Int. J. Environ. Res. Public Health 2009, 6 Table 1. Self-reported secondhand smoke exposure and cotinine measured exposure among nonsmokers by year and age group1: U.S., 1999-2006. Children (3-11) Self-Reported Home Exposure (%) 3 Cotinine Measured Exposure (%) 4 Geometric Mean Cotinine (ng/mL) Adolescents (12-19) Self-Reported Home Exposure (%) 3 Cotinine Measured Exposure (%) 4 Geometric Mean Cotinine (ng/mL) Adults (20+) Self-Reported Home 3 or Work Exposure (%) Home only (%) Work only (%) Home and Work (%) Cotinine Measured Exposure (%) 4 Geometric Mean Cotinine (ng/mL) 1999-2000 2001-2002 2003-2004 2005-2006 Sample Size 2 Mean (95% CI) Sample Size 2 Mean (95% CI) Sample Size 2 Mean (95% CI) Sample Size 2 Mean (95% CI) 1556 1179 1179 1517 1530 1530 2885 2885 2885 2885 2919 2919 22.7 (18.5- 26.8) 64.5 (56.4- 72.6) 0.16 (0.12- 0.20) 23.4 (19.4- 27.3) 63.2 (56.6- 69.9) 0.14 (0.12- 0.16) 15.7 (13.0- 18.3) 5.8 (4.8- 6.9) 8.7 (6.4- 11.1) 1.1 (0.5- 1.6) 47.4 (42.3- 52.5) 0.08 (0.07- 0.09) 1789 1423 1423 1610 1623 1623 3317 3317 3317 3317 3348 3348 23.7 (19.1- 28.3) 56.0 (47.8- 64.1) 0.16 (0.12- 0.20) 16.0 (12.5- 19.6) 45.7 (35.4- 56.0) 0.10 (0.08- 0.12) 13.1 (12.1- 14.2) 5.3 (4.6- 6.0) 7.2 (6.4- 8.1) 0.7 (0.2- 1.1) 37.3 (31.6- 43.1) 0.07 (0.06- 0.08) 1550 1265 1265 1524 1536 1536 3118 3118 3118 3118 3139 3139 22.3 (15.4- 29.2) 65.2 (56.2- 74.3) 0.18 (0.12- 0.26) 21.5 (16.1- 27.0) 56.6 (50.1- 63.2) 0.13 (0.11- 0.16) 14.8 (12.9- 16.6) 5.4 (4.1- 6.7) 8.5 (7.6- 9.4) 0.8 (0.2- 1.5) 42.4 (35.3- 49.5) 0.07 (0.06- 0.08) 1759 1300 1300 1519 1533 1533 3185 3185 3185 3185 3206 3206 14.6 (10.4- 18.8) 50.9 (45.8- 56.0) 0.11 (0.09- 0.13) 15.2 (10.9- 19.6) 47.0 (40.2- 53.8) 0.09 (0.08- 0.11) 35.8 (32.6- 39.0) 0.06 (0.06- 0.07) 1 Data source: National Health and Nutrition Examination Survey. 2 Unweighted 3 The presence of at least one household member who smokes in the home. 4 Detectable serum cotinine ≥ 0.05 ng/mL. * Significance of time trend analysis, P-value < 0.05. NA: Exposure rates are not reported because work exposure data are not yet available. Note: All the estimates are based on weighted analyses accounting for complex survey design. Adult self-reported exposures may not sum to total due to rounding. 1639 1999- 2006 Time Trend * * * * * 3.2. Self-Reported SHS Exposure Table 2 shows the percentage of nonsmokers who report SHS exposure in the home during the combined years of 1999-2006 for the three age groups disaggregated by sociodemographic characteristics. The prevalence rates of SHS exposure were 20.8%, 18.7%, and 14.5% respectively for children, adolescent, and adults. Prevalence rates of exposure were significantly higher for female children and adults compared to males, but were similar for male and female adolescents. Non- Hispanic Blacks had the highest exposure rates of all race/ethnic groups. These rates were significantly different from the rates for non-Hispanic white children and adults, even after controlling for other sociodemographic factors; however, the odds ratio for black children is less than one and significant.