TABLE 1

Comparison of Participants and Nonparticipants in the Longitudinal Study on Selected Demographic Variables

VariableParticipantsNonparticipantsP
Mothers
 n2024.23
 Mean age (SD; range), y30.6 (5.8; 18–44)28.6 (4.99; 21–37)
 Marital status, %
  Married5248.44
  Divorced/separated1736
  Never married2212
  Unknown94
 Race/ethnicity, %
  White 4659.97
  African American2624
  Hispanic96
  Other1312
 Maternal education, %
  High school or less 9 16.61
  Some college39 40
  College degree26 28
  Advanced degree26 12
  Unknown0 7
Child
 n2316.93
 Mean CGG repeat range (SD; range)68.1 (17.8; 55–129)67.6 (19.4; 55–129)