Study Results
The study team has not published outcome measurements, participant flow, or safety data for this trial yet. Check back later for updates.
Basic Information
Get a concise snapshot of the trial, including recruitment status, study phase, enrollment targets, and key timeline milestones.
COMPLETED
OBSERVATIONAL
1992-07-31
1994-04-30
Brief Summary
Review the sponsor-provided synopsis that highlights what the study is about and why it is being conducted.
Related Clinical Trials
Explore similar clinical trials based on study characteristics and research focus.
Genetic Epidemiology of Coronary Heart Disease Risk in Women Twins
NCT00005239
Stroke Risk in the NAS-NRC Twin Registry
NCT00005413
National Heart, Lung, and Blood Institute Twin Study
NCT00005124
Re-evaluating Triglycerides in Coronary Heart Disease
NCT00005442
Determinants of Coronary Disease in High Risk Families
NCT00005508
Detailed Description
Dive into the extended narrative that explains the scientific background, objectives, and procedures in greater depth.
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.
Conditions
See the medical conditions and disease areas that this research is targeting or investigating.
Eligibility Criteria
Check the participation requirements, including inclusion and exclusion rules, age limits, and whether healthy volunteers are accepted.
Inclusion Criteria
100 Years
MALE
No
Sponsors
Meet the organizations funding or collaborating on the study and learn about their roles.
National Heart, Lung, and Blood Institute (NHLBI)
NIH
References
Explore related publications, articles, or registry entries linked to this study.
Williams CJ, Wijesiri UW. Lipid data from NHLBI veteran twins: interpreting genetic analyses when model assumptions fail. Genet Epidemiol. 1993;10(6):551-6. doi: 10.1002/gepi.1370100637.
Williams CJ. On the covariance between parameter estimates in models of twin data. Biometrics. 1993 Jun;49(2):557-68.
Wijesiri UW, Williams CJ. Approximate solutions for the maximum-likelihood estimates in models of univariate human twin data. Behav Genet. 1995 May;25(3):211-6. doi: 10.1007/BF02197179.
Other Identifiers
Review additional registry numbers or institutional identifiers associated with this trial.
4326
Identifier Type: -
Identifier Source: org_study_id
More Related Trials
Additional clinical trials that may be relevant based on similarity analysis.