If at least half of us have H pylori, it is difficult to connect the dots and establish cause and effect. Even the endoscopic study identifying lesions, or not, in the stomach has biases based on reasons for performing the exam. Also, another study showed that eradication therapy did not affect the risk of Parkinson’s. Maybe the horse was already out of the barn.

These associations are important, and the ultimate answer is often surprising. It requires diligent research based on curiosity and an open mind.