Effect does not always equal cause
There are possibly other variables too. Did everyone in the group drink or smoke the same amount for example? Were participants mainly from one demographic? It's conceivable that eating red meat contributes to higher mortality rates IF combined with a specific other factor.
For example, it's like saying that lung cancer gives you yellow teeth. If you look at the number of people with lung cancer, a lot will have discoloured teeth - however, the 'mystery ingredient' so to speak is that the people with lung cancer are more often than not smokers and smoking may be what causes yellow teeth. However it's easy to present the findings I just made up regards the links to cancer and yellow teeth - or vice versa.
It could be that there is a catalyst outside of this study. The red meats for example, were the animals grass fed or grain fed? Were the people with high intake of red meat exercising any less or drinking alcohol with their meals.
All I'm saying is that there is a large margin for error and an even larger margin for making certain outcomes fit certain facts. Having said that, I think the probability is that the findings are to a degree credible, I'm just not so sure it's the specific 'red meat' variable that's the cause. The same as rich people die in more private jet crashes than poor people, therefore I can surmise that there is a direct correlation between excessive wealth and private jet mortality rates :o)
