of skin cancer, the recommendations to ensure adequate vitamin D status have been revised to include all infants, including those who are exclusively breastfed and older children and adolescents. It is now recommended that all infants and children, including adolescents, have a minimum daily intake of 400 IU of vitamin D beginning soon after birth. The current recommendation replaces the previous recommendation of a minimum daily intake of 200 IU/day of vitamin D supplementation beginning in the first 2 months after birth and continuing through adolescence. These revised guidelines for vitamin D intake for healthy infants, children, and adolescents are based on evidence from new clinical trials and the historical precedence of safely giving 400 IU of vitamin D per day in the pediatric and adolescent population. New evidence supports a potential role for vitamin D in maintaining innate immunity and preventing diseases such as diabetes and cancer. The new data may eventually refine what constitutes vitamin D sufficiency or deficiency.

Parathyroid hormone and the risk of incident hypertension

OBJECTIVE

The presence of parathyroid hormone receptor mRNA in a wide variety of tissues, including the endothelium, suggests that parathyroid hormone has potentially important effects in addition to the maintenance of calcium and phosphate homeostasis. We conducted a prospective study to examine the association between plasma intact parathyroid hormone levels and the subsequent risk of developing hypertension.

METHODS

We measured intact parathyroid hormone in 481 men without hypertension from the Health Professionals Follow-up Study. During 10 years of follow-up, we observed 142 cases of incident hypertension. Cox proportional hazards regression was used to adjust for age, race, body mass index, alcohol use, smoking, physical activity, predicted plasma 25-hydroxyvitamin D level, and other factors.

RESULTS

Median baseline levels of intact parathyroid hormone were 40.1 pg/ml in individuals who developed hypertension and 36.3 pg/ml in those who did not (P = 0.01). After multivariate adjustment, the relative risk for incident hypertension in men in the highest quartile of parathyroid hormone (median 56.0 pg/ml) compared with the lowest quartile of parathyroid hormone (median 26.3 pg/ml) was 1.83 (95% confidence interval 1.10-3.03; P for trend = 0.01). Analyses restricted to men in the lowest 90th percentage of the parathyroid hormone distribution (< or =58 pg/ml) yielded similar results. Further adjustment for the intake of calcium and sodium, as well as for season and fasting status at time of blood draw, did not materially change the results.

CONCLUSION

Plasma levels of intact parathyroid hormone, even within ranges considered normal, are positively and independently associated with a higher risk of incident hypertension.

Circulating 25-hydroxyvitamin D, VDR polymorphisms, and survival in advanced non-small-cell lung cancer

PURPOSE

We showed previously that in early-stage non-small-cell lung cancer (NSCLC), serum vitamin D levels and VDR polymorphisms were associated with survival. We hypothesized that vitamin D levels and VDR polymorphisms may also affect survival among patients with advanced NSCLC.

PATIENTS AND METHODS

We evaluated the relationship between circulating 25-hydroxyvitamin D levels; VDR polymorphisms, including Cdx-2 G>A (rs11568820), FokI C>T (rs10735810), and BsmI C>T (rs144410); and overall survival among patients with advanced NSCLC. Analyses of survival outcomes were performed using the log-rank test and Cox proportional hazards models, adjusting for sex, stage, and performance status.

RESULTS

There were 294 patients and 233 deaths, with median follow-up of 42 months. We found no difference in survival by circulating vitamin D level. The C/C genotype of the FokI polymorphism was associated with improved survival: median survival for C/C was 21.4 months, for C/T was 12.1 months, and for T/T was 15.6 months (log-rank P = .005). There were no significant effects on survival by the Cdx-2 or BsMI polymorphism. However, having increasing numbers of protective alleles was associated with improved survival (adjusted hazard ratio for two or more v zero to one protective alleles, 0.57; 95% CI, 0.41 to 0.79; P = .0008). On haplotype analysis, the G-T-C (Cdx-2-FokI-BsmI) haplotype was associated with worse survival compared with the most common haplotype of G-C-T (adjusted hazard ratio, 1.61; 95% CI, 1.21 to 2.14; P = .001).

CONCLUSION

There was no main effect of vitamin D level on overall survival in the advanced NSCLC population. The T allele of the VDR FokI>T polymorphism and the G-T-C (Cdx-2-FokI-BsmI) haplotype were associated with worse survival.

Current concepts in diet and prostate cancer

Increasing evidence suggests that diet influences the initiation and progression of prostate cancer. Herein, we review associations of specific foods and nutrients with prostate cancer, summarizing important and clinically relevant emerging data on this complex topic. Foods and nutrients associated with a decreased risk of prostate cancer include lycopene, soy, cruciferous vegetables, vitamin E and selenium. Although prospective clinical trials of dietary supplements and dietary modification to prevent or control prostate cancer are underway, definitive clinical evidence is currently lacking.

Calcium, dairy foods, vitamin D, and colorectal cancer risk: the Fukuoka Colorectal Cancer Study

Epidemiologic evidence supporting a protective role of calcium and vitamin D in colorectal carcinogenesis has been accumulating in Western populations, but it is limited in Asian populations, whose intake of calcium is relatively low. We investigated the association of intakes of these nutrients with colorectal cancer risk in Japanese. Study subjects were participants of a large-scale case-control study in Fukuoka, Japan. Diet was assessed through interview regarding 148 dietary items by showing typical foods or dishes on the display of a personal computer. In a multivariate analysis adjusting for potential confounding variables, calcium intake was significantly, inversely associated with colorectal cancer risk (P for trend=0.01); the odds ratio for the highest versus lowest quintile of calcium intake was 0.64 (95% confidence interval, 0.45-0.93). Higher levels of dietary vitamin D were significantly associated with decreased risk of colorectal cancer among those who had fewer chances of sunlight exposure at work or in leisure (P for trend=0.02). A decreased risk of colorectal cancer associated with high calcium intake was observed among those who had higher levels of vitamin D intake or among those who had a greater chance of daily sunlight exposure, but not among those with medium or lower intake of vitamin D or among those with potentially decreased sunlight exposure. These results add to support for a joint action of calcium and vitamin D in the prevention of colorectal carcinogenesis.

Frequency of leisure-time physical activity and serum 25-hydroxyvitamin D levels in the US population: results from the Third National Health and Nutrition Examination Survey

The decline in vitamin D status among older people is probably due to decreased synthesis of vitamin D by sun-exposed skin and/or decreased outdoor activity. The authors examined the association between outdoor leisure physical activity and serum 25-hydroxyvitamin D in the Third National Health and Nutrition Examination Survey (1988-1994) (n = 15,148 aged >/=20 years). The mean 25-hydroxyvitamin D concentration declined with increasing age, with 79, 73, and 68 nmol/liter for persons aged 20-39, 40-59, and 60 or more years. The proportion that engaged in outdoor activity in the past month was 80% for persons aged 20-39 and 40-59 years but 71% for those aged 60 or more years. In contrast, the mean difference in 25-hydroxyvitamin D between those who participated in outdoor activities daily compared with those who did not participate in the past month was similar for the youngest and oldest age groups: 13 and 16 nmol/liter, respectively. Those persons aged 60 or more years who participated in daily outdoor activities had a mean 25-hydroxyvitamin D concentration similar to that of persons aged 20-39 years: 77 versus 79 nmol/liter, respectively. These nationally representative data suggest that persons aged 60 or more years can synthesize enough vitamin D from daily outdoor activities to maintain vitamin D levels similar to those of young adults.

PIK3CA mutation in colorectal cancer: relationship with genetic and epigenetic alterations

Somatic PIK3CA mutations are often present in colorectal cancer. Mutant PIK3CA activates AKT signaling, which up-regulates fatty acid synthase (FASN). Microsatellite instability (MSI) and CpG island methylator phenotype (CIMP) are important molecular classifiers in colorectal cancer. However, the relationship between PIK3CA mutation, MSI and CIMP remains uncertain. Using Pyrosequencing technology, we detected PIK3CA mutations in 91 (15%) of 590 population-based colorectal cancers. To determine CIMP status, 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). PIK3CA mutation was significantly associated with mucinous tumors [P = .0002; odds ratio (OR) = 2.44], KRAS mutation (P < .0001; OR = 2.68), CIMP-high (P = .03; OR = 2.08), phospho-ribosomal protein S6 expression (P = .002; OR = 2.19), and FASN expression (P = .02; OR = 1.85) and inversely with p53 expression (P = .01; OR = 0.54) and beta-catenin (CTNNB1) alteration (P = .004; OR = 0.43). In addition, PIK3CA G-to-A mutations were associated with MGMT loss (P = .001; OR = 3.24) but not with MGMT promoter methylation. In conclusion, PIK3CA mutation is significantly associated with other key molecular events in colorectal cancer, and MGMT loss likely contributes to the development of PIK3CA G>A mutation. In addition, Pyrosequencing is useful in detecting PIK3CA mutation in archival paraffin tumor tissue. PIK3CA mutational data further emphasize heterogeneity of colorectal cancer at the molecular level.

Geographic location and vitamin D synthesis

Most of the population receive their nutritional vitamin D requirements through exposure to solar ultraviolet (UV) radiation, with cutaneous synthesis estimated to provide 80-100% of the vitamin D requirements of the body. However, little is understood about the basic interaction of sunlight (UV) exposure and the subsequent photobiology and photochemistry of vitamin D production in humans. Low vitamin D (blood serum 25[OH]D) status has been linked to the development of a surprisingly wide range of diseases. Epidemiological data and animal studies indicate that low vitamin D is linked to rickets, bone mass loss, multiple sclerosis, hypertension, breast cancer, prostate cancer, colorectal cancer, insulin dependent diabetes and schizophrenia. Importantly some this emerging research associates such diseases with location and subsequent ultraviolet radiation exposures. This paper overviews concepts important to consider when assessing the impact of location and UV exposure on vitamin D synthesis.

Incident solar radiation and coronary heart disease mortality rates in Europe

The reported low mortality rate from coronary heart disease in Portugal, Spain, Italy, Greece, and France, to a lesser extent, has been attributed in numerous nutritional studies to the consumption of a Mediterranean-type diet. There are still many unresolved issues about the direct causal effect of the Mediterranean dietary regime on low incidence of coronary heart disease. An analysis of coronary heart disease mortality rates in Europe from a latitudinal gradient perspective has shown to have a close correlation to incident solar radiation. It is surmised that the resulting increased in situ biosynthesis of Vitamin D(3) could be the critical missing confounder in the analysis of the beneficial health outcome of the Mediterranean diet.

25-hydroxyvitamin D levels and the risk of mortality in the general population

BACKGROUND

In patients undergoing dialysis, therapy with calcitriol or paricalcitol or other vitamin D agents is associated with reduced mortality. Observational data suggests that low 25-hydroxyvitamin D levels (25[OH]D) are associated with diabetes mellitus, hypertension, and cancers. However, whether low serum 25(OH)D levels are associated with mortality in the general population is unknown.

METHODS

We tested the association of low 25(OH)D levels with all-cause, cancer, and cardiovascular disease (CVD) mortality in 13 331 nationally representative adults 20 years or older from the Third National Health and Nutrition Examination Survey (NHANES III) linked mortality files. Participant vitamin D levels were collected from 1988 through 1994, and individuals were passively followed for mortality through 2000.

RESULTS

In cross-sectional multivariate analyses, increasing age, female sex, nonwhite race/ethnicity, diabetes, current smoking, and higher body mass index were all independently associated with higher odds of 25(OH)D deficiency (lowest quartile of 25(OH)D level, <17.8 ng/mL [to convert to nanomoles per liter, multiply by 2.496]), while greater physical activity, vitamin D supplementation, and nonwinter season were inversely associated. During a median 8.7 years of follow-up, there were 1806 deaths, including 777 from CVD. In multivariate models (adjusted for baseline demographics, season, and traditional and novel CVD risk factors), compared with the highest quartile, being in the lowest quartile (25[OH]D levels <17.8 ng/mL) was associated with a 26% increased rate of all-cause mortality (mortality rate ratio, 1.26; 95% CI, 1.08-1.46) and a population attributable risk of 3.1%. The adjusted models of CVD and cancer mortality revealed a higher risk, which was not statistically significant.

CONCLUSION

The lowest quartile of 25(OH)D level (<17.8 ng/mL) is independently associated with all-cause mortality in the general population.

Sun exposure and vitamin D sufficiency

Ultraviolet radiation is a carcinogen that also compromises skin appearance and function. Because the ultraviolet action spectra for DNA damage, skin cancer, and vitamin D(3) photosynthesis are identical and vitamin D is readily available from oral supplements, why has sun protection become controversial? First, the media and, apparently, some researchers are hungry for a new message. Second, the controversy is fueled by a powerful special interest group: the tanning industry. This industry does not target the frail elderly or inner-city ethnic minorities, groups for whom evidence of vitamin D(3) insufficiency is strongest, but rather fair-skinned teenagers and young adults, who are at highest risk of ultraviolet photodamage. Third, evolution does not keep pace with civilization. When nature gave humans the appealing capacity for cutaneous vitamin D(3) photosynthesis, life expectancy was <40 y; long-term photodamage was not a concern; and vitamin D(3) deficiency, with its resulting skeletal abnormalities (rickets), was likely to be fatal in early life. In the 21st century, life expectancy approaches 80 y in developed countries, vitamin D(3) is available at the corner store, and the lifetime risk of skin cancer is 1 in 3 among white Americans. Medical and regulatory groups should avoid poorly reasoned, sensationalistic recommendations regarding unprotected ultraviolet exposure. Instead, they should rigorously explore possible cause-and-effect relations between vitamin D(3) status and specific diseases while advocating the safest possible means of ensuring vitamin D(3) sufficiency.

Circulating 25-hydroxyvitamin d levels and survival in patients with colorectal cancer

PURPOSE

Higher plasma 25-hydroxyvitamin D(3) (25(OH)D) levels are associated with a decreased incidence of colorectal cancer, but the influence of plasma 25(OH)D on the outcome of patients with established colorectal cancer is unknown.

PATIENTS AND METHODS

We prospectively examined the association between prediagnosis 25(OH)D levels and mortality among 304 participants in the Nurses' Health Study (NHS) and the Health Professionals Follow-Up Study (HPFS) who were diagnosed with colorectal cancer from 1991 to 2002. Participants diagnosed within 2 years of blood collection were excluded. Patients were observed until death, June 2005 (NHS), or January 2005 (HPFS), whichever came first. The primary end point was overall mortality. Cox proportional hazards models were used to calculate hazard ratios (HR) adjusted for other risk factors for cancer survival.

RESULTS

Higher plasma 25(OH)D levels were associated with a significant reduction in overall mortality (P for trend = .02). Compared with the lowest quartile, participants in the highest quartile had an adjusted HR of 0.52 (95% CI, 0.29 to 0.94) for overall mortality. A trend toward improved colorectal cancer-specific mortality was also seen (HR = 0.61; 95% CI, 0.31 to 1.19). The results remained unchanged after excluding patients diagnosed within 5 years of blood collection (P for trend = .04); the multivariate HR for overall mortality comparing extreme quartiles was 0.45 (95% CI, 0.19 to 1.09).

CONCLUSION

Among patients with colorectal cancer, higher prediagnosis plasma 25(OH)D levels were associated with a significant improvement in overall survival. Further study of the vitamin D pathway and its influence on colorectal carcinogenesis and cancer progression is warranted.

Vitamin D insufficiency in a multiethnic cohort of breast cancer survivors

BACKGROUND

Little is known about vitamin D status in breast cancer survivors. This issue is important because vitamin D influences pathways related to carcinogenesis.

OBJECTIVE

The objective of this report was to describe and understand vitamin D status in a breast cancer survivor cohort.

DESIGN

Data are from the Health, Eating, Activity, and Lifestyle study. With the use of a cross-sectional design, we examined serum concentrations of 25-hydroxyvitamin D [25(OH)D] in 790 breast cancer survivors from western Washington state, New Mexico, and Los Angeles County. Cancer treatment data were obtained from Surveillance, Epidemiology, and End Results registries and medical records. Fasting blood, anthropometry, and lifestyle habits were collected after diagnosis and treatment. We examined distributions of 25(OH)D by race-ethnicity, season, geography, and clinical characteristics. Multivariate regression tested associations between 25(OH)D and stage of disease.

RESULTS

Five hundred ninety-seven (75.6%) of the women had low serum 25(OH)D, suggesting vitamin D insufficiency or frank deficiency. The overall mean (+/-SD) was 24.8 +/- 10.4 ng/mL, but it was lower for African Americans (18.1 +/- 8.7 ng/mL) and Hispanics (22.1 +/- 9.2 ng/mL). Women with localized (n = 424) or regional (n = 182) breast cancer had lower serum 25(OH)D than did women with in situ disease (n = 184) (P = 0.05 and P = 0.03, respectively). Multivariate regression models controlled for age, body mass index (in kg/m(2)), race-ethnicity, geography, season, physical activity, diet, and cancer treatments showed that stage of disease independently predicted serum 25(OH)D (P = 0.02).

CONCLUSIONS

In these breast cancer survivors, the prevalence of vitamin D insufficiency was high. Clinicians might consider monitoring vitamin D status in breast cancer patients, together with appropriate treatments, if necessary.