Does body mass index and adult height influence cancer incidence among Chinese living with incident type 2 diabetes?
Background: We investigated the site-specific cancer incidence risks among participants living with newly diagnosed type 2 diabetes (T2D) in relation to body mass index (BMI) and height. Methods: The sample consisted of 25,130 participants living in Ningbo (China) who were newly diagnosed with T2D between 01/01/2006 and 12/31/2007 but without cardiovascular disease or cancer diagnoses at baseline. Follow-up of the sample was from 01/01/2008 to 12/31/2014. Cancer incidence stratified by BMI categories and quartiles of height were analyzed using standardized incidence ratios (SIR; the ratio of observed to the expected number of diagnosed cases) with 95% confidence intervals (95%CI). Results: Follow-up included 22,795 participants, 155,845 person-years and 1063 cancer diagnoses. Compared with the general population of Ningbo, SIRs of all-cancer were 2.19 (95% CI: 2.01-2.37) for males and 1.80 (95% CI: 1.64-1.96) for females. The all-cancer SIRs for participants in the normal BMI category was 1.13 (95% CI: 1.00-1.38). By comparison, the SIRs for the overweight and obese groups were 0.62 (95% CI: 0.26-0.95) and 0.35 (95% CI: 0.03-0.71), respectively. Besides, higher participants had higher all-cancer SIRs. For males, SIRs were 1.08 (95% CI: 0.88-1.27) and 2.41 (95% CI: 2.05-2.78) in the lowest and highest quartiles of height, respectively. For females, SIRs were 1.03 (95% CI: 0.72-1.35) and 2.01 (95% CI: 1.66-2.58) in the lowest and highest quartiles of height, respectively. Conclusion: In this sample of participants living with newly diagnosed T2D, cancer incidence was higher among those who were taller, but also lower among those with higher BMI.