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Table 1 Characteristics of study sample in the Avon Longitudinal Study of Parents And Children cohort (N = 12,020)

From: Trimester effects of source-specific PM10 on birth weight outcomes in the Avon Longitudinal Study of Parents and Children (ALSPAC)

Characteristic of study births Na n (%) or mean ± SD Characteristic of mothers Na n (%) or mean ± SD
Completed gestational weeks 12,020 39.48 ± 1.83 Maternal age (Years) 11,250 27.79 ± 4.9
Birth weight (g) 11,896 3415.42 ± 540.13 Height (Cm) 10,534 163.92 ± 6.72
Head circumference (Cm) 9245 34.80 ± 1.50 Pre-pregnancy weight (Kg) 10,054 61.65 ± 10.93
Birth length (Cm) 7583 50.59 ± 2.14 Maternal BMI (Kg/m2) 12,020  
Infant’s sex 12,020   BMI < 18.5   510 (4.24%)
 Male   6215 (51.71%) 18.5 ≤ BMI < 25   7359 (61.22%)
 Female   5805 (48.29%) 25 ≤ BMI < 30   1537 (12.79%)
 Unknown   0 BMI ≥ 30   552 (4.59%)
PTB 12,020   Unknown   2062 (17.15%)
 PTB   601 (5.00%) Race 12,020  
 Not PTB   11,419 (95.00%) White   10,361 (86.20%)
 Unknown   0 Non-Whiteb   276 (2.30%)
TLBW 11,419   Unknown   1383 (11.51%)
 TLBW   217 (1.90%) Maternal education level 12,020  
 Not TLBW   11,085 (97.08%) Low: O level or below   6986 (58.12%)
 Unknown   117 (1.02%) High: A level or degree   3729 (31.02%)
SGA 12,020   Unknown   1305 (10.86%)
 SGA   928 (7.72%) Maternal smoke 12,020  
 Not SGA   10,968 (91.25%) Non-smoker   8538 (71.03%)
 Unknown   124 (1.03%) Smoker   2790 (23.21%)
   Unknown   692 (5.76%)
40 births are both PTB & SGA    Passive smoke 12,020  
   Not exposed   3516 (29.25%)
   Exposed   5543 (46.11%)
   Unknown   2961 (24.63%)
  1. arepresents number of births included in analysis
  2. bNon-white population including Black Caribbean, Black African, other black, Indian, Pakistani, Bangladeshi, Chinese and others