Postvoid residual urine volume will be determined by ultrasonic bladder scan. In females, the menopausal status will be verified by history taking (no menses > 1 year) and in case of doubt measurement of FSH-level (cut-off defined as >31 U/L). If subjects are eligible, the investigator will inform them within two weeks after screening. After inclusion, participants will enroll in a 4‐week run‐in period to allow for study effects.