The effect of vernal solar UV radiation on serum 25-hydroxyvitamin D concentration depends on the baseline level : observations from a high latitude in Finland

• Published in: International Journal of Circumpolar Health
• Main Authors: Karppinen, Toni, Ala-Houhala, Meri, Ylianttila, Lasse, Kautiainen, Hannu, Lakkala, Kaisa, Hannula, Henna-Reetta, Turunen, Esa, Viljakainen, Heli, Reunala, Timo, Snellman, Erna
• Other Authors: Department of General Practice and Primary Health Care, Clinicum, University of Helsinki, Children's Hospital, HUS Children and Adolescents
• Format: Article in Journal/Newspaper
• Language: English
• Published: International Union for Circumpolar Health 2017
• Subjects: 25(OH)D; vitamin D; ultraviolet; UVB; spring; VITAMIN-D PRODUCTION; HUMAN-SKIN; EXPOSURE; OZONE; SNOW; ALBEDO; COHORT; WOMEN; FACE; MASS; 3142 Public health care science; environmental and occupational health; Circumpolar Health; International Journal of Circumpolar Health
• Online Access: http://hdl.handle.net/10138/193765

Humans obtain vitamin D from conversion of 7-dehydrocholesterol in the skin by ultraviolet B (UVB) radiation or from dietary sources. As the radiation level is insufficient in winter, vitamin D deficiency is common at higher latitudes. We assessed whether vernal solar UVB radiation at latitudes 61 degrees N and 67 degrees N in Finland has an impact on serum 25-hydroxyvitamin D [S-25(OH) D] concentrations. Twenty-seven healthy volunteers participated in outdoor activities in snow-covered terrain for 4-10 days in March or April, with their face and hands sun-exposed. The personal UVB doses and S-25(OH) D levels were monitored. A mean UVB dose of 11.8 standard erythema doses (SED) was received during an average of 12.3 outdoor hours. The mean S-25(OH) D concentration in subjects with a baseline concentration below 90.0 nmol/L (n=13) increased significantly, by 6.0 nmol/L from an initial mean of 62.4 nmol/L (p Peer reviewed