Clinical trial NCT01798030: Vitamin D Retrospective Study and Role With Disease
Official title: Association of Vitamin D With Diabetes, Osteoporosis and Cardiovascular Risk
Study type: OBSERVATIONAL
Overall status: UNKNOWN
Conditions: Vitamin D Status
Glucose Tolerance
Blood Pressure
Bone Mineral Density
Hyperlipidemia
Keywords: Vitamin D
Diabetes
Osteoporosis
Cardiovascular Risk
Lead sponsor: Baltimore VA Medical Center
Sponsor class: FED
First posted: 2013-02-25
Enrollment: 362
Sex: ALL
Minimum age (years): 45
Maximum age (years): 85
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Observational model: OTHER
Time perspective: RETROSPECTIVE
Sampling method: NON_PROBABILITY_SAMPLE
Study population: obese, older men and postmenopausal women

Brief summary: 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.

Detailed description: 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.

Eligibility criteria: Inclusion Criteria: 45-85 years of age

Exclusion Criteria: none

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Primary outcomes:
measure: Vitamin D
timeFrame: Day 1
Secondary outcomes:
Other outcomes:
measure: IGF-1
timeFrame: Day 1
measure: IGF binding proteins
timeFrame: Day 1
measure: PTH
timeFrame: Day 1
Locations:
city: Baltimore
country: United States
facility: Baltimore VAMC
state: Maryland
Study officials:
affiliation: Baltimore VAMC
name: Alice S Ryan, PhD
role: PRINCIPAL_INVESTIGATOR
References:
citation: Sorkin JD, Vasaitis TS, Streeten E, Ryan AS, Goldberg AP. Evidence for threshold effects of 25-hydroxyvitamin D on glucose tolerance and insulin resistance in black and white obese postmenopausal women. J Nutr. 2014 May;144(5):734-42. doi: 10.3945/jn.114.190660. Epub 2014 Apr 9.