1. What factors affect the likelihood of testing with CLDRC?
Rea-Sandin, G., Simecek, I., Corley, R., Gross, A.
Institute for Behavioral Genetics, University of Colorado Boulder
Introduction
Methods
Results
Conclusions Future Directions• Used birth records of ~5000 twins born in Colorado between
1996-2002, focusing on the Front Range to gather zip code
data
• For distance, found most central US Post Office for each
family’s zip code and then mapped distance from each post
office to IBG using Google Maps
• For demographic variables (race/ethnicity, median income, %
high school graduates, % below poverty level), gathered 2010
data from United Stated Census Bureau for each zip code
• After data collection, compared families that participated and
those that didn’t
• Ran a logistic regression and t-test for each variable using R
• Differentiate between affected (ADHD or reading disability)
and control participants in our analyses
• Gather parental education and ethnicity factors from birth
records to run more precise demographic analyses
• Use current address at date of testing (rather than address at
time of birth) to gather more current demographic data
• Access statewide standardized test scores for each county
• Compare CO census info with national averages
• Expand analyses to other IBG studies such as ILTS, LTS, and
CTS
Variable Source Mean of
Tested
Mean of Non-
Tested
P-Value
Age of Mother Birth records 32.4 30.5 3.636e-08
Age of Father Birth records 34.5 32.7 2.522e-06
Distance Google Maps 34.7 miles 46.3 miles 4.478e-13
Median Income 2010 Census $71,722 $63,813 5.493e-09
% of High School
Grads
2010 Census 92.7% 89.6% 3.637e-12
% Below Poverty
Level
2010 Census 10.3% 13.2% 1.745e-10
% White 2010 Census 84.0% 80.1% 5.188e-10
% Hispanic 2010 Census 16.1% 21.4% 5.498e-11
% Asian 2010 Census 3.6% 3.1% 3.337e-05
• The objectives of the Colorado Learning Disabilities
Research Center (CLDRC) are the identification,
characterization, validation, and amelioration of reading
disabilities, writing disabilities, and ADHD
• These are the most prevalent and often, co-morbid disorders
of childhood
• The CLDRC aims to advance our understanding of their
differential diagnosis, comorbidity, and etiology, with
implications for early identification and intervention
• Twins are either placed in the affected group (having ADHD
and/or a reading disability) or the control group
Aims
• To discover how representative the CLDRC sample is to
Colorado in general
• To look at what variables may predict whether or not a family
is likely to participate in the CLDRC study
• Significant mean differences showing that participant families differ in
a variety of ways
• Although there are statistically significant differences, range in
variation is similar between the two groups
• Older mothers may be more likely to participate because of factors
such as higher education level, more stability, etc.
• Counties closer to Boulder have higher participation rates, moderated
downward by presence of mountains
• Relatively small differences in zip code ethnic distributions between
groups, but unlikely to be representative of USA as a whole
Variable Stats from Front Range Data