Biomedical subjects

D J Tancredi

Publications and source records attributed to D J Tancredi.

4 recordsLinked to original sources

PubMed2004

Multivariate longitudinal models for complex change processes.

Longitudinal studies offer us an opportunity to develop detailed descriptions of the process of growth and development or of the course of progression of chronic diseases. Most longitudinal analyses focus on characterizing change over time in a single outcome variable and identifying predictors of growth or decline. Both growth and degenerative diseases, however, are complex processes with multiple markers of change, so that it may be important to model more than one outcome measure and to understand their relationship over time. We consider random effects models for the association between the trajectories of two outcomes over time, and then compare their properties to approaches based on separate ordinary least-squares estimates of change. We then illustrate with an example from the Religious Orders Study, a longitudinal cohort study of more than 900 members of Catholic religious orders who have had up to eight annual clinical examinations.

Aged↗

PubMed2000

Parametric empirical Bayes estimates of disease prevalence using stratified samples from community populations.

Studies of chronic diseases in a community setting often employ stratified sample designs to enable the study to attain multiple research goals at a reasonable cost. One important goal is estimation of disease prevalence in the whole community and in important subgroups. Some adjustment for the sample design is necessary; if the design has many strata with very disparate sampling fractions, simply upweighting observed stratum prevalences may lead to unstable estimators. We propose a parametric empirical Bayes estimator in the spirit of the work of Efron and Morris, and we compare it to the direct upweighted estimator and a regression-smoothed estimator. Simulation studies in realistic settings suggest that the new estimator performs best, giving estimates with low bias and good precision under a variety of models.

Age Factors↗

PubMed1992

Information dissemination and the cesarean birth rate. The Illinois experience.

A study was initiated to investigate the impact of information dissemination in Illinois upon the projected rise in the cesarean birth rate over the period from 1986 through 1988. The total cesarean birth rate in Illinois had not changed significantly during this period, whereas the rate of vaginal births after cesarean sections (VBAC) increased by 58.4% (p < .001). Information dissemination may have contributed to stemming an increase in the cesarean birth rate in Illinois while promoting VBAC deliveries.

Adolescent↗

PubMedDate not supplied

Coronary risk factor behavior change in hospital personnel following a screening program.

We conducted a worksite cardiovascular disease (CVD) awareness and education program at a large medical center. The program consisted of employee screening for blood pressure and total serum cholesterol level, dissemination of information on risk factors for CVD, counseling on behavior change, and evaluation of the screening event as an educational tool. During this five-day event, 2,284 employees were screened for hypertension and hypercholesterolemia. Consenting employees completed a health risk appraisal survey (n = 2,255) and received counseling on their results and CVD risk factors. Appropriate referrals to health care professionals and educational programs were made according to national guidelines. We developed three-month and six-month follow-up surveys and distributed them to all participating employees. The analysis of these data suggests some positive impact upon behavior change within this employee population. In addition to the two follow-up surveys, we held a second blood pressure and serum cholesterol screening eight months after the initial screening. Comparison of the levels taken from both screenings (n = 234) suggests that worksite screening programs may influence significant serum cholesterol and blood pressure reductions in high-risk employees.

Adult↗