Distribution of Select Characteristics Among Participants in the Y6FUa and Among 6-y-old Participants in the NSCH (2011–2012)b

CharacteristicPercentage of Y6FU Sample (N = 1540)Weighted Percentage of NSCH Sample of 6-y-Old Children (N = 5021)Z Score Probabilityc
Maternal characteristics
 Age (y)
 Marital status
  Married or cohabiting85.174.5<0.001
  High school or less13.436.7<0.001
  More than high school86.663.3<0.001
 Income (% of poverty threshold)
  White only89.562.5<0.001
  Black only4.014.5<0.001
Child’s characteristics
 Child has any kind of health care coverage
 Dental visit in past 12 mo
 Received food assistance in past 12 mo
 Kind of school child is currently enrolled in
 Child has an Individualized Education Program
 Time child usually watches TV or videos or plays video games on an average weekday (min)
 Child has attention deficit disorder or attention-deficit/hyperactivity disorder now
 Child has autism or developmental delay now
 Child has asthma now
 Child has hearing problems now
  • a Information listed is from the Y6FU study and therefore is from the period when the children were 6 y old. For example, mother’s age is her age when she answered the Y6FU questionnaire and is about 6 y older than mother’s age in the IFPSII. Other characteristics may also have changed between the periods of infancy and young childhood.

  • b The NSCH sample was limited to 6-y-old children. Percentages shown were weighted as recommended in the study documentation.

  • c We were unable to combine the 2 data sets because of the complex sample design of the NSCH. Therefore, we could not use χ2 statistics when comparing these 2 samples. Instead, we used Z tests for the difference of proportions between each category of the variables and used sample weights and SUDAAN to estimate the standard errors for the NSCH data.

  • d In Y6FU, race and ethnicity were asked about the mother, whereas in NSCH, race and ethnicity were asked about the child.