High Insulin Doses in People With Type 1 Diabetes Linked to Cancer Risk

Higher insulin doses in people with type 1 diabetes may be associated with an increased risk of cancer, according to a recent study.

The researchers sought to evaluate the risk factors of cancer incidence in people with type 1 diabetes as they noted that no studies have examined this connection.

Data from the Diabetes Control and Complications Trial and the Epidemiology of Diabetes Interventions and Complications was utilized for the study. The researchers looked at data from 1303 patients with type 1 diabetes over a 28-year follow-up period.

Of the total patients in the cohort, 7% (n = 93) had a cancer diagnosis with an incidence rate of 2.8 (95% CI, 2.2 – 3.3) per 1000 people. Patients that were diagnosed with cancer were aged 50 years on average with a mean duration of diabetes of 25 years. The researcher broke down the data further, noting that of the 93 patients diagnosed with cancer, 61% (n = 57) were women and 39% (n = 36) were men.

Within 10 years, 9% (n = 8) patients developed cancer, with 33% (n = 31) of patients developing cancer between 11 and 20 years, and 58% (n = 54) of patients developing cancer between 21 and 28 years.

Additionally, the researchers found that daily insulin dose was associated with cancer risk with the hazard ratio (HR) being significantly higher in the high-dose group vs low-dose group. Cancer incidence was 2.11, 2.87, and 2.91 per 1000 people in the low-, medium, and high-dose group, respectively.

“A limitation of this study is the relatively small sample size, which precluded analyses with specific cancer types and resulted in a wide CI for daily insulin dose,” the researchers concluded. “Moreover, the association found may be subject to residual confounding and was not necessarily causal. Furthermore, larger studies in [type 1 diabetes] are needed to validate this association.

—Jessica Ganga

Reference:

Zhong W, Mao Y. Daily insulin dose and cancer risk among patients with type 1 diabetes. JAMA Oncol. Published online July 28, 2022. doi:10.1001/jamaoncol.2022.2960.