In modern contexts, experimentation must consider that many diseases result from multifaceted exposures and follow complex progression pathways. Cessation of exposure as Hill described may not reverse or appreciably slow the progression of disease. In some cases, multiple risk factors, including diet, exercise, smoking, chemical exposures, and genetic predisposition can contribute to disease onset and progression.

Thus, while the combination of these factors may culminate in disease, experimental manipulation of a single contributory factor may or may not result in observable decreases in disease incidence.