Socioeconomic Disparities in Cancer Risks Attributed to Diabetes: A Population-Based Study of Finland

Abstract Background Full spectrum of cancer risks attributed to DM have not been investigated accounting for socioeconomic disparities. Methods Total Finnish residents, aged 30+ years at the start of year 2010 were followed-up for cancer incidences until the end of 2021 based on multiple Finnish national registries. The associations between DM and different cancer risks would be estimated using via Cox regression model. Population attributable fractions (PAF) and excess number of cases number (ENC) associated with DM would be estimated across socioeconomic groups. Results Totally 3,290,884 Finnish residents were included in the study. For totally 1.0, 1.2 and 1.1 million subjects with low, medium and high education levels, about 23%, 15% and 11% were diabetic correspondingly. Diabetic individuals demonstrated elevated risks overall cancer (hazard ratio: HR 1.18, %95 CI 1.17-1.19), but the associations vary across socioeconomic groups (low: HR 1.15, %95 CI 1.13-1.16; medium: HR 1.19, %95 CI 1.17-1.20; high: HR 1.21, %95 CI 1.19-1.24). About 3.3%, 2.8% and 2.3% of overall cancer incidence were attributable to DM in samples with low, medium and high education groups correspondingly (ENC 3,756; 2,372 and 1,620). DM were significantly associated with higher risks of cancers of liver, pancreas, stomach, colon, kidney and bladder. Dipartites were observed in cancer risks across socioeconomic groups attributable to DM, especially for liver cancer (low: PAF 27%, ENC 618; medium: PAF 25%, ENC 344; high: PAF 23%, ENC 204) and pancreatic cancer (low PAF 20%, ENC 1000; medium PAF 19%, ENC 612; high PAF 16%, ENC 357). Conclusions DM was associated with increased risks of overall cancer, gastrointestinal cancers, kidney cancer and bladder cancer. Systematic disparities on cancer risks attributable to DM were observed across socioeconomic groups. Further investigations on the onset ages of DM and its effects on different histological types cancers were needed. Key messages • This registry-based study provided a full spectrum of cancer risks attributed to diabetes across socioeconomic groups in Finland. • These finds could support further investigations on cancer prevention associated with diabetes.