Table 2.

Median plasma PCB and OC pesticide concentrations (μg/L) (n = 669)

OC concentrations	Non-demented individuals (n = 513)	Incident cases of dementia (n = 156)	P-value
PCB congeners
PCB 105	0.03 (0.01–0.04)	0.03 (0.02–0.04)	0.82
PCB 118	0.14 (0.08–0.23)	0.14 (0.09–0.23)	0.85
PCB 138	0.24 (0.17–0.36)	0.24 (0.16–0.35)	0.77
PCB 153	0.43 (0.30–0.60)	0.44 (0.28–0.61)	0.98
PCB 156	0.06 (0.04–0.08)	0.06 (0.04–0.08)	0.34
PCB 163	0.08 (0.05–0.11)	0.08 (0.05–0.12)	0.43
PCB 170	0.10 (0.07–0.14)	0.10 (0.07–0.15)	0.63
PCB 180	0.34 (0.24–0.49)	0.35 (0.24–0.51)	0.82
PCB 183	0.03 (0.02–0.05)	0.03 (0.02–0.05)	0.62
PCB 187	0.10 (0.06–0.14)	0.09 (0.06–0.14)	0.52
OC pesticides
β-HCH	0.12 (0.08–0.19)	0.13 (0.08–0.19)	0.88
HCB	0.17 (0.10–0.27)	0.19 (0.10–0.30)	0.28
Oxychlordane	0.11 (0.07–0.14)	0.11 (0.08–0.14)	0.87
cis-Nonachlor	0.02 (0.01–0.03)	0.02 (0.01–0.03)	0.37
trans-Nonachlor	0.15 (0.10–0.21)	0.14 (0.11–0.20)	0.77
p,p’-DDT	0.07 (0.02–0.13)	0.07 (0.02–0.13)	0.80
p,p’-DDE	4.10 (2.10–7.60)	4.10 (2.00–8.05)	0.82

Note: β-HCH beta hexachlorocyclohexane, HCB hexaclorobenzene, OC organochlorine compound, PCBs polychlorinated biphenyl, p,p’-DDT, 1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane, p,p’-DDE, 1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene

Values in parentheses represent the interquartile range

P-values were obtained using non-parametric Wilcoxon rank-sum tests