Table 3.

Odds Ratios for Attention-Deficit/Hyperactivity Disorder in Offspring According to Regular Maternal Use of Acetaminophen During Different Exposure Periods, Nurses’ Health Study II, 1993–2005

Regular Acetaminophen Use	Main Analysis (n = 8,856)						Pregnancy Subset (n = 3,716)
	No. of Children	No. of Cases	Adjusted OR 1a	95% CI	Adjusted OR 2b	95% CI	No. of Children	No. of Cases	Adjusted OR 1a	95% CI	Adjusted OR 2b	95% CI
At time of pregnancy
Unexposed	7,626	596	1.00	Referent	1.00	Referent	3,203	266	1.00	Referent	1.00	Referent
Exposed	1,230	125	1.35	1.07, 1.71	1.34	1.05, 1.72	513	57	1.39	0.99, 1.95	1.46	1.01, 2.09
Before pregnancyc
Unexposed	7,410	588	1.00	Referent	1.00	Referent	3,123	266	1.00	Referent	1.00	Referent
Exposed	1,446	133	1.12	0.91, 1.38	1.06	0.85, 1.32	593	57	1.12	0.82, 1.53	1.08	0.78, 1.50
After pregnancyd
Unexposed	6,849	548	1.00	Referent	1.00	Referent	2,867	253	1.00	Referent	1.00	Referent
Exposed	2,007	173	1.05	0.88, 1.26	0.97	0.80, 1.18	849	70	0.91	0.69, 1.20	0.82	0.60, 1.11

Abbreviations: CI, confidence interval; OR, odds ratio.

^a Adjusted for maternal age, child’s birth year, child’s birth order, gestational diabetes, preeclampsia, and regular maternal use of aspirin or other nonsteroidal antiinflammatory drugs at the time of the pregnancy.

^b Adjusted for all of the above variables; additionally, acetaminophen use during all 3 periods was included in the same model.

^c Maternal acetaminophen use reported on the questionnaire completed 2 cycles before the one from which the pregnancy exposure was derived.

^d Maternal acetaminophen use reported on the questionnaire completed 2 cycles after the one from which the pregnancy exposure was derived.