A population-based cohort study of HRT use and breast cancer in southern Sweden
The overall tumour incidence and breast cancer incidence related to hormone replacement therapy (HRT) were followed in a population-based cohort of 29 508 women, aged 25-65 when interviewed in 1990-92. By the end of the follow up in December 1999, there were 226 611 person-years of observation. A total of 1145 malignant tumours were recorded (expected 1166.6; SIR = 0.98, 95% CI 0.93-1.04). There w