PAH, Epigenetic and Asthma Table 4. Number (%) of African Americans, Males, and Methylated Subjects by PAH Exposure Categories (,2.41, . = 2.41)a. Characteristics* Ethnicity (%AA) Gender (% Males) ACSL3 59CGI Status (% Methylated) PAH,2.41 (N = 30) PAH$2.41 (N = 26) Subjects (N = 56) Odds Ratios (95% CI’s) 15 (50%) 12 (40%) 7 (23%) 15 (58%) 12 (46%) 21 (81%) 30 (54%) 24 (43%) 28 (50%) 1.4 (0.5, 3.9) 1.3 (0.4, 3.7) 13.8 (3.8, 50.2)b Note: *Odds Ratios, 95% Confidence Intervals (OR, 95%CI) measuring the odds of high PAH exposure in African Amercians (Compared to Dominicans), males (Compared to Females), and subjects with methylated ACSL3 59CGI (compared to those with unmehtylated CGI) assayed by MSPCR (N = 56). aThe PAH cutpoint value 2.41 was obtained from an ROC curve where we considered that methylation status could be determined by PAH exposure level. We considered ACSL3 59CGI to be methylated (determined by MSPCR) above 2.41 and unmethylated below 2.41. The value of the cutpoint determined the sensitivity (i.e. number of correctly classified unmethylated subjects or true positives), the specificity (i.e. number of correctly classified unmethylated subjects or true negatives), and the number of false positives and false negatives. The median of samples with PAH exposure ,2.41 (N = 30) was 3.58 where that of samples with PAH exposure . = 2.41 was 1.55. bp,0.001. Odds Ratio(OR) = 13.8, which may also be interpreted as the odds of ACSL3 59CGI methylated when PAH = or .2.41 (compared to ,2.41). doi:10.1371/journal.pone.0004488.t004 Table 5. Characteristics of Subjects (Number, % Column Total) by ACSL3 59CGI methylation Status and Asthma Status Assayed by MSPCR (N = 56). ACSL3 59CGI Methylation Status Asthma (% Yes with asthma)a Median PAH exposure with in each groupb (Min, Max) Methylated 11/28 (39%) 3.39 ng/m3 (1.11, 34.48) Unmethylated All 4/28 (14%) 1.7 ng/m3 (0.49, 3.33) 15/56 (27%) 2.26 ng/m3 (0.49, 34.48) Odds Ratios (95% CI’s) 3.9 (1.1, 14.3) Note: ap = 0.03. OR = 3.9 measuring the odds of asthma given ACSL3 59-CGI was methylated (M) verus unmethylated (U). bp,0.001 testing the equality of median PAH exposure levels between subjects with methylated and unmethylated ACSL3 59CGI in their UCWBCs. doi:10.1371/journal.pone.0004488.t005 Table 6. Population characteristics. Category Baby’s sex (%) Ethnicity (%) Maternal ages (yrs)(mean6SD) Median total PAH (ng/m3) Probable asthmatic up to 5 years (%) Note: *Among N = 606 samples with available data. doi:10.1371/journal.pone.0004488.t006 Subcategory Full cohort (N = 729) Study sample (N = 56) p-value Male Female Dominican African American 25.164.9 48.3 51.7 63.5* 36.5 2.3 27.2 25.464.6 42.9 57.1 46.4 53.6 2.3 26.8 0.65 0.40 ,0.01 0.83 0.95 Table 7. Total maternal PAH exposure levels in the study sample as compared to the full cohort. Included in study Not included* N 56 546* Min 0.49 0.27 p25 1.48 1.45 p50 2.26 2.29 p75 3.43 3.69 Max 34.48 145.00 Geomean 2.37 2.38 95% CI 1.96, 2.86 2.23, 2.53 Note: *There are 127 participants in the full cohort for whom we are missing prenatal PAH. No significant differences by ttest (means) or kruskal-wallis (medians). p25, p50 and p75 denote means at the 25, 50 and 75 percentile. doi:10.1371/journal.pone.0004488.t007 PLoS ONE | www.plosone.org 12 February 2009 | Volume 4 | Issue 2 | e4488