Cameron and Pauling Vitamin C
Gave Vitamin C to 100 terminally ill cancer
patients
For each patient found 10 controls matched for
age, gender, cancer
site, and tumor type
Vitamin C patients survived four times longer
than controls
Later randomized study found no effect of vitamin
C
Turns out the control group was formed from
patients already dead
LESSONS:
- observational studies are tricky
-
randomized study is the gold standard
why?