Characterization of Hyperparathyroidism and Vitamin D Deficiency in Obesity
| Status: | Completed |
|---|---|
| Conditions: | Obesity Weight Loss, Other Indications, Endocrine, Gastrointestinal |
| Therapuetic Areas: | Endocrinology, Gastroenterology, Other |
| Healthy: | No |
| Age Range: | 18 - 65 |
| Updated: | 12/22/2018 |
| Start Date: | February 2006 |
| End Date: | July 2007 |
Obese persons are known to have elevated levels of parathyroid hormone (PTH) and low levels
of vitamin D. These hormones are important in regulation of the body's calcium stores and
bone health. We would like to investigate these abnormalities and the accuracy of our current
diagnostic tests by comparing results of standard assays for vitamin D and PTH to more
specific tests, in obese subjects at baseline and as vitamin D is replaced. We will also
compare two standard vitamin D replacement regimens to determine if one is more effective.
This is a pilot study with two parts: Part 1 will compare levels of PTH and vitamin D using
two different assays in obese subjects who have normal vitamin D and those who do not. We
plan to enroll 20 subjects who have normal vitamin D levels and 40 subjects who have vitamin
D insufficiency. All subjects will fill out questionnaires about the amount of calcium and
vitamin D in their diet, and their recent sunlight exposure. We will ask for blood samples so
that we can measure levels of calcium, vitamin D, albumin, creatinine, glucose, insulin and
the different forms of PTH.
Subjects who have vitamin D insufficiency will then be randomized to receive Vitamin D2 or
Vitamin D3 in standard doses for eight weeks, in an open label trial. At four and eight
weeks, these subjects will fill out the above questionnaires and have the blood tests
repeated. For safety purposes, urine calcium will also be monitored.
of vitamin D. These hormones are important in regulation of the body's calcium stores and
bone health. We would like to investigate these abnormalities and the accuracy of our current
diagnostic tests by comparing results of standard assays for vitamin D and PTH to more
specific tests, in obese subjects at baseline and as vitamin D is replaced. We will also
compare two standard vitamin D replacement regimens to determine if one is more effective.
This is a pilot study with two parts: Part 1 will compare levels of PTH and vitamin D using
two different assays in obese subjects who have normal vitamin D and those who do not. We
plan to enroll 20 subjects who have normal vitamin D levels and 40 subjects who have vitamin
D insufficiency. All subjects will fill out questionnaires about the amount of calcium and
vitamin D in their diet, and their recent sunlight exposure. We will ask for blood samples so
that we can measure levels of calcium, vitamin D, albumin, creatinine, glucose, insulin and
the different forms of PTH.
Subjects who have vitamin D insufficiency will then be randomized to receive Vitamin D2 or
Vitamin D3 in standard doses for eight weeks, in an open label trial. At four and eight
weeks, these subjects will fill out the above questionnaires and have the blood tests
repeated. For safety purposes, urine calcium will also be monitored.
Inclusion Criteria:
- Obese subjects with body mass indices greater than 40 kg/m2 or 35 kg/m2 with other
medical conditions secondary to obesity
- Willingness to take vitamin D supplements
- If baseline vitamin D level is >25 ng/ml subjects will be eligible for the control
group
- If baseline vitamin D level is <25 ng/ml subjects will be eligible for one of the two
vitamin D replacement groups
Exclusion Criteria:
- Hypercalcemia
- Kidney disease
- Liver disease
- Malabsorption
- Prior diagnosis of bone disease
- Medical conditions requiring daily use of calcium, antacids, or medications known to
affect bone metabolism or interact with vitamin D
- Hypersensitivity to any formulation of vitamin D
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