Frequency and association of self-reported oral cancer among individuals with type 2 diabetes at a tertiary care diabetes centre in South India - A retrospective study

Aim: To assess the frequency of self-reported oral cancer and associated factors among individuals with type 2 diabetes (T2D) at a tertiary care diabetes centre in South India. Methods: Individuals with T2D who reported that they had oral cancer were included from the Diabetes Electronic Medical Records (DEMR) database. To assess the association of oral cancer with T2D, a retrospective nested case-control study design was adopted. Individuals with T2D and oral cancer diagnosed after the diagnosis of T2D (n = 78) were considered 'cases', while T2D without oral cancer were considered 'controls' (312) [in a ratio of 1:4 for cases and controls]. The cases and controls were matched for age, gender and duration of diabetes. Logistic regression was used to model predictors of oral cancer in T2D patients. Results: Oral cancer was reported in 78 out of 379,138 (0.02%) individuals with T2D registered at the centre. Logistic regression analysis showed that a HbA1c value >= 9% had a significant association with oral cancer with an odds ratio of 2.3 (95% CI: 1.2-4.6) after adjusting for confounding factors. Among individuals with T2D, higher frequency of oral cancer prevalence and risk was observed among those who used any form of tobacco (32.6%, OR = 2.52, 95% CI: 1.5-4.3), consumed alcohol (29.2%, OR = 2.01, 95% CI: 1.2-3.3), and those with hypertension (23.9%, OR = 2.05, 95% CI: 1.2-3.6) and hypertriglyceridemia (24.7%, OR = 1.66, 95% CI: 1.01-2.7). Significant independent predictors of oral cancer among T2D were tobacco use (OR = 2.06, 95% CI: 1.1-4.00), high HbA1c (OR = 1.3, 95% CI: 1.03-1.5), hypertension (OR = 2.3, 95% CI: 1.3-4.2) and insulin use (OR = 1.8, 95% CI: 1.03-3.2). Conclusions: Regular dental check-ups as part of the follow-up for individuals with T2D will identify and diagnose oral cancer earlier. Further research is required to assess the physiological and biological mechanisms leading to oral cancer in individuals with T2D.