Overweight and obesity were more strongly associated with ER/PR+HER2− breast cancer among postmenopausal women than premenopausal women (Table 3; postmenopausal HR for BMI over 30 kg/m2 = 1.69, 95% CI 1.50–1.91). Here, ESR1 is linked to obesity due to melanocortin 4 receptor deficiency.