View source for 24. Experimental (interventional) epidemiological studies

* Clinical trials vs field trials
** Clinical trials
*** Are performed on patients
*** Involve treatments
*** Determine secondary and tertiary preventative measures
** Field trials
*** Are performed on healthy people
*** Involve prophylactic measures
*** Determine primary preventative measures
* Randomized control trials (RCT)
** Gold standard of clinical trials
** Steps
*** People from a sample population are randomly allocated into an intervention group and a control group
*** The intervention group is given the drug/therapy/etc.
*** The control group is given a placebo/the current gold standard in therapy/nothing
*** After a period of time the incidence of a specific disease between the two groups is compared
** Blinding
*** No blinding – the researchers and the study participants know which group they belong to
*** Single-blinded – only the researchers know which group the study participants belong to
*** Double-blinded – neither the researchers nor the study participants know who is in the control and who is in the interventional group
** Examples
*** 2 studies tried giving beta-carotene to smokers to see if cancer risk reduced – but the cancer risk actually increased
* Crossover trial
** Similar to RCT, but the people in the control and intervention group switch during the trial period
** This allows the patients to serve as their own controls

[[Category:Public health 2 - General epidemiology and demography]]