Table 4.

Odds ratios and 95% confidence intervals for associations between quartiles of prenatal brominated flame retardant serum concentrations and ASD (relative to GP controls).

BFR/quartile	PBDE concentrationa	Caseb ($n$)	Control ($n$)	Model 1c	Model 2d	p-Trende
BB153
Q1	$\le 0.5$	114	93	1.0	1.0	0.86
Q2	0.51–1.06	124	92	1.10 (0.75, 1.61)	1.14 (0.76, 1. 70)
Q3	1.07–1.80	117	100	0.96 (0.65, 1.40)	0.86 (0.56, 1.31)
Q4	$>1.80$	154	98	1.28 (0.88, 1.86)	1.12 (0.73, 1.71)
BDE-28
Q1	$\le 0.49$	142	94	1.0	1.0	0.31
Q2	0.5–0.8	130	93	0.92 (0.64, 1.34)	0.95 (0.65, 1.39)
Q3	0.81–1.30	114	90	0.84 (0.57, 1.23)	0.89 (0.60, 1.31)
Q4	$>1.3$	116	99	0.77 (0.53, 1.13)	0.82 (0.56, 1.22)
BDE-47
Q1	$\le 9.2$	178	103	1.0	1.0	0.07
Q2	9.3–16.8	134	105	0.74 (0.52, 1.05)	0.77 (0.53, 1.10)
Q3	16.9–31.5	116	104	0.64 (0.45, 0.92)	0.71 (0.49, 1.02)
Q4	$>31.5$	117	104	0.65 (0.45, 0.93)	0.73 (0.50, 1.05)
BDE-99
Q1	$\le 2.7$	183	107	1.0	1.0	0.05
Q2	2.8–4.8	117	100	0.71 (0.50, 1.02)	0.75 (0.52, 1.08)
Q3	4.9–9.7	145	102	0.64 (0.44, 0.92)	0.72 (0.49, 1.04)
Q4	$>9.7$	88	98	0.61 (0.42, 0.87)	0.70 (0.48, 1.01)
BDE-100
Q1	$\le 2.1$	181	99	1.0	1.0	0.05
Q2	2.2–3.8	116	102	0.62 (0.43, 0.89)	0.66 (0.45, 0.95)
Q3	3.9–7.5	120	103	0.63 (0.44, 0.91)	0.68 (0.47, 0.98)
Q4	$>7.5$	116	103	0.61 (0.43, 0.88)	0.69 (0.47, 1.00)
BDE-153
Q1	$\le 2.3$	179	95	1.0	1.0	0.01
Q2	2.4–4.1	116	103	0.60 (0.42, 0.86)	0.62 (0.43, 0.90)
Q3	4.2–8.8	134	107	0.66 (0.46, 0.95)	0.71 (0.49, 1.03)
Q4	$>8.8$	104	102	0.54 (0.37, 0.78)	0.56 (0.38, 0.84)
Sumf						0.01
Q1	$\le 20.2$	166	94	1.0	1.0
Q2	$>20.2–35.1$	118	94	0.82 (0.58, 1.16)	0.83 (0.58, 1.18)
Q3	35.1–70.5	134	94	0.93 (0.66, 1.31)	1.01 (0.71, 1.44)
Q4	$\ge 70.5$	84	94	0.58 (0.40, 0.84)	0.64 (0.44, 0.93)

Note: ASD, autism spectrum disorder; GP, general population controls.

^aLipid-adjusted concentration in ng/g lipid, categorized into quartiles based on control distribution.

^bColumns show number of cases and controls, respectively, in the quartile.

^cModel 1: logistic regression adjusted for study matching factors (child sex, month and year of birth).

^dModel 2: $\text{Model}1+\text{maternal}\text{age}$ (continuous), maternal race/ethnicity (non-Hispanic white, Asian, Black/Pacific Islander/or other, Hispanic, or Missing), maternal weight at time of sample collection (quartiles), parity (multi- vs. primiparous), and maternal education ($<\text{high}\text{school}$, high school, college, graduate).

^ep-Trend from model with quartile median-value variable, adjusted as Model 2.

^fSum of all congeners shown in this table (those with at least 55% of study population with values $>\text{LOD}$).