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Identification of the Region of Vitamin D Responsiveness (GRH-PN01)

This study has been completed.
ClinicalTrials.gov Identifier:
First Posted: September 25, 2012
Last Update Posted: September 25, 2012
The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details.
Information provided by (Responsible Party):
Creighton University

Hypothesis: low vitamin D status is associated with increased insulin resistance and increased blood pressure.

Approach: Multiple regression analysis of information extracted from a large database accumulated by a Canadian health foundation, specifically evaluating statistical associations between serum 25(OH)D levels and insulin responsiveness measures as well as blood pressure, after adjusting these variables for BMI, age, sex, and waist circumference.

Diabetes Hypertension

Study Type: Observational
Study Design: Observational Model: Ecologic or Community
Time Perspective: Cross-Sectional
Official Title: A Novel Approach Localizes the Association of Vitamin D Status With Insulin Resistance to One Region of the 25(OH)D Continuum.

Resource links provided by NLM:

Further study details as provided by Creighton University:

Primary Outcome Measures:
  • HOMA-IR [ Time Frame: Observational/cross-sectional study ]
    A composite measure of insulin resistance (HOMA-IR)

Secondary Outcome Measures:
  • Blood pressure [ Time Frame: cross-sectional study ]
    Blood Pressure

Enrollment: 4116
Study Start Date: February 2012
Study Completion Date: February 2012
Primary Completion Date: February 2012 (Final data collection date for primary outcome measure)
Detailed Description:
Data obtained from the entry records of 4,116 adult men and women in Calgary,Alberta previously enrolled in the Pure North S'Energy Foundation's health program. Individuals with a clinical diagnosis of diabetes mellitus or a HOMA-IR value above 16 were excluded. Standard statistical analyses carried out. An association between 25(OH)D and the endpoints of interest was first established. The residual values after adjusting HOMA-IR, serum insulin, QUICKI, and blood pressure for BMI, age, sex, and waist circumference were then regressed against serum 25(OH)D using 40-percentile data blocks, stepping upward from the lowest 25(OH)D values by 5 percentile increments through the 7th decile. Regression coefficients are then computed for each data block and each outcome variable. The location (along the 25(OF)D continuum) of the largest and most statistically significant coefficients is noted, and regions of null response noted as well.

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Ages Eligible for Study:   18 Years to 95 Years   (Adult, Senior)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   Yes
Sampling Method:   Non-Probability Sample
Study Population
Healthy adults living in or near Calgary and associated with the oil and gas industries

Inclusion Criteria:

  • Age > 18

Exclusion Criteria:

  • Diabetes
  • Elevated HOMA-IR (>16)
  Contacts and Locations
Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT01692028

Canada, Alberta
Pure North S'Energy Foundataion
Calgary, Alberta, Canada
Sponsors and Collaborators
Creighton University
  More Information

Responsible Party: Creighton University
ClinicalTrials.gov Identifier: NCT01692028     History of Changes
Other Study ID Numbers: GRH-PN01
First Submitted: September 13, 2012
First Posted: September 25, 2012
Last Update Posted: September 25, 2012
Last Verified: September 2012

Keywords provided by Creighton University:
vitamin D
Associational study

Additional relevant MeSH terms:
Vitamin D
Growth Substances
Physiological Effects of Drugs
Bone Density Conservation Agents