The following study included 7786 participants and the researchers followed the participants for an average time of 13 years (Chen Z, et.al., 2020).

They found that higher total protein intake was associated with higher all-cause mortality mainly explained by higher animal protein intake and cardiovascular disease mortality.

The association of animal protein intake and cardiovascular disease was mainly contributed to by protein from meat and dairy.

higher intake of protein from legumes, nuts, vegetables, and fruits was associated with lower risk of all-cause and cause-specific mortality.

Another study showed that higher plant protein intake is associated with a reduced risk of all-cause and cardiovascular related mortality (QI XX, Shen P, 2020). Higher intake of animal protein was associated with an increased risk of cardiovascular mortality.

References

Chen Z, Glisic M, Song M, Aliahmad HA, Zhang X, Moumdjian AC, Gonzalez-Jaramillo V, van der Schaft N, Bramer WM, Ikram MA, Voortman T. Dietary protein intake and all-cause and cause-specific mortality: results from the Rotterdam Study and a meta-analysis of prospective cohort studies. Eur J Epidemiol. 2020 May;35(5):411-429.

Qi XX, Shen P. Associations of dietary protein intake with all-cause, cardiovascular disease, and cancer mortality: A systematic review and meta-analysis of cohort studies. Nutr Metab Cardiovasc Dis. 2020 Jun 25;30(7):1094-1105.