As I wrote this kind of observational correlation does not really prove causation. But the story is slightly more complicated. Dr Lustig emailed me yesterday:
Mail from Lustig
Here’s part of the email:
Andreas, read your blog about our study. Wanted to add something for you and your audience.
While this an ecological study on its face, the statistics are from the field of econometrics, and special care was taken to assure dose, duration, directionality, and precedence. Furthermore, we controlled for poverty, urbanization, aging, total calories, all other calories in the diet, obesity, and physical inactivity. The only signal came from sugar, and sugar was 11 times more potent in explaining diabetes worldwide than was total calories.
While not “scientific proof”, this study satisfies all the criteria laid out by Austin Bradford Hill on “medical causal inference” for sugar as a specific cause of diabetes. This is the same degree of “proof” that implicated cigarettes as the cause of lung cancer back in the 1960’s. The cigarette industry obfuscated these results for decades, to our detriment. No doubt, the food industry will try to do the same here.
I asked Lustig if the statistics implicating cigarettes as the cause of lung cancer did not show a stronger effect. Meaning that a pack of cigarettes a day increases the risk of lung cancer a lot more (compared to a non-smoker) than the increased diabetes risk from a few cans of soda.
Here’s Lustig’s reply:
That’s because the baseline was lower to start with. Same with asbestos. The prevalence is almost zero.
But for diabetes and heart disease there is a significant baseline prevalence in the population to begin with. Much harder to show an effect. But it’s there!
And how about adolescents with Type 2? The baseline there is virtually zero. Of course, the IDF database did not collect that, so it is still an open question. But I can tell you, EVERY adolescent with T2DM that I have ever seen was a soda abuser.
Interesting points I think.
I really like this study. Like Lustig says, while this kind of data is far from perfect it’s similar to the evidence implicating cigarettes as the cause of lung cancer.
The question is, how long are we going to let kids drink all the sugar water they want until they get diabetes? Would we let them smoke all the cigarettes they wanted?
Lustig also pointed out that I still haven’t posted a full review of his new book “Fat Chance”. Guilty as charged. I have a dog-eared copy full of notes though. A review is coming up.