IS GEOLOGY RISKY TO HUMAN HEALTH? HOW DO WE KNOW?
For environmental hazards and chronic disease, it is more complex: multiple risk factors, and weaker relationships require testing associations, not cause. Bradford-Hill's nine criteria were used to show the association between cigarette smoking and lung cancer.
Such research requires large nationally representative datasets with both the risk factors and the outcomes. Statistical techniques include multivariate or multilevel models rather than direct experiments. Tests reveal associations, not cause.
A natural experiment revealed an environmental effect on health when federal researchers used the National Health and Examination Survey to show that eliminating lead in gasoline resulted in a significant reduction in blood lead levels in the US population.
The National Center for Health Statistics hosts many such health datasets, and can link in external datasets with environmental or geologic risk factors, such as air and water pollution data from the Environmental Protection Agency.
Such hazards can be linked through geocoded variables of state, county, census tract, and latitude and longitude. Any kind of environmental hazard data can be linked, if coded by one or more such variables.
If you have a hypothesis on a relationship between geology and human health, we have some data!