I know this isn't QUITE what you asked, but for what it's worth, my middle "sprout" (15 yrs) has been totally vegetarian/mostly vegansince birth (some lacto-ovo when away from my cooking) and she's very healthy and always has been, as evidenced by physical check-ups from her Doctor. I don't particularly think it's the occasional cheese on her pizza keeping her "healthy" either.
Is she "more" or "less" healthy than her older and younger siblings who have chosen to eat meat (once a month or less, when with their Dad)? I really couldn't say, they've always been very healthy too.
Sorry, I guess none of that helps your survey. Just wanted to throw in my two cents.