IntroductionDepression and diabetes commonly co-exist, however the temporal trends in the bidirectional association of both diseases in different sociodemographic setting has not been explored. We investigated the trends in prevalence and likelihood of having either depression or type 2 diabetes (T2DM) in African American (AA, or black) and White Caucasians (WC, or white). MethodsIn this nationwide population-based study, the US Centricity Electronic Medical Records was used to establish cohorts of >2.5 million adults diagnosed with either T2DM or depression between 2006 and 2017. Logistic regression models were used to investigate ethnic differences in: (a) subsequent probability of depression in individuals with T2DM; and (b) subsequent probability of T2DM in individuals with depression; stratified by age and sex. ResultsA total of 920,771 (15 % black) adults were identified with T2DM and 1,801,679 (10 % black) with depression. AA diagnosed with T2DM were much younger (56 vs. 60 years) and had significantly lower prevalence of depression (17 vs. 28 %). AA diagnosed with depression were slightly younger (46 vs. 48 years) and had significantly higher prevalence of T2DM (21 % vs. 14 %). The prevalence of depression in T2DM increased from 12 % (11, 14) to 23 % (20, 23) in black and 26 (25, 26) to 32 (32, 33) in white.Depressive AA above 50 years recorded the highest adjusted probability of T2DM (men: 6.3 % (5.8, 7.0), women: 6.3 % (5.9, 6.7)), while diabetic white women below 50 years had the highest probability of depression (20.2 % (18.6, 22.0)). No significant ethnic difference in diabetes was observed for younger adults diagnosed with depression: black 3.1 % (2.7, 3.7); white 2.5 % (2.2, 2.7). ConclusionsWe have observed significant difference in depression between AA and WC recently diagnosed with diabetes consistent across different demographics. Depression in people with diabetes is increasing with significantly higher values among white women younger than 50 years.