These are studies of the osteopathic dysfunctions associated with a disease.

Studies with a minimum of 300 cases of the diseases indicated for osteopathy.

They should include:

  • Inclusion and exclusion factors.
  • Random study groups/Control groups.
  • Double or triple-blinded interobserver.

This is a type of case-control, cross-sectional descriptive study with Odds Ratio, (minimum of 300 cases) or cohort study (300 to 500 patients at least in each group).

There are guidelines to talk about causal effect (Bradford Hill).

Hill’s causal relationship: gives cohort study, checks more things, helps to see the incidence.

The cohort study is more difficult than the case-control study. It enables an association to be established but not the incidence.

The cohort study enables the study of temporality (the cause is before the effect), dose-gradient (treatment) / effect (result), consistency (regardless of age, sex, country), the plausibility (it can be explained), experimental reproduction.