Insulin resistance under-diagnosed in non-diabetics with Parkinson's disease

August 2, 2018, IOS Press

Almost two-thirds of non-diabetic patients with Parkinson's disease (PD) may be insulin resistant, despite having normal blood sugar, report scientists in the Journal of Parkinson's Disease. Their findings suggest that insulin resistance in PD is a common and largely undetected problem, especially in patients who are overweight.

Reduced glucose tolerance has long been recognized as a potential risk factor for PD, and there is increasing scrutiny of resistance as a pathologic driver of neurodegeneration. The key link between the two conditions appears to be insulin resistance, a potentially reversible condition that not only predisposes individuals to type 2 diabetes (DM2) but is also associated with neurodegeneration. However, the prevalence of insulin resistance in PD is unknown.

"There is growing interest in the study of this relationship and the use of diabetes medications in the treatment of PD. However, there is little information regarding the prevalence of insulin resistance in PD," explained lead investigator Michele Tagliati, MD, from the Department of Neurology, Cedar-Sinai Medical Center, Los Angeles, CA, USA. "This study is the first to address this question in a large population of non-diabetic patients."

Investigators tested 154 non-diabetic PD patients for fasting blood sugar and insulin to assess the prevalence of insulin resistance and to correlate insulin resistance with other metabolic indicators, motor and non-motor symptoms of PD, and quality of life. Based a widely used formula, known as the HOMA index, they determined how many of these patients had a reduced response to their own insulin. Among other measurements, their weight and height were recorded and their movement and cognitive performance were measured.

Results showed that nearly two-thirds of patients (58.4%) had undiagnosed insulin resistance, despite normal fasting glucose and, in many cases, normal hemoglobin A1c (HbA1c), a test that is regularly performed for type 1 and type 2 diabetes. Their data confirmed previous studies that insulin resistance is more than double in obese compared with lean individuals, but the investigators also found a substantially higher percentage (41%) of lean PD patients with insulin resistance. They found no correlation between insulin resistance and cognitive decline.

The potential impact of this study is two-fold. Weight gain and obesity is a major public health challenge and insulin resistance appears linked to body weight. These findings could lead to increased screening of PD patients to detect and correct this condition.

The second and more specific impact is that identifying patients with insulin resistance could allow for personalized medicine, whereby PD patients with insulin may be treated with medications targeted to reverse the condition. Research on the use of diabetic medications for PD, such as GLP-1 agonists like exenatide and liraglutide, is ongoing.

"Now that, for the first time, we understand how common is in non-diabetic with PD, we can begin to address this public health challenge," commented Dr. Tagliati. "This increases the importance of finding new treatments and lifestyle interventions that can address this metabolic dysfunction with multiple implications, from diabetes to neurodegenerative disorders like PD and Alzheimer's disease."

Explore further: Resistance exercise improves insulin resistance, glucose levels

More information: Elliot Hogg et al, High Prevalence of Undiagnosed Insulin Resistance in Non-Diabetic Subjects with Parkinson's Disease, Journal of Parkinson's Disease (2018). DOI: 10.3233/JPD-181305

Related Stories

Resistance exercise improves insulin resistance, glucose levels

April 4, 2018
A new study suggests that resistance exercise may improve indicators of type 2 diabetes by increasing expression of a protein that regulates blood sugar (glucose) absorption in the body. The paper, published ahead of print ...

Insulin resistance may lead to faster cognitive decline

March 21, 2017
A new Tel Aviv University study published in the Journal of Alzheimer's Disease finds that insulin resistance, caused in part by obesity and physical inactivity, is also linked to a more rapid decline in cognitive performance. ...

An increase in low density lipoproteins favors insulin resistance

October 24, 2017
A study led by the University of Barcelona has proved that low-density proteins (VLDL) can worsen insulin resistance, a disease that favours the development of type 2 diabetes. According to the researchers, these results, ...

Research links fatty liver disease to type 2 diabetes

October 18, 2016
Insulin resistance in the liver is a major factor in the development of type 2 diabetes, and it is almost always associated with too much fat in the liver—a condition called non-alcoholic fatty liver disease (NAFLD). The ...

Insulin resistance ups T2D risk, independent of BMI

July 7, 2014
(HealthDay)—A genetic score for insulin resistance is associated with lower body mass index (BMI) and with incident type 2 diabetes (T2D) even among individuals of normal weight, according to a study published online June ...

Intestinal glucose stimulation has anti-incretin effect

September 13, 2017
(HealthDay)—Intestinal glucose stimulation has an anti-incretin effect, down regulating insulin sensitivity, according to a study published online Aug. 29 in Diabetes.

Recommended for you

New transgenic model of Parkinson's illuminates disease biology

October 11, 2018
Parkinson's disease (PD) is a neurodegenerative disorder that presents clinically with abnormal movement and tremors at rest. In the brain, PD is marked by the accumulation of the protein, α-synuclein (αS), into clumps ...

Early Parkinson's patients waiting too long to seek medical evaluation

September 27, 2018
The time between diagnosis and the institution of symptomatic treatment is critical in the effort to find a cure for Parkinson's Disease (PD). A paper published in Nature Partner Journal: Parkinson's Disease notes too many ...

Molecule capable of halting and reverting neurodegeneration caused by Parkinson's disease identified

September 25, 2018
The small SynuClean-D molecule interrupts the formation of the alpha-synuclein amyloid fibres responsible for the onset of Parkinson's disease, and reverts the neurodegeneration caused by the disease. The study, headed by ...

Genomic dark matter activity connects Parkinson's and psychiatric diseases

September 20, 2018
Dopamine neurons are located in the midbrain, but their tendril-like axons can branch far into the higher cortical areas, influencing how we move and how we feel. New genetic evidence has revealed that these specialized cells ...

Gene therapy shown to remove core component of Parkinson's disease

September 14, 2018
An international team led by Rush researcher Jeffrey Kordower, Ph.D., has moved a step closer to developing a treatment to clear brain cells of a protein that is an integral cause of Parkinson's disease. The team published ...

ADHD may increase risk of Parkinson's disease and similar disorders

September 12, 2018
While about 11 percent of children (4-17 years old) nationwide have been diagnosed with attention-deficit hyperactivity disorder (ADHD), the long-term health effects of having ADHD and of common ADHD medications remains understudied. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.