TABLE 4.

Associations between prenatal PCB and DDE exposure in quartiles and waist circumference in children 7 y of age according to maternal prepregnancy BMI, Faroese Cohort 1996–2001 (n = 539)¹

	Waist circumference
	Girls (regression coefficient; n = 259)				Boys (regression coefficient; n = 280)
	Normal-weight mothers (n = 172)		Overweight mothers (n = 87)		Normal-weight mothers (n = 188)		Overweight mothers (n = 92)
PCBs and DDE in quartiles	Estimate (95% CI)	P	Estimate (95% CI)	P	Estimate (95% CI)	P	Estimate (95% CI)	P
PCBs
Second quartile (0.75–1.18 μg/g lipid)	0.80 (−0.29, 1.89)	0.17	1.37 (0.13, 2.61)	0.03	0.41 (−0.46, 1.27)	0.36	−0.44 (−2.08, 1.20)	0.60
Third quartile (1.19–1.95 μg/g lipid)	1.00 (−0.07, 2.06)	0.08	2.20 (0.74, 3.65)	0.004	−0.05 (−0.95, 0.85)	0.94	−1.46 (−3.03, 0.11)	0.07
Fourth quartile (>1.95 μg/g lipid)	1.25 (0.04, 2.45)	0.04	2.48 (1.10, 3.85)	0.001	−0.15 (−1.05, 0.75)	0.97	0.12 (−1.49, 1.72)	0.89
Continuous	0.60 (0.05, 1.16)	0.03	1.15 (0.38, 1.92)	0.004	−0.12 (−0.58, 0.35)	0.87	−0.36 (−1.09, 0.38)	0.34
DDE
Second quartile (0.34–0.56 μg/g lipid)	−1.46 (−2.48, −0.44)	0.005	0.77 (−0.48, 2.03)	0.22	0.30 (−0.56, 1.16)	0.71	0.04 (−1.77, 1,85)	0.96
Third quartile (0.57–0.92 μg/g lipid)	0.81 (−0.16, 1.78)	0.12	2.20 (0.60, 3.80)	0.008	0.29 (−0.56, 1.15)	0.68	−0.29 (−1.20, 1.42)	0.74
Fourth quartile (>0.92 μg/g lipid)	0.03 (−1.04, 1.10)	0.86	2.21 (0.84, 3.56)	0.002	−0.01 (−0.92, 0.94)	0.82	0.02 (−1.66, 1.69)	0.98
Continuous	0.28 (−0.23, 0.79)	0.28	0.93 (0.36, 1.51)	0.002	−0.01 (−0.38, 0.40)	0.99	−0.26 (−0.91, 0.38)	0.94

¹Waist circumference was measured only at 7 y of age. PCB and DDE concentrations (in μg/g lipid) were measured in maternal serum and log transformed. The PCB concentration was based on the sum of PCB congeners 138, 153, and 180. Sex interactions between PCB and DDE concentrations and waist circumference at 7 y of age were significant at P < 0.10. Maternal normal weight was defined as maternal prepregnancy BMI (in kg/m²) <25, and maternal overweight was defined as maternal prepregnancy BMI ≥25. The interaction with maternal prepregnancy BMI between the DDE concentration and waist circumference was significant at P < 0.10. Regression coefficients were derived by using a multiple linear regression model adjusted for parity (pregnancies before the current one), maternal age, and child BMI at 7 y of age. Continuous estimated coefficients are the absolute change in BMI expected when the log-transformed PCB variable was multiplied by 10. DDE, p,p′-dichlorodiphenyldichloroethylene; PCB, polychlorinated biphenyl.