patients from dialysis clinics

Inclusion Criteria:

• Aged 18 years or older;
• Chronic maintenance dialysis of at least 3 months' duration;
• Mental competence;
• Willingness to participate in the study;
• Calcidiol levels within normal range.

Exclusion Criteria:

• Pregnancy;
• Systemic illnesses or organ diseases that may affect bone (except type 1 or type 2 diabetes mellitus);
• Clinical condition that may limit study participation (e.g., unstable angina, respiratory distress, infections).
• Chronic alcoholism and/or drug addiction;
• Participation in a study of an investigational drug during the past 90 days;
• Allergy to tetracycline.
• Planning to move out of the area within 2 years of the study;
• On active transplant list;
• Treatment within last 6 months with drugs that may affect bone metabolism (except for treatment with calcitriol, vitamin D analogs and/or calcimimetics).
• Calcidiol level below the normal range. The current routine clinical practice in our dialysis clinics is to check calcidiol status twice yearly and supplement with vitamin D according to serum calcidiol levels. It is therefore unlikely that a substantial number of patients will be excluded due to this exclusion criterion.