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' | Heart disease | The Guardian
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.