Showing papers by "Shankuan Zhu published in 2002"
TL;DR: This article demonstrates this bias and shows that its magnitude can be large, and presents a simple method-of-moments (MOM)-based procedure to obtain more-accurate estimates and demonstrates its validity via Monte Carlo simulation.
Abstract: An attractive feature of variance-components methods (including the Haseman-Elston tests) for the detection of quantitative-trait loci (QTL) is that these methods provide estimates of the QTL effect. However, estimates that are obtained by commonly used methods can be biased for several reasons. Perhaps the largest source of bias is the selection process. Generally, QTL effects are reported only at locations where statistically significant results are obtained. This conditional reporting can lead to a marked upward bias. In this article, we demonstrate this bias and show that its magnitude can be large. We then present a simple method-of-moments (MOM)–based procedure to obtain more-accurate estimates, and we demonstrate its validity via Monte Carlo simulation. Finally, limitations of the MOM approach are noted, and we discuss some alternative procedures that may also reduce bias.
74 citations
TL;DR: Data show no difference in HR-QOL between AA and W obese women and suggest that menopausal status may have an impact on HR- QOL, especially in AA women.
Abstract: Objective: To investigate the health-related quality of life (HR-QOL) in African-American (AA) and white (W) obese women.
Research Methods and Procedures: Participants were 145 obese women (80 AA and 65 W; 87 premenopausal and 58 postmenopausal) who completed the Medical Outcomes Study short form, the Brief Symptom Inventory, the Life Distress Inventory, the Satisfaction With Life Scale, and the Rosenberg Self-Esteem Scale before entering a weight-loss study. The mean age of the subjects was 46.3 ± 11.1 years and the mean body mass index was 35.2 ± 4.2 kg/m2.
Results: Although AA women were slightly heavier (95.3 ± 10.3 kg vs. 91.5 ± 11.6 kg, p < 0.05) and less educated (14.2 ± 3.7 years vs. 15.7 ± 3.7 years, p < 0.05) than the W women in the sample, there was no difference between the two ethnic groups in any of the reported HR-QOL variables. Menopausal status had a significant effect on HR-QOL, with premenopausal women being more distressed (p = 0.002), having more limitations in social activity (p = 0.007), and having less vitality (p < 0.001) than the postmenopausal women. This was especially true in the AA women.
Discussion: These data show no difference in HR-QOL between AA and W obese women and suggest that menopausal status may have an impact on HR-QOL, especially in AA women.
36 citations
TL;DR: The reliability for information given on previous illness was as good as that on smoking and drinking for a short interval, but was lower for a long-interval probably due to the development of new cases.
10 citations