Influenza, solar radiation and vitamin D

Dermatoendocrinol. 2009 Nov;1(6):307-9. doi: 10.4161/derm.1.6.11357.


The annual death numbers of influenza and pneumonia in Norway were studied for the time period 1980-2000. No direct relationships were found with the variations of the annual UVB fluences, probably due to the fact that these variations did not exceed 30%. However, there was a very pronounced seasonal variation of both influenza deaths and pneumonia deaths, the vast majority occurring during the winter. Vitamin D levels were also estimated from several publications. The data support the hypothesis that a high vitamin D level, as that found in the summer, acts in a protective manner with respect to influenza as well as pneumonia. The findings are discussed and compared with data from tropical and subtropical areas.

Keywords: UVB radiation; influenza; pneumonia; solar radiation; vitamin D.