Low level maternal smoking and infant birthweight reduction: genetic contributions of GSTT1 and GSTM1polymorphisms

Table 2 Influence of maternal characteristics on infant’s birthweight assessed by the crude and adjusted coefficient ß in linear regression (n=539 ^† )

Maternal characteristics continuous and binary	ß crude	SE	P-value	ß^*adjusted	SE	P-value
BMI^**	42.7	6.0	<0.001
Gestational age, week^**	191.0	9.2	<0.001
Age < 20 or > 30 years	−34.2	56.7	0.547	−11.43	41.3	0.783
Low education, ≤ 12 years	−279.7	91.7	0.002	−155.3	67.2	0.021
Not married	−148.9	64.7	0.022	−87.1	47.2	0.066
Parity 2nd and more	49.5	55.0	0.368	90.8	39.9	0.023
Miscarriage	15.2	69.7	0.828	4.0	50.8	0.937
Previous preterm	−400.1	135.2	0.003	82.5	100.0	0.409
Maternal stress	−94.7	70.7	0.181	5.4	51.6	0.916
Blood pressure > 120/80 mm/Hg	189.4	76.6	0.014	87.5	59.0	0.139
Maternal smoking	−114.9	76.1	0.132	−137.0	55.2	0.013
Parental smoking	−86.9	55.0	0.115	−93.3	40.1	0.020
GSTT1 null vs present	−104.1	72.7	0.153	−72.7	52.7	0.170
GSTM1 null vs present	−25.3	55.1	0.646	−26.0	40.0	0.516
GSTT1 null & smoking	−207.0	138.9	0.137	−211.8	100.8	0.036
GSTM1 null & smoking	−60.4	113.3	0.594	−150.2	82.4	0.069
GSTT1 & GSTM1 null and smoking	−294.0	194.4	0.131	−340.4	141.2	0.016

ß represent the difference in mean birthweight for maternal characteristics in each row.
ß^*adjusted for body mass index, gestational age and loss outlier.
^**Continuous variable.
SE standard error of the difference between the means.
^† Excluded outliers.

ISSN: 1471-2393