|
Activity Number:
|
257
|
|
Type:
|
Topic Contributed
|
|
Date/Time:
|
Tuesday, August 4, 2009 : 8:30 AM to 10:20 AM
|
|
Sponsor:
|
Section on Statistics in Epidemiology
|
| Abstract - #304297 |
|
Title:
|
Using Projection Splines to Explore Racial Differences in Gestational Age Distribution Among Very Low-Risk Women
|
|
Author(s):
|
Nedra Whitehead*+ and Jun Liu and Lei Li and Jason Hsia
|
|
Companies:
|
RTI International and PPD, Inc. and RTI International and CDC
|
|
Address:
|
2951 Flowers Road, Suite 119, Atlanta, GA, 30030,
|
|
Keywords:
|
SUDAAN ; Projection splines ; Distributions ; Gestational age
|
|
Abstract:
|
We adapted a method of comparing distributions that uses projection splines, which fit a regression line that allows the slope changes over the range of x, for use with complex survey data. We used SUDAAN to estimate the percentile distribution of gestational age among the infants of black women and those of white women. We calculated y as the difference between the percentile of the two groups divided by the variance of the difference and assumed y was identically and independently distributed. We compared the distributions by regressing y on the average of the two percentiles, starting with a model with a node every 7 days. We eliminated nonsignificant nodes stepwise until all nodes were significant at an alpha = 0.01. The final model had 6 significant nodes, indicating the gestational age distribution of infants of black women is shaped differently from that of infants of white women.
|
