Low serum 25-hydroxy vitamin D levels are associated with aggressive breast cancer variants and poor prognostic factors in patients with breast carcinoma

Association Between Vitamin D Deficiency and Tumor Characteristics in Breast Cancer Patients

Introduction Breast cancer is the most frequent cancer among women worldwide, but there is little literature regarding the effects of vitamin D on breast cancer patients in the Indian population. Hence, this study was planned to determine the correlation between vitamin D deficiency and tumor characteristics in breast cancer patients. Methods This was a cross-sectional study conducted in a tertiary healthcare facility in central India among all newly diagnosed patients with breast carcinoma who had received primary surgery and pathological confirmation. We performed universal sampling and included 50 patients in the study. We excluded patients with insufficient histopathological reports, those unfit for surgery, and those with hepatic or renal failure, metabolic bone disease, malabsorption, or recent consumption of vitamin D (patients who had received oral vitamin D in the preceding two weeks, or vitamin D injection in the preceding six months). Results Among the 50 patients, 86% were vitamin D deficient, with a mean deficiency of 23.54. Vitamin D deficiency is most common in the age groups 41-50 years and >60 years, with the mean age group of 51.49 years. The left side is more involved than the right in vitamin D-deficient patients. Most patients were moderately and poorly differentiated, suggesting a significant association between vitamin D deficiency and tumor differentiation. Almost half the patients were estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (Her-2/neu) status negative with vitamin D deficiency. Vitamin D deficiency was highest in Her-2/neu amplified, luminal A, and B patients. The mean lymph node-positive participants was 4.04, and the mean number of lymph nodes extracted was 15.58 in vitamin D-deficient breast cancer patients. Conclusion The prevalence of low vitamin D status was high among breast cancer patients. There is an association between vitamin D deficiency and tumors with poor prognostic features. Low vitamin D levels were considered a risk factor for ER, PR, and Her-2/neu-negative tumors along with positive lymph node status in breast cancer patients. Vitamin D status is a modifiable risk factor for breast cancer. Thus, it is concluded from this study that vitamin D has a potential role in the prevention of breast cancer, it may reduce its aggressiveness, and its deficiency is associated with an increased risk of breast cancer.

The Impact of Vitamin D and Its Dietary Supplementation in Breast Cancer Prevention: An Integrative Review

Vitamin D deficiency is currently a significant public health issue closely linked to numerous diseases, such as breast cancer. This study aims to determine the estimated optimal serum levels of vitamin D to have a protective effect against breast cancer, in addition to exploring the biological mechanisms and risk factors involved. A literature search of articles published in the last 5 years was conducted, and simple statistical analyses using mean and standard deviation were performed to calculate the average concentration of vitamin D from different available studies. It has been observed that serum levels of vitamin D ≥ 40.26 ng/mL ± 14.19 ng/mL could exert a protective effect against breast cancer. Additionally, various biological mechanisms, such as those related to the immune system, and risk factors like diet implicated in this relationship were elucidated. Consequently, it can be concluded that proper serum levels of vitamin D may have a protective effect against breast cancer, and dietary supplementation may be an appropriate procedure to achieve these optimal vitamin D concentrations.

Dual effect of vitamin D3 on breast cancer-associated fibroblasts

BACKGROUND

Cancer-associated fibroblasts (CAFs) play an important role in the tumor microenvironment. Despite the well-known in vitro antitumoral effect of vitamin D3 (VD3), its impact on breast CAFs is almost unknown. In this study, we analyzed the ex vivo effects of calcitriol on CAFs isolated from breast cancer tissues.

METHODS

CAFs were cultured with 1 and 10 nM calcitriol and their phenotype; gene expression, protein expression, and secretion were assessed. Calcitriol-treated CAFs-conditioned media (CM) were used to analyze the effect of CAFs on the migration and protein expression of MCF-7 and MDA-MB-231 cells.

RESULTS

Tumor tissues from VD3-deficient patients exhibited lower levels of β-catenin and TGFβ1, along with higher levels of CYP24A1 compared to VD3-normal patients. In VD3-deficient patients, CAF infiltration was inversely associated with CYP24A1 levels and positively correlated with OPN levels. Calcitriol diminished CAFs' viability, but this effect was weaker in premenopausal and VD3-normal patients. Calcitriol reduced mRNA expression of CCL2, MMP9, TNC, and increased PDPN, SPP1, and TIMP1. It also decreased the secretion of CCL2, TNC, and the activity of MMP-2, while increasing cellular levels of TIMP1 in CAFs from all patient groups. In nonmetastatic and postmenopausal patients, PDPN surface expression increased, and CAFs CM from these groups decreased MCF-7 cell migration after ex vivo calcitriol treatment. In premenopausal and VD3-deficient patients, calcitriol reduced IDO1 expression in CAFs. Calcitriol-treated CAFs CM from these patients decreased OPN expression in MCF-7 and/or MDA-MB-231 cells. However, in premenopausal patients, calcitriol-treated CAFs CM also decreased E-cadherin expression in both cell lines.

CONCLUSION

The effects of calcitriol on breast CAFs, both at the gene and protein levels, are complex, reflecting the immunosuppressive or procancer properties of CAFs. The anticancer polarization of CAFs following ex vivo calcitriol treatment may result from decreased CCL2, TNC (gene and protein), MMP9, and MMP-2, while the opposite effect may result from increased PDPN, TIMP1 (gene and protein), and SPP1. Despite these multifaceted effects of calcitriol on molecule expression, CAFs' CMs from nonmetastatic and postmenopausal patients treated ex vivo with calcitriol decreased the migration of MCF-7 cells.

Evaluation of the relationship between vitamin D levels with oocyte quality in breast cancer women: a cross-sectional study

Recent evidence suggests that vitamin D deficiency could play an important role in the development of non-skeletal diseases, including cancer. Vitamin D also affects the function of the reproductive system. In the present study, the relationship between 25(OH)D levels with oocyte quality in Breast Cancer (BC) women and control group have been investigated. After initial evaluations, ovarian stimulation began with the GnRH antagonist protocol in the BC group (N = 16) and control group (N = 16). The serum and follicular fluid (FF) 25(OH)D levels were measured at the time of oocyte retrieval and their relationship to oocyte quality was examined. The mean levels of serum and FF 25(OH)D in BC women were significantly lower than in the control group (22.26 ± 7.98 vs. 29.61 ± 9.12, P = 0.02, 21.65 ± 7.59 vs. 28.00 ± 9.05, P = 0.04, respectively). There was a significant correlation between the levels of 25(OH)D in FF and serum in BC women (r = 0.873, P < 0.001). But there was no correlation between the serum or FF 25(OH)D levels with the parameters related to oocytes (P > 0.05). In the BC women, the number of dysmorph and highly dysmorph oocytes was higher than in the control group (P < 0.001). Women with BC referring to infertility centers for fertility preservation are more likely to be deficient in serum 25(OH)D level; this subsequently affects the FF 25(OH)D level. However, serum and FF 25(OH)D levels may not be suitable indicators for examining maturity and quality of oocytes in terms of morphology in BC women, and the poor morphological quality of oocytes in BC women may be due to other factors.

The role of vitamin D in menopausal women's health

Vitamin D (VD) is known to play an important role in the maintenance of calcium homeostasis and bone metabolism. In recent years, there has also been a growing interest in Vitamin D for health issues beyond the bones. Menopausal women are at risk of reduced bone density and increased risk of fracture due to a decline in estrogen levels. There is also an increased risk of cardiovascular disease, diabetes and hyperlipidaemia due to impaired lipid metabolism. The menopausal and emotional symptoms due to menopause are also increasingly prominent. This article summarizes the role of Vitamin D in menopausal women's health, including the effects of Vitamin D on skeletal muscle, cardiovascular disease, Genitourinary Syndrome of Menopause (GSM), cancer and emotional symptoms. Vitamin D regulates the growth of vaginal epithelial cells and alleviates genitourinary tract problems in menopausal women. Vitamin D also modulates immune function and influences the production of adipokines. Vitamin D and its metabolites also have an anti-proliferative effect on tumour cells. This narrative review, by summarizing recent work on the role of Vitamin D in menopausal women and in animal models of menopause, aims to provide a basis for further development of the role of Vitamin D in the health of menopausal women.

FokI polymorphism of Vitamin D receptor gene and deficiency of serum Vitamin D increases the risk of breast cancer in North Indian women

INTRODUCTION

Breast cancer is a leading cause of cancer morbidity and mortality in females. Decreased availability of Vitamin D within breast cells, contributed by deficiency of serum Vitamin D and polymorphisms of Vitamin D receptor genes are possible risk factors for breast cancer.

OBJECTIVES

To study the association of FokI polymorphism of the Vitamin D Receptor gene with breast cancer in females and to study the levels of Vitamin D in breast cancer patients.

MATERIALS AND METHODS

VDR gene FokI genotyping was done by PCR-RFLP method and levels of serum Vitamin D were estimated by ELISA. Statistical analysis was done with SPSS v.21.

RESULTS

Serum Vitamin D was significantly lower in newly diagnosed breast cancer patients than in healthy controls (P = 0.016). Females with serum Vitamin D levels in the highest quartile have a lesser risk of breast cancer than those with serum Vitamin D levels in the lowest quartile (O. R = 2.4421, C.I = 1.09-5.45, P = 0.029). The risk of developing breast cancer is higher in women with the polymorphic T allele for VDR FokI genotype (CT/TT) than those homozygous for the wild C allele (CC). (O.R. = 4.295, C.I. = 2.2110-8.3451, p-value = <0.0001). Levels of serum Vitamin D were significantly higher (p < 0.001) in ER + patients and significantly low in those presenting with higher stages of cancer (p = 0.009).

CONCLUSIONS

FokI polymorphism of VDR gene and low circulating Vitamin D levels increase the risk of developing breast cancer in North Indian females. Serum Vitamin D can be used as a prognostic factor.

Gene expression of programmed cell death ligand-1 (PDL-1) and vitamin D receptor (VDR) with the serum vitamin D3 in lung cancer

Background

Lung cancer (LC) is one of the leading causes of death worldwide. Programmed cell death receptor 1 (PD-1) interacts with its ligand (PDL-1) on T cells inhibiting its functioning which may affect the patient's immunological response.

Aim

Investigate if there is a link between smoking and tissue expression of PDL-1 and vitamin D receptor (VDR) in lung cancer patients. In addition, the relation of vitamin D with smoking and these biochemical markers.

Methods

PDL-1 and VDR expressions were evaluated by real-time PCR in 54 lung cancer biopsy samples and 36 controls to prove this hypothesis. Vitamin D levels in the blood were measured using an ELISA.

Results

Expressions of PDL-1 were significantly upregulated in LC patients than in controls. The highest expression was in stage II and in squamous cell carcinoma followed by small cell carcinoma then adenocarcinoma. However, VDR expressions and vitamin D levels in serum were significantly downregulating in LC patients than in controls. There was a positive correlation between PDL-1expression and duration of smoking but not smoking index. Also, there is an inverse correlation between duration of smoking, smoking index, and VDR.

Conclusion

Expression of PDL-1 in LC was significantly upregulated and correlated with staging. Interestingly, our current study for the first time explained the role of duration of smoking on PDL-1 and VDR in the pathogenesis of LC. As PDL-1 expression increased with duration of smoking whereas VDR decreased, this novel findings may provide a possible link between the cumulative effect of smoking and the level of expressions of these biomarkers.

Vitamin D Levels in Newly Diagnosed Breast Cancer Patients according to Tumor Sub-Types

Vitamin D is an important regulator of bone health. In addition, as a ligand for a nuclear receptor expressed in breast cancer cells, vitamin D exerts neoplasia modulating effects in breast cancer. However, despite extensive investigations, associations of vitamin D levels with breast cancer patient characteristics and disease sub-types are conflicting. A retrospective review of medical records of consecutive breast cancer patients treated and followed in a single cancer center was undertaken. All patients with 25-hydroxyvitamin D (25-OHD, the circulating form of vitamin D) measurements available within 3 months of their diagnosis and before the start of any systemic treatment were included. Characteristics of patients and tumors with sufficient levels of 25-OHD were compared with those of patients with 25-OHD insufficiency. Two hundred ninety-two patients were included in the study. Almost two-thirds of the patients were 25-OHD insufficient, defined as having 25-OHD levels below 75 nmol/L. Compared with the group of patients who were 25-OHD sufficient, patients with 25-OHD insufficiency were younger and more often obese. Tumors of patients with 25-OHD insufficiency were more often ductal, of higher grade, and ER negative. 25-OHD insufficiency is prevalent in breast cancer patients and even more prevalent in younger and obese patients. 25-OHD insufficiency is associated with cancers that have aggressive characteristics, including higher grade and ER negativity.

Lower vitamin D levels and VDR variants are risk factors for breast cancer: an updated meta-analysis

Inadequate vitamin D levels and vitamin D variants have been shown to be associated with breast cancer (BC), however the results are inconsistent. To reach a definitive conclusion the present meta-analysis was conducted. When compared to healthy controls, BC patients had reduced vitamin D levels (standard difference in means = -0.564, p = 0.003). The meta-analysis revealed that the FokI mutation was linked with an increased BC susceptibility (CC vs. TT: OR = 1.107, p = 0.001, CC vs. TC + TT: OR = 1.114, p = 0.020). There was no role of other VDR variants (BsmI, TaqI, and ApaI). FokI mutation and diminished vitamin D increase the likelihood of developing BC.

The Association of Intra-Tumoral and Stromal Vitamin D Receptor (VDR) Expressions with Molecular Subtypes and Clinicopathological Factors in Breast Carcinoma

OBJECTIVE

This study aimed to investigate the association between intra-tumoral and stromal VDR expressions with molecular subtypes and clinicopathological factors.

METHODS

A total of 75 formalin-fixed paraffin embedded tissue samples were stained using immunohistochemical methods. The VDR expressions were measured by counting brown-stained nuclei in intra-tumoral and stromal areas. The association of VDR expression with molecular subtypes and clinopathological factors was examined. Statistical analysis was performed by chi square tests.

RESULTS

High intra-tumoral VDR expression was found in carcinomas with luminal molecular subtypes (p=0.039) and low histological degrees (p=0.035). High VDR expression in the stroma was found in breast carcinomas with large tumor sizes.

CONCLUSIONS

High intra-tumoral VDR expression is found in breast carcinomas with luminal subtypes and low histological grade (I/II). Both factors are known to have a good prognosis. These findings further strengthen the function of VDR as anti-tumorigenesis.

Effect of Selected Factors on the Serum 25(OH)D Concentration in Women Treated for Breast Cancer

Maintaining an optimal vitamin D concentration reduces the risk of recurrence and extends survival time in patients after breast cancer treatment. Data on vitamin D deficiency among Polish women after breast cancer therapy are limited. Thus, the aim of the study was the analysis of vitamin D status in post-mastectomy patients, considering such factors as seasons, social habits, vitamin D supplementation and its measurements. The study involved 94 women after breast cancer treatment. Serum vitamin D concentration was measured, and a questionnaire, gathering demographic and clinical data regarding cancer, diet, exposure to sun radiation, and knowledge of recommendations on vitamin D supplementation, was delivered twice, in both winter and in summer. The control group consisted of 94 age-matched women with no oncological history. In women after breast cancer treatment, 25-hydroxyvitamin D (25(OH)D) deficiency was much more frequent than in the general population. Only about half of the patients supplemented vitamin D at the beginning of the study. After the first test and the issuing of recommendations on vitamin D supplementation, the percentage of vitamin D supplemented patients increased by about 30% in study groups. The average dose of supplement also increased. None of the women that were not supplementing vitamin D and were tested again in winter had optimal 25(OH)D concentration. It was concluded that vitamin deficiency is common in women treated for breast cancer. Medical advising about vitamin D supplementation and monitoring of 25(OH)D concentration should be improved.

Association between serum 25-hydroxy vitamin D level and gastric adenocarcinoma - a cross sectional study

Introduction

Vitamin D is found to have anti-cancer properties. Although the preventive role of vitamin D in cancer is proven, its role in gastric cancer is equivocal.

Aim

To evaluate vitamin D deficiency in patients with gastric adenocarcinoma and its relationship with the disease characteristics.

Material and methods

This single-centre, prospective, cross sectional study was carried out from February 2017 to December 2018. Serum 25-hydroxy vitamin D levels of 94 patients with gastric adenocarcinoma and 94 age- and sex-matched healthy controls were estimated. Among cases, vitamin D levels and disease characteristics such as TNM stage, tumour grade, clinical stage and patient demographics were analysed.

Results

The vitamin D levels among cases (13.83 ±5.97 ng/ml) were significantly lower (p < 0.0001) than the control group (29.15 ±4.13 ng/ml). Vitamin D deficiency was found in 88% of cases and in 3% of controls. Among cases, age, T stage and clinical stage had a significant inverse relationship with vitamin D levels. Cases with distant metastasis and cases with pain had significantly lower levels of vitamin D compared to the cases without distant metastasis and without pain respectively. Other study parameters did not have a significant relationship with vitamin D.

Conclusions

Vitamin D deficiency is associated with occurrence of gastric adenocarcinoma and correlates with the disease severity. However, to assign a causal relationship and to study the beneficial effect of vitamin D in gastric cancer, further research is needed.

Vitamin D baseline levels at diagnosis of breast cancer: A systematic review and meta-analysis

BACKGROUND

Vitamin D is a steroid hormone that exerts its actions through ligation of the vitamin D receptor (VDR), a transcription factor of the nuclear receptor family. VDR has not only physiologic actions in calcium metabolism but also several other cellular effects through extensive binding to the DNA and modification of genome expression. In cancer, it has neoplasia-suppressive effects and various mechanisms of action mediating cancer cell inhibition have been described. Vitamin D deficiency has been linked to increased risk of breast cancer. A role of the vitamin once the disease has been diagnosed is also probable.

METHODS

A systematic review and meta-analysis of studies that report on vitamin D levels (in the form of its main circulating metabolite, 25-hydroxyvitamin D [25-OHD]) in patients with newly diagnosed breast cancer was performed. Outcomes of interest included the levels of serum 25-OHD in patients with breast cancer, those of matched controlled, in studies that included controls, as well as respective percentages of patients and controls with deficient and insufficient 25-OHD levels.

RESULTS

A total of 25 studies (10 with controls and 15 without controls) provided data on the outcomes of interest. Populations from all continents, besides Australia, were represented in the studies. The mean level of 25-OHD in patients with breast cancer was 26.88 ng/mL (95% CI 22.8-30.96 ng/mL) and the mean level of 25-OHD in control patients was 31.41 ng/mL (95% CI 19.31-43.5 ng/mL). In the patients with breast cancer group, 45.28% (95% CI 24.37%-53.51%) had levels of 25-OHD below 20 ng/mL, whereas this percentage was 33.71% (95% CI 21.61%-45.82%) in controls. Similarly, 67.44% (95% CI 48.32%-86.55%) of patients with breast cancer had a baseline level of 25-OHD below 30 ng/mL, whereas this percentage was 33.71% (95% CI 21.61%-45.82%) in controls.

CONCLUSION

A high prevalence of vitamin D insufficiency is observed in patients with newly diagnosed breast cancer and may be linked pathophysiologically with breast cancer development or progression. Therapeutic benefits may be provided by manipulation of the vitamin D pathway in breast cancer.

Lower levels of vitamin D are associated with SARS-CoV-2 infection and mortality in the Indian population: An observational study

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Differential distributions of vitamin D were observed in the Indian population.

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Vitamin D levels was inversely correlated with SARS-CoV-2 infection rate.

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COVID-19 mortality rate was negatively associated with mean vitamin D levels.

Background

The role of vitamin D in the susceptibility and severity of various viral diseases has been well documented. Recently, some reports highlighted the possible importance of vitamin D in severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Although India receives adequate sunlight throughout the year, the majority of Indians are deficient in vitamin D levels. In the present study, we hypothesized that vitamin D deficiency would be associated with the SARS-CoV-2 infection rate and mortality in the Indian population.

Materials and methods

SARS-CoV-2 infection and mortality data were obtained from the Government of India's official website (accessed on 16th August 2020). Various literature databases like PubMed and Google Scholar were searched to find the mean of 25-hydroxyvitamin D [25(OH)D] levels in different states and union territories of India, Pearson correlation was carried out to investigate the possible link between mean 25(OH)D levels and SARS-CoV-2 infection and mortality per million of the population.

Results

An inverse correlation was observed between the mean level of 25(OH)D and SARS-CoV-2 infection rate (r = −0.43, p = 0.02) and mortality rate (r = −0.42, p = 0.02).

Conclusions

The present observational study revealed an association of vitamin D with SARS-CoV-2 infection and related mortality. Further studies are required to validate our observations.

Association between pre-chemotherapy serum levels of vitamin D and clinicopathologic findings in gastric cancer

BACKGROUND

To examine the serum levels of vitamin D in newly diagnosed gastric cancer (GC) patients compared with normal subjects and any possible association with prognostic variables.

METHODS

One-hundred subjects (50 GC and 50 controls) were enrolled and serum vitamin D levels were assessed using ELISA. Based on two definitions, vitamin D was classified as a sufficient level (≥30 ng/dL) and optimal level (25-80 ng/dL). The χ²and unpaired t-test was used for data analysis with a significance level of 0.05.

RESULTS

The mean serum levels of vitamin D in patients and controls were 26.86 (±14.6) and 31.72 (±13.4), respectively (P=0.09). The prevalence of vitamin D insufficiency and deficiency was higher in GC cases than controls (P=0.045 if sufficient level ≥30 and P=0.065 if sufficient level ≥25). According to histological grade analysis, grade 3 patients (poorly differentiated) were found with significantly lower vitamin D concentrations in serum than grade 1 and 2 subjects (22.25 vs 33.29 ng/dL, P=0.021). No significant differences were observed between the two groups in pathological tumor-node-metastasis (pTNM) stages, distant metastasis, and location of the tumor.

CONCLUSION

Higher prevalence of vitamin D insufficiency and deficiency in GC patients may reflect its role in malignancy; however, further studies are needed to confirm this relationship and any possible benefits to the patients.

Unveiling molecular associations of polymorphic variants of VDR gene (FokI, BsmI and ApaI) in multiple myeloma patients of Indian population

Multiple myeloma (MM) is a plasma cell malignancy frequently accompanied with skeletal co-morbidity. Vitamin D (1,25(OH)₂D) is an important mediator of skeletal homeostasis that mediates its effect by binding to vitamin D receptor (VDR), a steroid family receptor and modulates various downstream pathways. Multiple polymorphisms have been determined in VDR gene that witnessed significant association with cancer development and progression. Therefore, in this maiden study, we recruited 75 newly diagnosed MM patients and 75 control subjects. 25-hydroxy vitamin D (25(OH)D) levels were measured in all recruited study subjects. Further, PCR-RFLP was performed in DNA samples of recruited study subjects. Results demonstrated significantly decreased 25(OH)D levels in MM patients compared to controls. Additionally, decreased 25(OH)D levels in MM patients inversely associated with disease severity. Further, single nucleotide polymorphism (SNP) analysis of VDR gene showed significantly higher risk of MM disease development in Ff + ff, Aa + aa, and Bb + bb genotypes. Additionally, FokI f, ApaI a and BsmI b alleles were significantly associated with MM occurrence. In conclusion, this study provided initial evidences of association between 25(OH)D insufficiency, VDR gene polymorphism and MM development. Thus, we suggest that a study involving assessment of 25(OH)D levels and VDR gene polymorphism in large patients' cohort might substantiate their role in MM development which would further provide impetus to give 25(OH)D supplementation along with conventional chemotherapeutic agents for myeloma treatment in future.

A multicenter case control study of association of vitamin D with breast cancer among women in Karachi, Pakistan

Background

The prevalence of vitamin D inadequacy and breast cancer are both high among women living in Karachi, Pakistan.

Methods

A matched case control study was conducted in two hospitals of Karachi, Pakistan to evaluate the association of vitamin D (serum 25-hydroxyvitamin D) concentrations, vitamin D supplementation and sun exposure with breast cancer among Pakistani women. A total of 411 newly diagnosed histologically confirmed primary breast cancer cases were enrolled and 784 controls, free of breast and any other cancers, were matched by age (year of birth ± 5 years), residence in the same geographic area and study site. Information was collected on sociodemographic history, history of vitamin D supplementation, past medical and obstetrical history, family history of breast cancer, sun exposure history, histopathology reports and anthropometric measurement and venous blood was collected to measure serum 25-hydroxyvitamin D (25(OH)D) concentration.

Results

Compared to patients with sufficient serum vitamin D (>30 ng/ml), women with serum vitamin D deficiency (<20ng/ml), had a higher risk of breast cancer (OR = 1.65, 95%CI: 1.10, 2.50). Women with history of vitamin D supplementation one year prior to enrollment, had significant protective effect against breast cancer (OR = 0.32, 95% CI: 0.24, 0.43).

Conclusions and recommendation

Serum vitamin D deficiency was associated with increased risk of breast cancer, while vitamin D supplementation was associated with decreased risk of breast cancer. In Pakistani women, where vitamin D deficiency is common, raising and maintaining serum vitamin D at population level is a safe and affordable strategy. It may play a role in reducing the incidence of both vitamin D deficiency and breast cancer, particularly among poor women where the breast cancer mortality is highest due to limited resources for early detection, diagnosis, and treatment. The effects of vitamin D with regard to breast cancer risk in Karachi Pakistan should be further evaluated.