The Influence of Solar-Simulated UV Radiation on Circulating 25(OH)D3, 24,25(OH)2D3 and Their Ratio in Younger and Older Adults
Abstract
1. Introduction
2. Materials and Methods
2.1. Study Cohort
2.2. Simulated Summer Sunlight Exposures
2.3. Parathyroid Hormone and Serum Biochemistry
2.4. Circulating Vitamin D Derivatives Analysis
2.5. Statistical Analyses
3. Results
3.1. 25(OH)D3
3.2. 24,25(OH)2D3
3.3. Vitamin D3 Metabolite Ratio (25-VMR)
3.4. 1,25(OH)2D3
3.5. Molar Ratio of 1,25(OH)2D3 to 24,25(OH)2D3 VMR
4. Discussion
5. Conclusions
Author Contributions
Funding
Institutional Review Board Statement
Informed Consent Statement
Data Availability Statement
Acknowledgments
Conflicts of Interest
References
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Younger | Older | |
---|---|---|
Participants, n | 11 (after 1 withdrew, 2 excluded) | 10 (after 1 excluded) |
Sex: male, female (n) | 7, 4 | 6, 4 |
Age (years) ± SD | 29.5 ± 6.3 | 70.2 ± 3.8 |
BMI (kg/m2) ± SD | 27.1 ± 4.8 | 26.8 ± 5.6 |
Skin type I, II, III (n) | 3, 2, 6 | 1, 2, 7 |
Oral vitamin D intake (IU/day) | 96 ± 10 | 160 ± 22 |
Younger | Older | ||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|
Minimum | Lower Quartile | Median | Upper Quartile | Maximum | Minimum | Lower Quartile | Median | Upper Quartile | Maximum | Normal Range | |
Parathyroid hormone (pmoL/L) | 2.4 | 3.2 | 4.1 | 4.5 | 8.2 | 2.5 | 3.5 | 4.3 | 5.4 | 6.6 | 1.5–7.6 |
eGFR | 77 | 93 | 110 | 114 | 127 | 59 | 66 | 74 | 85 | 131 | >60 |
Sodium (mmoL/L) | 137 | 138 | 139 | 140 | 144 | 137 | 138 | 139 | 140 | 142 | 133–146 |
Potassium (mmoL/L) | 3.9 | 4.2 | 4.2 | 4.4 | 4.6 | 3.6 | 4.1 | 4.2 | 4.5 | 4.7 | 3.5–5.3 |
Urea (mmoL/L) | 3.4 | 4.0 | 4.4 | 5.1 | 7.9 | 4.5 | 5.4 | 5.9 | 6.4 | 7.0 | 2.5–7.8 |
Creatinine (μmoL/L) | 49 | 61 | 73 | 80 | 95 | 52 | 76 | 81 | 84 | 100 | 62–115 (m) 44–97 (f) |
Adjusted Calcium (mmoL/L) | 2.3 | 2.3 | 2.4 | 2.4 | 2.5 | 2.3 | 2.3 | 2.4 | 2.4 | 2.6 | 2.2–2.6 |
Phosphate (mmoL/L) | 0.95 | 1.04 | 1.12 | 1.27 | 1.39 | 0.97 | 1.15 | 1.17 | 1.21 | 1.5 | 0.8–1.5 |
Albumin (g/L) | 46 | 47 | 47 | 48 | 51 | 43 | 45 | 45 | 47 | 48 | 35–50 |
Groups Combined | Younger | Older | |
---|---|---|---|
25(OH)D3 (nmoL/L) | |||
Baseline | 44.2 ± 22.9 * | 37.4 ± 18.9 | 51.7 ± 25.5 |
24 h post-UVR | 47.7 ± 22.3 * | 40.5 ± 18.6 | 54.1 ± 24.3 |
7 d post-UVR | 46.8 ± 21.0 | 41.3 ± 19.0 | 52.7 ± 22.4 |
24,25(OH)2D3 (nmoL/L) | |||
Baseline | 3.8 ± 1.9 ** | 3.2 ± 1.7 | 4.5 ± 2.1 |
24 h post-UVR | 3.8 ± 2.1 ** | 3.1 ± 1.7 | 4.4 ± 2.3 |
7 d post-UVR | 3.7 ± 1.9 | 3.1 ± 1.7 | 4.4 ± 2.0 |
Vitamin D Metabolite Ratio [25-VMR = 100 * (24,25(OH)2D3/25(OH)D3)] | |||
Baseline | 8.8 ± 2.9 | 8.7 ± 2.2 | 8.9 ± 3.7 |
24 h post-UVR | 7.5 ± 2.1 | 7.2 ± 2.2 | 7.7 ± 2.0 |
7 d post-UVR | 7.8 ± 1.0 | 7.2 ± 1.6 | 8.3 ± 1.4 |
1,25(OH)2D3 (pmoL/L) | |||
Baseline | 136.3 ± 37.6 | 145.1 ± 44.7 | 126.7 ± 26.9 |
24 h post-UVR | 137.1 ± 37.9 | 131.0 ± 45.9 | 142.5 ± 30.9 |
7 d post-UVR | 135.2 ± 57.8 | 163.1 ± 59.7 * | 104.6 ± 38.1 * |
Molar ratio of 1,25(OH)2D3 to 24,25(OH)2D3 | |||
Baseline | 56.7 ± 57.7 | 66.0 ± 58.8 | 46.4 ± 57.8 |
24 h post-UVR | 54.1 ± 44.0 | 60.4 ± 47.2 | 48.6 ± 40.5 |
7 d post-UVR | 48.4 ± 39.0 | 68.4 ± 45.1 | 26.4 ± 10.0 |
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Borecka, O.P.; Tang, J.C.Y.; Fraser, W.D.; Rhodes, L.E.; Webb, A.R. The Influence of Solar-Simulated UV Radiation on Circulating 25(OH)D3, 24,25(OH)2D3 and Their Ratio in Younger and Older Adults. Nutrients 2025, 17, 2039. https://doi.org/10.3390/nu17122039
Borecka OP, Tang JCY, Fraser WD, Rhodes LE, Webb AR. The Influence of Solar-Simulated UV Radiation on Circulating 25(OH)D3, 24,25(OH)2D3 and Their Ratio in Younger and Older Adults. Nutrients. 2025; 17(12):2039. https://doi.org/10.3390/nu17122039
Chicago/Turabian StyleBorecka, Oktawia P., Jonathan C. Y. Tang, William D. Fraser, Lesley E. Rhodes, and Ann R. Webb. 2025. "The Influence of Solar-Simulated UV Radiation on Circulating 25(OH)D3, 24,25(OH)2D3 and Their Ratio in Younger and Older Adults" Nutrients 17, no. 12: 2039. https://doi.org/10.3390/nu17122039
APA StyleBorecka, O. P., Tang, J. C. Y., Fraser, W. D., Rhodes, L. E., & Webb, A. R. (2025). The Influence of Solar-Simulated UV Radiation on Circulating 25(OH)D3, 24,25(OH)2D3 and Their Ratio in Younger and Older Adults. Nutrients, 17(12), 2039. https://doi.org/10.3390/nu17122039