Table 2.

Distribution of exposure and covariables of interest across participating studies.

Exposure and covariables of interest	INUENDO-Greenland	INUENDO-Ukraine	PCB cohort	HUMIS	DNBC	FETOTOXa	INMA-Valencia	INMA-Sabadell	INMA-Gipuzkoa
	($n=518$)	($n=485$)	($n=185$)	($n=989$)	($n=914$)	($n=759$)	($n=371$)	($n=378$)	($n=227$)
Measured PFOS concentrations {ng/mL [median (range)]}a	20.19 (4.1–87.3)	5.01 (0.8–18.1)	0.03 (0.0–0.7)	0.11 (0.0–0.5)	33.55 (6.4–106.7)	26.90 (3.9–103.8)	6.20 (0.8–18.5)	6.39 (0.3–38.6)	5.30 (1.2–17.5)
Measured PFOA concentrations {ng/mL [median (range)]}b	1.83 (0.5–5.1)	0.96 (0.2–9.8)	0.03 (0.0–0.2)	0.04 (0.0–0.2)	5.26 (0.5–41.5)	4.00 (0.5–17.7)	2.39 (0.3–10.1)	2.87 (0.3–31.6)	1.66 (0.4–8.1)
Child sex (% male)	53.5	52.8	43.2	54.2	50.3	80.4	51.8	51.9	50.2
Child birth weight [kg ($\text{mean}\pm \text{SD}$)]	$\mathrm{3,602}\pm 588$	$\mathrm{3,270}\pm 419$	$\mathrm{3,324}\pm 486$	$\mathrm{3,535}\pm 652$	$\mathrm{3,636}\pm 527$	$\mathrm{3,591}\pm 585$	$\mathrm{3,203}\pm 506$	$\mathrm{3,263}\pm 411$	$\mathrm{3,316}\pm 455$
Maternal educational level (%)
Low	56.8	60.6	46.5	8.4	2.6	4.6	26.1	23.7	10.2
Medium	41.7	39.4	50.3	13.7	30.5	37.4	45.0	44.4	37.2
High	1.5	0.0	3.2	77.9	66.9	58.0	28.8	31.9	52.7
Maternal age at delivery [y ($\text{mean}\pm \text{SD}$)]	$27.3\pm 6.3$	$25.1\pm 4.8$	$26.1\pm 4.9$	$30.3\pm 4.7$	$30.4\pm 4.3$	$29.6\pm 4.4$	$31.8\pm 4.0$	$31.8\pm 4.2$	$33.0\pm 3.3$
Maternal prepregnancy BMI [$\mathrm{kg}/{\mathrm{m}}^2$ ($\text{mean}\pm \text{SD}$)]	$27.2\pm 3.9$	$24.4\pm 3.1$	$22.3\pm 4.2$	$24.3\pm 4.2$	$23.7\pm 4.2$	$23.9\pm 4.3$	$23.8\pm 4.6$	$24.0\pm 4.7$	$22.9\pm 3.3$
Prenatal maternal smoking (% smokers)c	87.4	31.0	17.6	7.8	20.8	28.6	39.1	26.7	22.7
Parity (% nulliparous)	31.9	80.0	36.8	37.8	45.1	47.5	57.4	59.0	55.5
Duration of total breastfeeding [months ($\text{mean}\pm \text{SD}$)]	$9.3\pm 4.1$	$7.7\pm 3.9$	$9.8\pm 9.8$	$12.4\pm 5.2$	$8.0\pm 4.7$	$6.7\pm 4.8$	$5.3\pm 4.4$	$6.4\pm 4.5$	$7.0\pm 4.6$
Sample time from birth [months ($\text{mean}\pm \text{SD}$)]	$-3.2$ $\pm 2.7$	$-3.7$ $\pm 2.9$	$0.1\pm 0.0$	$1.2\pm 0.6$	$-7.3$ $\pm 0.5$	$-7.0$ $\pm 1.1$	$-6.2$ $\pm 0.4$	$-6.0$ $\pm 0.5$	$-6.0$ $\pm 0.5$

Note: BMI, body mass index; DNBC, Danish National Birth Cohort; HUMIS, Norwegian Human Milk Study; INMA, Infancia y Medio Ambiente; PCB, polychorinated biphenyl; PFOA, perfluorooctanoic acid; PFOS, perfluorooctane sulfonate; SD, standard deviation.

^aObservations in FETOTOX were selected using case–cohort sampling.

^bPFAS concentrations were measured in maternal serum/plasma in INUENDO-Greenland, INUENDO-Ukraine, DNBC, FETOTOX, INMA-Valencia, INMA-Sabadell, and INMA-Gipuzkoa and in breast milk in HUMIS and the PCB cohort. Specific details on chemical-analytical methods and detection/quantification limits in each study are included in Table S1.

^cIn INUENDO maternal smoking was assessed prior to pregnancy.