63% within 100%). One third of mothers were primiparous, and almost half of mothers had symptoms of depression (CES-D ≥ 16). About half of the children were in regular out- of-home child care at 3.5 years of age, and by 5 years, 69% had attended some preschool. At the time of their 5-year assessment, almost one third of children had started kindergarten. U r i n a r y D A P c o n c e n t r a t i o n s . O P metabolite concentrations are summarized in Table 2. The geometric mean (GM) of average prenatal maternal urinary DAP concentrations was 109.0 nmol/L. The two pregnancy DAP measurements were weakly correlated (r = 0.15; p = 0.009). The DAP concentrations were lower in children than in mothers during pregnancy. Child DAPs were uncorrelated with maternal DAPs (Pearson r = 0.03; p = 0.60 with 3.5-year measures and r = –0.02; p = 0.77 with 5-year measures). Attention in children 3.5 and 5 years of age. When children were 3.5 years old, approximately 5% of mothers reported child behaviors that were in the borderline clini- cal range for attention problems and ADHD symptoms, with poorer scores on CBCL atten- tion-related scales among boys than among girls [see Supplemental Material, Table 1 (doi:10.1289/ehp.1002056)]. The NEPSY visual attention scores averaged 8.8 ± 2.3. When children were 5 years old, 4% of their mothers reported behaviors consistent with attention problems and 7% reported ADHD symptoms in the borderline clinical range; again, scores were higher in boys than in girls [see Supplemental Material, Table 1 (doi:10.1289/ehp.1002056)]. On the K-CPT, 19% of children scored markedly atypical for errors of omission, 17% for errors of com- mission, and 6% for hit reaction time; taken together, 8% of children scored ≥ 70% on the standardized ADHD Confidence Index scale. Boys had higher average scores on the ADHD Confidence Index than girls [see Supplemental Material, Table 1 (doi:10.1289/ ehp.1002056)]. Psychometricians rated 7% of children ≥ 7 on ADHD-related behaviors on the Hillside scale, and 8.5% of children were classified as having ADHD symptoms at 5 years according to the composite score. Continuous CBCL scores were correlated across ages (Pearson r = 0.46–0.54; p < 0.01), and at each age, all continuous attention measures were correlated with one another (Pearson r = 0.16–0.85; p < 0.01) except for the NEPSY test of visual attention, which was not correlated with any outcome (r = –0.09 to 0.04). Relation between prenatal DAPs and attention. Table 3 (categorical outcomes) and Table 4 (continuous outcomes) present the relationship of prenatal DAP concentrations and measures of child attention, not control- ling for child DAPs in the models. Adding Environmental Health Perspectives • volume 118 | number 12 | December 2010 child DAPs as a covariate produced very simi- lar results (data not shown). When the children were 3.5 years of age, prenatal DAP concentrations were positively associated with attention problems [OR = 3.0; 95% confidence interval (CI), 0.7–11.7; p = 0.12] and ADHD (OR = 3.1; 95% CI, 0.8–11.5; p = 0.09) in the borderline clinical range on the CBCL, although estimates were not statistically significant. When the children were 5 years of age, prenatal total DAP levels, and DM levels spe- cifically, were associated with maternal report (CBCL) of both ADHD scores and poorer attention scores when the scores were exam- ined as continuous outcomes (Table 4) but Organophosphate pesticides and attention not as categorical outcomes (Table 3). Total DAP concentrations (and total DM and DE concentrations separately) were nonsignifi- cantly associated with the continuous K-CPT ADHD Confidence Index scores (Table 4) and were significantly associated with this index when it was modeled as a dichotomous vari- able (Table 3). Specifically, for each 10-fold increase in DAP concentrations, children had five times the odds of scoring > 70% on the ADHD Confidence Index (OR = 5.1; 95% CI, 1.7–15.7). Prenatal total DAP concentrations were nonsignificantly associated with the psy- chometrician Hillside ratings of poor attention (OR = 3.0; 95% CI, 0.9–9.8; p = 0.06). Total DAP concentrations, and DM concentrations Table 2. GM concentrations (nmol/L) of average maternal urinary DAP metabolitesa during pregnancy, CHAMACOS Study, Salinas Valley, California [GM (95% CI)]. Marker of exposurea Pregnancy (n = 348) 3.5 Years (n = 290) 5 Years (n = 320) Total DAPs 109.0 (99.4–119.6) 77.5 (65.4–91.9) 92.6 (78.6–109.0) Total DEs 17.7 (16.1–19.4) 7.0 (5.8–8.3) 7.2 (6.0–8.7) Total DMs 76.8 (69.3–85.0) 62.5 (52.2–74.7) 72.4 (61.0–86.0) aNot adjusted for creatinine; measurements below the LOD were assigned a value of LOD/√2. Table 3. Adjusteda logistic models for attention-related outcomes at 3.5 and 5 years of age per 10-fold increase in prenatal urinary DAP concentrations [OR (95% CI)]. noutcome/n DAPs DEs DMs 3.2 (0.9–11.3)* 1.3 (0.4–4.4) 2.0 (0.5–8.5) 1.3 (0.4–4.0) 1.9 (0.9–4.1) 1.2 (0.6–2.7) 1.1 (0.3–3.6) 6.6 (2.2–19.3)# 2.3 (0.7–7.4) 1.7 (0.5–5.5) DEs 0.0 (–0.5 to 0.4) –0.2 (–0.9 to 0.6) –0.2 (–0.8 to 0.5) 0.4 (–0.1 to 0.9) 0.7 (–0.2 to 1.5) 3.4 (–1.7 to 8.6) 1771 Model 3.5 Years CBCL Attention problems ADHD 5 Years CBCL Attention problems ADHD K-CPT Markedly atypical Percent omissions Percent commissions Hit reaction time ADHD Confidence Index > 70th percentile Hillside Behavioral Rating Scale Attention ≥ 7 of 12 Composite ADHD indicator ADHD indicator Model 3.5 Years CBCL Attention problems ADHD NEPSY Visual attention 5 Years CBCL Attention problems ADHD K-CPT ADHD Confidence Index 17/330 18/329 13/322 23/322 59/312 54/312 20/311 25/297 23/322 27/319 3.0 (0.7–11.7) 3.1 (0.8–11.5)* 0.8 (0.2–3.8) 1.1 (0.3–3.5) 1.5 (0.7–3.3) 1.0 (0.5–2.2) 1.6 (0.5–5.2) 5.1 (1.7–15.7)# 3.0 (0.9–9.8)* 3.5 (1.1–10.7)** 2.1 (0.6–7.0) 2.8 (0.9–8.9)* 0.7 (0.2–2.8) 1.1 (0.4–3.2) 1.3 (0.6–2.8) 0.8 (0.4–1.6) 1.5 (0.5–4.6) 3.2 (1.2–8.9)** 2.9 (1.0–8.5)* 3.0 (1.1–8.2)** n 330 329 319 322 322 297 DAPs 0.3 (–0.2 to 0.7) 0.5 (–0.3 to 1.3) 0.2 (–0.5 to 0.8) 0.7 (0.2 to 1.2)** 1.3 (0.4 to 2.1)** 3.4 (–1.8 to 8.7) DMs 0.3 (–0.1 to 0.7)* 0.6 (–0.1 to 1.3)* 0.1 (–0.5 to 0.6) 0.6 (0.2 to 1.0)** 1.1 (0.3 to 1.9)** 2.0 (–2.8 to 6.9) aAdjusted for psychometrician, age at assessment, sex, child care, breast-feeding, maternal education, depressive symptoms, and PPVT. *p < 0.10. **p < 0.05. #p < 0.01. Table 4. Adjusteda linear models for attention-related outcomes at 3.5 and 5 years of age per 10-fold increase in prenatal urinary DAP concentrations [β (95% CI)]. aAdjusted for psychometrician, age at assessment, sex, child care, breast-feeding, maternal education, depressive symptoms, and PPVT. *p < 0.10. **p < 0.05.