Fascinating. But note that these are still very old people with declining cholesterol as they age. The study is more relevant to physicians deciding whether to prescribe statins to their elderly patients, and less relevant to young people deciding whether to keep cholesterol low throughout life with diet.
I'd need to read the whole study, but what I see so far doesn't even contradict the hypothesis I outlined. The abstract says that people who had low cholesterol at the last two examinations did worse than people who had low cholesterol at only the last examination. But most of these old people had declining cholesterol. So maybe this just means that the earlier your cholesterol starts to decline from aging, the sooner you die.
Anyway, I put more stock in the cross-cultural epidemiology and intervention trials, than in these observational studies trying to parse small differences within relatively homogeneous, free-living populations. We know that the longest-lived, healthiest populations in the world ate a low saturated-fat diet that induces low cholesterol. And we know that Dean Ornish was able to reverse heart disease with a lifestyle intervention including a cholesterol-lowering diet. Show me a population as healthy as the Okinawans with high cholesterol, or an intervention as effective as Ornish's without lowering cholesterol, and I'll reconsider. Otherwise, I do consider the issue settled from a pragmatic perspective, even if some of the academic questions remain to be answered. That is, it may be possible to have a healthy lifestyle that raises cholesterol, but we don't have any proven examples of such a lifestyle to emulate, do we? Mike Darwin gave a good explanation of this idea in "Interventive Gerontology".
Discussion of a Norwegian study looking at 50,000 people who didn't have pre-existing heart disease for ten years. http://drmalcolmkendrick.files.wordpress.com/2012/09/mortality-and-cholesterol1.png?w=600&h=309
Here's the study.
Here's the actual conclusion from the study, which dhoe pointed out in comments is considerably milder than the quote above:
However, the chart (the png link above-- I don't know how to make the image appear) shows that the all cause mortality for women was lower if their cholesterol results were higher.
A different big study which also found that low cholesterol was dangerous, but high cholesterol was also dangerous in terms of heart attacks, though mostly for men under fifty, and (I think) not so much for women.
A comment explains that the usual test for cholesterol isn't actually for cholesterol, it's for the lipoproteins which keep all sorts of fat molecules from forming large blobs in a watery environment.
This sort of thing appeals to a number of my prejudices, so I'm hoping to get some more meticulous angles on it from LW.
Post edited to add discussion of the conclusion of the Norwegian study.