Table 2.

Adjusted GM concentrations (95% CIs) of 2,4-DCP and 2,5-DCP (μg/L) according to age, NHANES cycle, and race/ethnicity × family income, NHANES 2003–2010.

Variable	Sample size (n)	2,5-DCP adjusted GM (95% CI)	2,4-DCP adjusted GM (95% CI)
Age group (years)
6–11	1,474	10.57 (8.93, 12.52)	1.12 (1.08, 1.16)
12–19	2,245	7.79 (6.59, 9.19)	0.88 (0.84, 0.91)
20–59	4,480	8.32 (7.44, 9.31)	0.88 (0.85, 0.90)
> 60	2,227	10.91 (9.34, 12.74)	1.06 (1.02, 1.10)
NHANES cycle
2003–2004	2,525	12.27 (10.10, 14.9)	1.01 (0.94, 1.07)
2005–2006	2,548	9.5 (7.12, 12.69)	0.95 (0.90, 1.010)
2007–2008	2,604	8.71 (7.17, 10.58)	0.97 (0.92, 1.01)
2009–2010	2,749	6.07 (5.05, 7.30)	0.80 (0.77, 0.84)
Race/ethnicity by family incomea
Mexican American: below poverty	748	31.95 (22.54, 45.30)	1.95 (1.86, 2.04)
Mexican American: low	695	23.02 (16.60, 31.91)	1.69 (1.61, 1.77)
Mexican American: middle	467	18.83 (12.87, 27.56)	1.40 (1.30, 1.50)
Mexican American: high	235	9.28 (6.12, 14.08)	0.95 (0.83, 1.07)
Non-Hispanic white: below poverty	607	7.98 (6.37, 10.00)	0.86 (0.80, 0.92)
Non-Hispanic white: low	935	6.71 (5.49, 8.20)	0.74 (0.69, 0.79)
Non-Hispanic white: middle	1,078	6.47 (5.38, 7.80)	0.80 (0.77, 0.84)
Non-Hispanic white: high	1,551	6.21 (5.46, 7.06)	0.79 (0.75, 0.82)
Non-Hispanic black: below poverty	653	26.02 (19.81, 34.16)	1.53 (1.44, 1.62)
Non-Hispanic black: low	612	31.56 (23.39, 42.57)	1.83 (1.74, 1.92)
Non-Hispanic black: middle	577	26.55 (20.82, 33.87)	1.69 (1.62, 1.76)
Non-Hispanic black: high	435	20.70 (15.95, 26.88)	1.27 (1.18, 1.36)
Adjusted GMs were estimated using the regression equation with the intercept and regression coefficient for a given level of the categorical variable specified, and multiplying the β coefficient for all other categorical covariates by their estimated weighted percentage distribution. aBelow poverty, PIR < 1; low, PIR = 1–1.93; middle, PIR = 1.93–3.71; high, PIR > 3.71.