Parkinson’s disease accompanies the loss of dopaminergic neurons responsible for synthesising the neurotransmitter dopamine. Dopamine is often known as the molecule that controls motivation through a reward mechanism. Naturally, the chemical earned the reputation of being responsible for addiction, pleasure etc.
An illness negatively correlated with an addiction-causing chemical is thus an ideal candidate for seeing confounding. Let’s take some well-known addictions, namely coffee, smoking and alcohol.
Coffees’ negative correlation with Parkinson’s is something we have seen earlier. Next up is smoking, and lo and behold, smoking is associated with a lower tendency of Parkinson’s disease! Now, I have no choice but to search for alcoholism. This one appears more complex. Most of the studies showed no association or weak negative correlation.
Confounding, is it?
It has all the ingredients to be a confounding phenomenon. But until a new study came up with a mechanistic explanation – Nicotins effect on neuron survival.
