Ignite Creation Date:
2024-05-05 @ 10:00 AM
Last Modification Date:
2024-10-26 @ 9:05 AM
Study NCT ID:
NCT00005408
Status:
COMPLETED
Last Update Posted:
2016-03-16
First Post:
2000-05-25
Brief Title:
Reanalysis of CVD Risk Factors Via Likelihood Methods
Sponsor:
National Heart Lung and Blood Institute NHLBI
Organization:
National Heart Lung and Blood Institute NHLBI
Study Overview
Official Title:
None
Status:
COMPLETED
Status Verified Date:
2000-05
Last Known Status:
None
Delayed Posting:
No
If Stopped, Why?:
Not Stopped
Has Expanded Access:
False
If Expanded Access, NCT#:
N/A
Has Expanded Access, NCT# Status:
N/A
Acronym:
None
Brief Summary:
To reanalyze data on risk factors for cardiovascular disease CVD including total cholesterol and high density lipoprotein HDL cholesterol for the subjects in the first second and third exams of the NHLBI Twin Study
Detailed Description:
BACKGROUND
The results of these longitudinal analyses yielded new insights on genetic effects affecting CVD risk factors during the aging process
DESIGN NARRATIVE
The analyses utilized maximum likelihood estimators of genetic variance which were asymptotically more efficient than the method-of-moments estimators used in previous analyses The models used incorporated terms to partition the variance in a trait from twin data into either i additive genetic variance and unshared environmental variance the AE model ii additive genetic variance dominance genetic variance and unshared environmental variance the ADE model or iii additive genetic variance shared environmental variance and unshared environmental variance the ACE model The AE ADE and ACE models were fitted separately to data from each of the three exams to obtain a cross-sectional analysis The investigators also extended these models for use with longitudinal data by incorporating terms to represent the covariance of variance components from different exams
Two important additional objectives of this study were i to introduce resistant estimation techniques in twin modeling which trimmed the effect of outlier data points smoothly and ii to carefully study the performance of maximum likelihood and method-of-moments estimators when assumptions of the twin model were violated The results of these parts of the study should yield a more complete understanding of the relative merits and limitations of twin modeling procedures
The study completion date listed in this record was obtained from the End Date entered in the Protocol Registration and Results System PRS record
The results of these longitudinal analyses yielded new insights on genetic effects affecting CVD risk factors during the aging process
DESIGN NARRATIVE
The analyses utilized maximum likelihood estimators of genetic variance which were asymptotically more efficient than the method-of-moments estimators used in previous analyses The models used incorporated terms to partition the variance in a trait from twin data into either i additive genetic variance and unshared environmental variance the AE model ii additive genetic variance dominance genetic variance and unshared environmental variance the ADE model or iii additive genetic variance shared environmental variance and unshared environmental variance the ACE model The AE ADE and ACE models were fitted separately to data from each of the three exams to obtain a cross-sectional analysis The investigators also extended these models for use with longitudinal data by incorporating terms to represent the covariance of variance components from different exams
Two important additional objectives of this study were i to introduce resistant estimation techniques in twin modeling which trimmed the effect of outlier data points smoothly and ii to carefully study the performance of maximum likelihood and method-of-moments estimators when assumptions of the twin model were violated The results of these parts of the study should yield a more complete understanding of the relative merits and limitations of twin modeling procedures
The study completion date listed in this record was obtained from the End Date entered in the Protocol Registration and Results System PRS record
Study Oversight
Has Oversight DMC:
Is a FDA Regulated Drug?:
Is a FDA Regulated Device?:
Is an Unapproved Device?:
Is a PPSD?:
Is a US Export?:
Is an FDA AA801 Violation?:
Secondary IDs
| Secondary ID | Type | Domain | Link |
|---|---|---|---|
| R03HL046674 | NIH | None | httpsreporternihgovquickSearchR03HL046674 |