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The latest on vitamin D and cancer:
Dr William Grant's brilliant review.
Dr William Grant, who writes and compiles
research as fast as I can read it, gave me a tremendous
assist in keeping me abreast of the current research as I
wrote my book.
His latest paper is entitled "How strong
is the evidence that solar ultraviolet B and vitamin D
reduce the risk of cancer?"
An examination using Hill's criteria for
causality[1]
Although the link between vitamin D deficiency
and cancer should well-established, there are those who
stubbornly demand more proof while millions more die of
cancer caused by vitamin D deficiency.
In this paper, there is sufficient proof
to convince all but the most biased reader.
He uses a well-accepted scientific
assessment, known as Hill's criteria for causality, which
determines whether the presence or absence of one factor
causes the presence of another.
In this case the "causal" factor is
vitamin D deficiency, and the caused factor (result) is
cancer.
Here are the qualifications for causality
as established by Dr. A Bradford Hill:
1. Strength of association
2. Consistency (repeated observation)
3. Specificity (one agent, one result)
4. Temporality (exposure precedes effect)
5. Biological gradient (dose-response
relation)
6. Plausibility (e.g., mechanisms)
7. Coherency (no serious conflict with the
generally known facts
of the natural history and biology of the disease)
8. Experimental verification (randomized,
controlled trial)
9. Analogy with other causal relationships
Using these criteria, Dr. Grant discusses
the voluminous research pointing out that the vitamin
D-deficiency theory of cancer causality in most deadly
cancers satisfies most, if not all, of Hill's criteria.
In other words, there is little doubt that
vitamin D deficiency is a primary cause of cancer.
For those who are scientifically inclined,
I suggest you read the paper, which you can find online by
searching the citation below.
If you are not so inclined, take my word
for it; this paper makes an irrefutable case.
Neglect your sunlight and your optimal
vitamin D levels at your peril.
But remember, never burn!
[1] Grant, W. How strong is the evidence
that solar ultraviolet B and vitamin D reduce the risk of
cancer? An examination using Hill’s criteria for causality
Dermato-Endocrinology 2009:1:14-21.
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