为了研究并量化摄入总蛋白、动物蛋白和植物蛋白与全因、心血管疾病和癌症死亡风险之间的潜在剂量反应关系，研究组在PubMed、Scopus和ISI Web of Science等数据库中检索2019年12月之前的数据，筛选出关于18岁以上成人全因、心血管疾病和癌症死亡风险评估的前瞻性队列研究，并进行系统评价和荟萃分析。
Title: Dietary intake of total, animal, and plant proteins and risk of all cause, cardiovascular, and cancer mortality: systematic review and dose-response meta-analysis of prospective cohort studies
Author: Sina Naghshi, Omid Sadeghi, Walter C Willett, Ahmad Esmaillzadeh
Abstract: Objective To examine and quantify the potential dose-response relation between intake of total, animal, and plant protein and the risk of mortality from all causes, cardiovascular disease, and cancer.
Design Systematic review and meta-analysis of prospective cohort studies.
Data sources PubMed, Scopus, and ISI Web of Science until December 2019, and references of retrieved relevant articles.
Study selection Prospective cohort studies that reported the risk estimates for all cause, cardiovascular, and cancer mortality in adults aged 18 or older.
Data synthesis Random effects models were used to calculate pooled effect sizes and 95% confidence intervals for the highest versus lowest categories of protein intake and to incorporate variation between studies. Linear and non-linear dose-response analyses were done to evaluate the dose-response relations between protein intake and mortality.
Results 32 prospective cohort studies were included in the systematic review and 31 in the meta-analysis. During the follow-up period of 3.5 to 32 years, 113039 deaths (16429 from cardiovascular disease and 22303 from cancer) occurred among 715128 participants. Intake of total protein was associated with a lower risk of all cause mortality (pooled effect size 0.94, 95% confidence interval 0.89 to 0.99, I2=58.4%, P<0.001). Intake of plant protein was significantly associated with a lower risk of all cause mortality (pooled effect size 0.92, 95% confidence interval 0.87 to 0.97, I2=57.5%, P=0.003) and cardiovascular disease mortality (pooled hazard ratio 0.88, 95% confidence interval 0.80 to 0.96, I2=63.7%, P=0.001), but not with cancer mortality. Intake of total and animal protein was not significantly associated with risk of cardiovascular disease and cancer mortality. A dose-response analysis showed a significant inverse dose-response association between intake of plant protein and all cause mortality (P=0.05 for non-linearity). An additional 3% energy from plant proteins a day was associated with a 5% lower risk of death from all causes.
Conclusions Higher intake of total protein was associated with a lower risk of all cause mortality, and intake of plant protein was associated with a lower risk of all cause and cardiovascular disease mortality. Replacement of foods high in animal protein with plant protein sources could be associated with longevity.