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Despite the
popularity of biomarkers, their use as a tool for measuring human health effects or human
exposures is not always necessary or applicable in other branches of epidemiology. One
reason for this is that there are other epidemiologic methods or study designs that can
serve as more appropriate alternatives. In pharmacoepidemiology, for example, clinical
trials can be used not only to test the efficacy of a therapeutic measure, but also to
monitor the adverse health effects from the dosing. It was mentioned in Slide 9 that in
1747, James Lind was credited with designing one of the first clinical trials. Clinical
(sometimes referred to as human intervention) trials are planned experiments designed to
assess the efficacy of a treatment in man by contrasting the outcomes of a group of
patients or subjects treated with the test treatment with those observed in a comparable
group of patients receiving a control treatment. In the case with James Lind, he used
lemon juice as the treatment for scurvy, which can be caused by vitamin C deficiency. Lind’s
clinical trial was not the very first of its kind. In 1537, French army surgeon Ambroise
Pare (a barber surgeon as well) applied an experimental treatment for battlefield wounds
with a “digestive” made from rose oil, turpentine, and egg yolks (see e.g.,
Friis and Sellers, 1999; Sawyer, 2000). In addition to treatment efficacy, which actually
reflects the effects of dosing or exposure, side effects are often included in a trial as
outcomes of interest. Because side effects are linked to dosing, clinical trials are in
fact a simplified, special version of health risk assessments. |