Validity of mortality data for Parkinson's disease.

Accepted for publication 13 April 1999 Although mortality data have been used to examine both the time trends and the geo graphical distribution of Parkinson's disease,12 there are no recent investigations of the validity of such data in the United Kingdom. Studies carried out in the United States of America and elsewhere suggest that there might be a consid erable degree of under-reporting of this diagnosis on death certificates.3 4 We investi gated how fully Parkinson's disease was re corded on death certificates among cases in one area of England between 1966 and 1997.