In Saint-Vast-en-Chaussy, near Amiens (Somme), an investigation was launched this week by the Hautes-de-France regional health agency (ARS) after an unusually high number of deaths following Charcot disease were reported. Five people living on the same street died from amyotrophic lateral sclerosis (ALS), a devastating neurodegenerative disease (see our video below).
Simple chance or environmental reasons?
In this town of 500 souls, we wonder. Could this trigger a “cluster”? Are there local, environmental causes that would explain this statistical discrepancy? Dr. For Pierre-Francois Pradat, neurologist and co-president of the Scientific Committee of ARSLA (Association for Research on Amyotrophic Lateral Sclerosis), we should not ignore any phenomenon. However, we must be careful. “We can, and this is often the first hypothesis, explain the concentration of cases in a geographic area by chance. »
A “common rare disease”
Charcot disease is not rare. Certainly, only 8,000 patients in France suffer from it, but this is mainly because the deaths are numerous. “We believe there are 2,500 new cases per year,” says Dr. ALS. Creates a “common rare disease” for the provider. So it is entirely possible that multiple cases can happen at the same place. “It’s a cognitive bias that makes you think that random events will be uniformly distributed. This is not the case. For example, if I take matches and throw them on the ground, there will inevitably be small piles of matches that can be considered clusters, but which are completely random. is. »
In Savoie, during the 2000s, health officials noticed what they initially thought was an ALS cluster. According to some scientists, local mushrooms eaten by local people are to blame. But “investigations were conducted and led to the conclusion that there was no statistically significant increase,” Dr. According to the provider.
Multiple data to study
Because yes, the number of people suffering from Charcot disease was not that high for this region. We should not just look at the death toll, we should put it in perspective with other data.
ALS is a disease that usually develops between the ages of 50 and 70. Is the average age of the local population close to this? When we talk about residents, are we sure that we are not also counting people who have a country house and who come only for a few weeks a year? etc. This is one of the reasons why investigations by health authorities take so long. For now, in Saint-Vast-en-Chaussy, we can only await the results of the investigation.
