The Association between Serum Vitamin D Levels and Urinary Tract Infection Risk in Children: A Systematic Review and Meta-Analysis

Nonantibiotic prophylaxis for urinary tract infections: a network meta-analysis of randomized controlled trials

OBJECTIVE

Recent guidelines indicated that, in addition to antibiotics, nonantibiotic interventions serve as available preventive options for urinary tract infections (UTIs). This study aimed to compare the efficacy and safety of various nonantibiotic interventions in preventing UTIs.

METHODS

The authors systematically searched databases for eligible studies. The inclusion criteria encompassed randomized controlled trials (RCTs) focusing on one or more nonantibiotic interventions for UTI prevention, with the incidence of UTIs being a key outcome measure. Subgroup analyses were performed according to age, sex, and follow-up.

RESULTS

50 RCTs comprising 10,495 subjects and investigating 14 interventions, were included. Nearly 80% of the RCTs utilized double-blind or triple-blind designs. In the whole group, D-mannose (risk ratio [RR] 0.34, 0.21 to 0.56), vaccine (RR 0.65, 0.52 to 0.82), probiotics (RR 0.69, 0.50 to 0.94), cranberry (RR 0.72, 0.60 to 0.87), and triple therapy (cranberry plus probiotics plus vitamin A) (RR 0.27, 0.09 to 0.87), exhibited a significant reduction in UTI incidence compared to the placebo. Probiotics (RR 0.50, 0.28 to 0.89) were the most effective in the nonadult group, while vitamin D (RR 0.46, 0.27 to 0.81) showed the highest efficacy in the long follow-up group (≥ 1 year). There was no significant difference in the incidence of adverse events between the interventions and the placebo group.

CONCLUSIONS

D-mannose, triple therapy, vaccine, probiotics, and cranberry serve as potential nonantibiotic intervention options for clinical UTI prevention.

Vitamin D: What We Know and What We Still Do Not Know About Vitamin D in Preterm Infants-A Literature Review

BACKGROUND/OBJECTIVES

Preterm infants represent a population group at increased risk for vitamin D deficiency (VDD) and for its negative impact on various outcomes like metabolic bone disease or rickets, respiratory complications like respiratory distress syndrome and the development of bronchopulmonary dysplasia, necrotizing enterocolitis, or retinopathy of prematurity.

METHODS

Despite the growing interest in vitamin D research, there is still uncertainty regarding clear recommendations for each high-risk category of premature infants concerning the optimal dosage, optimal product, and timing for initiating vitamin D supplementation to prevent VDD.

RESULTS

An analysis of the literature suggests that early intervention for the optimal enteral supplementation of vitamin D is not only successful in achieving higher 25-hydroxi-vitamin D (25(OH)D) at one month but is also linked with improved outcomes.

CONCLUSIONS

The traditional concepts and current recommendations for assessing vitamin D status and optimal supplementation need to be revised. Since parenteral nutrition, fortified mothers' own milk, and special formula for preterm infants cannot provide adequate vitamin D levels, initiating oral supplementation soon after birth is essential to correct VDD in preterm infants.

Vitamin D and its analogs in immune system regulation

Vitamin D was discovered as the cure for nutritional rickets, a disease of bone growth arising from inadequate intestinal calcium absorption, and for much of the 20th century, it was studied for its critical role in calcium homeostasis. However, we now recognize that the vitamin D receptor and vitamin D metabolic enzymes are expressed in numerous tissues unrelated to calcium homeostasis. Notably, vitamin D signaling can induce cellular differentiation and cell cycle arrest. Moreover, the vitamin D receptor and the enzyme CYP27B1, which produces the hormonal form of vitamin D, 1,25-dihydroxyvitamin D (1,25D), are expressed throughout the immune system. In addition, CYP27B1 expression in immune cells is regulated by physiological inputs independent of those controlling its expression in calcium homeostatic tissues. These observations have driven the development of 1,25D-like secosteroidal analogs and nonsecosteroidal analogs to separate the effects of vitamin D on cell differentiation and function from its calcemic activities. Notably, some of these analogs have had considerable success in the clinic in the treatment of inflammatory and immune-related disorders. In this review, we described in detail the mechanisms of vitamin D signaling and the physiological signals controlling 1,25D synthesis and catabolism, with a focus on the immune system. We also surveyed the effects of 1,25D and its analogs on the regulation of immune system function and their implications for human immune-related disorders. Finally, we described the potential of vitamin D analogs as anticancer therapeutics, in particular, their use as adjuncts to cancer immunotherapy. SIGNIFICANCE STATEMENT: Vitamin D signaling is active in both the innate and adaptive arms of the immune system. Numerous vitamin D analogs, developed primarily to minimize the dose-limiting hypercalcemia of the active form of vitamin D, have been used widely in preclinical and clinical studies of immune system regulation. This review presents a description of the mechanisms of action of vitamin D signaling, an overview of analog development, and an in-depth discussion of the immunoregulatory roles of vitamin D analogs.

Vitamin D Deficiency Meets Hill's Criteria for Causation in SARS-CoV-2 Susceptibility, Complications, and Mortality: A Systematic Review

Clinical trials consistently demonstrate an inverse correlation between serum 25-hydroxyvitamin D [25(OH)D; calcifediol] levels and the risk of symptomatic SARS-CoV-2 disease, complications, and mortality. This systematic review (SR), guided by Bradford Hill's causality criteria, analyzed 294 peer-reviewed manuscripts published between December 2019 and November 2024, focusing on plausibility, consistency, and biological gradient. Evidence confirms that cholecalciferol (D3) and calcifediol significantly reduce symptomatic disease, complications, hospitalizations, and mortality, with optimal effects above 50 ng/mL. While vitamin D requires 3-4 days to act, calcifediol shows effects within 24 h. Among 329 trials, only 11 (3%) showed no benefit due to flawed designs. At USD 2/patient, D3 supplementation is far cheaper than hospitalization costs and more effective than standard interventions. This SR establishes a strong inverse relationship between 25(OH)D levels and SARS-CoV-2 vulnerability, meeting Hill's criteria. Vitamin D3 and calcifediol reduce infections, complications, hospitalizations, and deaths by ~50%, outperforming all patented, FDA-approved COVID-19 therapies. With over 300 trials confirming these findings, waiting for further studies is unnecessary before incorporating them into clinical protocols. Health agencies and scientific societies must recognize the significance of these results and incorporate D3 and calcifediol for prophylaxis and early treatment protocols of SARS-CoV-2 and similar viral infections. Promoting safe sun exposure and adequate vitamin D3 supplementation within communities to maintain 25(OH)D levels above 40 ng/mL (therapeutic range: 40-80 ng/mL) strengthens immune systems, reduces hospitalizations and deaths, and significantly lowers healthcare costs. When serum 25(OH)D levels exceed 70 ng/mL, taking vitamin K2 (100 µg/day or 800 µg/week) alongside vitamin D helps direct any excess calcium to bones. The recommended vitamin D dosage (approximately 70 IU/kg of body weight for a non-obese adult) to maintain 25(OH)D levels between 50-100 ng/mL is safe and cost-effective for disease prevention, ensuring optimal health outcomes.

Bioactive Compounds as Alternative Approaches for Preventing Urinary Tract Infections in the Era of Antibiotic Resistance

Urinary tract infections (UTIs) are among the most common bacterial infections worldwide. They occur in the urinary system when a microorganism, commonly present on the perineal skin or rectum, reaches the bladder through the urethra, and adheres to the luminal surface of uroepithelial cells, forming biofilms. The treatment of UTIs includes antibiotics, but their indiscriminate use has favored the development of multidrug-resistant bacteria strains, which represent a serious challenge to today's microbiology. The pathogenesis of the infection and antibiotic resistance synergistically contribute to hindering the eradication of the disease while favoring the establishment of persistent infections. The repeated requirement for antibiotic treatment and the limited therapeutic options have further contributed to the increase in antibiotic resistance and the occurrence of potential relapses by therapeutic failure. To limit antimicrobial resistance and broaden the choice of non-antibiotic preventive approaches, this review reports studies focused on the bacteriostatic/bactericidal activity, inhibition of bacterial adhesion and quorum sensing, restoration of uroepithelial integrity and immune response of molecules, vitamins, and compounds obtained from plants. To date, different supplementations are recommended by the European Association of Urology for the management of UTIs as an alternative approach to antibiotic treatment, while a variety of bioactive compounds are under investigation, mostly at the level of in vitro and preclinical studies. Although the evidence is promising, they are far from being included in the clinical practice of UTIs.

A Perspective on the Interaction Between Recurrent Lower Urinary Tract Infections and Irritable Bowel Syndrome

INTRODUCTION

Given the potential overlap in risk factors associated with both irritable bowel syndrome (IBS) and lower urinary tract infections (LUTIs), we aimed to identify factors that may contribute to the development of both conditions, as well as recurrent lower urinary tract infections (RLUTIs). Our research also sought to explore overlapping symptoms and interactions between these two disorders.

MATERIALS AND METHODS

The study included young women with a history of urinary tract infections. Participants were divided into three groups: women with sporadic LUTIs (NRLUTIs), women with recurrent LUTIs (RLUTIs), and women with both a history of urinary infections (NRLUTI or RLUTI) and a diagnosis of IBS. The diagnosis of IBS is primarily clinical, relying on symptoms and the exclusion of other gastrointestinal disorders. Data from intestinal microbiota tests were combined with information on patients' symptom perception, dietary habits, lifestyle, and knowledge regarding their conditions.

RESULTS

Abdominal pain, constipation, insufficient knowledge about antibiotic and probiotic use, and nutritionally unbalanced diets were identified as common factors associated with both LUTI-IBS and RLUTI.

CONCLUSIONS

Our research identified shared risk factors between LUTI, IBS, and RLUTI, suggesting a pathological interdependence between these conditions. Notably, women with RLUTIs often experience gastrointestinal symptoms such as abdominal pain and constipation after consuming foods known to trigger IBS. This highlights that gut dysbiosis is both a risk factor and a potential consequence of RLUTI. The presence of either condition appears to exacerbate the symptoms of the other, further underscoring the intricate connection between RLUTI and IBS in affected individuals.

Unveiling the Interplay-Vitamin D and ACE-2 Molecular Interactions in Mitigating Complications and Deaths from SARS-CoV-2

The interaction of the SARS-CoV-2 spike protein with membrane-bound angiotensin-converting enzyme-2 (ACE-2) receptors in epithelial cells facilitates viral entry into human cells. Despite this, ACE-2 exerts significant protective effects against coronaviruses by neutralizing viruses in circulation and mitigating inflammation. While SARS-CoV-2 reduces ACE-2 expression, vitamin D increases it, counteracting the virus's harmful effects. Vitamin D's beneficial actions are mediated through complex molecular mechanisms involving innate and adaptive immune systems. Meanwhile, vitamin D status [25(OH)D concentration] is inversely correlated with severity, complications, and mortality rates from COVID-19. This study explores mechanisms through which vitamin D inhibits SARS-CoV-2 replication, including the suppression of transcription enzymes, reduced inflammation and oxidative stress, and increased expression of neutralizing antibodies and antimicrobial peptides. Both hypovitaminosis D and SARS-CoV-2 elevate renin levels, the rate-limiting step in the renin-angiotensin-aldosterone system (RAS); it increases ACE-1 but reduces ACE-2 expression. This imbalance leads to elevated levels of the pro-inflammatory, pro-coagulatory, and vasoconstricting peptide angiotensin-II (Ang-II), leading to widespread inflammation. It also causes increased membrane permeability, allowing fluid and viruses to infiltrate soft tissues, lungs, and the vascular system. In contrast, sufficient vitamin D levels suppress renin expression, reducing RAS activity, lowering ACE-1, and increasing ACE-2 levels. ACE-2 cleaves Ang-II to generate Ang(1-7), a vasodilatory, anti-inflammatory, and anti-thrombotic peptide that mitigates oxidative stress and counteracts the harmful effects of SARS-CoV-2. Excess ACE-2 molecules spill into the bloodstream as soluble receptors, neutralizing and facilitating the destruction of the virus. These combined mechanisms reduce viral replication, load, and spread. Hence, vitamin D facilitates rapid recovery and minimizes transmission to others. Overall, vitamin D enhances the immune response and counteracts the pathological effects of SARS-CoV-2. Additionally, data suggests that widely used anti-hypertensive agents-angiotensin receptor blockers and ACE inhibitors-may lessen the adverse impacts of SARS-CoV-2, although they are less potent than vitamin D.

Strategies to build stronger bones in Indian children: Challenges for implementation

Background & objectives Globally, vitamin D deficiency has been incriminated in poor bone health and growth retardation in children, impaired adult musculoskeletal health (classically described), increased risk of cardiovascular events, immune dysfunction, neurologic disorders, insulin resistance and its multiple sequelae, polycystic ovary syndrome (PCOS) and certain cancers. This review intends to holistically highlight the burden of vitamin D deficiency among children in India, the public health importance, and potential therapeutic and preventive options, utilizing the concept of implementation research. Methods A systematic search was carried out on PubMed, Embase, China National Knowledge Infrastructure (CNKI) and Cochrane database, clinicaltrials.gov, Google Scholar, and ctri.nic.in with the keywords or MeSH terms namely 'vitamin D', 'cholecalciferol', 'ergocalciferol', 'children', connected with appropriate boolean operators. Results Vitamin D deficiency/insufficiency prevalence varies from 70-90 per cent in Indian children. Rickets, stunting, impaired bone mineral health, and dental health are common problems in these children. Serum 25-hydroxy vitamin D (25(OH)D) should be maintained >20 ng/ml in children. Oral vitamin D supplementation has a high therapeutic window (1200-10,000 IU/d well tolerated). Fortification of grains, cereal, milk, bread, fruit juice, yogurt, and cheese with vitamin D has been tried in different countries across the globe. From Indian perspective, fortification of food items which is virtually used by everyone would be ideal like fortified milk or cooking oil. Fortification of "laddus" made from "Bengal gram" with vitamin D as a part of a mid-day meal programme for children can be an option. Interpretation & conclusions There is enough evidence from India to suggest the importance and utility of food fortification with vitamin D to address the epidemic of vitamin D deficiency/insufficiency in children.

Association of Vitamin A and D Deficiencies with Infectious Outcomes in Children Undergoing Intensive Induction Therapy for Acute Lymphoblastic Leukemia

OBJECTIVE

To evaluate the association between deficiency of vitamin A or D at diagnosis of pediatric acute lymphoblastic leukemia (ALL) and subsequent infectious complications during induction therapy.

STUDY DESIGN

We conducted an institutional review board-approved, retrospective cohort study of children with newly diagnosed ALL from 2007 to 2017 at St. Jude Children's Research Hospital. We measured vitamin D, vitamin D binding protein, retinol binding protein as a surrogate for vitamin A, and immunoglobulin isotypes in serum obtained at ALL diagnosis, and we assessed the association between vitamin deficiencies or levels and infection-related complications during the 6-week induction phase using Cox regression models.

RESULTS

Among 378 evaluable participants, vitamin A and D deficiencies were common (43% and 17%, respectively). Vitamin D deficiency was associated with higher risks of febrile neutropenia (adjusted hazard ratio [aHR], 1.7; P = .0072), clinically documented infection (aHR, 1.73; P = .025), and likely bacterial infection (aHR, 1.86; P = .008). Conversely, vitamin A deficiency was associated solely with a lower risk of sepsis (aHR, 0.19; P = .027).

CONCLUSIONS

In this retrospective study, vitamin D deficiency was associated with an increased risk of common infection-related complications during induction therapy for ALL. Additional studies are warranted to evaluate whether vitamin D supplementation could mitigate this effect.

Relationship between urinary tract infections and serum vitamin D level in adults and children- a literature review

Over time, researchers have accumulated significant evidence indicating that vitamin D deficiency not only impacts skeletal health but also contributes to the development and progression of various diseases, including cancer, diabetes, and cardiovascular conditions. The risk of low serum 1, 25(OH)2D3 level ultimately directs the way to morbidity, the beginning of new diseases, and numerous infections. Infections are the first entity that affects those with vitamin D deficiency. The common infection is urinary tract infection (UTI), and its relationship with vitamin D deficiency or insufficiency remains controversial. This infection affects both men and women, but comparatively, women are more prone to this infection because of the short length of the urethra, which makes an easy entry for the bacteria. The low level of serum vitamin D increases the risk of UTIs in children. Recurrent UTIs are one of the major weaknesses in women; if left untreated, they progress to appallingly serious conditions like kidney dysfunction, liver damage, etc. Hence improving the vitamin D status may help to improve the immune system, thus making it more resistant to infections. In this review, we have focused on examining whether vitamin D deficiency and insufficiency are the causes of UTIs and the association between them in women and children. We have also described the connection between vitamin D deficiency and insufficiency with UTIs and additional nanotechnology- based treatment strategies.

Scientific Advances in Understanding the Pathogenesis, Diagnosis, and Prevention of Urinary Tract Infection in the Past 10 Years

Urinary tract infection (UTI) is a very common disease that is accompanied by various complications in the affected person. UTI triggers diverse inflammatory reactions locally in the infected urinary bladder and kidney, causing tissue destruction and organ failure. Moreover, systemic responses in the entire body carry the risk of urosepsis with far-reaching consequences. Understanding the cell-, organ-, and systemic mechanisms in UTI are crucial for prevention, early intervention, and current therapeutic approaches. This review summarizes the scientific advances over the last 10 years concerning pathogenesis, prevention, rapid diagnosis, and new treatment approaches. We also highlight the impact of the immune system and potential new therapies to reduce progressive and recurrent UTI.