<b>Association between age at diabetes diagnosis and subsequent incidence of cancer: a longitudinal population-based cohort</b>

<p dir="ltr"><b>Objective</b></p><p dir="ltr">Diabetes presenting at younger age has more aggressive nature.<b> </b>We aimed to explore the association of age at type 2 diabetes mellitus (T2DM) diagnosis with subsequent cancer incidence in a large Chinese population.</p><p dir="ltr"><b>Research design and methods</b></p><p dir="ltr">The prospective population-based longitudinal cohort included 428,568 newly diagnosed T2DM patients from 2011 to 2018. Participants were divided into six groups according to their age at diagnosis: 20-54, 55-59, 60-64, 65-69, 70-74, ≥75. The incidence of overall and 14 site-specific cancers were compared to Shanghai general population including 100,649,346 person-years.</p><p dir="ltr"><b>Results</b></p><p dir="ltr">A total of 18,853 and 582,643 overall cancer cases were recorded in the T2DM cohort and the general population. The age-standardized rate of overall cancer in T2DM patients was 501 (95% CI: 491, 511) per 100,000 person years and the standardized incidence ratio (SIR) was 1.10 (1.09, 1.12). Younger age at T2DM diagnosis was associated with higher incidence of overall and site-specific cancers. SIRs for overall cancer with T2DM diagnosis at ages 20-54, 55-59, 60-64, 65-69, 70-74, and ≥75 years were 1.48 (1.41, 1.54), 1.30 (1.25, 1.35), 1.19 (1.15, 1.23), 1.16 (1.12, 1.20), 1.06 (1.02, 1.10) and 0.86 (0.84, 0.89) respectively. Similar trends were observed for site-specific cancers including respiratory, colorectum, stomach, liver, pancreatic, bladder, CNS, kidney, gallbladder cancer, and lymphoma among both males and females.</p><p dir="ltr"><b>Conclusions</b></p><p dir="ltr">Our findings highlight the necessity of stratifying management for T2DM according to age of diagnosis. <a href="" target="_blank">As with a range of vascular outcomes, age-standardised cancer risks are greater in younger compared to later onset T2DM.</a></p><p><br></p>