<P> Developed and proposed for the first time in England by Dr. Stephen Lewis and Dr. Ken Heaton at the University Department of Medicine , Bristol Royal Infirmary , it was suggested by the authors as a clinical assessment tool in 1997 in the journal Scandinavian Journal of Gastroenterology after a previous prospective study , conducted in 1992 on a sample of the population ( 838 men and 1,059 women ) , had shown an unexpected prevalence of defecation disorders related to the shape and type of stool . The authors of the former paper concluded that the form of the stool is a useful surrogate measure of colon transit time . That conclusion has since been challenged as having limited validity , and only in types 1 and 2 when the subject is not constipated ; however , it remains in use as a research tool to evaluate the effectiveness of treatments for various diseases of the bowel , as well as a clinical communication aid . </P>
where did the bristol stool chart come from
England Dr. Stephen Lewis Dr. Ken Heaton Scandinavian Journal of Gastroenterology