I've got a copy of the full article. Looks like they were trolling the Nurses and Health Professionals studies for data. I don't have time to read the entire thing, if anyone wants to take a whack at it, PM me your e-mail.
A few quickies from a 30 second skim:
Data based on dietary recall questionnaires, for both studies these were gathered from participants not more than yearly, some of them several years apart. Don't know about you, but I have trouble remembering what I ate yesterday little less a year from now.
Low carb deciles, lowest seems to be an average of 37.2% carbs - not what I'd call low carb.
Overall lowcarb, animal LC, and plant LC: the lower the carbs consumed the lower the incidence of CHD.
Yes, the plant LC folks did show a lower all cause mortality. For women, 10th decile: Animal - 1328, plant - 1122. For how long this study was and the number of "participants", not a huge gap.
This "study" wasn't specific to the LC diet, it was just a data troll to get publishing credit.