TABLE 1

Characteristics of the Children and Their Families

CharacteristicsCaffeine Group (n = 432)Placebo Group (n = 438)P
Children at birth
 Mean birth wt (SD), g967 (181)956 (182).39
 Mean gestational age (SD), wk27.3 (1.7)27.3 (1.8).48
 Female sex, No. (%)222 (51.4)199 (45.4).08
 Birth wt <10th percentile for gestational age, No. (%)a59 (13.7)67 (15.3).49
 Exposure to antenatal corticosteroids, No. (%)390 (90.3)394 (90.0).95
 Singleton birth, No. (%)297 (68.8)315 (71.9).31
Outcomes at 18 mo
 Disability, No./total No. (%)b122/418 (29.2)153/424 (36.1).03
 Cerebral palsy, No./total No. (%)14/427 (3.3)27/433 (6.2).04
 Moderate cognitive delay, No./total No. (%)c113/416 (27.2)133/423 (31.4).17
 Severe cognitive delay, No./total No. (%)d38/416 (9.1)52/423 (12.3).14
 Severe ROP, No./total No. (%)e18/432 (4.2)26/438 (5.9).23
Outcomes at 5 y
 Disability, No./total No. (%)f56/415 (13.5)72/411 (17.5).11
 Motor impairment, No./total No. (%)g5/424 (1.2)13/425 (3.1).06
 Cognitive impairment, No./total No. (%)h18/417 (4.3)12/421 (2.9).25
 Full-scale IQ, mean (SD)100 (16)99 (15).10
 Behavior problem, No./total No. (%)i23/415 (5.5)29/413 (7.0).38
11-y follow-up
 Median age (IQR), y11.4 (11.1, 11.8)11.4 (11.1, 11.8).88
 Schooling
  Mainstream school (public or private), No. (%)418 (96.8)424 (96.8).63
  Special education facility, No. (%)10 (2.3)11 (2.5)
  Homeschool, No. (%)4 (0.9)2 (0.5)
  Hospital or chronic care facility, No. (%)0 (0.0)1 (0.2)
 Primary caregivers and family arrangements at follow-up
  Relationship to child
   Biological mother, No. (%)369 (85.4)379 (86.5).23
   Biological father, No. (%)47 (10.9)51 (11.6)
   Other or unknown, No. (%)16 (3.7)8 (1.8)
 Race
  White, No. (%)350 (81.0)355 (81.1).70
  Black, No. (%)14 (3.2)18 (4.1)
  Asian, No. (%)45 (10.4)44 (10.0)
  Indigenous, No. (%)11 (2.5)14 (3.2)
  Other or unknown, No. (%)12 (2.8)7 (1.6)
 Level of caregiver education
  Did not finish high school or Eq, No. (%)83 (19.2)89 (20.3).53
  Completed high school or Eq, No. (%)86 (19.9)91 (20.8)
  Some college or university, No. (%)75 (17.4)60 (13.7)
  College or university graduate, No. (%)188 (43.5)198 (45.2)
 Family arrangement
  Single parent, No. (%)56 (13.0)52 (11.9).44
  Single parent with partner closely involved, No. (%)39 (9.0)28 (6.4)
  2-parent family, No. (%)319 (73.8)341 (77.9)
  Other or unknown, No. (%)18 (4.2)17 (3.9)
 Other children <18 y old living in the household, median (IQR)1 (1, 2)1 (1, 2).61
 Family’s main source of financial support
  Earnings from employment or self-employment, No. (%)374 (86.6)390 (89.0).12
  Government benefits (excluding pensions), No. (%)41 (9.5)37 (8.4)
  Other, No. (%)10 (2.3)2 (0.5)
  • These data are for the 870 children who completed data for at least one measurement instrument. Percentages may not sum to 100 because of rounding. Eq, equivalent.

  • a The 10th percentile for gestational age in a normal population was reported by Kramer et al.19

  • b Disability at 18 mo was defined as at least 1 of cerebral palsy, moderate cognitive delay, deafness, or blindness.

  • c Moderate cognitive delay was defined as a Mental Development Index score of <85 on the Bayley Scales of Infant Development, second edition.

  • d Severe cognitive delay was defined as a Mental Development Index score of <70 on the Bayley Scales of Infant Development, second edition.

  • e Severe ROP was defined as unilateral or bilateral stage 4 or 5 disease or as receipt of retinal therapy in at least 1 eye.

  • f Disability at 5 y of age was defined as at least 1 of motor impairment, cognitive impairment, behavior problems, poor general health, deafness, or blindness.

  • g Motor impairment was defined as a Gross Motor Function Classification System level of >2.

  • h Cognitive impairment was defined as a full-scale IQ of <70 on the Wechsler Preschool and Primary Scale of Intelligence–III.

  • i A behavior problem was defined as a Total Problem T score of >69 on the Child Behavior Checklist.