As it happens the vegetarian control group, even if some of them do wear leather shoes, tends to outlive thoseI am sorry, but no such thing happens. There's a lot written on the subject why you can not directly compare "vegetarians" to "everyone else". For example, vegetarians not only do not eat meat, but also smoke and drink less, and exercise more than the general population and are in general more health conscious. So there are many confounding factors involved.
However, if you study people who are vegetarians not for health reasons, but, for example, religion - you suddenly find no health benefits, but rather quite a few increased risks.
Here's one of the articles on the topics, and plenty of scientific links inside for the curious.
http://rawfoodsos.com/2011/01/06/vegetarians-and-heart-disea...
Key quotes for those who like TL;DRs:
The good news for the vegetarians is that their Lp-PLA2—a marker specifically for vascular inflammation—was lower than in the control group. But that’s where the good news ends. The researchers seemed pretty surprised to report that the vegetarians had higher levels of CRP (borderline significant at p=0.05) than the omnivores, along with higher homocysteine and triglycerides.
The surprising results? The vegetarians had significantly thicker arterial walls (p<0.0001), reduced flow-mediated dilation (a predictor of cardiovascular events) (p<0.0001), higher blood pressure (p<0.05), and higher triglycerides (p<0.05) than the omnivores. (According to the paper, the raised blood pressure might be related to some popular high-sodium vegetarian foods such as processed protein food substitutes, fake oyster sauce, and tomato paste.)
In the researchers’ multivariate statistical models, vegetarianism had the strongest association with both artery thickness and diminished flow-mediated dilation out of all the variables documented—including age, gender, and triglyceride levels.
As might be expected, the vegetarians also had lower B12 levels and higher homocysteine than the control group—but even after adjusting for these, vegetarianism remained strongly linked with less-healthy hearts. The researchers concluded with this:
In summary, contrary to common belief, vegetarians, at least in the Chinese, might have accelerated atherosclerosis and abnormal arterial endothelial function, compared with omnivore control subjects. The increased risk could only be partially explained by their higher blood pressure, triglyceride, homocysteine, and lower vitamin B12 concentrations.