C3-Epimer of 25-Hydroxyvitamin D3 as a Superior Marker for Predicting the Severity of Chronic Kidney Disease in Rheumatoid Arthritis Patients

Differential performance regarding the relationship of C3-epi-25(OH)D3 levels and %C3-epi-25(OH)D3 with common pediatric diseases: a case control study

BACKGROUND

Recently, the C3-epimer of 25-hydroxyvitamin D [C3-epi-25(OH)D] has become a topic of interest among 25-hydroxyvitamin D [25(OH)D] metabolites. Although it can lead to an overestimation of vitamin D storage, its relationship with disease occurrence remains controversial, possibly related to the great extent of tracking of 25(OH)D by C3-epi-25(OH)D over time. This study aimed to investigate the differential performance of C3-epi-25(OH)D3 and its percentage [%C3-epi-25(OH)D3] with respect to 20 common paediatric diseases.

METHODS

This study involved 805 healthy children and adolescents and 2962 patients with common paediatric diseases. We investigated sex, age, and seasonal differences in C3-epi-25(OH)D3 and %C3-epi-25(OH)D3 levels; their variations on 20 common paediatric diseases; and their degree of correlation with 25(OH)D3 levels and various diseases.

RESULTS

Among the healthy underage participants, C3-epi-25(OH)D3 and %C3-epi-25(OH)D3 changed similarly, with no sex differences. Moreover, their levels were higher in the infant period than in the other periods (t = 5.329-5.833, t = 4.640-5.711, all Padj < 0.001), and in spring and summer than in autumn and winter (t = 3.495-6.061, t = 3.495-5.658, all Padj < 0.01). Under healthy and disease conditions, C3-epi-25(OH)D3 was positively correlated with 25(OH)D3 (ρ = 0.318 ~ 0.678, all P < 0.017), whereas %C3-epi-25(OH)D3 was not, except in patients with nephrotic syndrome (ρ=-0.393, P = 0.001). Before and after adjusting for 25(OH)D3, the relationship of C3-epi-25(OH)D3 with the diseases was notably different. However, it was almost consistent for %C3-epi-25(OH)D3. Our results indicated that %C3-epi-25(OH)D3 was associated with short stature, nephrotic syndrome, lymphocytic leukaemia, rickets, paediatric malnutrition, and hypovitaminosis D (OR = 0.80 ~ 1.21, all P < 0.05).

CONCLUSIONS

The %C3-epi-25(OH)D3 can correct the properties of C3-epi-25(OH)D3 to better track 25(OH)D3 and may be more suitable for exploring its pathological relevance. Further detailed studies of each disease should be conducted.

Association between serum 25-hydroxyvitamin D and asthma: Evidence from the National Health and Nutrition Examination Survey (NHANES) 2011-2018

BACKGROUND AND OBJECTIVE

Asthma is a heterogeneous respiratory disease characterized by airway hyper-responsiveness and reversible airflow blockage. There is ongoing debate about the impact of vitamin D on asthma. This research is focused on investigating the correlation between serum levels of 25-hydroxyvitamin D and asthma.

METHODS

This cross-sectional study comprised 22,708 eligible participants. Data on asthma and serum 25-hydroxyvitamin D levels from the National Health and Nutrition Examination Survey (NHANES) 2011-2018 were analyzed. Serum 25-hydroxyvitamin D levels were the main factor, with the presence of asthma as the outcome variable. Weighted logistic regression was utilized to investigate the relationship between serum levels of 25-hydroxyvitamin D and asthma, while accounting for factors such as age, gender, race, length of time in US, annual family income, education level, high-density lipoprotein, low-density lipoprotein, triglycerides, and cholesterol.

RESULTS

Upon adjusting all variables in model III, epi-25-hydroxyvitamin D3 displayed a negative correlation with current asthma at the lower quartile Q1 (0.784, [0.697 to 0.922]), Q2 (0.841, [0.729 to 0.946]), Q3 (0.396, [0.240 to 0.653]) when compared to the highest quartile Q4 level. However, no significant difference was observed between asthma and 25-hydroxyvitamin D2, as well as 25-hydroxyvitamin D3.

CONCLUSIONS

In the U.S. population, elevated levels of epi-25-hydroxyvitamin D3 are correlated with an increased risk of developing existing asthma. However, it is important to interpret this finding carefully given the constraints of cross-sectional studies.

C3-epi-25(OH)D3 percentage, not level, may be a potential biomarker to reflect its pathological increase in multiple diseases: a cross-sectional case-control study

National surveys in developed countries have examined the presence of C3-epimer of 25-hydroxyvitamin D3 [C3-epi-25(OH)D3]. However, controversy remains regarding its association with disease occurrence due to its high correlation with 25-hydroxyvitamin D3 [25(OH)D3]. This study aims to investigate whether %C3-epi-25(OH)D3 can serve as an indicator for this relationship with various diseases. A total of 3086 healthy participants and 4120 patients were included in this study. We investigated the association between C3-epi-25(OH)D3 and %C3-epi-25(OH)D3 levels with gender, age, and season; compared the performance of C3-epi-25(OH)D3 and %C3-epi-25(OH)D3 across different disease conditions; and explored the correlation between %C3-epi-25(OH)D3 and various diseases. Results indicated that C3-epi-25(OH)D3 varied significantly by gender, age, and season (z/χ2 = 3.765, 10.163, and 150.975, all P < 0.01), while only season for %C3-epi-25(OH)D3 (χ2 = 233.098, P < 0.001). In contrast to the significant decrease in C3-epi-25(OH)D3, %C3-epi-25(OH)D3 showed a significant increase in 8 out of 11 disease categories (z = 3.464 ~ 11.543, all Padj < 0.05). Similar opposite changes were also observed in most of the investigated 32 specific diseases. Moreover, an elevation in %C3-epi-25(OH)D3 was found to be significantly associated with 29 specific diseases both in univariate analysis (OR = 1.16 ~ 2.10, all P < 0.05) and after adjusting for gender, age, and season (OR = 1.15 ~ 1.50, all P < 0.05). However, after further adjustment for 25(OH)D3 levels, the association remained significant only for 15 specific diseases (OR = 1.11 ~ 1.50, all P < 0.05). Seasonal stratification analysis further supports the consistent association of %C3-epi-25(OH)D3 with disease across all or nearly all four seasons. In conclusion, %C3-epi-25(OH)D3 may better reflect the production of C3-epi-25(OH)D3 in disease conditions, thereby offering a more applicable approach to investigate its association with diseases. However, the interpretation of this relationship may be confounded by 25(OH)D3 as a potential covariate.

Causal Associations between Vitamin D Levels and Psoriasis, Atopic Dermatitis, and Vitiligo: A Bidirectional Two-Sample Mendelian Randomization Analysis

BACKGROUND

Vitamin D level has been reported to be associated with psoriasis, atopic dermatitis, and vitiligo. However, its causal relationship with the risk of these three diseases remains unclear.

METHODS

We obtained genome-wide association statistics for three measures of circulating vitamin D levels (25(OH)D in 120,618 individuals, and 25(OH)D3 and epimeric form C3-epi-25(OH)D3 in 40,562 individuals) and for the diseases psoriasis (3871 cases and 333,288 controls), atopic dermatitis (21,399 cases and 95,464 controls), and vitiligo (4680 cases and 39,586 controls). We performed Mendelian randomization using inverse-variance weighted, weighted median, MR-Egger, and MR-pleiotropy residual sum and outlier methods. We carried out sensitivity analyses to evaluate the robustness of the results.

RESULTS

We showed that elevated vitamin D levels protected individuals from developing psoriasis (OR = 0.995, p = 8.84 × 10-4 for 25(OH)D; OR = 0.997, p = 1.81 × 10-3 for 25(OH)D3; and OR = 0.998, p = 0.044 for C3-epi-25(OH)D3). Genetically predicted risk of atopic dermatitis increased the levels of 25(OH)D (OR = 1.040, p = 7.14 × 10-4) and 25(OH)D3 (OR = 1.208, p = 0.048). A sensitivity analysis suggested the robustness of these causal associations.

CONCLUSIONS

This study reported causal relationships between circulating vitamin D levels and the risk of psoriasis, atopic dermatitis, and vitiligo. These findings provide potential disease intervention and monitoring targets.