It would be interesting to know if such diets also reduce all-cause mortality. That isn't a given. The study is based on questionnaires that also include strokes, heart attacks and diabetes. But those results aren't in the article either, and it seems to be non-trivial to extract them from the linked papers.
[0] https://bmcmedicine.biomedcentral.com/articles/10.1186/s1291...
[1] https://adventisthealthstudy.org/studies/AHS-2