Table 2.
Total | Educational level | p value | Working status | p value | Neighborhood deprivation | p value | ||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
0–9 years | 10–12 years | ≥ 13 years | Housewives/unemployed | Students | Employed | Least deprived | Medium deprived | Most deprived | ||||||
Manual | Non-manual | |||||||||||||
Smoking | ||||||||||||||
Smoking initiation* | ||||||||||||||
Age (years) | 16.5 ± 3.5 | 15.8 ± 3.4 | 16.3 ± 3.3 | 17.8 ± 3.7 | < 0.001 | 15.5 ± 3.6 | 15.0 ± 1.8 | 16.6 ± 3.3 | 17.3 ± 3.6 | < 0.001 | 16.8 ± 3.7 | 16.4 ± 3.5 | 16.4 ± 3.5 | 0.768 |
Smoking status before pregnancy | ||||||||||||||
Never smokers | 366 (59.1%) | 72 (19.7%) | 121 (33.0%) | 173 (47.3%) | < 0.001 | 60 (16.4%) | 8 (2.2%) | 119 (32.5%) | 179 (48.9%) | < 0.001 | 122 (35.2%) | 118 (34.0%) | 107 (30.8%) | 0.550 |
Former smokers | 82 (13.3%) | 19 (23.2%) | 28 (34.1%) | 35 (42.7%) | 14 (17.1%) | 1 (1.2%) | 26 (31.7%) | 41 (50.0%) | 21 (27.2%) | 26 (33.8%) | 30 (39.0%) | |||
Current smokers | 171 (27.6%) | 68 (39.8%) | 70 (40.9%) | 33 (19.3%) | 54 (31.6%) | 3 (1.7%) | 66 (38.6%) | 48 (28.1%) | 55 (32.2%) | 55 (32.2%) | 61 (35.6%) | |||
Smoking status at birth | ||||||||||||||
Never smokers | 366 (59.1%) | 72 (19.7%) | 121 (33.1%) | 173 (47.2%) | < 0.001 | 60 (16.4%) | 8 (2.2%) | 119 (32.5%) | 179 (48.9%) | < 0.001 | 122 (35.2%) | 118 (34.0%) | 107 (30.8%) | 0.638 |
Former smokers | 163 (26.3%) | 42 (25.8%) | 64 (39.3%) | 57 (34.9%) | 34 (20.9%) | 2 (1.2%) | 56 (34.4%) | 71 (43.5%) | 48 (30.4%) | 51 (32.3%) | 59 (37.3%) | |||
Current smokers | 90 (14.6%) | 45 (50.0%) | 34 (37.8%) | 11 (12.2%) | 34 (37.8%) | 2 (2.2%) | 36 (40.0%) | 18 (20.0%) | 28 (31.1%) | 30 (33.3%) | 32 (35.6%) | |||
Cessation rate** | ||||||||||||||
No cessation | 90 (52.3%) | 45 (50.0%) | 34 (37.8%) | 11 (12.2%) | 0.012# | 34 (37.8%) | 2 (2.2%) | 36 (40.0%) | 18 (20.0%) | 0.257# | 28 (31.1%) | 30 (33.3%) | 32 (35.6%) | 0.144# |
Before pregnancy | 7 (4.1%) | 2 (28.6%) | 2 (28.6%) | 3 (42.8%) | 1 (14.3%) | 0 | 2 (28.6%) | 4 (57.1%) | 1 (14.2%) | 3 (42.9%) | 3 (42.9%) | |||
1st trimester | 59 (34.3%) | 15 (25.4%) | 26 (44.1%) | 18 (30.5%) | 13 (22.0%) | 1 (1.7%) | 22 (37.3%) | 23 (39.0%) | 23 (39.0%) | 15 (25.4%) | 21 (35.6%) | |||
2nd trimester | 8 (4.6%) | 5 (62.5%) | 3 (37.5%) | 0 | 4 (50.0%) | 0 | 3 (37.5%) | 1 (12.5%) | 0 | 4 (50.0%) | 4 (50.0%) | |||
3rd trimester | 3 (1.7%) | 1 (33.3%) | 2 (66.7%) | 0 | 1 (33.3%) | 0 | 2 (66.7%) | 0 | 1 (33.3%) | 2 (66.7%) | 0 | |||
Exposure to ETS*** | ||||||||||||||
Before pregnancy | ||||||||||||||
No | 191 (42.6%) | 32 (16.8%) | 53 (27.7%) | 106 (55.5%) | 0.004 | 27 (14.1%) | 4 (2.1%) | 54 (28.3%) | 106 (55.5%) | 0.130 | 62 (34.1%) | 66 (36.2%) | 54 (29.7%) | 0.550 |
Yes | 257 (57.4%) | 59 (23.0%) | 96 (37.3%) | 102 (39.7%) | 47 (18.3%) | 5 (1.9%) | 91 (35.4%) | 114 (44.4%) | 81 (33.5%) | 78 (32.2%) | 83 (34.3%) | |||
1st trimester | ||||||||||||||
No | 222 (48.8%) | 37 (16.7%) | 60 (27.0%) | 125 (56.3%) | < 0.001 | 30 (13.5%) | 4 (1.8%) | 64 (28.8%) | 124 (55.9%) | 0.049 | 68 (32.4%) | 80 (38.1%) | 62 (29.5%) | 0.208 |
Yes | 233 (51.2%) | 56 (24.0%) | 91 (39.1%) | 86 (36.9%) | 45 (19.3%) | 5 (2.2%) | 83 (35.6%) | 100 (42.9%) | 76 (34.4%) | 67 (30.3%) | 78 (35.3%) | |||
2nd trimester | ||||||||||||||
No | 250 (48.6%) | 41 (16.4%) | 74 (29.6%) | 135 (54.0%) | < 0.001 | 36 (14.4%) | 5 (2.0%) | 73 (29.2%) | 136 (54.4%) | 0.042 | 81 (34.2%) | 87 (36.7%) | 69 (29.1%) | 0.149 |
Yes | 264 (51.4%) | 67 (25.4%) | 103 (39.0%) | 95 (35.6%) | 52 (19.7%) | 5 (1.9%) | 96 (36.4%) | 111 (52.0%) | 86 (34.0%) | 75 (29.6%) | 92 (36.4%) | |||
3rd trimester | ||||||||||||||
No | 262 (50.2%) | 44 (16.8%) | 77 (29.4%) | 141 (53.8%) | < 0.001 | 41 (15.7%) | 5 (1,9%) | 74 (28.2%) | 142 (54.2%) | 0.022 | 86 (34.7%) | 92 (37.1%) | 70 (28.2%) | 0.053 |
Yes | 260 (49.8%) | 69 (26.5%) | 103 (39.6%) | 88 (33.9%) | 51 (19.6%) | 5 (1.9%) | 98 (37.7%) | 106 (40.8%) | 81 (32.4%) | 74 (29.6%) | 95 (38.0%) |
Row percentages are presented in all cases, except for total, that indicates column percentages.
*Mean ± SD; **4 missing values; ***ETS exposure was calculated considering non-smokers and former smokers at each time point.
#Likelihood ratio test instead of chi-square test.