There is growing evidence that patients with type 2 diabetes mellitus have an increased risk of developing Parkinson's disease and share similar dysregulated pathways. There is growing evidence that patients with type 2 diabetes mellitus have an increased risk of developing Parkinson’s disease and share similar dysregulated pathways, which suggests the presence of common underlying pathological mechanisms.
Type 2 diabetes develops from insulin resistance, leading to a variety of detrimental effects on metabolism and inflammation. Similar dysregulation of glucose and energy metabolism are early events in the pathogenesis of sporadic Parkinson's disease and to some degree in Alzheimer's disease as well as amyotrophic lateral sclerosis (Lou Gehrig disease). Trials of intranasal insulin administered to patients with mild cognitive dysfunction and early Alzheimer's disease led to improvements in verbal memory and cognition.
For example it is possible to induce a Parkinson disease like in rats, by feeding them with a high fat diet. Scientists in a new publication, aimed to determine whether the risk of Parkinson disease increases as diabetes progresses among patients with type 2 Diabetes mellitus.
Using a nationally representative database from the Korean National Health Insurance System, 2,362,072 individuals with type 2 Diabetes mellitus who underwent regular health checkups during 2009-2012 were followed up until the end of 2018.
There is still no universal agreement on the optimal data needed to create a reliable diabetes severity measure, despite the presence of some diabetes-specific severity indices.
The diabetes severity score parameters included the number of oral hypoglycemic agents, diabetes duration, insulin use, or presence of chronic kidney disease, diabetic retinopathy, or cardiovascular disease.
Each of these characteristics was scored as one unit of diabetes severity and their sum was defined as a diabetes severity score from 0-6.
The scientists identified 17,046 incident Parkinson disease cases during the follow-up. Each component of the diabetes severity score showed a similar intensity for the risk of Parkinson disease.
Diabetes severity, as measured by diabetic complication status, treatment complexity, and duration of diabetes, was strongly associated with an increased risk for Parkinson’s disease. All characteristics indicative of diabetes severity had an additive association with the risk of Parkinson’s disease in patients with type 2 DM. The coexistence of conditions such as retinopathy, nephropathy, CVD, the complexity of diabetes treatments, or the long duration of diabetes was more strongly associated with Parkinson’s disease risk than the presence of a single condition alone. People with a diabetes severity score of 4 or higher had a more than doubled risk of Parkinson’s disease compared with those with a score of 0, and those with a score of 6 had a 2.78-fold increased risk of Parkinson’s disease. These associations became stronger for younger diabetic patients.
Compared with subjects with no parameters, HR values of Parkinson disease were 1.09 in subjects with one diabetes severity score parameter, 1.28 in subjects with two parameters, 1.55 in subjects with three parameters, 1.96 in subjects with four parameters, 2.08 in subjects with five parameters, and 2.78 in subjects with six parameters.
Diabetes severity was associated with an increased risk of developing Parkinson disease. Severe diabetes may be a risk factor for the development of Parkinson disease. Yet this was an observational study, so the association found between the stratification parameters and endpoints may not be causal.