Exposure to prenatal secondhand smoke and early neurodevelopment: Mothers and Children’s Environmental Health (MOCEH) study

Table 3 Association between maternal urine cotinine in early pregnancy and children’s neurodevelopment at 24 months stratified by genetic polymorphism and breastfeeding behavior

	Cotinine	≤ 1.90^a					> 1.90^a
	Cotinine	n	β^b	95% C.I.	P	P _interaction ^d	n	β^b	95% C.I.	P	P _interaction ^d
MDI	GSTM1/GSTT1
	Any present	241	2.51	(−1.14, 6.16)	0.18	0.25	251	− 1.64	(−4.79, 1.52)	0.31	0.16
	Both null	119	−0.40	(−5.53, 4.74)	0.88	0.25	98	−5.78	(−10.69, − 0.87)	0.02	0.16
	Breastfeeding only up to 6 months³
	Yes	135	0.35	(−4.38, 5.09)	0.88	0.38	122	−0.24	(−4.69, 4.20)	0.91	0.22
	No	195	2.31	(−1.94, 6.56)	0.29	0.38	188	−3.75	(−7.51, 0.00)	0.05	0.22
PDI	GSTM1/GSTT1
	Any present	241	2.45	(−1.07, 5.98)	0.17	0.83	251	−0.42	(−3.35, 2.51)	0.78	0.87
	Both null	119	2.26	(−2.95, 7.46)	0.39	0.83	98	−1.25	(−5.64, 3.14)	0.57	0.87
	Breastfeeding only up to 6 months^c
	Yes	135	−0.70	(−5.86, 4.46)	0.79	0.16	122	0.86	(−3.55, 5.27)	0.70	0.23
	No	195	3.29	(−0.51, 7.09)	0.09	0.16	188	−0.70	(−3.96, 2.56)	0.67	0.23

^amedian of urinary cotinine level = 1.90 (ng/ml)
^bGeneral Linear Model adjusted for maternal age, maternal education, gestational age, infant sex, region, breastfeeding behavior, primary caregiver, and creatinine
^cGeneral Linear Model adjusted for maternal age, maternal education, gestational age, infant sex, region, primary caregiver, and creatinine
^dP-value for interaction
MDI Mental Development Index, PDI Psychomotor Development Index, GSTM1 Glutathione S-transferases mu1, GSTT1: Glutathione S-transferases theta 1

ISSN: 1476-069X