Researchers find association between high insulin dose and cancer in T1D patients
When examining the correlation between daily insulin dose and cancer incidence in patients with type 1 diabetes (T1DM), researchers found that a higher insulin dose is positively associated with cancer incidence in some people compared to the general population.
The researchers also found that this association is stronger in people with insulin resistance.
The result of the study was a study published in the Journal of the American Medical Association (JAMA) Oncology.
“In patients with T1D, our results show that traditional metabolic factors such as obesity (represented by body mass index), sugar control (represented by hemoglobin A1c) and blood pressure control are not associated with cancer incidence,” noted Yuanjie Mao, MD. , Ph.D., a graduate of Peking University with a residency in internal medicine at Cleveland Clinic Akron General and additional training in endocrinology, diabetes, and metabolism at the University of Arkansas.
“However, the incidence of cancer was higher in those who took a higher dose of insulin. Our results implied that clinicians may need to balance the potential risk of cancer when treating patients with diabetes mellitus. type 1 with a high daily insulin dose or that improving insulin sensitivity may be better than just increasing the insulin dose,” Mao added.
To conduct the study, Mao collaborated with Wenjun Zhong, Ph.D., an epidemiologist at Merck Research Labs in West Point, Pennsylvania to analyze associations of more than 50 common risk factors such as smoking, alcohol, exercise, metabolic risk factors, medication use, and family history of cancer incidence in 1,303 patients with T1D whose data was collected over 28 years.
The researchers acquired and analyzed data from the National Institute of Diabetes and Digestive and Kidney Diseases Central Repository. The data acquired included data from the Diabetes Control and Complications Trial (DCCT), which was designed to test the glucose hypothesis and determine whether T1D complications could be prevented or delayed, and its follow-up, the Epidemiology of Diabetes Interventions and Complications (EDIC) observational follow-up study to determine the durability of the effects of DCCT on later stages of diabetes complications.
DCCT was a controlled clinical trial involving 1,441 patients with T1D who were randomized to conventional diabetes treatment or intensive therapy to assess whether reducing high blood sugar would reduce the risk of T1D complications.
Mao also found that age and gender are associated with cancer incidence when assessed separately and that a daily dose of insulin poses a higher cancer risk than age, especially a dose higher insulin.
According to the document, when the daily insulin dose is classified into three groups, low: less than 0.5; medium: greater than or equal to 0.5 or less than 0.8; and high: greater than or equal to 0.8 units/kg per day, the relative risks were significantly higher in the high dose group compared to the low dose group. Cancer incidence was 2.11, 2.87, and 2.91 per 1,000 people in the low, medium, and high dose insulin groups, respectively.
He went on to explain that specifically, women are at higher risk than men; however, it was unclear which risk factors may contribute to the higher cancer incidence in T1D.
“We know that people with type 1 diabetes have a higher incidence of cancer than people without diabetes,” Liz Beverly, Ph.D. co-director of the diabetes institute and professor at Heritage College, said. .
“This research identifies a potential mechanism to explain this association. The findings will lead to further research in this area and potential policy changes in cancer screening and insulin dosing recommendations,” added Beverly.
Although previous studies have concluded that patients with diabetes have a higher risk of cancer in general, this is the first study to explore the cancer incidence factors associated with T1D.
A higher incidence
“T1D accounts for about 5-10% of all diabetes cases, and recent studies of type 1 diabetes have also found a higher incidence of certain cancers such as stomach, liver, pancreatic cancers , endometrium and kidney in the population compared to the general population,” Mao said.
“Whereas, in T2DM, increased risk is attributed to metabolic factors such as obesity, chronic inflammatory state and insulin resistance,” Mao added.
Further investigation is needed
Although the study results suggest that the higher the insulin dose, the higher the incidence of cancer, Mao says further investigation is still needed.
 Zhong W, Mao Y. Daily insulin dose and cancer risk in patients with type 1 diabetes. JAMA Oncol. 2022 July 28. doi: 10.1001/jamaoncol.2022.2960. Epub ahead of print. PMID: 35900757.