Identification of the Region of Vitamin D Responsiveness

Completed

• Conditions: Diabetes; Hypertension

• Registration Number: NCT01692028
• Lead Sponsor: Creighton University

Brief Summary

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.

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 Timeline

• Study Start: 2012-02
• Primary Completion: 2012-02
• Study Completion: 2012-02
• Status Verified: 2012-09
• Study First Submitted: 2012-09-13
• Study First Submitted QC: 2012-09-21
• Last Update Submitted: 2012-09-21
• Study First Posted: 2012-09-25
• Last Update Posted: 2012-09-25

Recruitment & Eligibility

• Status: COMPLETED
• Sex: All
• Target Recruitment: 4116

Inclusion Criteria

• Age > 18

Exclusion Criteria

• Diabetes
• Elevated HOMA-IR (>16)

Study & Design

• Study Type: OBSERVATIONAL
• Study Design: Not specified

Primary Outcome Measures

Name	Time	Method
HOMA-IR	Observational/cross-sectional study	A composite measure of insulin resistance (HOMA-IR)

Secondary Outcome Measures

Name	Time	Method
Blood pressure	cross-sectional study	Blood Pressure

Trial Locations

Locations (1)

Pure North S'Energy Foundataion; 🇨🇦 Calgary, Alberta, Canada