Th17 mediators and vitamin D status in influenza A (H1N1)
Critical Care volume 14, Article number: 417 (2010)
Regarding Bermejo-Martin and colleagues' article  and my comments , the authors concluded in their response that 'vitamin D should thus be considered in the context of a wider spectrum of factors influencing severe disease'. Although this is a reasonable proposal, it should be emphasized that vitamin D has been recognized as an important immuno-modulating factor , and studies show that both obesity  and seasonal sunlight deprivation  play important roles in the severity of influenza, not just in the western countries, where obesity is widely present, but worldwide. Overall better living conditions coupled with a disproportionately better health-care system could explain the absence of a significantly higher incidence of obesity-related critically ill H1N1 patients in the western versus the developing countries.
Regarding the exposure to sunlight, which is well correlated with vitamin D synthesis in the skin, there is a variation throughout the world largely due to differences in the geographical latitude. Populations have adapted to the regional intensity of the solar irradiation in different latitudes through evolutionary changes in skin pigmentation . Hence, when compared to the natives of higher latitudes, people in the tropical regions may require longer periods of a direct skin exposure to intense sunlight to generate physiologically required quantities of vitamin D. The problem of insufficient-solar-irradiation-related vitamin D deficiency becomes prominent particularly in darker-skinned migrant populations when they move to higher latitudes [7, 8]. This could be translated into a higher risk of developing severe illness if exposed and infected by an influenza virus, which should be taken into consideration when treating critically ill patients.
Bermejo-Martin JF, Ortiz de Lejarazu R, Pumarola T, Rello J, Almansa R, Ramírez P, Martin-Loeches I, Varillas D, Gallegos MC, Serón C, Micheloud D, Gomez JM, Tenorio-Abreu A, Ramos MJ, Molina ML, Huidobro S, Sanchez E, Gordón M, Fernández V, Del Castillo A, Marcos MA, Villanueva B, López CJ, Rodríguez-Domínguez M, Galan JC, Cantón R, Lietor A, Rojo S, Eiros JM, Hinojosa C, et al.: Th1 and Th17 hypercytokinemia as early host response signature in severe pandemic influenza. Crit Care 2009, 13: R201. 10.1186/cc8208
Krstić G: Th17 mediators and vitamin D status. Crit Care 2010, 14: 410. 10.1186/cc8894
Cutolo M: Vitamin D and autoimmune rheumatic diseases. Rheumatology 2009, 48: 210-212. 10.1093/rheumatology/ken394
Louie JK, Acosta M, Winter K, Jean C, Gavali S, Schechter R, Vugia D, Harriman K, Matyas B, Glaser CA, Samuel MC, Rosenberg J, Talarico J, Hatch D, California Pandemic (H1N1) Working Group: Factors associated with death or hospitalization due to pandemic 2009 influenza A(H1N1) infection in California. JAMA 2009, 302: 1896-1902. 10.1001/jama.2009.1583
Cannell JJ, Zasloff M, Garland CF, Scragg R, Giovannucci E: On the epidemiology of influenza. Virol J 2008, 5: 29. 10.1186/1743-422X-5-29
Jablonski NG, Chaplin G: The evolution of human skin coloration. J Hum Evol 2000, 39: 57-106. 10.1006/jhev.2000.0403
Hintzpeter B, Scheidt-Nave C, Müller MJ, Schenk L, Mensink GBM: Higher prevalence of vitamin D deficiency is associated with immigrant background among children and adolescents in Germany. J Nutr 2008, 138: 1482-1490.
Genuis SJ, Schwalfenberg GK, Hiltz MN, Vaselenak SA: Vitamin D status of clinical practice populations at higher latitudes: Analysis and applications. Int J Environ Res Public Health 2009, 6: 151-173. 10.3390/ijerph6010151
The authors declare that they have no competing interests.
About this article
Cite this article
Krstić, G. Th17 mediators and vitamin D status in influenza A (H1N1). Crit Care 14, 417 (2010). https://doi.org/10.1186/cc8995
- Influenza Virus
- High Latitude
- Skin Pigmentation