Study Details Cancer Incidence, Mortality in Type 1 Diabetes from UK

Results from an analysis of data related to a cohort of 23,000 patients with type 1 diabetes are offering new insight into cancer incidence and mortality among this patient population.

An analysis of data from registries of UK-resident patients with insulin-treated diabetes, results of the study indicate patients with type 1 diabetes were at significantly increased risks for ovarian and vulval cancers, with this risk most apparent in those diagnosed at 10-14 years, which investigators suggest could be indicative of the susceptibility of these organs at puberty to metabolic disruption.¹

“Our large cohort of patients with type 1 diabetes has shown significantly raised risks of ovarian and vulval cancers, greatest in patients diagnosed with diabetes at ages 10 to 14, the usual ages at puberty in the UK, and an overall diminished risk of cancer, reflecting diminished risks of smoking and alcohol-related cancers, likely because of healthier lifestyles in these respects of the diabetes patients, and of prostate cancer, which might be connected to the reduced testosterone levels in men with diabetes,” wrote investigators.¹

As investigators noted within their study, cancer incidence and mortality among type 2 diabetes has been a focal point of numerous research efforts. An example of this is a January 2023 study in Diabetologia, which assessed cancer mortality rates in people with type 2 diabetes using the Clinical Practice Research Datalink and provided evidence of constant upward trends in mortality rates for pancreatic, liver, and lung cancer at all ages from 1998-2018.²

In the current study, a team of investigators, which was led by Anthony Swerdlow, PhD, MPH, of the Division of Genetic and Epidemiology at the Institute of Cancer Research, sought to explore the cancer incidence and mortality in people with type 1 diabetes using long-term follow-up data, with a specific interest in examining the effect of age at diagnosis. With this in mind, investigators designed the study as an analysis of data recorded among people with insulin-treated diabetes diagnosed between 1972-1993 from multiple registers of UK-based patients.¹

The final study cohort contained 28,531 patients. Investigators pointed out 20,444 were diagnosed at aged of 20 years or less and 15,476 were male. Investigators also pointed out this cohort had a mean follow-up time of 30.1 years per subject, with a cumulative follow-up period of 859,230 person-years. During the follow-up period, 8094 patients died, 1146 emigrated, 345 were censored when they reached age 85 years, and 18,946 reached the follow-up end date alive and aged under 85 years.¹

Upon analysis, results indicated those aged less than 30 years at cancer diagnosis had significantly increased risks for ovarian (Standardized incidence ratio [SIR], 1.53 [95% confidence interval [CI], 1.16-2.11]; P <.01) and vulval (SIR, 3.55 [95% CI, 1.94-5.96]; P <.001) cancers. Further analysis demonstrated this apparent increase in risk became even greater when diabetes is diagnosed at ages of 10-14 years. In contrast, the risks of cancer overall and site-specific cancers, including lung and larynx, were significantly lower among those with type 1 diabetes (SIR, 0.89 [95% CI, 0.84-0.95]; P <.001).¹

In subgroup analyses, patients diagnosed with diabetes at ages 30-49 years had significantly elevated risks for liver (SIR< 1.76 [95% CI, 1.08-2.72]) and kidney (SIR, 1.46 [95% CI, 1.03-2.00]) cancers. Investigators highlighted this subgroup also had a decreased risk of cancer overall (SIR, 0.89 [95% CI, 0.84-0.95]).¹

“Unlike other studies, analyses were possible on age at diabetes diagnosis. Risks were significantly raised for incidence of ovarian and vulval cancers especially if diabetes was diagnosed at ages 10 to 14, that is, likely around puberty, but were significantly decreased for cancer overall,” investigators added.¹

References:

1. Swerdlow AJ, Jones ME, Slater SD, et al. Cancer incidence and mortality in 23 000 patients with type 1 diabetes in the UK: Long-term follow-up [published online ahead of print, 2023 May 15]. Int J Cancer. 2023;10.1002/ijc.34548. doi:10.1002/ijc.34548
2. Campbell P. 20-year study finds cancer mortality on the rise people with type 2 diabetes. HCP Live. January 25, 2023. Accessed May 16, 2023. https://www.hcplive.com/view/20-year-study-finds-cancer-mortality-on-the-rise-people-with-type-2-diabetes.