historical cohort study การใช้

• Though historical studies are sometimes referred to as retrospective study, it a misnomer as the methodological principles of historical cohort studies and prospective studies are the same.
• In 2012 a historical cohort study of > 175 000 patients without previous cancer who were examined with CT head scans in UK between 1985 and 2002 was published.
• In a historical cohort study the data concerning exposure and occurrence of a disease, births, a political attitude or any other categorical variable are collected after the events have taken place, and the subjects ( those exposed and unexposed to the agent under study ) are assembled from existing records or health care registers.