【求助】为什么这篇META没有文献质量评价却能发在lancet？

近日在研究META时，发现一篇META发在了LANCET（IF:30）上，却没有质量评价，想请教各位：
具体如下：
此文发表在LANCET 2006年的某期，题目名为：Fruit and vegetable consumption and stroke: meta-analysis of cohort studies。
除了在纳入标准有一些介绍外，全文再无提到关于quality的说明，更没有相应的质量评价表格：
附：Inclusion and exclusion criteria
For inclusion, studies had to ful?l the following criteria:
have a prospective cohort design; report relative risks or hazard ratios and their corresponding 95% CIs; and provide the frequency of fruit and vegetable consumption. Studies were excluded if: case-control design was used; mixed healthy diet was reported; only two categories of fruit and vegetable intake (eg, daily
vs never) were reported that could not allow for adequate classi?cation of intake.

我目前的解释是：这样的纳入标准已足以证明所纳入的cohort是这个研究这个题目里的最好的文章了，已不再需要质量评价，并且现在的质量评价并不统一。是这样的吗？请教.

附这篇META的全文。