Could someone help me with the following question?

Assuming artificial sweeteners are correlated to an increased risk of heart disease (apparently it is, although not that strongly), did they put in other factors to control for eating behaviours etc.?

It seems obvious that people who consume more diet coke also have a less healthy over-all diet than people who stick to water and tea.

(I'm too lazy too read it all... apologies, if it's in there)