 |
|
On the Use of Clusters to Determine Environmental Influence on Disease
|
|
| Since this article does not have an abstract, we have provided the first 150 words of the full text and any section headings. |
|
|
|
In the article titled "Clustering of Parkinson Disease: Shared Cause or Coincidence?,"1 3 clusters of Parkinson disease (PD) in Canada were analyzed to come to the conclusion that there is an important role for environmental causation. We disagree with this conclusion since the authors examined outliers while ignoring the population as a whole. Our conclusion is the opposite: that such clusters, while rare, are to be expected in a country the size of Canada, and therefore no conclusion can be drawn regarding environmental factors.
As an illustration, consider 2 of the clusters. In one, a group of 125 worked together in a recording studio, and 4 went on to develop PD. In another, 3 of 7 people in a garment factory developed PD.
The working population of Canada is 16 million. For simplicity, consider Canada divided into either groups of 125 workers or groups of 7 workers. In the first . . . [Full Text of this Article] AUTHOR INFORMATION
Michael Hutchinson, MD, PhD;
Sergey Lebedev, PhD
RELATED ARTICLE
On the Use of Clusters to Determine Environmental Influence on Disease—Reply
Ajit Kumar, Susan Calne, Michael Schulzer, Edwin Mak, Zbigniew Wszolek, Chris Van Netten, Joseph K. C. Tsui, A. Jon Stoessl, and Donald B. Calne
Arch Neurol. 2005;62(2):331-332.
EXTRACT
| FULL TEXT
|
