Insufficient exposure to ultraviolet radiation may be an
important risk factor for cancer in Western Europe and North
America, according to a new study published in the prominent
Cancer journal that directly contradicts official advice about
The research examined cancer mortality in the United States.
Deaths from a range of cancers of the reproductive and digestive
systems were approximately twice as high in New England as
in the southwest, despite a diet that varies little between
An examination of 506 regions found a
close inverse correlation between cancer mortality and levels
of ultraviolet B light. The likeliest mechanism
for a protective effect of sunlight is vitamin D, which is
synthesized by the body in the presence of ultraviolet B.
The study's author, Dr William Grant (firstname.lastname@example.org)
, says northern parts of the United States may be dark enough
in winter that vitamin D synthesis shuts down completely.
While the study focused on white Americans, the same geographical
trend affects black Americans, whose overall cancer rates
are significantly higher. Darker skinned people require more
sunlight to synthesize vitamin D.
There are 13 malignancies that show this inverse correlation,
mostly reproductive and digestive cancers.
The strongest inverse correlation is with breast, colon, and
Other cancers apparently affected by sunlight include tumors
of the bladder, uterus, esophagus, rectum, and stomach.
Cancer March 2002;