RLong-Term ultraviolet B irradiation at 297 nm with light-emitting diode improves bone health via vitamin D regulation

Ultraviolet radiation is the primary determinant for vitamin D synthesis. Sunlight is inefficient and poses a risk, particularly for long-Term exposure. In this study, we screened the most favorable wavelength for vitamin D synthesis among four types of narrowband light-emitting diodes (LEDs) and then irradiated osteoporosis rats with the optimal wavelength for 3-12 months. The 297 nm narrowband LED was the most efficient. Long-Term radiation increased vitamin D levels in all osteoporotic rats and improved bone health. No skin damage was observed during irradiation. Our findings provide an efficient and safe method of vitamin D supplementation. c 2024 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement.