A large-scale, observational study to investigate the current status of diabetes complication and their prevention in Japan: incidence/risk factors for malignancies during follow-up-JDCP study 11 (English version).

In the large-scale, prospective, observational JDCP study, a total of 5944 people with type 2 diabetes (mean age at baseline, 61.4 years old; women, 39.9%; and duration of diabetes, 10.8 years) were followed up for incidence of malignancy. During a mean 5.38 ± 2.92 years of follow-up, malignancies occurred in 322 individuals, accounting for a crude incidence of 10.35/1000 person-years. The 3 most frequently reported malignancies included colorectal cancers (20.4%), breast cancer (16.5%) and lung cancers (13.6%) in women, and gastric cancers (18.3%), colorectal cancers (15.7%) and lung/prostate cancers (12.7%) in men. During follow-up, men had a significantly higher relative risk for malignancy than women. In contrast, women had a significantly shorter time to the first diagnosis of malignancy following a diagnosis of diabetes than men (13.79 ± 7.90 and 17.11 ± 8.50 years, respectively), although there was no marked difference in the age at the diagnosis of malignancy (67.39 ± 7.27 and 68.44 ± 6.62 years, respectively). Cox proportional hazard models revealed that increasing age, a history of drinking and a history of acute myocardial infarction were significantly associated with an increased risk of malignancy. This report may be of interest in that it provides valuable insight into which malignancies Japanese people with type 2 diabetes are likely to be at risk of developing over time.