A 10-year study of men and women ages 45 and older tracked what kinds of beverages the subjects were drinking and then monitored their health. It found that those who drank one or more diet drinks a day had a risk of stroke that was three times higher than those who drank less than 1 diet drink a week. It’s important to realize that the association between diet drinks and stroke isn’t cause and effect. There may be other reasons why people who drank diet soda were more likely to have a stroke—perhaps they were diagnosed with cardiovascular disease and switched from regular to diet drinks in an attempt to lose weight.
Conclusion—there is weak evidence that sugar substitutes lead to stroke.