This is a research study to investigate cardiovascular health in people with mild hyperparathyroidism. Previous research has suggested that severe hyperparathyroidism may be associated with abnormalities in the heart and blood vessels. It is unclear whether mild hyperparathyroidism affects cardiovascular health. This study involves the investigation of the heart and blood vessels of people with mild hyperparathyroidism. Various non-invasive laboratory and radiological test to assess cardiovascular and bone health will be done at set intervals over the course of 2 years. It is our hypothesis that patients with primary hyperparathyroidism will have subtle abnormalities in their cardiovascular system. Using state-of-the art techniques that are sufficiently sensitive to detect these subtle abnormalities, we will define cardiovascular features of this disease that have, up to now, eluded clear definition. We expect taht the extent of these findings will be related to the severity of the underlying primary hyperparathyroidism. We further hypothesize that cardiovascular manifestations may regress with successful cure of the hyperparathyroid state.

This study involves a total of 4 visits over a 2-year period. A variety of tests to evaluate your cardiovascular and bone health are performed. The details and timing of the tests are explained below.

VISIT #1 During the first visit, a research doctor or assistant explains the procedures in detail and answers questions. Blood is drawn (about 1-2 tablespoons) to confirm the diagnosis of hyperparathyroidism and get baseline blood values.

VISIT #2-4 During the following visits, a variety of procedures are performed to evaluate cardiovascular and bone health. The details of the procedures and when they will be performed are outlined below.

1. Blood tests are performed at each visit. Approximately 1-2 tablespoons of blood will be drawn at each visit.
2. A 24-hour urine collection is done 3 times during the 2 year study.
3. Bone mineral density testing (known as DXA) is performed at baseline, 12 and 24 months after enrollment.
4. Carotid Ultrasound: At the baseline visit, 12 and 24 months after enrollment, carotid ultrasound is performed.
5. Echocardiogram: At the baseline visit, 12 and 24 months after enrollment, an echocardiogram is performed.
6. Endothelial Function: At baseline, 6 and 12 months after enrollment, flow mediated dilation of the brachial artery is performed.

Inclusion Criteria:

-Primary Hyperparathyroidism

Exclusion Criteria:

• Current use of oral bisphosphonates
• Addition or change in cholesterol lowering medication
• impaired renal function (creatinine >2.0 mg/dl)

Adults age 50 to 75 with Primary Hyperparathyroidism