Table 1

Distribution of characteristics in Born in Bradford (BiB) children with complete data

CharacteristicMean (SD)
Letter ID score107.07 (12.5) range 68–143
Visual acuity (logMAR)0.13 (0.09) range 0.0–0.8
British Picture Vocabulary Score100.97 (14.47) range 39–160
Mean Spherical Equivalent* (D)1.07 (0.64) range −2–+9.5
Birth weight (g)3191 (541) range 680–5180
Gestational age (weeks)39.14 (1.63) range 27–43
Sex at birth (M:F)1010:1015
Ethnicity†n (%)
 White British671 (33.2)
 Pakistani1106 (54.6)
 Other248 (12.2)
Baseline questionnaire language†n (%)
 English1541 (76)
 Other language484 (24)
UK-born mother†n (%)
 Yes1177 (58)
 No848 (42)
Receiving benefits†n (%)
 Yes880 (43.46)
 No1145 (56.54)
Mothers level of education†n (%)
 Low (<5 GCSE equivalent and unknown)567 (28)
 Medium (5 GCSE and A level equivalent)1050 (52)
 High (higher than A level)408 (20)
Mother smoked in pregnancy†n (%)
 Yes282 (14)
 No1743 (86)
  • *n=1893 all other variables n=2025.

  • †Determined by mothers’ response to the baseline questionnaire.

  • D, dioptres; F, female; GCSE, general certificate of secondary education; M, male.