Overall and age-specific incidence densities and relative hazards of breast cancer (ICD-9∶174) in the diabetes and control groups.

ID, incidence density; CI, confidence interval; HR, hazard ratio; AHR, adjusted hazard ratio.*Based on Poisson assumption.†Based on Cox proportional hazard regression with adjustment for age, geographic area, urbanization status, Charlson’s score, history of hypertension, endometriosis, and abortion, and frequency of medical visit.