Mary Chris Jaklevic is a reporter-editor at HealthNewsReview.org. She tweets as @mcjaklevic.
Some headlines over the weekend heralded dire-sounding news about HDL, the so-called “good” cholesterol:
But those scary statements are misleading. Here’s why.
The stories are based on an abstract presented at the European Society of Cardiology (ESC) Congress 2018 in Munich, which showed an association between very high HDL and higher incidence of heart-related deaths and heart attacks.
That observational study did not show that having very high HDL caused those bad events.
The headlines stumbled by using that language that suggested a cause-and-effect relationship.
Newsweek continued the misleading causal phrasing in its lead, which said too much HDL “could raise the risk” of heart attacks and death. IANS did better in its lead, which accurately stated high HDL was “associated with” bad events.
Both stories appeared to rely exclusively on an ESC news release that used similar misleading cause-and-effect framing in its headline: “Too much of a good thing? Very high levels of ‘good cholesterol may be harmful.”
It’s not the first time we’ve taken ESC to task. In 2014 the group earned a spot on HealthNewsReview.org’s wall of shame for a different news release that implied a causal relationship between drinking tea and lower mortality.
Significantly, the stories didn’t explain that the research doesn’t change guidance on preventing heart disease.
While there’s a plethora of advice on how to raise your HDL level — like consuming olive oil and hitting the gym — cardiologist Christopher Labos, MD, a HealthNewsReview.org contributor, said via email that there’s no evidence behind it:
“There’s not much you can do about your HDL (much of it is genetic) so it’s not clear what people are supposed to do with this information. The general advice we give everyone about diet exercise and the cardiac risk factors holds true whatever your HDL level is. “
There were other issues with the coverage.
The stories and the news release said people with very high HDL had a nearly 50% increased risk but provided no precise numbers to help readers understand the size of that risk. The coverage conveyed the incidence of bad events for all patients in the study, but did not break it down by HDL level.
Another important point that readers might have missed — since it didn’t appear near the top of the coverage — was that most of the patients in the study already had heart disease.
Both stories ran this provocative quote from lead researcher Marc Allard-Ratich, MD, of Emory University in Atlanta:
“It may be time to change the way we view HDL cholesterol. Traditionally, physicians have told their patients that the higher your ‘good’ cholesterol, the better. However, the results from this study and others suggest that this may no longer be the case.”
But Allard-Ratich gave a more nuanced message during a conference presentation, saying HDL is “very complicated” and “significantly more research” is needed. He said it’s unclear how to intervene with the estimated 1 to 5% of people who have very high HDL.
The researcher also offered fellow clinicians a takeaway message that we’re fairly certain won’t grab any headlines. As always, he said, when it comes to risk factors for heart disease, “focus on on things that we can control such as smoking, drinking, obesity and activity level.”
Please note: Observational studies (as with the research that linked smoking to cancer and other problems) can indeed pile up such overwhelming evidence that it would be prudent to make public health recommendations on that basis. However, it’s rare that observational studies reported in the news media rise to this level of evidence. Moreover, an observational study cannot prove cause and effect. Statistical association is not proof of cause-and-effect. It is not unimportant. But no one should make it more than what it is.