研究病因联系前瞻性调查的价值大于回顾性调查,前者是从“因”推出“果”的,从逻辑上来说其说服力强。本法的基本概念是:按人群暴露的有无或暴露剂量大小来分组,然后随访若干年,观察两组的发病或死亡,计算率并加以比较,求出相对危险度(RR)或标化发病(死亡)率比。前瞻性调查的基 The value of prospective investigation of etiology is greater than that of retrospective surveys. The former is based on the introduction of “fruit” from “cause” and is logically convincing. The basic concept of this law is to classify groups according to whether the population is exposed or exposed to radiation and then follow up for several years to observe the morbidity or mortality, calculate rates, and compare the two groups to find the relative risk (RR) The incidence (death) rate than. Prospective survey of the base