Although the potential effect of glitazones on Parkinson's disease had previously been demonstrated in rodents and in vitro, the authors believe this is the first study to show the relationship between glitazone use and incidence of Parkinson's disease in humans.
The results showed a 28% reduction in incidence of Parkinson's disease among people taking glitazones compared with those taking other antidiabetic treatments. Adjustments for risk factors associated with Parkinson's disease (including smoking and head injury) had no impact on the findings.
The results suggest that the reduced risk of Parkinson's disease was only associated with current treatment with glitazones, and that there is little or no longer lasting benefit if people have taken the drug in the past before stopping or switching to another medication.
The authors note that their study only included patients with diabetes who had not been diagnosed with Parkinson's disease when they started taking glitazones, and therefore they cannot establish whether taking the drug slows or prevents the progression of the disease. They also highlight that glitazones have been associated with some serious side effects.