Solving the Diet-Cancer Mystery:
Scientific Studies Provide Clues
Epidemiological: Ecologic Studies
Ecologic studies look at diet and cancer at the population level. Think of this as the view from 30,000 feet. For example, you’ve probably heard about studies that found lower cancer rates in Asian communities that consume a lot of fish. Those are ecologic studies.
Strengths of Ecologic Studies
Ecologic studies can provide powerful clues pointing in a particular direction, especially when they compare large populations with different diets.
Weaknesses of Ecologic Studies
Ecologic studies can’t prove cause and effect. If a detective keeps noticing a certain person near the scene of a series of burglaries, he may consider the person a suspect.
But maybe the person is a nosy neighbor, or a reporter. The detective would need more evidence to prove that the person committed the crimes. Similarly, scientists need more evidence–other studies to help prove the connection that ecologic studies point to.