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

A Novel Approach Localizes the Association of Vitamin D Status With Insulin Resistance to One Region of the 25(OH)D Continuum.

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.

Study Overview

• Status: Completed
• Conditions: Hypertension; Diabetes

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.

• Study Type: Observational
• Enrollment (Actual): 4116

Contacts and Locations

Study Locations

• Canada
  • Alberta
    • Calgary, Alberta, Canada
      • Pure North S'Energy Foundataion

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 18 years to 95 years (Adult, Older Adult)
• Accepts Healthy Volunteers: Yes
• Genders Eligible for Study: All

• Sampling Method: Non-Probability Sample

Study Population

Healthy adults living in or near Calgary and associated with the oil and gas industries

Description

Inclusion Criteria:

• Age > 18

Exclusion Criteria:

• Diabetes
• Elevated HOMA-IR (>16)

Study Plan

How is the study designed?

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
HOMA-IR	A composite measure of insulin resistance (HOMA-IR)	Observational/cross-sectional study

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Blood pressure	Blood Pressure	cross-sectional study

Collaborators and Investigators

• Sponsor: Creighton University

Study record dates

Study Major Dates

• Study Start: February 1, 2012
• Primary Completion (Actual): February 1, 2012
• Study Completion (Actual): February 1, 2012

Study Registration Dates

• First Submitted: September 13, 2012
• First Submitted That Met QC Criteria: September 21, 2012
• First Posted (Estimate): September 25, 2012

Study Record Updates

• Last Update Posted (Estimate): September 25, 2012
• Last Update Submitted That Met QC Criteria: September 21, 2012
• Last Verified: September 1, 2012

More Information

Terms related to this study

• Keywords: vitamin D; Associational study
• Additional Relevant MeSH Terms: Cardiovascular Diseases; Vascular Diseases; Hypertension
• Other Study ID Numbers: GRH-PN01