Table 4.

Instrumental variable estimates of the unbiased associations of duration of exclusive breastfeeding on BMI (continuous), waist circumference, overweight and obesity (binary) and standing height at 11.5 years using randomized treatment as the instrumental variable

	Cluster adjusted			Further adjusted for baseline factorsa
	<3 m	3–<6 m	≥6 m	<3 m	3–<6 m	≥6 m
		Difference in mean (95% CI)			Difference in mean (95% CI)
BMI (kg/m2)	0.0 (ref)	0.46 (−0.36, 1.27)	0.81 (−0.51, 2.13)	0.0 (ref)	0.37 (−0.25, 0.98)	0.71 (−0.37, 1.79)
Waist circumference (cm)	0.0 (ref)	0.79 (−4.03, 5.61)	1.55 (−5.49, 8.59)	0.0 (ref)	1.51 (−3.46, 6.48)	2.59 (−6.60, 11.78)
Standing height (cm)	0.0 (ref)	1.60 (−2.39, 5.59)	2.15 (−3.99, 8.30)	0.0 (ref)	1.30 (−1.01, 3.61)	1.59 (−1.37, 4.56)
		Odds ratio (95% CI)			Odds ratio (95% CI)
BMI ≥85th percentileb	1.0 (ref)	1.61 (0.99, 2.63)	1.94 (0.86, 4.39)	1.0 (ref)	1.52 (1.05, 2.17)	1.71 (0.96, 3.04)
BMI ≥ 95th percentileb	1.0 (ref)	1.51 (0.86, 2.67)	1.98 (0.73, 5.37)	1.0 (ref)	1.45 (0.90, 2.34)	1.80 (0.82, 3.94)

BMI = body mass index; CI = confidence interval;

^aAdjusted for stratum-level variables (urban versus rural and East versus West Belarus), and for child age at follow-up, sex, birthweight and both maternal and paternal education;

^bbased on Centers for Disease Control and Prevention (CDC) 2000 reference data¹⁹ vs < 85^th percentile.