What you don't know can hurt you after all -- and it might even kill you, too.

Some 80 million Americans suffer from a form of illiteracy that has nothing to do with how well they read.

It's about how they understand -- or fail to understand -- information about their own health, and researchers say those who suffer from "health illiteracy" are more likely suffer from actual health problems and are even at risk for an early death.

Researchers looked at 96 studies on health literacy and found that people with the lowest scores had worse health, more hospitalizations, more ER visits, and a higher death risk than people with adequate health literacy.

Not surprisingly, low-literacy patients also had problems understanding basic health messages as well as difficulties with drug labels and instructions, according to the study in the Annals of Internal Medicine.

In one of the studies in the review, researchers tracked some 3,300 seniors for seven years. During that time, 38 percent of those with low health literacy died, versus just 19 percent of those with adequate literacy.

That's double the death rate over a failure to understand basic health information.

The only problem with the new review is the obvious mainstream bias: It seems anyone who didn't toe the party line was put on the "illiterate" list. For example, the researchers say patients with low health literacy were less likely to get flu shots and mammograms.

Really, now?

Either ignorance is truly bliss -- or these were some of the smartest people in the room, because you don't need flu shots or mammograms to stay healthy.

Health literacy isn't about blindly following a doctor's orders, falling for the latest Big Pharma sales pitch, or even getting a flu shot every year. It's about knowing how to sort the good information from the bad.

I'd like to think you already know how to do that, and I hope House Calls plays some small role in keeping you informed so you can continue to make your own decisions.

Make sure your friends and loved ones don't suffer from illiteracy -- forward them a copy of this newsletter.

Who knows... you might even save a life just by hitting the "send" button.