Table 3.

Median and quartiles of total maternal PFC serum concentrations^a by maternal and child characteristics.

Group	Median (quartiles)	p-valueb
Mother’s highest education		0.31
CSE/none	24.7 (21.6–30.8)
Vocational	28.1 (23.5–35.8)
O-level	27.0 (21.3–35.2)
A-level	29.6 (23.0–35.0)
Degree	26.6 (20.4–35.4)
Mother’s social class		0.92
Lower	27.4 (21.1–33.1)
Middle	28.7 (23.0–36.2)
Upper	28.7 (22.0–36.8)
Mother’s age at menarche		0.40
8–11 years	27.5 (22.7–35.7)
12–14 years	27.1 (21.4–34.4)
≥ 15 years	29.0 (24.2–35.2)
Mother’s pre-pregnancy BMI		0.46
<18.5	24.6 (21.2–31.6)
18.5–24.9	27.5 (21.6–35.5)
25.0–29.9	29.5 (24.5–35.0)
≥ 30.0	25.6 (21.1–33.2)
Mother’s age at delivery		0.27
<20 years	23.3 (20.2–28.2)
20–24 years	26.8 (21.4–33.5)
25–29 years	28.6 (22.0–35.2)
≥ 30 years	27.1 (21.4–35.7)
Child birth order		<0.0001
First born	30.8 (25.0–37.7)
Second born	27.1 (21.9–34.0)
Third born or later	24.4 (19.2–30.6)
Child ethnic background		0.03
White	27.3 (21.8–35.2)
Non-white	23.4 (20.3–32.5)

^aThe limits of detection (LOD) were 0.1 ng/mL (PFOSA, PFHxS, PFOA, PFNA) and 0.2 ng/mL (Et-PFOSA-AcOH, Me-PFOSA-AcOH, PFOS and PFDeA).

^bp-value for difference.