Polybrominated diphenyl ether serum concentrations in a Californian population of children, their parents, and older adults: an exposure assessment study

Wu, Xiangmei (May); Bennett, Deborah H; Moran, Rebecca E; Sjödin, Andreas; Jones, Richard S; Tancredi, Daniel J; Tulve, Nicolle S; Clifton, Matthew Scott; Colón, Maribel; Weathers, Walter; Hertz-Picciotto, Irva

doi:10.1186/s12940-015-0002-2

Environmental Health

Table 3 Results of multiple regression models predicting log-transformed PBDE serum concentrations (ng/g lipid) ^a

From: Polybrominated diphenyl ether serum concentrations in a Californian population of children, their parents, and older adults: an exposure assessment study

Effects	BDE-47	BDE-99	BDE-100	BDE-153	BDE-154	BDE-209
N	162	159	160	162	162	158
Intercept	2.67(0.27)**	0.83(0.29)	0.95(0.27)	1.72(0.33)	-2.28(0.79)	-2.44(1.14)
Age class (ref = parents of young children)
Young children	1.24(0.19)**	1.40(0.21)**	1.38(0.19)**	1.18(0.23)**	2.41(0.57)**	1.16(0.82)
Older adults	0.32(0.20)	0.11(0.22)	0.24(0.21)	0.21(0.25)	0.47(0.52)	2.31(0.90)*
Floor wipe concentration (pg/cm²)	0.03(0.01)**	0.03(0.01)*	0.12(0.03)**	-0.01(0.02)	0.69(0.25)**	0.01(0.003)*
Frequency of having fast food (ref = never)
<1 time/week	-0.18(0.24)	-0.02(0.26)	-0.06(0.24)	-0.10(0.29)	1.15(0.66)	-1.05(0.89)
≥1 time/week	-0.09(0.24)	-0.04(0.26)	0.12(0.24)	-0.04(0.29)	1.01(0.64)	-1.04(0.92)
Frequency of having pre-packed candy or bakery (ref = never)
<1 time/week	0.37(0.21)	0.35(0.23)	0.51(0.22)⁺	0.42(0.25)	0.59(0.54)	1.93(0.88)*
≥1 time/week	0.05(0.19)	-0.05(0.21)	0.005(0.19)	0.001(0.23)	-0.32(0.51)	0.36(0.81)
Frequency of eating (time/week)
dairy (based on dairy fat intake)	-0.02(0.01)	-0.002(0.01)	-0.01(0.01)	-0.01(0.01)	-0.03(0.03)	-0.02(0.04)
Beef	-0.03(0.05)	-0.06(0.05)	-0.03(0.05)	-0.07(0.06)	0.04(0.13)	0.21(0.19)
Pork	-0.05(0.06)	-0.08(0.07)	-0.09(0.06)	-0.08(0.07)	-0.46(0.20)*	-0.23(0.36)
Poultry	0.04(0.04)	0.04(0.04)	-0.002(0.04)	0.001(0.05)	0.05(0.10)	-0.09(0.17)
canned meat	0.67(0.26)*	0.89(0.27)*	0.55(0.26)⁺	0.14(0.31)	1.67(0.77)*	-10.05(6.47)
canned meat entrées	-0.04(0.10)	-0.05(0.11)	0.03(0.10)	-0.03(0.12)	0.94(0.38)*	1.25(0.50)*
canned fish	0.06(0.13)	-0.002(0.14)	0.06(0.13)	0.19(0.15)	-0.57(0.42)	-0.34(0.60)
fresh tuna and white ocean fish	0.12(0.10)	0.07(0.11)	0.17(0.10)	0.36(0.12)*	0.33(0.26)	0.68(0.40)
Salmon	0.05(0.15)	0.20(0.16)	0.06(0.15)	-0.06(0.18)	0.51(0.39)	-0.38(0.63)
fresh water fish	-0.13(0.18)	-0.08(0.20)	-0.13(0.18)	-0.03(0.22)	-0.58(0.50)	-1.73(1.34)
Variance components^b: Full Model (Null Model)
Between-household (Level 2)	0.64 (0.92)	0.51 (0.93)	0.59 (0.97)	0.84 (1.07)
Within-household (Level 1)	0.15 (0.22)	0.42 (0.42)	0.24 (0.24)	0.34 (0.26)
Intra-cluster correlation coefficient	0.81 (0.81)	0.55 (0.69)	0.71 (0.80)	0.71 (0.80)
Singer & Willett Pseudo R-square^c
Household variance component	0.30	0.45	0.38	0.21
Residual error variance component	0.30	0.00	-0.01	-0.29
Pseudo R-square	0.30^d	0.31^d	0.31^d	0.12^d	0.38^e	0.40^e

^aBDE-47, 99, 100, 153 were analyzed by generalized linear mixed-effect model, and BDE-154 and 209 were analyzed by logistic regression model due to their low detection. Results in top section of table are estimated regression coefficients (and standard error).
^bVariance components estimated by restricted maximum likelihood estimates and reported for full model as well as for the so-called null model that contains only random household intercepts and no fixed effects. Intra-cluster correlation coefficient is the ratio of the between-household variance component to the sum of the between- and within-household variance components.
^cSinger & Willett Pseudo R-squares describe for each variance component the proportional reduction in the null model variance component attributed to the full model [18].
^dR-square for mixed-effects linear regression model are reported as the proportional reduction in mean squared prediction error, using Snijder and Bosker’s estimator for a two-level random-intercepts model (the proportional reduction in the sum of variance components) [19].
^eR-square of the logistic regression model is the max-scaled R-square [20].
^**p-value < 0.01; ^*p-value < 0.05; ⁺marginally statistically significant, p = 0.05-0.07

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