Golf, doctors, and Parkinson’s disease

Q: Did you see golf courses cause Parkinson’s Disease?

A: Maybe?

Q: Pesticides. In groundwater.  We should close down the Auckland golf courses!

A: Possibly, but for other reasons.

Q: Aren’t the pesticides bad?

A: There are some pesticides with reasonable links to Parkinson’s Disease, in particular paraquat (actually a herbicide) and organophospates. Most of the evidence in humans comes from farm workers, who get exposed to quite a lot of the stuff

Q: So these could explain the golf courses?

A: They could, but there are other differences between the people with and without Parkinson’s in the study, not just golf courses

Q: Some dude on Twitter said the cases were all near the Mayo Clinic and the controls were from all over

A: That sort of thing, but in fact the research paper includes an analysis with controls just from the same county as the cases, and the results aren’t all that different. It could still be that that the cases lived nearer the medical center; we can’t tell.

Q: So doctors cause Parkinson’s Disease?

A: More the reverse.  The researchers did make sure the cases lived in the right county at the time of diagnosis, but family history can matter, and the cases had seen a doctor more often in previous five years than the controls.  Also, doctors do cause diagnosis of Parkinson’s disease, which is what was measured.

Q: But it might be real?

A: Plausibly, yes.

Q: What about Auckland, then?

A: We get our water mostly from the Waitakeres and the Hunua ranges, which are not topographically suited to golf courses.  And most of the groundwater used in New Zealand is deep enough to be relatively safe.  And NZ is a bit fussier about what herbicides and pesticides we allow.