Associations between maternal smoking and children's asthma and FEF25-75 according to maternal and child GSTM1-null genotypes
| GSTM1 | Asthma | FEF25–75 | ||||||||
| Mother | Child | N | Cases (%) | OR | (95% CI) | p Value | N | AM difference | (95% CI) | p Value |
| + | + | 1137 | 137 (12.0) | 1.23 | (1.02 to 1.48) | 0.03 | 999 | 0.02 | (−0.05 to 0.09) | 0.63 |
| + | – | 525 | 60 (11.4) | 0.77 | (0.54 to 1.08) | 0.13 | 477 | −0.04 | (−0.13 to 0.05) | 0.36 |
| − | + | 513 | 64 (12.5) | 1.05 | (0.79 to 1.39) | 0.76 | 456 | 0.03 | (−0.08 to 0.14) | 0.58 |
| − | − | 1396 | 196 (14.0) | 1.05 | (0.88 to 1.24) | 0.6 | 1227 | −0.08 | (−0.14 to −0.02) | 0.012 |
AM, arithmetic mean; FEF25–75, maximal mid expiratory flow; +, one or more copies of GSTM1; −homozygous deletion of GSTM1.