Vitamin D-related Genes and Metabolic Disorders
![]() |
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. |
ClinicalTrials.gov Identifier: NCT03279432 |
Recruitment Status :
Completed
First Posted : September 12, 2017
Last Update Posted : September 12, 2017
|
Tracking Information | |||||||
---|---|---|---|---|---|---|---|
First Submitted Date | September 8, 2017 | ||||||
First Posted Date | September 12, 2017 | ||||||
Last Update Posted Date | September 12, 2017 | ||||||
Actual Study Start Date | August 18, 2004 | ||||||
Actual Primary Completion Date | July 7, 2013 (Final data collection date for primary outcome measure) | ||||||
Current Primary Outcome Measures |
|
||||||
Original Primary Outcome Measures | Same as current | ||||||
Change History | No Changes Posted | ||||||
Current Secondary Outcome Measures | Not Provided | ||||||
Original Secondary Outcome Measures | Not Provided | ||||||
Current Other Pre-specified Outcome Measures | Not Provided | ||||||
Original Other Pre-specified Outcome Measures | Not Provided | ||||||
Descriptive Information | |||||||
Brief Title | Vitamin D-related Genes and Metabolic Disorders | ||||||
Official Title | Vitamin D Receptor and Megalin Gene Polymorphisms and Their Association With Obesity, Central Obesity and the Metabolic Syndrome | ||||||
Brief Summary | The link between metabolic disturbances and vitamin D receptor (VDR) and MEGALIN (or LRP2) gene polymorphisms remains unclear, particularly among African-American adults. The associations of single nucleotide polymorphisms (SNPs) for VDR [rs1544410(BsmI:G/A), rs7975232(ApaI:A/C), rs731236(TaqI:G/A)] and MEGALIN [rs3755166:G/A,rs2075252:C/T, rs2228171:C/T] genes with incident and prevalent metabolic disturbances, including obesity, central obesity and metabolic syndrome (MetS) were evaluated. From 1,024 African-Americans participating in the Healthy Aging in Neighborhoods of Diversity across the Life Span (HANDLS, Baltimore, MD, 2004-2013) study, 539 subjects were selected who had complete genetic data as well as covariates selected for metabolic outcomes at two consecutive examinations (visits 1 and 2) with a mean follow-up time of 4.64±0.93y. Haplotype (HAP) analyses generated polymorphism groups that were linked to incident and prevalent metabolic disturbances. |
||||||
Detailed Description | Adiposity, especially central adiposity, is a key component of the metabolic syndrome (MetS), which is accompanied by hyperglycemia, elevated blood pressure, lower HDL cholesterol and hypertriglyceridemia.(Ford, et al., 2003,Grundy, 1999)_ENREF_4 MetS increases the risk of type 2 diabetes (T2D) and cardiovascular disease by 1.7- and 5-folds, respectively.(Alberti, et al., 2009,Ford, et al., 2003,Galassi, et al., 2006) MetS is heritable and polygenic.(Maes, et al., 1997) Genetic variability contributes to 16%-85% of changes in Body Mass Index (BMI)(Yang, et al., 2007) and 37%-81% in waist circumference (WC) (e.g.(Ochs-Balcom, et al., 2011)). MetS is a major public health concern, increasing all-cause mortality rates, disability and health care costs.(Appels and Vandenbroucke, 2006,Bender, et al., 2006,Colditz, 1999,Doig, 2004,Ferrucci and Alley, 2007,Hill, et al., 2004,Solomon and Manson, 1997,Stevens, 2000,Wolf and Colditz, 1998) Obesity is implicated in the etiology of vitamin D deficiency. Serum 25-hydroxyvitamin D [25(OH)D] concentration correlates inversely with adiposity.(Beydoun, et al., 2010,Dorjgochoo, et al., 2012) Conversely, vitamin D3 may play a role in obesity by modulating intracellular calcium homeostasis, because higher intracellular calcium triggers lipogenesis and suppresses lipolysis.(Zemel, 2003) Many organs express vitamin D receptor (VDR), a part of the nuclear hormone receptor super-family. The VDR-1,25(OH)2D3 complex modulates transcription of vitamin D responsive genes(Kato, 2000) and influences adipocyte differentiation both in vitro and in vivo.(Wood, 2008) Epidemiological studies have shown associations of VDR gene polymorphisms with adiposity and related metabolic disorders.(Filus, et al., 2008,Grundberg, et al., 2004,Gu, et al., 2009,Ochs-Balcom, et al., 2011,Oh and Barrett-Connor, 2002,Ortlepp, et al., 2001,Ortlepp, et al., 2003,Speer, et al., 2001,Ye, et al., 2001) However, studies specifically examining adiposity outcomes either had small sample sizes (<400), (e.g.(Filus, et al., 2008,Grundberg, et al., 2004,Speer, et al., 2001)) or were restricted to one sex, (e.g. (Grundberg, et al., 2004,Ochs-Balcom, et al., 2011)) but more importantly were all cross-sectional or case-control by design.(Filus, et al., 2008,Grundberg, et al., 2004,Gu, et al., 2009,Ochs-Balcom, et al., 2011,Oh and Barrett-Connor, 2002,Ortlepp, et al., 2001,Ortlepp, et al., 2003,Speer, et al., 2001,Ye, et al., 2001) MEGALIN (aka low-density lipoprotein receptor-related protein-2 [LRP-2]), is the endocytic vitamin D-binding protein receptor which allows vitamin D entry into cells and whose expression is directly regulated by both vitamin D (Gressner, et al., 2008)) and vitamin A.(Liu, et al., 1998) MEGALIN may influences obesity by mediating leptin transport through the blood-brain barrier and modulating leptin signaling,(Dietrich, et al., 2008) or by facilitating transcytosis of its precursor hormone thyroglobulin.(Lisi, et al., 2005) Collectively, leptin and thyroid hormones affect adiposity through energy metabolism regulation.(Beydoun, et al., 2011) MEGALIN acting also as the receptor for sex-hormone binding globulin (SHBG) may play a role in the interaction between estrogen, vitamin D and intracellular calcium in adipocytes, resulting in sex-specific effects of MEGALIN polymorphisms on obesity phenotypes.(Ding, et al., 2008) In this study, it is hypothesized that selected polymorphisms in VDR and MEGALIN genes have sex-specific associations with several key metabolic disturbances in a longitudinal study of African-American urban adults. | ||||||
Study Type | Observational | ||||||
Study Design | Observational Model: Cohort Time Perspective: Prospective |
||||||
Target Follow-Up Duration | Not Provided | ||||||
Biospecimen | Retention: Samples With DNA Description: Study participants were genotyped to 907,763 single nucleotide polymorphisms (SNPs) using the Illumina 1M and 1M-Duo genotyping arrays. Sample quality control inclusion criteria were: (1) concordance between self-reported sex and X-chromosome estimated sex; (2) sample call rate >95%, (3) concordance between self-reported African ancestry and ancestry estimated using genotyped SNPs, and (4) proportional sharing of genotypes < 15% between samples, excluding close relatives from the final sample. SNPs in HANDLS were selected when the following criteria were met: (1) Hardy-Weinberg equilibrium p-value (HWE P >10-7); (2) Missing by haplotype P > 10-7; (3) Minor allele frequency>0.01, and (4) SNP call rate >95%. Quality control and data management for each genotype was conducted using PLINKv1.06.
|
||||||
Sampling Method | Probability Sample | ||||||
Study Population | Of the 3,720 baseline participants (mean±SD age(y) of 48.3±9.4, 45.3% men, and 59.1% African-American), genetic data were available on 1,024 African-American participants. Incomplete covariate data reduced the sample to n=769, while additional exclusions lead to a sample size ranging between 574 and 598 participants, with 539 having complete data on all baseline and follow-up outcome measures (cross-sectional part of the analysis). In the longitudinal analysis, metabolic disturbance-free at baseline participants were selected for each outcome. Sample sizes ranged from n=246 (central obesity-free) to n=466 (hyperglycemia-free). There were n=294 MetS-free individuals at baseline (Figure 1). | ||||||
Condition |
|
||||||
Intervention | Not Provided | ||||||
Study Groups/Cohorts | Not Provided | ||||||
Publications * |
|
||||||
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline. |
|||||||
Recruitment Information | |||||||
Recruitment Status | Completed | ||||||
Actual Enrollment |
1021 | ||||||
Original Actual Enrollment | Same as current | ||||||
Actual Study Completion Date | July 7, 2013 | ||||||
Actual Primary Completion Date | July 7, 2013 (Final data collection date for primary outcome measure) | ||||||
Eligibility Criteria | Inclusion Criteria:
Exclusion Criteria:
|
||||||
Sex/Gender |
|
||||||
Ages | 30 Years to 64 Years (Adult) | ||||||
Accepts Healthy Volunteers | Yes | ||||||
Contacts | Contact information is only displayed when the study is recruiting subjects | ||||||
Listed Location Countries | Not Provided | ||||||
Removed Location Countries | |||||||
Administrative Information | |||||||
NCT Number | NCT03279432 | ||||||
Other Study ID Numbers | NIA | ||||||
Has Data Monitoring Committee | No | ||||||
U.S. FDA-regulated Product |
|
||||||
IPD Sharing Statement |
|
||||||
Responsible Party | May Ahmad Baydoun, National Institute on Aging (NIA) | ||||||
Study Sponsor | National Institute on Aging (NIA) | ||||||
Collaborators | Not Provided | ||||||
Investigators |
|
||||||
PRS Account | National Institute on Aging (NIA) | ||||||
Verification Date | September 2017 |