Could ultraviolet B irradiance and vitamin D be associated with lower incidence rates of lung cancer?
- 1Department of Family and Preventive Medicine 0631C, University of California, San Diego, La Jolla, CA, USA
- 2Sunlight and Nutrition Research Center, San Francisco, CA, USA
- Dr Cedric F Garland, PH, FACE, Department of Family and Preventive Medicine 0631C, University of California, San Diego, La Jolla, CA 92093, USA; cgarland{at}ucsd.edu
- Accepted 31 January 2007
Abstract
Background: This study examines whether insufficient ultraviolet B (UVB) irradiance, a marker of vitamin D inadequacy, might contribute to lung cancer incidence.
Methods: The association of latitude and UVB irradiance with age-adjusted incidence rates of lung cancer in 111 countries was investigated. Independent associations with UVB irradiance, cloud cover, anthropogenic aerosols, and cigarette smoking, were assessed using multiple regression.
Results: Latitude was positively related to incidence rates in men (R2 = 0.55, p<0.01) and women (R2 = 0.36, p<0.01). In men, cigarette consumption (p<0.001) was positively related to risk, whereas UVB irradiance was inversely associated (p = 0.003). There were positive associations with UVB absorbers, in particular cloud cover (p = 0.05) and aerosol optical depth (p = 0.005). The R2 for the model was 0.78 (p<0.001). UVB irradiance was also inversely associated with incidence rates in women (p = 0.0002), whereas cigarette consumption (p<0.001), total cloud cover (p = 0.02) and aerosol optical depth (p = 0.005) were positively associated. The R2 for the model was 0.77 (p<0.001).
Conclusions: Lower levels of UVB irradiance were independently associated with higher incidence rates of lung cancer in 111 countries.
Footnotes
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Competing interests: None declared.
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Funding: This research was supported by a congressional allocation to the Penn State Cancer Institute of the Milton S. Hershey Cancer Center, Hershey, Pennsylvania, USA, through the Department of the Navy, Bureau of Medicine and Surgery, under work unit no. 60126.
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The views expressed in this report are those of the authors and do not represent an official position of the Department of the Navy, Department of Defense, or the US Government.
