A 52-year-old woman presents to her general practitioner with concerns about irregular menstrual bleeding over the past six months. She has a history of obesity, with a BMI of 32 kg/m², and was recently diagnosed with type 2 diabetes mellitus. She reports that her periods have been irregular for the past few years, often skipping months. She is not currently on any hormone replacement therapy. On examination, she has no signs of hirsutism or virilization. Her blood pressure is 140/85 mmHg, and her fasting blood glucose level is 8.5 mmol/L. Which of the following groups of women is most at risk for developing endometrial hyperplasia?