"Eating duration <8 h was linked to 135 % higher cardiovascular mortality, but was not associated with all-cause and cancer mortality."

...

"Although a positive association was observed between eating duration <8 h and cardiovascular mortality, further research is required to understand whether this risk is attributed to the short eating duration itself or residual confounding resulting from its contributing factors."

I think I've seen a preprint of this study discussed a little while back. What some experts(?) were suggesting is to widen the window to something like 10 or 12 hours.