Vitamin D Retrospective Study

This study is ongoing, but not recruiting participants.
Sponsor:
Information provided by (Responsible Party):
Alice S. Ryan, PhD, Baltimore VA Medical Center
ClinicalTrials.gov Identifier:
NCT01798030
First received: February 21, 2013
Last updated: September 5, 2014
Last verified: September 2014
  Purpose

Vitamin D deficiency is associated with a heightened risk for developing type 2 diabetes, hypertension, and osteopenia/osteoporosis. Vitamin D is made in the skin when it is exposed to sunlight and it is also obtained from the diet and dietary supplements. Older people, individuals with high skin pigmentation, obese and sedentary individuals have low levels of Vitamin D because pigmentation blocks Vitamin D production in the skin, aging and physical inactivity are associated with reduced exposure to sunlight, and obesity is associated with the storage of Vitamin D in fat preventing its utilization by muscle, bone and other tissues that require its metabolic action. These conditions are also associated with heightened risk for developing type 2 diabetes, glucose intolerance, hypertension, and osteopenia/osteoporosis in older and obese individuals. This is particularly heightened in older women who tend to have increased body fat, are more physically inactive and are at high risk for central obesity and its metabolic consequences of diabetes, hypertension and osteoporosis.

The heightened prevalence of obesity in aging especially in postmenopausal women suggests that interventions to raise Vitamin D levels might be preventive of these diseases. Investigators have completed studies of the effects of weight loss and exercise interventions in approximately 400 older women and men over the last 15 years, many of whom are obese. Investigators have data on glucose tolerance, blood pressure and bone density in these studies and stored plasma in which investigators can analyze Vitamin D levels. Vitamin D may be an important risk factor for these metabolic diseases and the availability of these samples for Vitamin D analysis will allow investigators to perform a cross-sectional study to address relationships of Vitamin D levels to glucose intolerance and diabetes, hypertension/blood pressure status, bone mineral density, the degree of obesity, and physical activity status measured as maximal aerobic capacity and accelerometry in these older men and women.

The results of this study have the potential to impact clinical practice in the prevention and treatment of diabetes, hypertension, and osteopenia/osteoporosis. This would circumvent the current dilemma for prevention of these chronic diseases through treatment of obesity, as these data would provide immediate prospects for changing the recommended doses of Vitamin D beneficial for reducing risk for these diseases.

The purpose of this study is to 1) determine the prevalence of Vitamin D deficiency in obese, older men and postmenopausal women and 2) the association of Vitamin D levels to glucose tolerance, blood pressure, bone mineral density, and hyperlipidemia, as well as association with Vitamin D receptor gene polymorphisms affecting metabolic responses to Vitamin D.


Condition Intervention
Vitamin D Status
Glucose Tolerance
Blood Pressure
Bone Mineral Density
Hyperlipidemia
Other: Vitamin D

Study Type: Observational
Study Design: Time Perspective: Retrospective
Official Title: Association of Vitamin D With Diabetes, Osteoporosis and Cardiovascular Risk

Resource links provided by NLM:


Further study details as provided by Baltimore VA Medical Center:

Primary Outcome Measures:
  • Vitamin D [ Time Frame: Day 1 ] [ Designated as safety issue: No ]
    Vitamin D level ng/dl


Other Outcome Measures:
  • IGF-1 [ Time Frame: Day 1 ] [ Designated as safety issue: No ]
    Insulin like growth factor

  • IGF binding proteins [ Time Frame: Day 1 ] [ Designated as safety issue: No ]
    Insulin Growth Factor Binding protein levels

  • PTH [ Time Frame: Day 1 ] [ Designated as safety issue: No ]
    Parathyroid Hormone levels


Biospecimen Retention:   Samples With DNA

Vitamin D, IGF-1, and PTH levels will be measured in coded plasma samples belonging to the PI and collaborating Investigators within the GRECC that are stored in our freezers (from previously approved studies: HP-00040261,HP-00040975, HP-00041166 and HP-00041199) . The Nutrition Obesity research center genetics core will determine Vitamin D receptor polymorphisms on de-identified samples. No clinical information will accompany the samples.


Enrollment: 362
Study Start Date: November 2009
Estimated Study Completion Date: September 2015
Primary Completion Date: November 2009 (Final data collection date for primary outcome measure)
Groups/Cohorts Assigned Interventions
Vitamin D
Specimen analysis
Other: Vitamin D
N/A, frozen specimen study

  Eligibility

Ages Eligible for Study:   45 Years to 85 Years
Genders Eligible for Study:   Both
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population

obese, older men and postmenopausal women

Criteria

Inclusion Criteria: 45-85 years of age

Exclusion Criteria: none

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  Contacts and Locations
Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the Contacts provided below. For general information, see Learn About Clinical Studies.

Please refer to this study by its ClinicalTrials.gov identifier: NCT01798030

Locations
United States, Maryland
Baltimore VAMC
Baltimore, Maryland, United States, 21201
Sponsors and Collaborators
Baltimore VA Medical Center
Investigators
Principal Investigator: Alice S Ryan, PhD Baltimore VAMC
  More Information

No publications provided by Baltimore VA Medical Center

Additional publications automatically indexed to this study by ClinicalTrials.gov Identifier (NCT Number):
Responsible Party: Alice S. Ryan, PhD, Professor, Baltimore VA Medical Center
ClinicalTrials.gov Identifier: NCT01798030     History of Changes
Other Study ID Numbers: 43973
Study First Received: February 21, 2013
Last Updated: September 5, 2014
Health Authority: United States: Institutional Review Board
United States: Federal Government

Keywords provided by Baltimore VA Medical Center:
Vitamin D
Diabetes
Osteoporosis
Cardiovascular Risk

Additional relevant MeSH terms:
Hyperlipidemias
Dyslipidemias
Lipid Metabolism Disorders
Metabolic Diseases
Vitamins
Vitamin D
Ergocalciferols
Micronutrients
Growth Substances
Physiological Effects of Drugs
Pharmacologic Actions
Bone Density Conservation Agents

ClinicalTrials.gov processed this record on September 30, 2014