Worthless study.
I hate narrow studies that focus on one aspect of a potentially bad life style. I could do a study that concludes spicy foods lead to higher unemployment rates if I narrow the focus enough.
Everyone with a high school diploma earned before 1980 knows that eating a lot of red meat is bad. Any extreme in eating has the potential to be bad. Vegans are among the highest users of health care in some states. Does that make a vegan life style inherently bad? No.
Yet there are hundreds of babies a year in the US that are born to vegan couples that are suffering with old and forgotten problems like scurvy and rickets because the kids are more malnourished than an average Ethiopian. A strong case can be made for NOT putting growing children on a vegan diet.
Going back to an earlier point. With our crappy school systems is it any wonder people have no clue how to eat a balanced diet?