SEATTLE – Lots of people swear by acupuncture for all sorts of things, including relieving back aches. Well, there’s an interesting new study out this week that raises some provocative questions about how well acupuncture really works.

Daniel Cherkin of the Group Health Center for Health Studies in Seattle and his colleagues compared four different types of treatment in a randomized clinical trial involving 638 adults with chronic low back pain in Seattle and Oakland, Calif.

The study subjects received one of four treatments: standard medical treatment (including drugs and physical therapy), standard acupuncture treatments, a course of acupuncture tailored to the individual patient by an acupuncturist or simulated acupuncture in which practitioners used a toothpick inside of an acupuncture needle guide tube to mimic the real thing. The participants were then quizzed over the phone after two months, six months and then a year about how their backs were doing.

Now here’s the interesting part. After eight weeks about 40 percent of those who received standard medical care reported feeling better and about 60 percent of those getting acupuncture reported improvement. But it didn’t matter what kind of acupuncture. Even those who got the phony version said they felt better. It was about the same after a year.

So what’s going on? The researchers, who report their findings in this week’s issue of the Archives of Internal Medicine, are withholding judgment. They say it could be that there’s something about even the phony version that stimulates some sort of physiological response that is beneficial. Or it could just be that interacting with an acupuncturist makes people feel better. Or maybe it’s just that people think it works and so they feel better — in other words, the placebo effect.