"When looking at people with GERD vs people without, those with GERD are much more likely to have a HH."
When I say, small to moderate HH, that means < 2.5cm. An official link to GERD means that there have been peer-reviewed studies published in recognized journals. Yes, it appears that there is a significant percentage of HH in patients who also have symptoms of GERD, but are you prepared to say that, as a result of this appearance, that it's the HH that causes GERD? Or is it perhaps another pathology (or undiscovered/unrecognized link) that produces both conditions? Do you see the reluctance from the medical community to make the commitment here?
To illustrate this, let's say that, in some patients, HH is an aging phenomenon as the hiatus relaxes and stretches. Let's also say that the LES loses strength as part of the same aging phenomenon, causing reflux. Do you say that the HH causes the GERD, or is it a coincidental pathology as part of an aging factor? Certainly there are other reasons for reflux, so it's difficult to say that something like a HH is the causal factor in *all* instances of the disease.
Given that HH can be produced/observed in poorly-done EGDs (the inflation problem), or misinterpreted by novice GIs, there isn't always clear evidence of a significant HH in patients. So, to draw conclusions based upon sometimes questionable diagnoses is perhaps premature.
I've been to eight doctors in four years, in one university hospital and three major medical centers across the southeastern U.S., as well as audited medical videos of GERD procedures performed by highly-skilled surgeons. I have understood the same comments of HH from all these sources. As much as we'd like to believe to the contrary, the standard of scientific understanding of reflux is not as advanced as we'd always like to think.
It may be true that HH can sometimes cause GERD, but given the hit-or-miss correlations between GERD patients and those with HH < 2.5cm., the jury is still out.