Lower rates of colorectal cancer are seen in areas that have more sunlight
The more recent studies included a number of other risk-modifying factors in the analysis including alcohol consumption, smoking, and urban/rural residence.
In Japan, there was an increase in colorectal cancer with decreasing annual solar radiation7.
In Spain, non-melanoma skin cancer mortality rate, an index of lifetime solar UVB irradiance, was significantly inversely correlated with colon and rectal cancer for both males and females; however, latitude was inversely correlated only with rectal cancer8.
Note that ecological studies integrate the effect of solar UVB and vitamin D throughout the entire lifetime.
Page last edited: 22 August 2011
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- Freedman, D. M. Dosemeci, M. McGlynn, K. Sunlight and mortality from breast, ovarian, colon, prostate, and non-melanoma skin cancer: a composite death certificate based case-control study. Occup Environ Med. 2002 Apr; 59 (4): 257-62.
- Garland, C. F. Garland, F. C. Do sunlight and vitamin D reduce the likelihood of colon cancer?. Int J Epidemiol. 1980 Sep; 9 (3): 227-31.
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- Grant, W. B. Lower vitamin-D production from solar ultraviolet-B irradiance may explain some differences in cancer survival rates. J Natl Med Assoc. 2006 Mar; 98 (3): 357-64.
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