Table 4.

Maternal smoking by tobacco consumption burden, leukemia cases, and control mothers, children <2 year, Brazil, 1999–2007.

Timing of exposure/smoking burden	Controls (n = 423), n (%)	ALL (n = 193), n (%)	AML (n = 59), n (%)	ALL		AML
				OR (95% CI)	OR Adjusteda (95% CI)	OR (95% CI)	OR Adjusteda (95% CI)
PRECONCEPTIONb
Non-smokers	304 (71.9)	137 (71.0)	47 (79.7)	1.00	1.00	1.00	1.00
Moderate smokers	109 (25.7)	45 (23.3)	11 (18.6)	0.92 (0.61–1.37)	0.93 (0.59–1.45)	0.65 (0.33–1.30)	0.59 (0.27–1.28)
Heavy smokers	10 (2.4)	11 (5.7)	1 (1.7)	2.44 (1.01–5.88)	2.52 (0.95–6.72)	0.65 (0.81–5.17)	0.80 (0.93–6.90)
FIRST TRIMESTER
Non-smokers	354 (83.7)	154 (79.8)	53 (89.8)	1.00	1.00	1.00	1.00
Moderate smokers	65 (15.4)	33 (17.1)	5 (8.5)	1.17 (0.74–1.85)	1.10 (0.65–1.82)	0.51 (0.20–1.33)	0.44 (0.15–1.31)
Heavy smokers	4 (0.9)	6 (3.1)	1 (1.7)	3.45 (0.96–12.39)	3.35 (0.75–15.0)	1.67 (0.18–15.23)	2.70 (0.27–26.5)
SECOND TRIMESTER
Non-smokers	356 (84.2)	164 (85.0)	54 (91.5)	1.00	1.00	1.00	1.00
Moderate smokers	65 (15.4)	23 (11.9)	4 (6.8)	0.77 (0.46–1.28)	0.47 (0.02–0.92)	0.41 (0.14–1.16)	0.17 (0.01–2,14)
Heavy smokers	2 (0.4)	6 (3.1)	1 (1.7)	6.51 (1.30–32.0)	6.82 (1.09–4.30)	3.30 (0.30–37.0)	5.97 (0.47–76.0)
THIRD TRIMESTER
Non-smokers	357 (84.4)	165 (85.5)	54 (91.5)	1.00	1.00	1.00	1.00
Moderate smokers	64 (15.2)	22 (11.4)	4 (6.8)	0.74 (0.44–1.25)	0.96 (0.54–1.69)	0.41 (0.14–1.16)	0.43 (0.10–1.18)
Heavy smokers	2 (0.4)	6 (3.1)	1 (1.7)	6.49 (1.30–32.0)	6.81 (1.09–42.7)	3.30 (0.30–37.0)	6.03 (0.47–77.0)
BREASTFEEDINGc
No smokers	357 (84.4)	164 (85.0)	55 (93.2)	1.00	1.00	1.00	1.00
Moderate smokers	64 (15.2)	22 (11.4)	3 (5.1)	0.75 (0.45–1.26)	0.94 (0.53–1.66)	0.30 (0.09–1.00)	0.37 (0.11–1.28)
Heavy smokers	2 (0.4)	7 (3.6)	1 (1.7)	7.62 (1.57–32.0)	7.78 (1.33–45.5)	3.25 (0.29–36.4)	6.05 (0.47–77.0)

^aAdjusted OR by maternal age at birth, maternal education, oral contraceptives use during pregnancy, birth weight, and infant skin color.

^bThree months before pregnancy.

^cThree months after birth.