Fizzy headlines

Herald (Daily Mail) headline: How just one can of fizzy drink a day raises the risk of developing type 2 diabetes by 50pc. Here’s the research abstract

1. The research was about pre-diabetes, or ‘elevated fasting glucose/impaired glucose tolerance’ as it used to be called, not diabetes.  They aren’t remotely the same thing. According to this other research, so-called pre-diabetes has about a 5-10% chance per year of turning into diabetes and about the same chance of just going away.  About half the people in the study  developed pre-diabetes over a seven-year period, even among those who didn’t drink any soft drinks.
2. The researchers distinguished sugar-sweetened and diet drinks (they saw no suggestion of a risk increase for diet drinks) but did not distinguish fizzy from non-fizzy sugar-sweetened drinks. So the headline divides drinks up in a completely different way from the research. This wasn’t ‘fizzy drink’ research.
3. The research paper reports multiple estimates of the risk increase. Some models said nearly 50%, but some said about 25%.
4. There’s a lot of uncertainty even in the purely mathematical sense: the model that says nearly 50% increase came with an uncertainty interval that goes down to 16%, and the one that says 25% has an uncertainty interval going all the way down to zero.

The research itself is perfectly reasonable, providing a bit more evidence on the risks of high-sugar diet (disclaimer: I know a few of the researchers). Even the story isn’t too bad, but the headline is basically completely wrong.