TABLE 1

Baseline and Follow-up Characteristics of Non-ADHD Controls and ADHD Cases; ADHD Cases Separately by Treatment Status

CharacteristicADHD Case StatusPaADHD Cases Treated With Stimulants for ≥3 MonthsbPa
Non-ADHD Controls (N = 394)ADHD Cases (N = 243)Yes (N = 171)No (N = 65)
Baseline
 Gender, n (%).88.027
  Male286 (72.6)175 (72.0)130 (76.0)40 (61.5)
  Female108 (27.4)68 (28.0)41 (24.0)25 (38.5)
 Birth length (cm), mean (SD)51.8 (2.8)51.7 (2.9).7351.7 (3.0)51.8 (2.7).83
 Birth wt (g), mean (SD)3522 (560)3456 (566).153449 (547)3472 (619).78
 Maternal age at subject’s birth, mean (SD)26.4 (4.7)26.1 (4.9).4726.2 (4.7)26.1 (5.4).87
 Maternal education at subject’s birth, n (%).011.29
  Not available, n4219154
  Less than high school26 (7.4)14 (6.3)9 (5.8)5 (8.2)
  High school graduate106 (30.1)97 (43.3)72 (46.2)21 (34.4)
  Some college130 (36.9)71 (31.7)48 (30.8)21 (34.4)
  College graduate90 (25.6)42 (18.8)27 (17.3)14 (23.0)
Follow-up
 Age at last recorded height measurement (y), mean (SD)24.6 (5.8)26.8 (5.0)<.00126.8 (4.8)26.7 (5.7).91
 Number of height measurements per subject in 3-y age windows, median (IQR)
  Birth to <3 y9 (7, 12)8 (6, 12)8 (6, 12)8 (6, 9)
  3 to <6 y3 (2, 6)4 (2, 7)4 (2, 7)3 (2, 4)
  6 to <9 y3 (2, 6)4 (2, 7)5 (3, 8)4 (2, 6)
  9 to <12 y4 (2, 6)5 (3, 8)5 (3,8)5 (4, 7)
  12 to <15 y4 (2, 6)5 (3, 8)5 (3, 8)4 (3, 7)
  15 to <18 y3 (1, 5)3 (2, 6)4 (2, 7)3 (1, 5)
  ≥18 y5 (1, 12)8 (3, 18)8 (3, 18)9 (2, 18)
  Overall35 (26, 49)44 (33, 60)<.00146 (34, 62)41 (33, 53).16
 Age met ADHD research criteria (y), mean (SD)n/a10.3 (3.6)n/a9.9 (3.4)11.3 (3.8).006
  • IQR, interquartile range.

  • a Comparisons between groups were evaluated by using the χ2 test for gender, the 2-sample t test for birth length, birth wt, and age, and the Wilcoxon rank-sum test for the maternal education categories and number of height measurements.

  • b Duration of stimulant treatment was unknown for 7 of the 243 ADHD cases.