Skip to main content

Table 1 Characteristics of the EDEN study population (n = 568)

From: Immediate and durable effects of maternal tobacco consumption alter placental DNA methylation in enhancer and imprinted gene-containing regions

Characteristics All (n = 568), n (%) Non-smoker (n = 381 (67%)), n (%) Former smoker (n = 70 (12%)), n (%) Current smoker (n = 117 (21%)), n (%) p value*
Center      < 0.01
 Poitiers 231 (41) 140 (37) 25 (36) 66 (56)  
 Nancy 337 (59) 241 (63) 45 (64) 51 (44)  
Sex of offspring      0.24
 Male 293 (52) 206 (54) 33 (47) 54 (46)  
 Female 275 (48) 175 (46) 37 (53) 63 (54)  
Parity      0.71
 0 239 (42) 155 (41) 35 (50) 49 (42)  
 1 226 (40) 156 (41) 24 (34) 46 (39)  
 ≥ 2 102 (18) 69 (18) 11 (16) 22 (19)  
 Missing 1 (0) 1 (0)    
Maternal age at the end of education (years)      < 0.01
 ≤ 18 105 (18) 51 (13) 12 (17) 42 (36)  
 19–20 89 (16) 58 (15) 11 (16) 20 (17)  
 21–22 127 (22) 91 (24) 12 (17) 24 (21)  
 23–24 134 (24) 105 (28) 14 (20) 15 (13)  
 ≥ 25 113 (20) 76 (20) 21 (30) 16 (14)  
Season of conception      0.50
 January to March 120 (21) 80 (21) 15 (21) 25 (21)  
 April to June 129 (23) 89 (23) 19 (27) 21 (18)  
 July to September 157 (28) 110 (29) 18 (26) 29 (25)  
 October to December 162 (29) 102 (27) 18 (26) 42 (36)  
Pre-pregnancy body mass index (kg/m2)      0.08
 < 18.5 47 (8) 26 (7) 5 (7) 16 (14)  
 18.5–25 385 (68) 258 (68) 52 (74) 75 (64)  
 25–30 94 (17) 65 (17) 12 (17) 17 (15)  
 ≥ 30 34 (6) 25 (7)   9 (8)  
 Missing 8 (1) 7 (2) 1 (1)   
Preterm births 30 (5) 20 (5) 4 (6) 6 (5) 0.98
Paternal smoking at conception      < 0.01
 No 265 (46.7) 233 (61.2) 17 (24.6) 15 (12.8)  
 Yes 220 (38.8) 100 (26.2) 41 (59.4) 79 (67.5)  
 Missing 82 (14.5) 48 (12.6) 11 (15.9) 23 (19.7)  
Paternal smoking during pregnancy      < 0.01
 No 285 (50) 247 (65) 24 (34) 14 (12)  
 Yes 206 (36) 91 (24) 36 (51) 79 (68)  
 Missing 77 (14) 43 (11) 10 (14) 24 (21)  
Maternal passive smoking during pregnancy      < 0.01
 No 365 (64) 300 (78.7) 45 (64.3) 20 (17.1)  
 Yes 158 (28) 51 (13.4) 18 (25.7) 89 (76.1)  
 Missing/intermittently exposed 45 (8) 30 (7.9) 7 (10.0) 8 (6.8)  
  Continuous covariates  
Median [IQR] Median [IQR] Median [IQR] Median [IQR]
Maternal age (years) 29 [26, 32] 30 [27, 33] 28 [26, 32] 27 [24, 31] < 0.01
Gestational duration (weeks) 40 [39, 41] 40 [39, 41] 40 [39, 41] 40 [39, 41] 0.23
Birthweight (g) 3330 [3030, 3630] 3360 [3070, 3670] 3330 [3070, 3657] 3230 [2920, 3420] < 0.01
Estimated cellular heterogeneity
 1st covariate 0.14 [0.05, 0.22] 0.14 [0.04, 0.22] 0.12 [0.03, 0.21] 0.15 [0.09, 0.22] 0.10
 2nd covariate 0.15 [0.06, 0.24] 0.15 [0.06, 0.24] 0.17 [0.09, 0.25] 0.15 [0.05, 0.25] 0.57
 3rd covariate 0.34 [0.17, 0.46] 0.35 [0.17, 0.47] 0.33 [0.18, 0.42] 0.31 [0.17, 0.46] 0.54
 4th covariate 0.11 [0.06, 0.18] 0.10 [0.05, 0.16] 0.13 [0.08, 0.19] 0.13 [0.07, 0.19] 0.01
 5th covariate 0.06 [0.01, 0.12] 0.06 [0.01, 0.12] 0.06 [0.00, 0.10] 0.09 [0.03, 0.13] 0.05
 6th covariate 0.11 [0.04, 0.21] 0.11 [0.05, 0.24] 0.11 [0.05, 0.22] 0.09 [0.04, 0.16] 0.11
  1. *Kruskal-Wallis test for continuous covariates and chi-square test for categorical covariates