The results reveal that once factors including age, sex, smoking status and socioeconomic status were taken into account, fish eaters had a 13% lower risk of coronary heart disease than meat-eaters, while vegetarians had a 22% lower risk.
Meanwhile, vegetarians had a 20% higher risk of having a stroke than meat-eaters. There was no clear effect for fish-eaters.

Being vegetarian 'lowers heart disease risk but increases chance of stroke'
Findings of major UK study have mixed results for those giving up eating meat
There were not enough vegans in the study to make these a separate group, so they were lumped in with the vegetarians.
The study analysed data from more than 48,000 adults in the UK who had signed up to to a study between 1993 and 2001.
A few reasons why vegetarians seem to be at higher risk of stroke are suggested towards the end of the article: less B12, lower cholesterol (although this was also suggested as a reason why they have lower risk for coronary heart disease) and less likely to take blood pressure lowering medication for hypertension.