I agree they may be just a correlation- but for me it’s enough to be worried about long-term effects. From what I read from other pieces of research it’s not the artificial sweeteners alone but how they can screw up your metabolism, contribute to insulin resistance and cause problems down the road. Again, I’m not talking about drinking soda once in a while but for those who drink it every day it may not be safe. Here’s another piece of research pointing to the effect of artificial sweeteners on https://www.inc.com/minda-zetlin/diet-soda-weight-gain-metabolism-insulin-brain-fat-metabolic-syndrome.html