Ultraviolet B irradiance and vitamin D status are inversely associated with incidence rates of pancreatic cancer worldwide

The association between circulating 25-hydroxyvitamin D and pancreatic cancer: a systematic review and meta-analysis of observational studies

PURPOSE

The relationship between circulating 25-hydroxyvitamin D [25(OH)D] and pancreatic cancer has been well studied but remains unclear. The purpose of this study was to elucidate the association between circulating 25(OH)D and pancreatic cancer by using a meta-analytic approach.

METHODS

PubMed, Embase, and Wed of Science databases were searched through October 15, 2022. A random or fixed-effects model was used to estimate the pooled odds ratio (OR), risk ratio (RR), hazard ratio (HR) and their 95% confidence intervals (CIs).

RESULTS

A total of 16 studies including 529,917 participants met the inclusion criteria, of which 10 reported incidence and 6 reported mortality. For the highest versus lowest categories of circulating 25(OH)D, the pooled OR of pancreatic cancer incidence in case-control studies was 0.98 (95% CI 0.69-1.27), and the pooled HRs of pancreatic cancer mortality in cohort and case-control studies were 0.64 (95% CI 0.45-0.82) and 0.78 (95% CI 0.62-0.95), respectively. The leave-one-out sensitivity analyses found no outliers and Galbraith plots indicated no substantial heterogeneity.

CONCLUSION

Evidence from this meta-analysis suggested that high circulating 25(OH)D levels may be associated with decreased mortality but not incidence of pancreatic cancer. Our findings may provide some clues for the treatment of pancreatic cancer and remind us to be cautious about widespread vitamin D supplementation for the prevention of pancreatic cancer.

Vitamin D: Promises on the Horizon and Challenges Ahead for Fighting Pancreatic Cancer

Simple Summary

Pancreatic cancer is an almost universally lethal cancer, largely due to its late diagnosis, early metastasis, and therapeutic resistance. This highlights the need to develop novel and effective intervention strategies to improve the outcomes of patients with pancreatic cancer. Vitamin D is one of the hottest topics in cancer research and clinics because of its pleiotropic functions on the hallmarks of cancer. Here we critically review past and current efforts that define the effects of vitamin D on the risk, incidence, patient survival, and mortality of pancreatic cancer. We also provide overviews on the opportunities and challenges associated with vitamin D as an economic adjunct to improve the efficacy of immunotherapy and chemo- or radiotherapy for pancreatic cancer.

Abstract

Pancreatic cancer has a dismal prognosis, while its incidence is increasing. This is attributed, in part, to a profound desmoplastic and immunosuppressive tumor microenvironment associated with this cancer and resistance to current available therapies. Novel and effective intervention strategies are urgently needed to improve the outcomes of patients with pancreatic cancer. Vitamin D has pleiotropic functions beyond calcium–phosphate homeostasis and has been extensively studied both in the laboratory and clinic as a potential preventive agent or adjunct to standard therapies. Accumulating evidence from ecological, observational, and randomized controlled trials suggests that vitamin D has beneficial effects on risk, survival, and mortality in pancreatic cancer, although controversies still exist. Recent advances in demonstrating the important functions of vitamin D/vitamin D receptor (VDR) signaling in the regulation of stromal reprogramming, the microbiome, and immune response and the emergence of checkpoint immunotherapy provide opportunities for using vitamin D or its analogues as an adjunct for pancreatic cancer intervention. Many challenges lie ahead before the benefits of vitamin D can be fully realized in pancreatic cancer. These challenges include the need for randomized controlled trials of vitamin D to assess its impact on the risk and survival of pancreatic cancer, optimizing the timing and dosage of vitamin D or its analogues as an adjunct for pancreatic cancer intervention and elucidating the specific role of vitamin D/VDR signaling in the different stages of pancreatic cancer. Nevertheless, vitamin D holds great promise for reducing risk and improving outcomes of this disease.

The Role of Stellate Cells in Pancreatic Ductal Adenocarcinoma: Targeting Perspectives

Pancreatic ductal adenocarcinoma (PDAC) is a gastrointestinal malignancy with a dismal clinical outcome. Accumulating evidence suggests that activated pancreatic stellate cells (PSCs), the major producers of extracellular matrix (ECM), drive the severe stromal/desmoplastic reaction in PDAC. Furthermore, the crosstalk among PSCs, pancreatic cancer cells (PCCs) as well as other stroma cells can establish a growth-supportive tumor microenvironment (TME) of PDAC, thereby enhancing tumor growth, metastasis, and chemoresistance via various pathways. Recently, targeting stroma has emerged as a promising strategy for PDAC therapy, and several novel strategies have been proposed. The aim of our study is to give a profound review of the role of PSCs in PDAC progression and recent advances in stroma-targeting strategies.

Global Patterns and Trends in Pancreatic Cancer Incidence: Age, Period, and Birth Cohort Analysis

OBJECTIVES

We aim to provide a global geographical picture of pancreatic cancer incidence and temporal trends from 1973 to 2015 for 41 countries.

METHODS

Joinpoint regression and age-period-cohort model was used.

RESULTS

In 2012, the highest age-adjusted rate was in Central and Eastern Europe for males and North America for females. Most regions showed sex disparities. During the recent 10 years, increasing trends were observed in North America, Western Europe, and Oceania. The greatest increase occurred in France. For recent birth cohorts, cohort-specific increases in risk were pronounced in Australia, Austria, Brazil, Canada, Costa Rica, Denmark, Estonia, France, Israel, Latvia, Norway, Philippines, Republic of Korea, Singapore, Spain, Sweden, the Netherlands, United States, and US white male populations and in Australia, Austria, Brazil, Bulgaria, Canada, China, Czech Republic, Finland, France, Italy, Japan, Lithuania, Norway, Republic of Korea, Singapore, Spain, The Netherlands, United Kingdom, United States, and US white female populations.

CONCLUSIONS

In contrast to the favorable effect of the decrease in smoking prevalence, other factors, including the increased prevalence of obesity and diabetes and increased physical inactivity, increased intake of red or processed meat and inadequate intake of fruits and vegetables are likely to have an unfavorable role in pancreatic cancer incidence worldwide.

Does sunlight protect us from cancer?

The Ultraviolet (UV) radiation contained in sunlight is a powerful mutagen and immune suppressant which partly explains why exposure to solar UV is the biggest risk factor for the development of cutaneous tumours. Evidence is building that sunlight may be protective against some internal malignancies. Because patients with these tumours are often vitamin D deficient, this has led some to propose that vitamin D supplementation will be beneficial in the treatment of these cancers. However, the results from already completed trials have been disappointing which has given weight to the argument that there must be something else about sunlight that explains its cancer-protecting properties.

Circulating concentrations of vitamin D in relation to pancreatic cancer risk in European populations

Evidence from in vivo, in vitro and ecological studies are suggestive of a protective effect of vitamin D against pancreatic cancer (PC). However, this has not been confirmed by analytical epidemiological studies. We aimed to examine the association between pre-diagnostic circulating vitamin D concentrations and PC incidence in European populations. We conducted a pooled nested case-control study within the European Prospective Investigation into Cancer and Nutrition (EPIC) and the Nord-Trøndelag Health Study's second survey (HUNT2) cohorts. In total, 738 primary incident PC cases (EPIC n = 626; HUNT2 n = 112; median follow-up = 6.9 years) were matched to 738 controls. Vitamin D [25(OH)D2 and 25(OH)D3 combined] concentrations were determined using isotope-dilution liquid chromatography-tandem mass spectrometry. Conditional logistic regression models with adjustments for body mass index and smoking habits were used to estimate incidence rate ratios (IRRs) and 95% confidence intervals (95%CI). Compared with a reference category of >50 to 75 nmol/L vitamin D, the IRRs (95% CIs) were 0.71 (0.42-1.20); 0.94 (0.72-1.22); 1.12 (0.82-1.53) and 1.26 (0.79-2.01) for clinically pre-defined categories of ≤25; >25 to 50; >75 to 100; and >100 nmol/L vitamin D, respectively (p for trend = 0.09). Corresponding analyses by quintiles of season-standardized vitamin D concentrations also did not reveal associations with PC risk (p for trend = 0.23). Although these findings among participants from the largest combination of European cohort studies to date show increasing effect estimates of PC risk with increasing pre-diagnostic concentrations of vitamin D, they are not statistically significant.

Non-musculoskeletal benefits of vitamin D

The aim of this study is to determine and critically evaluate the plausible relationships of vitamin D with extra-skeletal tissues in humans. Severe vitamin D deficiency results in rickets in children and osteomalacia in adults; these beneficial effects in the musculoskeletal system and certain physiological functions are well understood. Nevertheless, mounting reports support additional beneficial effects of vitamin D, outside the musculoskeletal system. This review explores the recent advances in knowledge about the non-skeletal effects of vitamin D. Peer-reviewed papers were extracted from research databases using key words, to assess correlations between vitamin D and extra-skeletal diseases and conditions. As per the guidelines of the Preferred Reporting Items for Systematic Reviews (PRISMA); general interpretations of results are included; taking into consideration the broader evidence and implications. This review summarizes current knowledge of the effects of vitamin D status on extra-skeletal tissues with special attention given to relationships between vitamin D status and various diseases commonly affecting adults; the effects of intervention with vitamin D and exposure to sunlight. Evidence suggests that vitamin D facilitates the regulation of blood pressure; and cardiac; endothelial; and smooth muscle cell functions; playing an important role in cardiovascular protection. In addition; 1,25(OH)₂D improves immunity; subdues inflammation; and reduces the incidence and severity of common cancers; autoimmune diseases and infectious diseases. Almost all adequately powered; epidemiological and biological studies that use; adequate doses of vitamin D supplementation in D-deficient populations have reported favorable outcomes. These studies have concluded that optimizing 25(OH)D status improves the functionality of bodily systems; reduces comorbidities; improves the quality of life; and increases survival. Although accumulating evidence supports biological associations of vitamin D sufficiency with improved physical and mental functions; no definitive evidence exists from well-designed; statistically powered; randomized controlled clinical trials. Nevertheless, most studies point to significant protective effects of vitamin D in humans when the minimum 25(OH)D serum level exceeds 30ng/mL and is maintained throughout the year.

Murine Pancreatic Acinar Cell Carcinoma Growth Kinetics Are Independent of Dietary Vitamin D Deficiency or Supplementation

Vitamin D has been proposed as a therapeutic strategy in pancreatic cancer, yet evidence for an effect of dietary vitamin D on pancreatic cancer is ambiguous, with conflicting data from human epidemiological and intervention studies. Here, we tested the role of dietary vitamin D in the in vivo context of the well-characterized Ela1-TAg transgenic mouse model of pancreatic acinar cell carcinoma. Through longitudinal magnetic resonance imaging of mice under conditions of either dietary vitamin D deficiency (<5 IU/kg vitamin D) or excess (76,500 IU/kg vitamin D), compared to control diet (1,500 IU/kg vitamin D), we measured the effect of variation of dietary vitamin D on tumor kinetics. No measurable impact of dietary vitamin D was found on pancreatic acinar cell carcinoma development, growth or mortality, casting further doubt on the already equivocal data supporting potential therapeutic use in humans. The lack of any detectable effect of vitamin D, within the physiological range of dietary deficiency or supplementation, in this model further erodes confidence in vitamin D as an effective antitumor therapeutic in pancreatic acinar cell carcinoma.

Global temporal patterns of pancreatic cancer and association with socioeconomic development

Pancreatic cancer induces a substantial global burden. We examined its global incidence/mortality rates and their correlation with socioeconomic development (Human Development Index [HDI] and Gross Domestic Product [GDP] in 2000 as proxy measures). Data on age-standardized incidence/mortality rates in 2012 were retrieved from the GLOBOCAN database. Temporal patterns in 1998–2007 were assessed for 39 countries according to gender. The Average Annual Percent Change (AAPC) of the incidence/mortality trends was evaluated using joinpoint regression analysis. The age-standardized incidence ranged between 0.8–8.9/100,000. When compared among countries, Brazil (AAPC = 10.4, 95%C.I. = 0.8,21) and France (AAPC = 4.7, 95%C.I. = 3.6,5.9) reported the highest incidence rise in men. The greatest increase in women was reported in Thailand (AAPC = 7, 95%C.I. = 2.1,12.1) and Ecuador (AAPC = 4.3, 95%C.I. = 1.3,7.3). For mortality, the Philippines (APCC = 4.3, 95%C.I. = 2,6.6) and Croatia (AAPC = 2, 95% C.I. = 0,3.9) reported the biggest increase among men. The Philippines (AAPC = 5.8, 95% C.I. 4.5,7.2) and Slovakia (AAPC = 3.1, 95% C.I. 0.9,5.3) showed the most prominent rise among women. Its incidence was positively correlated with HDI (men: r = 0.66; women: r = 0.70) and GDP (men: r = 0.29; women: r = 0.28, all p < 0.05), and similarly for mortality (men: r = 0.67; women: r = 0.72 [HDI]; men: r = 0.23; women: r = 0.28 [GDP]). In summary, the incidence and mortality of pancreatic cancer were rising in many countries, requiring regular surveillance.

Retrospective analysis of the influence of 25-hydroxyvitamin D on disease progression and survival in pancreatic cancer

Background

Vitamin D deficiency is implicated in neoplastic processes in multiple organs, including the pancreas. While animal and human data have established a relationship between serum vitamin D (25(OH)D) and the development of pancreatic cancer, few studies have examined the effects of 25(OH)D on time to progression (TTP) and overall survival (OS) in this patient population. We hypothesize that lower baseline serum concentrations (BSC) of 25(OH)D will be associated with decreased TTP and OS.

Methods

This retrospective analysis of 1222 patients with pancreatic cancer aims to identify potential relationships between 25(OH)D and both TTP and OS, while controlling for the effects of ethnicity and body mass index (BMI). Baseline 25(OH)D was divided into quartiles defined as deficient (<20 ng/mL), insufficient (20–39 ng/mL), sufficient (40–59 ng/mL), and optimal (≥60 ng/ml). Statistical significance was declared if the two-sided p-value was ≤ 0.05.

Results

For the 627 subjects included for analysis, the median 25(OH)D was 27 ng/mL (range 4 to 114), 30.0 % were 25(OH)D deficient (<20 ng/mL), and 47.2 % were insufficient (20–39 ng/mL). Ethnicity (p < 0.0001) and BMI (p = 0.05) were significantly associated with (BSC)of 25(OH)D, while TTP (p = 0.39) and OS (p = 0.37) were not associated.

Conclusion

Suboptimal vitamin D levels (<60 ng/mL) occurred in 96 % of patients analyzed. Both ethnicity and BMI were statistically significantly associated with vitamin D deficiency and insufficiency. Similar to results previously reported in the literature, this analysis did not identify a significant association between BSC of 25(OH)D and OS or TTP in patients with pancreatic cancer.

Cloud cover-adjusted ultraviolet B irradiance and pancreatic cancer incidence in 172 countries

BACKGROUND

Controversy exists regarding whether vitamin D deficiency could influence the etiology of pancreatic cancer. Several cohort studies have found that high serum 25-hydroxyvitamin D [25(OH)D] concentrations are associated with low risk of pancreatic cancer, while others have not.

HYPOTHESIS

Low ultraviolet B irradiance is associated with high incidence of pancreatic cancer.

METHODS

Age-standardized pancreatic cancer incidence rates were obtained from GLOBOCAN in 2008. The association between cloud-adjusted UVB irradiance and age-standardized incidence rates of pancreatic cancer was analyzed using regression.

RESULTS

Overall, the lower the cloud-adjusted UVB irradiance, the higher the incidence rate of pancreatic cancer. Residents of countries with low UVB irradiance had approximately 6 times the incidence rates as those in countries with high UVB irradiance (p<0.0001 for males and p<0.0001 for females). This association persisted after adjustment for traditional risk factors of pancreatic cancer (p=0.0182 for males and p=0.0029 for females).

CONCLUSIONS

There was an inverse association of cloud-adjusted UVB irradiance with incidence of pancreatic cancer that persisted after adjustment. This result is consistent with an inverse association of overall vitamin D deficiency in countries with lower UVB irradiance with risk of pancreatic cancer. Further research on the role of 25(OH)D in reduction of pancreatic cancer in individuals would be desirable to expand the limited avenues available for prevention of this highly fatal disease. This article is part of a Special Issue entitled '17th Vitamin D Workshop'.

Vitamin D and pancreatic cancer: a pooled analysis from the Pancreatic Cancer Case-Control Consortium

BACKGROUND

The potential role of vitamin D in the aetiology of pancreatic cancer is unclear, with recent studies suggesting both positive and negative associations.

PATIENTS AND METHODS

We used data from nine case-control studies from the International Pancreatic Cancer Case-Control Consortium (PanC4) to examine associations between pancreatic cancer risk and dietary vitamin D intake. Study-specific odds ratios (ORs) were estimated using multivariable logistic regression, and ORs were then pooled using a random-effects model. From a subset of four studies, we also calculated pooled estimates of association for supplementary and total vitamin D intake.

RESULTS

Risk of pancreatic cancer increased with dietary intake of vitamin D [per 100 international units (IU)/day: OR = 1.13, 95% confidence interval (CI) 1.07-1.19, P = 7.4 × 10(-6), P-heterogeneity = 0.52; ≥230 versus <110 IU/day: OR = 1.31, 95% CI 1.10-1.55, P = 2.4 × 10(-3), P-heterogeneity = 0.81], with the association possibly stronger in people with low retinol/vitamin A intake.

CONCLUSION

Increased risk of pancreatic cancer was observed with higher levels of dietary vitamin D intake. Additional studies are required to determine whether or not our finding has a causal basis.

Are low ultraviolet B and vitamin D associated with higher incidence of multiple myeloma?

The purpose of this study was to determine whether an inverse association exists between latitude, solar ultraviolet B (UVB) irradiance, and incidence rates of multiple myeloma.Methods Associations of latitude and UVB irradiance with age-standardized incidence rates of multiple myeloma were analyzed for 175 countries while controlling for sex-specific obesity prevalence, cigarette consumption, and alcohol consumption using multiple linear regression.Results Incidence rates of multiple myeloma were greater at higher latitudes (R(2) for latitude for males=0.31, p<0.0001; females R(2)=0.27, p<0.0001). In regression models for males (R(2)=0.62, p<0.0001) and females (R(2)=0.51, p<0.0001), UVB irradiance was independently inversely associated with incidence rates.Conclusions Age-adjusted incidence rates of multiple myeloma were higher in countries with lower solar UVB irradiance. Further investigation is warranted in individuals of the association of prediagnostic serum 25(OH)D with risk.

The vitamin D system is deregulated in pancreatic diseases

The vitamin D system is deregulated during development and progression of several cancer types. Data on the expression of the vitamin D system in the diseased pancreas are missing. The aim of this study was to investigate the expression of the vitamin D receptor (VDR), 1,25-dihydroxyvitamin D3 24-hydroxylase (CYP24A1), and the calcium-sensing receptor (CaSR), a vitamin D target gene, in the different regions of the pancreas in patients with chronic pancreatitis (n=6) and pancreatic ductal adenocarcinomas (PDAC) (n=17). We analyzed the expression of these genes at mRNA and protein level with quantitative real-time RT-PCR and immunostaining. mRNA expression of CYP24A1 and VDR was significantly increased in tumors compared with the adjacent non-tumorous tissue (p<0.01), while CaSR mRNA expression decreased. Both the VDR and the CaSR protein were highly expressed in the endocrine compared with the exocrine pancreas. In CP the CYP24A1 expression was highest in the endocrine pancreas, while in PDACs in the transformed ducts. In the PDAC patients CYP24A1 expression in the islets was significantly lower than in CP patients. Our data suggest that during ductal adenocarcinoma development the vitamin D system in the pancreas becomes deregulated on two levels: in the islets CYP24A1 expression decreases weakening the negative feedback regulation of the vitamin D-dependent insulin synthesis/secretion. In the transformed ducts CYP24A1 expression increases, impairing the antiproliferative effect of vitamin D in these cells.

A multicountry ecological study of cancer incidence rates in 2008 with respect to various risk-modifying factors

Observational and ecological studies are generally used to determine the presence of effect of cancer risk-modifying factors. Researchers generally agree that environmental factors such as smoking, alcohol consumption, poor diet, lack of physical activity, and low serum 25-hdyroxyvitamin D levels are important cancer risk factors. This ecological study used age-adjusted incidence rates for 21 cancers for 157 countries (87 with high-quality data) in 2008 with respect to dietary supply and other factors, including per capita gross domestic product, life expectancy, lung cancer incidence rate (an index for smoking), and latitude (an index for solar ultraviolet-B doses). The factors found to correlate strongly with multiple types of cancer were lung cancer (direct correlation with 12 types of cancer), energy derived from animal products (direct correlation with 12 types of cancer, inverse with two), latitude (direct correlation with six types, inverse correlation with three), and per capita gross national product (five types). Life expectancy and sweeteners directly correlated with three cancers, animal fat with two, and alcohol with one. Consumption of animal products correlated with cancer incidence with a lag time of 15–25 years. Types of cancer which correlated strongly with animal product consumption, tended to correlate weakly with latitude; this occurred for 11 cancers for the entire set of countries. Regression results were somewhat different for the 87 high-quality country data set and the 157-country set. Single-country ecological studies have inversely correlated nearly all of these cancers with solar ultraviolet-B doses. These results can provide guidance for prevention of cancer.

Association between ultraviolet radiation, skin sun sensitivity and risk of pancreatic cancer

BACKGROUND

Ecological studies showing an inverse association between pancreatic cancer incidence and mortality and levels of ultraviolet radiation (UVR), suggest that higher levels of sun exposure may reduce risks of pancreatic cancer but there has been only one individual-level study that examined this issue. We aimed to examine the association between pancreatic cancer and markers of exposure to solar UVR, namely skin type, treatment of skin lesions, ambient UVR and time outdoors on work days.

METHODS

We used data from an Australian case-control study. Location at birth, residential location during adulthood, outdoors work, history of skin lesion treatment and sensitivity of the skin to the sun were obtained by questionnaire. We limited the analyses to Caucasians who answered the questionnaire about UVR (controls=589/711 recruited; cases=496/705 recruited). We used NASA's Total Ozone Mapping Spectrometer to estimate ambient UVR.

RESULTS

Being born in or living in areas of higher ambient UVR (compared to lower ambient UVR) was associated with about 30-40% lower risk of pancreatic cancer. People with fair skin colour had 47% lower risk of pancreatic cancer than those with dark skin colour (95% CI 0.37-0.75). There was some suggestion of increased risk with increased average number of hours spent outside at work.

CONCLUSIONS

This study suggests that people with light skin colour or those born or living in areas of high ambient UVR have lower risk of pancreatic cancer. Our analysis supports an association between UVR and pancreatic cancer, possibly mediated through production of vitamin D.

Epidemiology, risk factors, and the promotion of pancreatic cancer: role of the stellate cell

There are approximately 277,000 new cases of pancreatic cancer and 266,000 deaths from pancreatic cancer annually, indicating a mortality rate of 96% of the cases diagnosed. Because of the ineffectiveness of therapies, a major emphasis needs to be placed on prevention. This paper reviews the epidemiology and risk factors for pancreatic cancer, and uses this information to propose plausible research directions for determining the biological mechanisms mediating the effects of risk factors on the promotion of pancreatic cancer, with a focus on the pancreatic stellate cell.

Is dietary fat, vitamin D, or folate associated with pancreatic cancer?

Although potentially modifiable risk factors for pancreatic cancer include smoking, obesity, and diabetes, less is known about the extent to which diet affects cancer risk. Recent studies have demonstrated some consistency for dietary fat being associated with elevated pancreatic cancer risk, particularly from animal sources. However, less is known about which fatty acids pose the greatest risk. Vitamin D, due to its endogenous production following UV-B exposure, is a unique risk factor in that researchers have created several methods to assess its exposure in humans. Studies that measured vitamin D exposure differently have shown inconsistent results. Dietary studies suggest protective associations, whereas studies of circulating 25-hydroxyvitamin D status show null or positive associations with low or very high concentrations, respectively. Several, but not all epidemiologic studies provide evidence of an inverse relationship between total and/or dietary folate and risk of pancreatic cancer. Protective associations for circulating folate are more often observed among populations with inadequate status. This article reviews the current epidemiological and experimental evidence investigating the relationship of dietary fat, vitamin D, and folate with pancreatic cancer. Additionally the mechanisms by which these risk factors may contribute to cancer, the methodological challenges involved with assessing risk, and other obstacles encountered when ascertaining the magnitude and direction of these three exposures are discussed.

Plasma 25-hydroxyvitamin D and risk of pancreatic cancer

BACKGROUND

Laboratory studies suggest that vitamin D may inhibit pancreatic cancer cell growth. However, epidemiologic studies of vitamin D and pancreatic cancer risk have been conflicting.

METHODS

To determine whether prediagnostic levels of plasma 25-hydroxyvitamin D (25[OH]D; IDS Inc.; enzyme immunoassay) were associated with risk of pancreatic cancer, we conducted a pooled analysis of nested case-control studies with 451 cases and 1,167 controls from five cohorts through 2008. Median follow-up among controls was 14.1 years in Health Professionals Follow-Up Study (HPFS), 18.3 years in Nurses' Health Study (NHS), 25.3 years in Physicians' Health Study (PHS), 12.2 years in Women's Health Initiative-Observational Study (WHI), and 14.4 years in Women's Health Study (WHS). Logistic regression was used to compare the odds of pancreatic cancer by plasma level of 25(OH)D.

RESULTS

Mean plasma 25(OH)D was lower in cases versus controls (61.3 vs. 64.5 nmol/L, P = 0.005). In logistic regression models, plasma 25(OH)D was inversely associated with odds of pancreatic cancer. Participants in quintiles two through five had multivariable-adjusted ORs (95% confidence intervals) of 0.79 (0.56-1.10), 0.75 (0.53-1.06), 0.68 (0.48-0.97), and 0.67 (0.46-0.97; P(trend) = 0.03), respectively, compared with the bottom quintile. Compared with those with insufficient levels [25[OH]D, <50 nmol/L], ORs were 0.75 (0.58-0.98) for subjects with relative insufficiency [25[OH]D, 50 to <75 nmol/L] and 0.71 (0.52-0.97) for those with sufficient levels [25[OH]D, ≥ 75 nmol/L]. No increased risk was noted in subjects with 25(OH)D ≥100 nmol/L, as suggested in a prior study. In subgroup analyses, ORs for the top versus bottom quartile of 25(OH)D were 0.72 (0.48-1.08) for women, 0.73 (0.40-1.31) for men, and 0.73 (0.51-1.03) for Whites.

CONCLUSIONS

Among participants in five large prospective cohorts, higher plasma levels of 25(OH)D were associated with a lower risk for pancreatic cancer.

IMPACT

Low circulating 25(OH)D may predispose individuals to the development of pancreatic cancer.

Role of vitamin d in the prevention of pancreatic cancer

Pancreatic cancer is a malignancy of poor prognosis which is mostly diagnosed at advanced stages. Current treatment modalities are very limited creating great interest for novel preventive and therapeutic options. Vitamin D seems to have a protective effect against pancreatic cancer by participating in numerous proapoptotic, antiangiogenic, anti-inflammatory, prodifferentiating, and immunomodulating mechanisms. 25-hydroxyvitamin D [25(OH)D] serum concentrations are currently the best indicator of vitamin D status. There are three main sources of vitamin D: sun exposure, diet,and dietary supplements. Sun exposure has been associated with lower incidence of pancreatic cancer in ecological studies. Increased vitamin D levels seem to protect against pancreatic cancer, but caution is needed as excessive dietary intake may have opposite results. Future studies will verify the role of vitamin D in the prevention and therapy of pancreatic cancer and will lead to guidelines on adequate sun exposure and vitamin D dietary intake.

Vitamin d and pancreatic cancer-an update

The non-classical actions of vitamin D, namely anti-proliferation, pro-differentiation, immune function modulation, and anti-inflammation, have received great attention during the past decade, in particular, the potential of vitamin D analogs alone or in combination with other anticancer agents for the treatment of a variety of cancers. The association between vitamin D status and the higher incidence of many forms of cancer has suggested that vitamin D may play a role in the etiology of these types of cancer. Although it is still controversial whether this association exists for pancreatic cancer, biochemical evidence clearly indicates pancreatic cancer cells are responsive to the inhibitory effect of vitamin D and its analogs. In this review, we discuss briefly the origin and current therapy of pancreatic cancer, the history, source, metabolism and functions of vitamin D, the recent progress in the epidemiological studies of sunlight, and vitamin D status, and biochemical studies of vitamin D analogs in the prevention and treatment of pancreatic cancer.

An ecological study of cancer incidence and mortality rates in France with respect to latitude, an index for vitamin D production

France has unexplained large latitudinal variations in cancer incidence and mortality rates. Studies of cancer rate variations in several other countries, as well as in multicountry studies, have explained such variations primarily in terms of gradients in solar ultraviolet-B (UVB) doses and vitamin D production. To investigate this possibility in France, I obtained data on cancer incidence and mortality rates for 21 continental regions and used this information in regression analyses with respect to latitude. This study also used dietary data. Significant positive correlations with latitude emerged for breast, colorectal, esophageal (males), lung (males), prostate, both uterine cervix and uterine corpus, all and all less lung cancer. Although correlations with latitude were similar for males and females, the regression variance for all and all less lung cancer was about twice as high for males than for females. Lung cancer incidence and mortality rates for females had little latitudinal gradient, indicating that smoking may have also contributed to the latitudinal gradients for males. On the basis of the available dietary factor, micro- and macronutrient data, dietary differences do not significantly affect geographical variation in cancer rates. These results are consistent with solar UVB's reducing the risk of cancer through production of vitamin D. In the context of serum 25-hydroxyvitamin D level-cancer incidence relations, cancer rates could be reduced significantly in France if everyone obtained an additional 1,000 IU/day of vitamin D. Many other benefits of vitamin D exist as well.

An ecological study of cancer mortality rates in the United States with respect to solar ultraviolet-B doses, smoking, alcohol consumption and urban/rural residence

The Cohort Consortium Vitamin D Polling Project of Rarer Cancers (VDPP ) study failed to find a beneficial role of prediagnostic serum 25-hydroxyvitamin D [25(OH)D] levels on risk of seven types of rarer cancer: endometrial, esophageal, gastric, kidney, ovarian and pancreatic cancer and non-Hodgkin's lymphoma (NHL). However, ecological studies and studies of oral vitamin D intake have generally found solar ultraviolet B (UVB) and oral vitamin D inversely correlated with incidence and/or mortality rates of these cancers. To explore the discrepancy, I conducted an ecological study of cancer mortality rates for white Americans in the United States for 1950-1994 with data for 503 state economic areas in multiple linear regression analyses with respect to UVB for July, lung cancer, alcohol consumption and urban/rural residence. UVB was significantly inversely correlated with six types of cancer (not pancreatic cancer) in both periods. However, the adjusted R(2) values were much lower for cancers with lower mortality rates than those in an earlier ecological study that used state-averaged data. This finding suggests that the VDPP study may have had too few cases. Thus, the VDPP study should not be considered as providing strong evidence against the solar UVB-vitamin D-cancer hypothesis.