You can’t read about a health study without seeing the phrase “such and such is linked to such and such” or it’s variation of “such and such is associated with such and such.”
If you read “driving a car is associated with heart disease,” what would you think? You would probably think “Well, that’s a load of BS,” but you would be wrong. Or you would probably be wrong…I haven’t seen a study that links driving a car to heart disease, but I think it’s a pretty safe bet that most people who have heart disease also drive cars.
The problem with “linked to” and “associated with” is that people think that means the same thing as “such and such causes such and such.” Guess what? It doesn’t.
When a behavior is “linked to” or “associated with” a certain outcome (like obesity, diabetes, cancer or premature death), all that means is that behavior and that outcome were observed as happening in the same people more than it doesn’t happen.
Driving a car and heart disease presents a kind of apples and oranges scenario. Those two things so clearly don’t seem to go together, that you simply don’t believe any suggestion that they do. But what if you put these combos together:
- Exercise and longevity
- Vegetable intake and cancer risk
- Whole grain intake and cholesterol levels
You wouldn’t bat an eye, would you? Well, each of those behavior-outcome combos has been examined in more than one study, and yes, links have been found and associations have been made. But what about cause and effect?
Specifically, what about all of those associations between whole grains and heart disease, whole grains and type 2 diabetes, whole grains and colon cancer, whole grains and body weight. Associations, yes, but cause and effect? Well look at the details tomorrow.