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Duration of Type 2 Diabetes and Incidence of Cancer
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This study examined the association of age and diabetes duration with the risk of incident cancer in people with type 2 diabetes. The authors analyzed data from the Clinical Practice Research Datalink database in the UK, totaling 130,764 individuals with newly diagnosed type 2 diabetes. There was no association between diabetes duration and the risk of all cancers, obesity-related cancers, and the four common cancers in the UK (colorectal, lung, prostate, and breast).
- This large cohort study involving individuals with type 2 diabetes found no association between diabetes duration and cancer incidence.
abstract
This abstract is available on the publisher's site.
Access this abstract now Full Text Available for ClinicalKey SubscribersOBJECTIVE
To investigate the association between duration of type 2 diabetes and cancer incidence.
RESEARCH DESIGN AND METHODS
In the Clinical Practice Research Datalink database, we identified 130,764 individuals with type 2 diabetes aged ≥35 years at diagnosis who were linked to hospital and mortality records. We used sex-stratified Royston-Parmar models with two timescales to estimate incidence rates of all cancers, the four commonest cancers in the U.K. (colorectal, lung, prostate, breast), and the obesity-related cancers (e.g., liver, ovary) between 1 January 1998 and 14 January 2019, by age and diabetes duration.
RESULTS
During 1,089,923 person-years, 18,977 incident cancers occurred. At the same age, rates of all cancers in men and women did not vary across durations ranging from diagnosis to 20 years; conversely, for any duration, there was a strong, positive association between age and cancer rates. In men, the rate ratio (95% CI) comparing 20 with 5 years of duration was 1.18 (0.82-1.69) at 60 years of age and 0.90 (0.75-1.08) at 80 years; corresponding ratios in women were 1.07 (0.71-1.63) and 0.84 (0.66-1.05). This pattern was observed also for the four commonest cancers. For obesity-related cancers, although rates were generally higher in individuals with a higher BMI, there was no association with duration at any level of BMI.
CONCLUSIONS
In this study, we did not find evidence of an association between duration of type 2 diabetes and risk of cancer, with the higher risk observed for longer durations related to ageing.
Additional Info
Disclosure statements are available on the authors' profiles:
Duration of Type 2 Diabetes and Incidence of Cancer: An Observational Study in England
Diabetes Care 2023 Nov 01;46(11)1923-1930, F Zaccardi, S Ling, K Brown, M Davies, K KhuntiFrom MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
Recent studies have reported that, in the UK, cancer has overtaken CVD as the leading cause of death in individuals with diabetes. In general, longer duration of diabetes increases the risk of complications, such as CVD and renal disease; however, whether it increases cancer risk is unclear. Cancer incidence and diabetes prevalence increase with advancing age, making it difficult to separate the effects of age and diabetes duration on cancer risk. In this study, the authors attempted to disentangle how age and duration of diabetes are associated with the incidence of the most common cancers in the UK and obesity-associated cancers using the Clinical Practice Research Datalink, a primary care database. As anticipated, they found that cancer incidence increased with age, but longer duration of diabetes was not associated with greater cancer risk. In fact, in some cases the cancer risk ratio was lower after 20 years than 5 years of diabetes. These results were contrary to the hypothesis that longer exposure to the metabolic effects of diabetes contributes to cancer, but were consistent with previous international studies that discovered that the greatest risk of cancer is in the initial years after diabetes diagnosis. After the initial years, cancer risk typically declines and then plateaus. The authors discuss potential causes for this phenomenon, including ascertainment bias and reverse causality. However, from a metabolic perspective, individuals with prediabetes and shorter duration of diabetes have more hyperinsulinemia than those with longer duration of diabetes, where β-cell function declines. Therefore, although no mechanistic data are included this epidemiology study, the results add support to the hypothesis that hyperinsulinemia rather than hyperglycemia is a main metabolic contributor to cancer development and growth.