Genetically Predicted Lifelong Circulating 25(OH)D Levels are Associated With Serum Calcium Levels and Kidney Stone Risk

Blood Calcium, Genetic Risk, and Risk of Incident Kidney Stone: A Population-Based Cohort Study

OBJECTIVE

To investigate the association between blood calcium concentration and incident kidney stone as well as to assess the role played by genetic susceptibility.

METHODS

We performed a population-based cohort study based on participants from the UK Biobank. A multivariable Cox proportional hazards regression model was used to estimate hazard ratios (HRs) and 95% CIs of incident kidney stone for blood calcium level and polygenic risk score (PRS). In addition, the potential interaction was explored. The study was conducted from January 28, 2023, through June 4, 2023.

RESULTS

During the follow-up of 423,301 participants with a total of 5,490,332 person-years (median follow-up of 13.4 years), 4502 cases of kidney stone were recorded. Compared with the low blood calcium concentration group (first tertile), individuals in the high (third tertile) and moderate (second tertile) concentration groups had higher risks of kidney stone with HRs of 1.24 (95% CI, 1.15 to 1.33) and 1.11 (1.04 to 1.20), respectively. The PRS for kidney stone contained 40 independent single-nucleotide polymorphisms and was used to assign individuals to 3 groups according to the quintile. Participants with high (Q5) and moderate (Q2 to Q4) genetic risks had increased risks of kidney stone compared with low (Q1) genetic risk with HRs of 1.70 (1.53 to 1.89) and 1.31 (1.20 to 1.44), respectively. There was a joint cumulative risk of incident kidney stone between blood calcium concentration and genetic susceptibility.

CONCLUSIONS

Blood calcium concentration and PRS are significantly associated with incident kidney stone risk. Excessive blood calcium concentration might bring additional stone risk in populations at high genetic risk. A nonlinear correlation between blood calcium concentration and kidney stone risk was indicated.

The Safety Profile of Vitamin D Supplements Using Real-World Data from 445,493 Participants of the UK Biobank: Slightly Higher Hypercalcemia Prevalence but Neither Increased Risks of Kidney Stones nor Atherosclerosis

Background: Potential calcium-related adverse events of vitamin D supplement use have not been addressed in large-scale, real-world data so far. Methods: Leveraging data from the UK Biobank, encompassing 445,493 individuals aged 40-69, we examined associations of high 25-hydroxyvitamin (25(OH)D) levels ≥ 100 nmol/L and vitamin D supplementation with hypercalcemia (serum calcium > 2.6 mmol/L), kidney stones, and atherosclerosis assessments (pulse wave arterial stiffness index and carotid intima-medial thickness). Regression models were comprehensively adjusted for 49 covariates. Results: Approximately 1.5% of the participants had high 25(OH)D levels, 4.3% regularly used vitamin D supplements, and 20.4% reported regular multivitamin use. At baseline, the hypercalcemia prevalence was 1.6%, and 1.1% was diagnosed with kidney stones during follow-up. High 25(OH)D levels were neither associated with calcium-related adverse events nor atherosclerosis assessments. Vitamin D and multivitamin supplementation were associated with an increased prevalence of hypercalcemia (odds ratios and 95% confidence intervals: 1.46 [1.32-1.62] and 1.11 [1.04-1.18], respectively) but were neither associated with atherosclerosis nor future kidney stones. Conclusions: High 25(OH)D levels observable in routine care were not associated with any adverse outcome. Vitamin D users have a slightly higher prevalence of hypercalcemia, possibly due to co-supplementation with calcium, but without a higher atherosclerosis prevalence or risk of kidney stones.

Association between serum 25-hydroxyvitamin D concentrations and kidney stone: a cohort study in the UK Biobank

OBJECTIVE

To investigate the association between serum 25(OH)D and kidney stone disease (KSD) in participants from the UK Biobank.

METHODS

We used data from the UK Biobank. Our analysis involved Cox proportional hazards models to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) to estimate the association between serum 25(OH)D levels (measured at the time of recruitment) and the risk of KSD, which was determined using hospital records.

RESULTS

This study involved 444,343 participants, with 4,458 cases of KSD identified during an average follow-up period of 12.6 years. Higher 25(OH)D levels were not associated with developing kidney stones in general population model 3 (HR = 0.88 [95% CI 0.77-1.01]). Interestingly, higher serum 25(OH)D concentrations in women over 60 years old were associated with a lower risk of kidney stone disease. The multivariate HRs and 95% CIs for participants who had serum 25(OH)D ≥ 50 nmol/L or ≥ 75 nmol/L, compared with those who were severely deficient (25[OH]D < 25 nmol/L), were 0.74 (0.58-0.95), 0.60 (0.43-0.85) for KSD, respectively (P for trend < 0.01). However, this trend was not statistically significant in the subgroup analysis of serum calcium ion concentration.

CONCLUSION

High 25(OH)D levels were not associated with a higher incidence of kidney stones if serum calcium levels are within a normal range. The findings alleviate physiological concerns regarding the supplementation of vitamin D alone to raise serum 25(OH)D concentration.

Vitamin D and human health: evidence from Mendelian randomization studies

We summarized the current evidence on vitamin D and major health outcomes from Mendelian randomization (MR) studies. PubMed and Embase were searched for original MR studies on vitamin D in relation to any health outcome from inception to September 1, 2022. Nonlinear MR findings were excluded due to concerns about the validity of the statistical methods used. A meta-analysis was preformed to synthesize study-specific estimates after excluding overlapping samples, where applicable. The methodological quality of the included studies was evaluated according to the STROBE-MR checklist. A total of 133 MR publications were eligible for inclusion in the analyses. The causal association between vitamin D status and 275 individual outcomes was examined. Linear MR analyses showed genetically high 25-hydroxyvitamin D (25(OH)D) concentrations were associated with reduced risk of multiple sclerosis incidence and relapse, non-infectious uveitis and scleritis, psoriasis, femur fracture, leg fracture, amyotrophic lateral sclerosis, anorexia nervosa, delirium, heart failure, ovarian cancer, non-alcoholic fatty liver disease, dyslipidemia, and bacterial pneumonia, but increased risk of Behçet's disease, Graves' disease, kidney stone disease, fracture of radium/ulna, basal cell carcinoma, and overall cataracts. Stratified analyses showed that the inverse association between genetically predisposed 25(OH)D concentrations and multiple sclerosis risk was significant and consistent regardless of the genetic instruments GIs selected. However, the associations with most of the other outcomes were only pronounced when using genetic variants not limited to those in the vitamin D pathway as GIs. The methodological quality of the included MR studies was substantially heterogeneous. Current evidence from linear MR studies strongly supports a causal role of vitamin D in the development of multiple sclerosis. Suggestive support for a number of other health conditions could help prioritize conditions where vitamin D may be beneficial or harmful.

Integrative genome-wide analyses identify novel loci associated with kidney stones and provide insights into its genetic architecture

Kidney stone disease (KSD) is a complex disorder with high heritability and prevalence. We performed a large genome-wide association study (GWAS) meta-analysis for KSD to date, including 720,199 individuals with 17,969 cases in European population. We identified 44 susceptibility loci, including 28 novel loci. Cell type-specific analysis pinpointed the proximal tubule as the most relevant cells where susceptibility variants might act through a tissue-specific fashion. By integrating kidney-specific omics data, we prioritized 223 genes which strengthened the importance of ion homeostasis, including calcium and magnesium in stone formation, and suggested potential target drugs for the treatment. The genitourinary and digestive diseases showed stronger genetic correlations with KSD. In this study, we generate an atlas of candidate genes, tissue and cell types involved in the formation of KSD. In addition, we provide potential drug targets for KSD treatment and insights into shared regulation with other diseases.

Association of serum 25-hydroxyvitamin D concentrations with all-cause mortality among individuals with kidney stone disease: the NHANES database prospective cohort study

Background

The purpose of this study was to investigate the correlation between serum 25(OH)D concentrations and all-cause mortality in patients with kidney stone disease (KSD) as the effects of a deficiency in 25-hydroxyvitamin D on KSD patients are currently unclear.

Methods

For our prospective cohort study, we included 2,916 participants from the National Health and Nutrition Examination Survey (NHANES) 2007-2018. The National Death Index (NDI) was utilized to identify all causes of death and cause-specific mortality until December 31, 2018. We calculated hazard ratios (HR) and 95% confidence intervals (CIs) using multivariate Cox regression models.

Results

During the 18,859 person-years of follow-up, a total of 375 fatalities occurred, including 83 deaths from cardiovascular disease (CVD) and 79 deaths from cancer. At baseline, individuals with higher blood 25(OH)D concentrations had lower levels of glucose, glycohemoglobin, CRP, and insulin, as well as higher levels of HDL cholesterol (P < 0.01). In the fully adjusted model (Model 3), compared to the group with the lowest 25(OH)D concentrations, those with serum 25(OH)D concentrations ≥75 nmol/L had hazard ratios (HRs) and 95% confidence intervals (CIs) of 0.48 (0.26, 0.87) for all-cause mortality (P=0.02, P for trend = 0.02). The association between serum 25(OH)D concentrations and all-cause mortality in KSD patients was found to be significantly non-linear. A 7% decrease in the risk of death from all causes was observed for each unit-nmol/L increase in serum 25(OH)D concentrations when the concentrations were below 27.7 nmol/L (P < 0.05).

Conclusion

Based on the findings, KSD patients with insufficient serum 25(OH)D concentrations were at a higher risk of all-cause mortality. Therefore, it is crucial to maintain sufficient blood 25(OH)D concentrations and prevent 25(OH)D insufficiency in order to extend the lifespan of KSD patients.

Lifestyle factors, serum parameters, metabolic comorbidities, and the risk of kidney stones: a Mendelian randomization study

Background and objective

The early identification of modifiable risk factors is important for preventing kidney stones but determining causal associations can be difficult with epidemiological data. We aimed to genetically assess the causality between modifiable factors (lifestyle factors, serum parameters, and metabolic comorbidities) and the risk of kidney stones. Additionally, we aimed to explore the causal impact of education on kidney stones and its potential mediating pathways.

Methods

We conducted a two-sample Mendelian randomization (MR) study to explore the causal association between 44 modifiable risk factors and kidney stones. The FinnGen dataset initially explored the causal relationship of risk factors with kidney stones and the UK Biobank dataset was used as the validation set. Then, a meta-analysis was conducted by combining discovery and validation datasets. We used two-step MR to assess potential mediators and their mediation proportions between education and kidney stones.

Results

The combined results indicated that previous exposures may increase the risk of kidney stones, including sedentary behavior, urinary sodium, the urinary sodium/potassium ratio, the urinary sodium/creatinine ratio, serum calcium, 25-hydroxyvitamin D (25OHD), the estimated creatinine-based glomerular filtration rate (eGFRcrea), GFR estimated by serum cystatin C (eGFRcys), body mass index (BMI), waist circumference, type 2 diabetes mellitus (T2DM), fasting insulin, glycated hemoglobin, and hypertension. Coffee intake, plasma caffeine levels, educational attainment, and the urinary potassium/creatinine ratio may decrease the risk of kidney stones. Ranked by mediation proportion, the effect of education on the risk of kidney stones was mediated by five modifiable risk factors, including sedentary behavior (mediation proportion, 25.7%), smoking initiation (10.2%), BMI (8.2%), T2DM (5.8%), and waist circumference (3.2%).

Conclusion

This study provides MR evidence supporting causal associations of many modifiable risk factors with kidney stones. Sedentary lifestyles, obesity, smoking, and T2DM are mediating factors in the causal relationship between educational attainment and kidney stones. Our results suggest more attention should be paid to these modifiable factors to prevent kidney stones.

Causal relationship of genetically predicted circulating micronutrients levels with the risk of kidney stone disease: a Mendelian randomization study

Background

Current studies have reported conflicting associations between circulating micronutrient levels and kidney stone disease (KSD). We aimed to elucidate the causal relationship between circulating micronutrient levels and KSD by a two-sample Mendelian randomization (MR) analysis.

Methods

Total of 36 single nucleotide polymorphisms (SNPs) from published genome-wide association studies (GWAS) significantly associated with eight micronutrients (vitamin B12, folic acid, magnesium, iron, phosphorus, copper, zinc, and selenium) were used as instrumental variables. The GWAS summary data associated with KSD (8,060 cases and 301,094 controls) were obtained from the FinnGen consortium. Inverse variance weighted was the main MR analysis method. MR-Pleiotropy RESidual Sum and Outlier (MR-PRESSO), weighted median and MR-Egger were used to assess pleiotropy and heterogeneity.

Results

Genetically predicted circulating vitamin B12 and zinc levels were causally associated with the risk of KSD (vitamin B12: OR: 1.17, 95% CI: 1.04-1.32, p = 0.008; zinc: OR: 1.15, 95% CI: 1.03-1.28, p = 0.015). We found no evidence that other circulating micronutrients were associated with risk of KSD. p-value for Cochrane Q test, MR Egger intercept test, and MR-PRESSO were >0.05, indicating no significant heterogeneity or horizontal pleiotropy in this MR analysis.

Conclusion

Increasing circulating zinc levels may increase the risk of KSD. More studies are needed to provide evidence on whether genetically predicted circulating vitamin B12 and zinc levels are a risk factor for KSD.

The relationship between blood lipid and risk of psoriasis: univariable and multivariable Mendelian randomization analysis

Background

Psoriasis is a chronic inflammatory skin disease. Dyslipidemia may be a risk factor of psoriasis. But the causal relationship between psoriasis and blood lipid still remains uncertain.

Methods

The two data of blood lipid were obtained from UK Biobank (UKBB) and Global Lipid Genetics Consortium Results (GLGC). The primary and secondary database were from large publicly available genome-wide association study (GWAS) with more than 400,000 and 170,000 subjects of European ancestry, respectively. The psoriasis from Finnish biobanks of FinnGen research project for psoriasis, consisting of 6,995 cases and 299,128 controls. The single-variable Mendelian randomization (SVMR) and multivariable Mendelian randomization (MVMR) were used to assess the total and direct effects of blood lipid on psoriasis risk.

Results

SVMR estimates in primary data of blood lipid showed low-density lipoprotein cholesterol (LDL-C) (odds ratio (OR): 1.11, 95%, confidence interval (CI): 0.99-1.25, p = 0.082 in stage 1; OR: 1.15, 95% CI: 1.05-1.26, p = 0.002 in stage 2; OR: 1.15, 95% CI: 1.04-1.26, p = 0.006 in stage 3) and triglycerides (TG) (OR: 1.22, 95% CI: 1.10-1.35, p = 1.17E-04 in stage 1; OR: 1.15, 95% CI: 1.06-1.24, p = 0.001 in stage 2; OR: 1.14, 95% CI: 1.05-1.24, p = 0.002 in stage 3) had a highly robust causal relationship on the risk of psoriasis. However, there were no robust causal associations between HDL-C and psoriasis. The SVMR results in secondary data of blood lipid were consistent with the primary data. Reverse MR analysis showed a causal association between psoriasis and LDL-C (beta: -0.009, 95% CI: -0.016- -0.002, p = 0.009) and HDL-C (beta: -0.011, 95% CI: -0.021- -0.002, p = 0.016). The reverse causation analyses results between psoriasis and TG did not reach significance. In MVMR of primary data of blood lipid, the LDL-C (OR: 1.05, 95% CI: 0.99-1.25, p = 0.396 in stage 1; OR: 1.07, 95% CI: 1.01-1.14, p = 0.017 in stage 2; OR: 1.08, 95% CI: 1.02-1.15, p = 0.012 in stage 3) and TG (OR: 1.11, 95% CI: 1.01-1.22, p = 0.036 in stage 1; OR: 1.09, 95% CI: 1.03-1.15, p = 0.002 in stage 2; OR: 1.07, 95% CI: 1.01-1.13 p = 0.015 in stage 3) positively correlated with psoriasis, and there had no correlation between HDL-C and psoriasis. The results of the secondary analysis were consistent with the results of primary analysis.

Conclusions

Mendelian randomization (MR) findings provide genetic evidence for causal link between psoriasis and blood lipid. It may be meaningful to monitor and control blood lipid level for a management of psoriasis patients in clinic.

Vitamin D and Calcium Supplementation and Urolithiasis: A Controversial and Multifaceted Relationship

Patients with urolithiasis, and particularly those with hypercalciuria, frequently have a marked reduction of bone mineral content up to the levels of osteoporosis, with a significant increase in bone fracture risk. For these reasons, the indication to prescribe vitamin D and/or calcium supplementations is very frequent in such patients. On the other hand, both calcium supplementation, and even more vitamin D therapy, can worsen the risk of developing urolithiasis by increasing calcium, phosphate, and oxalate urinary excretion. Despite the clinical and practical relevance of this issue, the evidence on this topic is scarce and contradictory. Therefore, some concerns exist about how and whether to prescribe such supplements to a patient with a history of kidney stones. In this narrative review, we resume some pivotal pathophysiological concepts strictly related to the dealt topic, and we draw some considerations and personal opinions on the pros and cons of such prescriptions. Finally, we share with the reader our pragmatic algorithm for handling the urolithiasis risk in patients who have strong indications to be prescribed vitamin D and calcium supplementations.

Causal association of genetically determined circulating vitamin D metabolites and calcium with multiple sclerosis in participants of European descent

BACKGROUND

Vitamin D is an important regulator of calcium. Mendelian randomization (MR) studies exclusively focused on the circulating total 25-hydroxyvitamin D (25(OH)D) as a biomarker of vitamin D status, and have found the causal association between 25(OH)D and the risk of multiple sclerosis (MS). However, it currently remains unclear about the causal association of the 25(OH)D subtypes including 25(OH)D3 and C3-epi-25(OH)D3, as well as calcium with the risk of MS.

METHODS

We performed a two-sample MR study to evaluate the causal association of circulating total 25(OH)D, 25(OH)D3, C3-epi-25(OH)D3, and calcium with the risk of MS using large-scale genome-wide association studies (GWAS) datasets from total 25(OH)D (n = 417,580), 25(OH)D3 (n = 40,562), C3-epi-25(OH)D3 (n = 40,562), calcium (n = 305,349), and MS (14,802 MS and 26,703 controls). We selected five MR methods including inverse-variance weighted (IVW), simple median, weighted median, MR-Egger, MR-PRESSO (Mendelian Randomization Pleiotropy Residual Sum and Outlier), and contamination mixture method.

RESULTS

IVW showed that the genetically increased circulating 25(OH)D level (OR = 0.81, 95% CI: 0.70-0.94, P = 4.00E-03), circulating 25(OH)D3 level (OR = 0.85, 95% CI: 0.76-0.95, P = 5.00E-03), and circulating C3-epi-25(OH)D3 level (OR = 0.85, 95% CI: 0.74-0.98, P = 2.30E-02) were causally associated with reduced risk of MS. However, IVW showed no causal association between circulating calcium level and the risk of MS with OR = 2.85, 95% CI: 0.42-19.53, P = 2.85E-01.

CONCLUSIONS

Our current findings together with evidence from other MR studies support the use of vitamin D but not calcium supplementation for the prevention of MS.

Blood Pressure Mediated the Effects of Urinary Uromodulin Levels on Myocardial Infarction: a Mendelian Randomization Study

Background:

The causal links between urinary uromodulin (uUMOD) and cardiovascular disease (CVD) are still not clarified.

Methods:

We first assessed the relationship between uUMOD and CVD using bidirectional 2-sample Mendelian randomization. Then, multivariable Mendelian randomization and product of the coefficients methods were used to investigate the role of blood pressure in mediating the effect of uUMOD on CVD.

Results:

1-unit higher uUMOD level was associated with a higher risk of myocardial infarction (MI), with an odds ratio of 1.08 ([95% CI, 1.02–1.14]; P =0.009), while MI was not associated with uUMOD levels in reverse. Our study did not support the causal effects of uUMOD on other CVD outcomes, including coronary artery disease, atrial fibrillation, heart failure, and ischemic stroke. In multivariable Mendelian Randomization, the direct effects of uUMOD on MI were attenuated to null after introducing systolic blood pressure or diastolic blood pressure. Mediation analysis showed that the indirect effect of uUMOD on MI mediated by systolic blood pressure or diastolic blood pressure was 1.05 ([95% CI, 1.04–1.06]; mediation proportion=69%) and 1.07 ([95% CI, 1.05–1.08]; mediation proportion=87%), respectively. Similar results were found in sensitivity analysis based on different sets of genetic instruments.

Conclusions:

Our findings provide evidence for the effect of higher uUMOD on increasing blood pressure, which mediates a consequent effect on MI risk in the general population. Further studies are necessary to verify the associations between uUMOD and other CVD outcomes.