Abstract Details
Activity Number:
|
692
|
Type:
|
Contributed
|
Date/Time:
|
Thursday, August 8, 2013 : 10:30 AM to 12:20 PM
|
Sponsor:
|
Section on Statistics in Epidemiology
|
Abstract - #309575 |
Title:
|
Piecewise Spline to Compare Weight Gain Pattern Before and After Diagnosis of Asthma of Children Ages Less Than 5 Years
|
Author(s):
|
Md Jobayer Hossain and Li Xie*+ and Weili Lai and Iman Sharif and H Timothy Bunnell and Timothy T. Wysocki
|
Companies:
|
Nemours Biomedical Research A.I. DuPont Children Hospital and Johns Hopkins Bloomberg School of Public Health and University of Delaware and A I dupont Children Hospital and Nemours Biomedical Research and Nemours Biomedical Research A.I. DuPont Children Hospital
|
Keywords:
|
Piecewise spline ;
weight gain ;
BMIz ;
estimated variance
|
Abstract:
|
weight-for-length (age < 2 years) and BMI (>= 2 years)are commonly used measures of weight gain. We used standardized scores (BMIz) of these two measures of 1173 asthmatic children of ages 0-5 years to compare the pattern of weight gain before and after diagnosis of asthma. Lowess smoothed curve showed a linear increase in BMIz over time but with a different slopes before and after diagnosis of asthma among these children. A piecewise linear mixed effect model with a knot at the age of asthma diagnosis showed a significant difference (p< .001) in the mean trend of BMIz between before and after diagnosis. The slope showed a shallow increase(p=0.79) in BMIz before diagnosis of asthma, while it showed a sharp increase (p< .0001) after diagnosis. The post-diagnosis rate of increase in BMIz is more than 20 times as high as it is during pre-diagnosis period. The estimated variance of time slope during pre-asthma diagnosis is about 3 times as high as it is during post-asthma diagnosis. About 51% children were expected to have an increase in BMIz during the post-diagnosis period, while an about 82% children were expected to have an increase after diagnosis.
|
Authors who are presenting talks have a * after their name.
Back to the full JSM 2013 program
|
2013 JSM Online Program Home
For information, contact jsm@amstat.org or phone (888) 231-3473.
If you have questions about the Continuing Education program, please contact the Education Department.
The views expressed here are those of the individual authors and not necessarily those of the JSM sponsors, their officers, or their staff.
Copyright © American Statistical Association.