Vitamin D Ancillary Study in 5 Populations of African Origin

NCT02111902 | Withdrawn

• 2 other identifiers: 2025381R01DK090360-01A1
• Study Type: observational
• Target: N/A
• Locations: 5 countries
• Sites: 5

Brief Summary

The availability of data on plasma 25-Hydroxyvitamin D (25(OH)D) concentrations in the last two rounds of the National Health and Nutrition Examination Survey (NHANES) has generated a high level of interest in the consequences of 25(OH)D deficiency and in particular its potential impact on black Americans. Fundamental new questions about the biology of vitamin D have now come to the fore. Are low 25(OH)D-intact parathyroid hormone (iPTH) levels a physiologic "abnormality" in African Americans or does the 25(OH)D-iPTH system have sufficient plasticity to adapt to low sunlight exposure? Could the low 25(OH)D levels which result from the "gene- environment discordance" observed in dark skinned populations in the US be a risk factor for metabolic disorders? Ultimately, the public health community and regulatory bodies must offer recommendations for optimal levels and supplementation. The investigators propose to utilize cohorts from an ongoing NIH-funded study designed to identify determinants of weight change and cardiovascular disease risk in five Afro-origin populations \[Modeling the Epidemiologic Transition Study (METS)\] to examine these questions. The five METS countries include Ghana, Seychelles, South Africa, Jamaica and the US; the five populations differ greatly in terms of sun exposure and dietary intakes. In addition to the extensive energy expenditure, dietary intake and obesity-related metabolic markers being measured in METS, the investigators propose to assess plasma 25(OH)D, iPTH, serum and urinary calcium, plasma markers of bone resorption and formation, and quantitative ultrasound of the calcaneus. The associations of adiposity, weight change, cardiovascular disease (CVD) risk factors such as blood pressure and insulin, and bone strength with 25(OH)D and iPTH will be assessed. The proposed study will provide a comprehensive assessment of the distribution and determinants of 25(OH)D-iPTH and related physiologic measures across a wide range of latitude and lifestyles. These data should contribute substantially to the understanding of the "normal" range within which these hormones function and their significance in Afro- origin populations.

Conditions

Cardiovascular Disease; Obesity

Keywords

Cardiovascular Disease; Obesity; Physical Activity; Vitamin D deficiency; African Americans

Outcome Measures

Primary Outcomes (7)

• 25-Hydroxyvitamin D

  Baseline

• Parathyroid Hormone (iPTH)

  Baseline

• Blood Pressure

  Baseline, 2.5 years

• Body Composition

  Body composition is estimated using bioelectrical impedance analysis (BIA) and race/sex specific equations. However, all participants will have body composition also measured using DXA (Dual energy x-ray absorptiometry).

  Baseline, 2.5 years

• Dietary Intake

  Each participant will complete at least two 24-hour recalls using the multiple pass method during each examination, one at the initial clinic visit and the second when the activity monitor is collected.

  Baseline, 2.5 years

• Physical Activity

  Accelerometer

  Baseline, 2.5 years, 4 years

• Bone Mineral Density

  Dual energy x-ray absorptiometry (DXA) is a densitometry technique which provides a two-dimensional image of the bone being measured, to produce bone mineral density (BMD) values (mass of bone tissue per unit area).

  2.5 years

Secondary Outcomes (3)

• Serum Calcium

  Baseline, 2.5 years

• Serum Albumin

  Baseline, 2.5 years

• Urinary Calcium

  Baseline, 2.5 years

Eligibility Criteria

• Age: 25 Years - 44 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64)
• Sampling Method: Probability Sample

Study Population

A community-based probability sampling strategy is being used to recruit 500 adults, ages 25-44, from metropolitan Chicago, Spanish Town Jamaica, rural Ghana near Kumasi, Cape Town South Africa, and the Seychelles in the Indian Ocean

You may qualify if:

• Ages 25-44

You may not qualify if:

• Pregnant women will be excluded

Sponsors & Collaborators

• Loyola University: lead
• National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK): collaborator
• Kwame Nkrumah University of Science and Technology: collaborator
• University of Cape Town: collaborator
• The University of The West Indies: collaborator
• University Institute of Social and Preventive Medicine, Switzerland: collaborator
• University of Washington: collaborator
• Winthrop University Hospital: collaborator

Study Sites (5)

Department of Public Health Sciences; Loyola University Chicago

Maywood, Illinois, 60153, United States

Location

Kwame Nkrumah University of Science and Technology

Kumasi, Ghana

Location

University of the West Indies

Kingston, Jamaica

Location

University Institute of Social and Preventive Medicine

Victoria, Seychelles

Location

University of Cape Town

Cape Town, South Africa

Location

Related Publications (1)

• Durazo-Arvizu RA, Camacho P, Bovet P, Forrester T, Lambert EV, Plange-Rhule J, Hoofnagle AN, Aloia J, Tayo B, Dugas LR, Cooper RS, Luke A. 25-Hydroxyvitamin D in African-origin populations at varying latitudes challenges the construct of a physiologic norm. Am J Clin Nutr. 2014 Sep;100(3):908-14. doi: 10.3945/ajcn.113.066605. Epub 2014 Jul 9.

  PMID: 25008852 DERIVED

Biospecimen

Retention: SAMPLES WITH DNA

Blood Serum Urine

MeSH Terms

Conditions

Cardiovascular Diseases; Obesity; Motor Activity; Vitamin D Deficiency

Condition Hierarchy (Ancestors)

Overweight; Overnutrition; Nutrition Disorders; Nutritional and Metabolic Diseases; Body Weight; Signs and Symptoms; Pathological Conditions, Signs and Symptoms; Behavior; Avitaminosis; Deficiency Diseases; Malnutrition

Study Officials

• Ramon A Durazo-Arvizu, PhD

  Loyola University Chicago

  PRINCIPAL INVESTIGATOR

Study Design

• Study Type: observational
• Observational Model: COHORT
• Time Perspective: PROSPECTIVE
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: April 4, 2014
• First Posted: April 11, 2014
• Study Start: September 1, 2011
• Primary Completion: September 1, 2011
• Study Completion: September 1, 2011
• Last Updated: August 30, 2017

Record last verified: 2017-08

Locations

ZA (1); GH (1); US (1); JA (1); SE (1)