Table 2. Association between breastfeeding and childhood overweight and obesity.

	Unmatched sample,unadjusted analyses(n = 13163)		Matched sample, unadjusted analyses*n = 8034		Matched sample, adjusted analyses*n = 8034
Overweight
	OR (95% CI)	p-value	OR (95% CI)	p-value	OR (95% CI)		p-value
Breastfeeding		<0.001		<0.001			0.002
<4 months	1		1		1
≥4 months	0.63 (0.57–0.69)		0.76 (0.67–0.86)		0.81 (0.71–0.92)
Age							<0.001
3–6 years					1
7–10 years					1.96 (1.63–2.36)
11–13 years					2.24 (1.84–2.74)
14–17 years					2. 09 (1.71–2.55)
Sex							0.541
male					1
female					0.96 (0.84–1.09)
Socioeconomic status							<0.001
low					1
middle					0.73 (0.61–0.89)
high					0.53 (0.42–0.66)
Parental overweight							<0.001
both parents					1
one parent					0.47 (0.40–0.54)
no parent					0.23 (0.20–0.28)
Obesity
	OR (95% CI)	p-value			OR (95% CI)	p-value
Breastfeeding		<0.001		<0.001		0.005
<4 months	1		1		1
≥4 months	0.54 (0.47–0.64)		0.69 (0.57–0.85)		0.75 (0.61–0.92)
Age						<0.001
3–6 years					1
7–10 years					2.01 (1.49–2.72)
11–13 years					2.04 (1.47–2.81)
14–17 years					2.86 (2.10–3.88)
Sex						0.540
male					1
female					0.94 (0.77–1.15)
Socioeconomic status						<0.001
low					1
middle					0.69 (0.52–0.90)
high					0.45 (0.32–0.63)
Parental overweight						<0.001
both parents					1
one parent					0.40 (0.32–0.49)
no parent					0.19 (0.14–0.26)

*adjusted for age group, sex, socioeconomic status, and parental overweight