Figure 1Interaction between C-reactive protein (CRP) and polychlorinated biphenyls (PCBs) or organochlorine (OC) pesticides for estimation of homeostasis model assessment of insulin resistance (HOMA-IR). Detectable values of each persistent organic pollutant (POP) were individually ranked, and the rank orders of the individual POPs in each subclass were summed to arrive at the subclass value. All undetectable values were ranked as 0. The summary values were categorized by cutoff points of 25th, 50th, and 75th values of the sum of ranks. Geometric means of HOMA-IR values are plotted. Adjusted for age, sex, race, poverty income ratio, body mass index, waist circumference, smoking status, physical activity, alcohol consumption, and OC pesticides (in models including PCBs) or PCBs (in models including OC pesticides).
Table 1.General characteristics of the study subjects according to quartiles of C-reactive protein
|
Quartiles of C-reactive protein (mg/L)
|
|
Total |
< 25th (≦0.09) |
25th - <50th (0.10 - 0.21) |
50th - < 75th (0.22 - 0.48) |
≥75th (≧0.49) |
p-trend1
|
|
n = 748 |
n = 194 |
n = 177 |
n = 190 |
n = 187 |
|
Mean±standard deviation |
|
|
|
|
|
|
Age (y) |
48.2±18.8 |
42.7±18.9 |
49.7±18.1 |
50.3±18.0 |
50.3±19.3 |
<0.01 |
Poverty income ratio |
2.7±1.6 |
3.0±1.6 |
2.7±1.6 |
2.5±1.5 |
2.5±1.4 |
<0.01 |
Body mass index (kg/m2) |
27.6±5.7 |
24.7±4.6 |
26.8±4.4 |
28.2±4.9 |
30.8±6.6 |
<0.01 |
Waist circumference (cm) |
95.2±14.3 |
87.0±13.5 |
94.1±12.0 |
97.1±12.5 |
103.0±14.4 |
<0.01 |
Alcohol intake (g/d) |
8.9±24.1 |
11.1±29.2 |
11.7±28.1 |
7.1±19.7 |
5.7±16.8 |
<0.01 |
HOMA-IR |
2.9±2.2 |
2.1±1.2 |
2.5±1.7 |
3.0±1.8 |
3.7±3.1 |
<0.01 |
Proportion (%) |
|
|
|
|
|
|
Men |
46.3 |
57.7 |
52.0 |
43.7 |
31.6 |
<0.01 |
Non-Hispanic white |
49.5 |
47.4 |
50.3 |
53.2 |
47.1 |
0.03 |
Current smoker |
19.1 |
15.0 |
23.2 |
19.0 |
19.8 |
0.27 |
Physically inactive |
46.3 |
38.7 |
45.2 |
41.6 |
59.9 |
<0.01 |
Table 2.Adjusted1 geometric means of C-reactive protein by quartiles2 of PCDDs, PCDFs, dioxin-like PCBs, nondioxin-like PCBs, and OC pesticides
Analyte |
Quartiles of POPs
|
p-trend3
|
< 25th |
25th - < 50th |
50th - < 75th |
≥ 75th |
PCDDs |
No. of subject |
187 |
187 |
187 |
187 |
|
|
Model 1 |
0.19 |
0.21 |
0.21 |
0.21 |
0.44 |
|
Model 2 |
0.19 |
0.21 |
0.20 |
0.21 |
0.50 |
PCDFs |
No. of subject |
187 |
187 |
187 |
187 |
|
|
Model 1 |
0.23 |
0.18 |
0.22 |
0.19 |
0.43 |
|
Model 2 |
0.22 |
0.19 |
0.21 |
0.19 |
0.47 |
Dioxin-like PCBs |
No. of subject |
186 |
188 |
187 |
187 |
|
|
Model 1 |
0.22 |
0.22 |
0.20 |
0.19 |
0.28 |
|
Model 2 |
0.22 |
0.23 |
0.20 |
0.19 |
0.27 |
|
Model 3 |
0.23 |
0.23 |
0.19 |
0.17 |
0.04 |
Non-dioxin like PCBs |
No. of subject |
187 |
187 |
187 |
187 |
|
|
Model 1 |
0.24 |
0.22 |
0.21 |
0.17 |
0.04 |
|
Model 2 |
0.22 |
0.22 |
0.20 |
0.19 |
0.28 |
|
Model 3 |
0.24 |
0.23 |
0.20 |
0.17 |
0.04 |
OC pesticides |
No. of subject |
186 |
188 |
187 |
187 |
|
|
Model 1 |
0.15 |
0.21 |
0.20 |
0.25 |
0.01 |
|
Model 2 |
0.16 |
0.22 |
0.19 |
0.23 |
0.05 |
|
Model 3 |
0.15 |
0.22 |
0.20 |
0.28 |
0.01 |
Table 3.Adjusted1 geometric means of C-reactive protein by quartiles2 of POPs belonging to dioxin-like PCBs, non-dioxin-like PCBs, and OC pesticides
Analyte |
Not detectable |
Quartiles of POPs
|
p-trend3
|
< 25th |
25th - < 50th |
50th - < 75th |
≥ 75th |
Dioxin-like PCBs |
|
|
|
|
|
|
PCB74 |
0.23 |
0.22 |
0.19 |
0.20 |
0.15 |
0.03 |
PCB118 |
0.23 |
0.22 |
0.19 |
0.20 |
0.17 |
0.12 |
PCB126 |
0.22 |
0.20 |
0.20 |
0.23 |
0.18 |
0.62 |
PCB169 |
0.26 |
0.22 |
0.21 |
0.17 |
0.17 |
<0.01 |
Non-dioxin like PCBs |
|
|
|
|
|
|
PCB138 |
0.24 |
0.20 |
0.21 |
0.20 |
0.17 |
0.05 |
PCB153 |
0.25 |
0.22 |
0.22 |
0.21 |
0.15 |
0.01 |
PCB170 |
0.21 |
0.23 |
0.19 |
0.25 |
0.16 |
0.40 |
PCB180 |
0.24 |
0.22 |
0.20 |
0.21 |
0.16 |
0.03 |
PCB187 |
0.22 |
0.23 |
0.22 |
0.20 |
0.14 |
0.03 |
OC pesticides |
|
|
|
|
|
|
p,p’-DDE |
- |
0.18 |
0.20 |
0.23 |
0.22 |
0.06 |
Oxychlordane |
0.18 |
0.19 |
0.20 |
0.24 |
0.23 |
0.09 |
Trans-nonachlor |
0.17 |
0.18 |
0.22 |
0.22 |
0.25 |
0.03 |
β-hexachlorocyclohexane |
0.16 |
0.19 |
0.23 |
0.23 |
0.25 |
0.01 |
Table 4.Adjusted1 geometric means of HOMA-IR, and interactions2 between C-reactive protein and PCBs or OC pesticides for estimating HOMA-IR
Analyte |
Quartiles of C-reactive protein
|
p-interaction |
<25th |
25th - < 50th |
50th -< 75th |
≥ 75th |
Quartiles3 of PCBs |
|
|
|
<0.01 |
<25th |
3.67 |
3.28 |
4.05 |
3.55 |
|
25th - <50th |
3.39 |
3.57 |
3.43 |
3.69 |
|
50th - <75th |
3.18 |
3.39 |
3.70 |
3.90 |
|
≥75th |
3.15 |
3.27 |
3.67 |
3.90 |
|
Quartiles3 of OC pesticides |
|
|
|
<0.01 |
<25th |
3.42 |
3.23 |
3.74 |
3.20 |
|
25th - <50th |
3.37 |
3.14 |
3.57 |
3.59 |
|
50th - <75th |
3.33 |
3.60 |
3.76 |
3.77 |
|
≥75th |
3.17 |
3.59 |
3.82 |
4.31 |
|