To be conducted at the Karolinska University Hospital, Stockholm. Patients with fb-glucos >6.1 and HbA1c without medical treatment will be included after informed consent and randomised to parathyroidectomy (PTX) within three months or not. The groups will be examined 4 ±4 weeks before and 12±2 weeks after PTX, similar for the control group. The number of participants will be estimated by power calculations based on a pilot study including 20 patients.