Associations between serum vitamin D and the risk of female reproductive tumors: A meta-analysis with trial sequential analysis

Vitamins in Gynecologic Malignancies

The combination of vitamin A and D derivatives with classical chemotherapeutic treatments results in more satisfactory outcomes. The use of drug combinations, such as 9cUAB130 with carboplatin and cisplatin with TAC-101, shows enhanced cytotoxic effects and reductions in ovarian tumor volume compared to single-drug treatments. Combining cisplatin with calcitriol and progesterone increases VDR expression, potentially enhancing the effectiveness of anticancer therapy in ovarian cancer. The effectiveness of vitamin derivatives in anticancer treatment may vary depending on the characteristics of the tumor and the cell line from which it originated. An increase in thiamine intake of one unit is associated with an 18% decrease in HPV infection. Higher intake of vitamin C by 50 mg/day is linked to a lower risk of cervical neoplasia. Beta-carotene, vitamin C, and vitamin E are associated with risk reductions of 12%, 15%, and 9% in endometrial cancer, respectively. A balanced daily intake of vitamins is important, as both deficiency and excess can influence cancer development. It has been observed that there is a U-shaped relationship between group B vitamins and metabolic markers and clinical outcomes.

EMAS position statement: Vitamin D and menopausal health

INTRODUCTION

There is increasing evidence that vitamin D has widespread tissue effects. In addition to osteoporosis, vitamin D deficiency has been associated with cardiovascular disease, diabetes, cancer, infections and neurodegenerative disease. However, the effect of vitamin D supplementation on non-skeletal outcomes requires clarification, especially in postmenopausal women.

AIM

This position statement provides an evidence-based overview of the role of vitamin D in the health of postmenopausal women based on observational and interventional studies.

MATERIALS AND METHODS

Literature review and consensus of expert opinion.

RESULTS AND CONCLUSIONS

Vitamin D status is determined by measuring serum 25-hydroxyvitamin D levels. Concentrations <20 ng/ml (<50 nmol/l) and <10 ng/ml (<25 nmol/l) are considered to constitute vitamin D deficiency and severe deficiency, respectively. Observational data suggest an association between vitamin D deficiency and adverse health outcomes in postmenopausal women, although they cannot establish causality. The evidence from randomized controlled trials concerning vitamin D supplementation is not robust, since many studies did not consider whether people were deficient at baseline. Moreover, high heterogeneity exists in terms of the population studied, vitamin D dosage, calcium co-administration and duration of intervention. Concerning skeletal health, vitamin D deficiency is associated with low bone mass and an increased risk of fractures. Vitamin D supplementation at maintenance doses of 800-2000 IU/day (20-50 μg/day), after repletion of vitamin D status with higher weekly or daily doses, may be of benefit only when co-administered with calcium (1000-1200 mg/day), especially in the elderly populations and those with severe vitamin D deficiency. Concerning cardiovascular disease, vitamin D deficiency is associated with an increased prevalence of cardiovascular risk factors, mainly metabolic syndrome, type 2 diabetes mellitus and dyslipidemia. Vitamin D deficiency, especially its severe form, is associated with an increased risk of cardiovascular events (coronary heart disease, stroke, mortality), independently of traditional risk factors. Vitamin D supplementation may have a modestly beneficial effect on lipid profile and glucose homeostasis, especially in obese individuals or those ≥60 years old and at doses of ≥2000 IU/day (≥50 μg/day). However, it has no effect on the incidence of cardiovascular events. Concerning cancer, vitamin D deficiency is associated with increased incidence of and mortality from several types of cancer, such as colorectal, lung and breast cancer. However, the data on other types of gynecological cancer are inconsistent. Vitamin D supplementation has no effect on cancer incidence, although a modest reduction in cancer-related mortality has been observed. Concerning infections, vitamin D deficiency has been associated with acute respiratory tract infections, including coronavirus disease 2019 (COVID-19). Vitamin D supplementation may decrease the risk of acute respiratory tract infections and the severity of COVID-19 (not the risk of infection). Concerning menopausal symptomatology, vitamin D deficiency may have a negative impact on some aspects, such as sleep disturbances, depression, sexual function and joint pains. However, vitamin D supplementation has no effect on these, except for vulvovaginal atrophy, at relatively high doses, i.e., 40,000-60,000 IU/week (1000-1500 IU/week) orally or 1000 IU/day (25 μg/day) as a vaginal suppository.

Vitamin D, Menopausal Health and COVID-19: Critical Appraisal of Current Data

Inconsistency exists across studies conducted in postmenopausal women regarding the effect of vitamin D deficiency (VDD) and supplementation on several aspects of menopausal health, such as fractures, vasomotor symptomatology, cardiovascular disease (CVD), cancer and infections, including coronavirus disease 2019 (COVID-19). The aim of this review is to critically summarize the evidence provided by observational studies and randomized controlled trials (RCTs) of vitamin D supplementation in postmenopausal women with VDD. Observational studies have found that VDD is associated with an increased risk of falls and fractures after the menopause. VDD also has a negative effect on menopausal symptomatology. VDD, especially its severe form, is associated with an increased risk of CVD risk factors and CVD events. VDD is associated with increased risk and mortality from several cancer types and risk of infections. The evidence from RCTs regarding the effect of vitamin D supplementation on falls, fractures, menopausal symptoms, cardiovascular disease, cancer and infections is not robust. Thus, skeletal health may benefit only when vitamin D is co-administered with calcium, especially in those ≥70 years old and with severe VDD. There is no evidence of a favorable effect on menopausal symptoms or risk of CVD or cancer, except for a modest reduction in cancer-related mortality. Inconsistency still exists regarding its effect on infection risk, disease severity and mortality due to COVID-19.

Vitamin D and Multiple Health Outcomes: An Umbrella Review of Observational Studies, Randomized Controlled Trials, and Mendelian Randomization Studies

Observational studies, randomized controlled trials (RCTs), and Mendelian randomization (MR) studies have yielded inconsistent results on the associations of vitamin D concentrations with multiple health outcomes. In the present umbrella review we aimed to evaluate the effects of low vitamin D concentrations and vitamin D supplementation on multiple health outcomes. We summarized current evidence obtained from meta-analyses of observational studies that examined associations between vitamin D concentrations and multiple health outcomes, meta-analyses of RCTs that investigated the effect of vitamin D supplementation on multiple health outcomes, and MR studies that explored the causal associations of vitamin D concentrations with various diseases (international prospective register of systematic reviews PROSPERO registration number CRD42018091434). A total of 296 meta-analyses of observational studies comprising 111 unique outcomes, 139 meta-analyses of RCTs comprising 46 unique outcomes, and 73 MR studies comprising 43 unique outcomes were included in the present umbrella review. Twenty-eight disease outcomes were identified by both meta-analyses of observational studies and MR studies. Seventeen of these reported disease outcomes had consistent results, demonstrating that lower concentrations of vitamin D were associated with a higher risk for all-cause mortality, Alzheimer's disease, hypertension, schizophrenia, and type 2 diabetes. The combinations of consistent evidence obtained by meta-analyses of observational studies and MR studies together with meta-analyses of RCTs showed that vitamin D supplementation was associated with a decreased risk for all-cause mortality but not associated with the risk for Alzheimer's disease, hypertension, schizophrenia, or type 2 diabetes. The results indicated that vitamin D supplementation is a promising strategy with long-term preventive effects on multiple chronic diseases and thus has the potential to decrease all-cause mortality. However, the current vitamin D supplementation strategy might not be an efficient intervention approach for these diseases, suggesting that new strategies are highly needed to improve the intervention outcomes.

Vitamin D in gynecological diseases

BACKGROUND

Most reproductive system studies suggest the protective effects of vitamin D, but vitamin D deficiency and insufficiency are growing global health issues. The present study investigates the association between vitamin D deficiency/insufficiency and gynecologic diseases to identify illness risks at different serum vitamin D levels in Taiwan.

METHODS

A total of 7699 female adults aged ≥20 years with results for both serum vitamin D and gynecologic-associated diseases were drawn from the Taiwan MJ cohort. We analyzed the correlation between serum vitamin D levels and results from reproductive system evaluations, including history of dysmenorrhea, results of Pap smear, high-risk human papillomavirus (HPV) infection of the cervix, mammography, and ultrasound of breast and pelvis.

RESULTS

Over 80% of participants showed vitamin D deficiency/insufficiency. Participants with abnormal Pap smear results, high-risk HPV infection, and history of dysmenorrhea showed significantly lower levels of serum vitamin D (p < 0.001-0.05). Serum vitamin D deficiency was significantly associated with positive high-risk HPV infection of the cervix (p < 0.05) and dysmenorrhea (p < 0.001). After controlling for age as a confounding variable for each gynecologic disease, level of serum vitamin D was significantly associated with abnormal breast ultrasound (odds ratio = 0.724) and uterus ultrasound (odds ratio = 0.673 - 0.8), and dysmenorrhea (odds ratio = 0.829).

CONCLUSION

Associations were found between vitamin D deficiency and endometriosis, uterine myoma, dysmenorrhea, abnormal Pap smear results, and high-risk HPV infection of the cervix. Therefore, vitamin D supplements may present a cost-effective benefit for the prevention and treatment of gynecologic diseases, and thus reduction of healthcare expenditures.

Correlation of low serum vitamin-D with uterine leiomyoma: a systematic review and meta-analysis

BACKGROUND

There is a growing body of evidence on low serum vitamin-D levels and the risk of uterine leiomyomas (UL). Therefore, this systematic review and meta-analysis was conducted to investigate the association between serum vitamin D levels and UL occurrence.

METHODS

Searches were systematically conducted of the electronic databases PubMed, Scopus, EMBASE, Web of Science (ISI), Cochrane library, Ovid, and Google Scholar to identify relevant studies from inception until February 6, 2020. Heterogeneity across the included studies was examined using Cochran's Q and I-square (I²). Data was pooled using random effects modeling and expressed as standardized mean differences (SMDs).

RESULTS

Nine eligible studies with a total of 1730 participants (835 patients with UL and 895 controls) were included in the current meta-analysis. Pooled results with random effects modeling indicated that serum vitamin D levels were significantly lower in patients with UL than in the control group (n = 9, SMD = - 0.67; 95% CI, - 0.98, - 0.35, p < 0.001; I² = 89.3%, p < 0.001). Based on the findings of subgroup analyses, it was found that the SMD values across the included studies from Asia (n = 4, SMD = - 1.20; 95% CI, - 1.45, - 0.96, p < 0.001; I² = 30.6%, p = 0.229) were lower than those from Europe (n = 3, SMD = - 0.34; 95% CI, - 0.49, - 0.18, p < 0.001; I² = 0.0%, p = 0.602) and Africa (n = 2, SMD = - 0.13; 95% CI, - 0.29, 0.04, p = 0.128; I² = 0.0%, p = 0.417), although the difference was not significant in Africa. Publication year was also found to be a potential contributor's variable in the pooled SMD using the meta-regression method (t = - 3.00, p = 0.02).

CONCLUSIONS

To the best of our knowledge, the current meta-analysis showed for the first time that serum vitamin D levels were significantly lower in women with UL in selected populations.

Vitamin D supplementation for prevention of cancer: The D2d cancer outcomes (D2dCA) study

Evidence on biological plausibility from mechanistic studies and data from observational studies suggest that vitamin D may be linked to risk of several types of cancer. However, evidence from clinical trials evaluating the effect of vitamin D supplementation on cancer risk is limited. The Vitamin D and Type 2 Diabetes (D2d) study is a multi-center, randomized, placebo-controlled clinical trial conducted to examine the causal relationship between oral vitamin D supplementation and development of diabetes among overweight adults with prediabetes. The D2d study provides a unique opportunity to assess the effect of vitamin D supplementation at a higher dose (4000 IU/day) than has been used in other clinical trials with cancer outcomes, in a population at higher than average risk for cancer. This paper provides: Krishnan and Feldman (2011) a) baseline characteristics of the D2d population included in the D2d cancer outcomes secondary study (D2dCA) and comparison to other large trials of vitamin D supplementation and cancer risk; Leyssens et al. (2013) b) description of data that are being collected during the trial and the planned statistical analyses to test whether vitamin D supplementation at a dose of 4000 IU/day has an effect on incident cancer overall, on incidence of certain types of cancer, and on incidence of precancerous lesions. Results of D2dCA will help guide future research and clinical recommendations related to vitamin D and cancer risk.