Table 3.

ORs and 95% CIs from logistic regression analysis for the association between urinary trichlorophenols and attention deficit hyperactivity disorder among children aged 6–15 years, NHANES, 1999–2004

Chemicals	Total sample (n)	Cases (n)	Crude odd ratios	Adjusted odd ratios*
2,4,5-TCP
Below the LOD	1776	145	Referent group	Referent group
<Median (1.03 μg/g)	367	30	1.27 (0.78 to 2.06)	1.01 (0.47 to 2.20)
≥Median (1.03 μg/g)	368	24	0.89 (0.48 to 1.65)	0.98 (0.48 to 1.99)
p for trend	–	–	0.72	0.95
2,4,6-TCP
Below the LOD	846	56	Referent group	Referent group
<Median (3.58 μg/g)	834	84	1.84 (1.25 to 2.72)	1.54 (0.97 to 2.43)
≥Median (3.58 μg/g)	834	59	1.56 (1.12 to 2.16)	1.77 (1.18 to 2.66)
p for trend	–	–	0.008	0.006

^*Adjusted for age, gender, poverty-to-income ratio, maternal smoking during pregnancy, low birth weight, blood lead and serum cotinine.

LOD, limit of detection; TCP, trichlorophenol.