As is painfully obvious to us all, researchers have yet to discover just how multiple sclerosis begins in a given individual. The current theories include both environmental and genetic factors as predisposing a person to developing MS. Small studies in the recent past have shown that those MS'ers with early birth order positions (e.g., the first child), have a higher risk of developing MS than their younger siblings.
This gave rise to the the so-called "hygiene hypothesis", wherein younger siblings would be exposed to more illnesses as a child (via their older siblings) and as a result of this more robust immune system 'training,' have a lower risk of developing multiple sclerosis. In other words, these findings supported the role of environmental factors over genetic factors when determining the risk of developing MS.
This new study tested these preliminary findings with a very large data set, looking at nearly 11,000 MS'ers and their 26,000 healthy siblings. The results: Exactly the opposite of what the small studies found-- they conclude that birth order has no link with MS risk. They in fact discovered that for large groups of siblings, the youngest siblings might actually have a higher risk of developing MS.
There are two major takeaways here, one general and one specific:
1) Small studies can provide misleading results, and this can often only be determined by running a much larger experiment
2) According to the researchers, "The data presented here cast no doubt on the importance of environmental factors to MS risk, and suggest that environmental risks for MS must be accounted for by factors that do not affect birth-order position.”
Click "read more" for the link to the article abstract...
Advertisement
Link to Article Abstract
Click here
