Factors associated with plasma concentrations of polychlorinated biphenyls (PCBs) and dichlorodiphenyldichloroethylene (p,p’-DDE) in the Canadian population

Figures & data

Table 1. Description of study population (CHMS, Cycle 1).

	Nunweighted	Nweighted	%weighted*
Total	1668	23 308 581	100.0%
Sex  Males  Females	801 867	11 661 741 11 646 841	50.0% 50.0%
Age  20–39  40–59  60–80	526 596 546	8 776 558 9 641 941 4 890 082	37.7% 41.4% 21.0%
Region of residence  Quebec  Ontario  Rest of Canada	439 604 625	5 588 808 8 965 508 8 754 266	24.0% 38.5% 37.6%
Region of birth  North America Europe  South/East/Southeast Asia or  Other	1309 120 238	18 207 857 1 333 433 3 762 641	78.1% 5.7% 16.1%
Ethnic origin  Caucasian  All other	1418 210	19 081 510 3 614 593	84.1% 15.9%
Education – household  Less than secondary school graduation  Secondary school graduation  Some post-secondary  Post-secondary graduation	112 181 108 1220	1 155 055 2 621 103 1 354 579 17 234 603	5.2% 11.7% 6.1% 77.1%
Income quartile – household  Q1 (0-$35 000)  Q2 ($36 000-$60 000)  Q3 ($61 000-$99 000)  Q4 ($100 000-$500 000)	442 447 361 418	5 243 878 5 845 791 5 553 451 6 665 461	22.5% 25.1% 23.8% 28.6%
Occupational status – last 12 months  Employed  Unemployed	1189 432	18 349 395 4 591 031	80.0% 20.0%
Body mass index  Normal weight  Overweight  Obese/Very obese/Severely obese	573 652 416	8 760 036 8 956 475 5 146 357	38.3% 39.2% 22.5%
Breastfed at least 1 baby**  Yes  No	473 195	5 667 162 2 485 369	69.5% 30.5%
Smoking Status  Daily  Occasionally  Not at all	271 49 1348	4 617 401 748 184 17 942 996	19.8% 3.2% 77.0%
Fish consumption***  Low (0.00–1.00)  Medium (1.02–2.02)  High (2.04–15.50)	628 483 552	9 036 941 6 586 538 7 615 853	38.9% 28.3% 32.8%
Egg and egg dish consumption***  Low (0.00–1.00)  Medium (1.25–2.00)  High (2.50–28.00)	838 401 429	11 501 909 5 144 657 6 662 015	49.3% 22.1% 28.6%
Dairy product consumption***  Low (0.00–7.10)  Medium (7.11–13.50)  High (13.75–63.50)	551 557 560	7 744 454 7 624 467 7 939 660	33.2% 32.7% 34.1%
Red meat consumption***  Low (0.00–2.00)  Medium (3.00)  High (3.75–35.00)	712 426 530	10 014 934 5 913 559 7 380 089	43.0% 25.4% 31.7%
Liver consumption***  None  Yes (0.02–7.00)	1059 607	14 219 925 9 059 011	61.1% 38.9%

* Percentages were calculated from weighted N, within each category. Percentages may not sum exactly to 100 within a category due to rounding.

** Female respondents who have given birth.

*** Numbers in parentheses represent weekly food consumption frequencies.

Table 2. Wet-weight and lipid-adjusted plasma concentrations of PCBs and p,p’-DDE in the Canadian population (CHMS, Cycle 1).

	Wet-Weight N	Wet-Weight Nweighted	% < LOD	Plasma Wet-Weight GM (95% CI) (µg/L)	Lipid-Adjusted GM (95% CI) (µg/kg lipid) *
PCB-118	1668	23 308 581	9.7	0.027 (0.023, 0.031)	4.4 (3.8, 5.2)
PCB-138	1668	23 308 581	1.4	0.061 (0.053, 0.069)	10.1 (8.9, 11.5)
PCB-146	1668	23 308 581	37.1	0.012 (0.011, 0.014)	2.0 (1.8, 2.3)
PCB-153	1668	23 308 581	2.5	0.110 (0.094, 0.13)	18.3 (15.8, 21.2)
PCB-156	1668	23 308 581	28.8	0.016 (0.015, 0.017)	2.6 (2.4, 2.9)
PCB-163	1668	23 308 581	21.3	0.019 (0.017, 0.022)	3.2 (2.8, 3.7)
PCB-170	1668	23 308 581	14.9	0.028 (0.025, 0.031)	4.6 (4.1, 5.2)
PCB-180	1668	23 308 581	1.4	0.091 (0.082, 0.10)	15.2 (13.5, 17.1)
PCB-187	1668	23 308 581	19.6	0.022 (0.019, 0.026)	3.7 (3.2, 4.3)
PCB-194	1668	23 308 581	29.5	0.017 (0.016, 0.019)	2.9 (2.6, 3.3)
PCB-201	1668	23 308 581	30.9	0.016 (0.014, 0.017)	2.6 (2.3, 2.9)
PCB-203	1668	23 308 581	35.6	0.013 (0.012, 0.015)	2.2 (2.0, 2.5)
∑PCBs	1661	23 223 792	NA	0.635 (0.581, 0.694)	106.2 (96.4, 117.0)
p,p’-DDE	1668	23 308 581	< 0.6	0.910 (0.759, 1.091)**	152.3 (127.2, 182.2)

*Plasma concentrations adjusted for serum lipids.

** Coefficient of variation (CV) = 87.4% for plasma wet-weight p,p’-DDE. The high CV does not meet Statistics Canada’s quality standards.

CI = confidence interval; DDE = dichlorodiphenyldichloroethylene; GM = geometric mean; LOD = limit of detection; NA = not applicable; PCB = polychlorinated biphenyl

Figure 1. Profiles of PCB congeners in the CHMS, Cycle 1.

Detection rates and concentrations of PCB congeners by age group, measured as part of CHMS Cycle 1 (based on data reported in HC (2010). A) Circles denote that the congener was detected (concentration ≥ LOD) and areas of the circles represent the per cent of CHMS samples in which a congener was detected (range from 1–100%). Shaded circles represent congeners detected in ≥ 60% of samples for which a geometric mean was calculated and shown in Figure 1B. B. Areas of circles represent geometric mean concentrations of the congeners ranging from 2.29 µg/kg lipid (PCB-146 in 40–59 years age group) to 41.27 µg/kg lipid (PCB-180 in 60–79 years age group).

Table 3. Univariate analysis of lipid-adjusted plasma concentrations of PCBs and p,p’-DDE by subgroup (CHMS, Cycle 1).

	Subgroup	Lipid-Adjusted GM (95% CI) plasma concentrations (µg/kg lipid)*	p value**
∑PCBs	Age
	20–39	58.3 (52.4, 64.8)
	40–59	125.0 (111.7, 139.9)	< 0.001
	60–79	225.9 (201.8, 252.9)	< 0.001
	Region of residence
	Ontario	114.8 (104.9, 125.7)
	Quebec	115.9 (78.9, 170.3)	NS
	Rest of Canada	92.6 (81.9, 104.7)	< 0.05
	Region of birth
	North America	99.7 (92.2, 107.8)
	Europe	242.4 (185.9, 316.1)	< 0.001
	South Asia	53.4 (39.6, 72.1)	< 0.05
	East/Southeast Asia	105.8 (66.1, 169.4)	NS
	Other	125.0 (107.2, 145.8)	NS
	Ethnic origin
	Caucasian	109.3 (97.7, 122.4)
	All Other	95.5 (83.1, 109.8)	< 0.05
	Education – household
	< Secondary school graduation	158.1 (122.4, 204.3)
	Secondary school graduation	129.6 (110.5, 152.0)	NS
	Some post-secondary	90.4 (74.2, 110.1)	< 0.01
	Post-secondary graduation	101.1 (90.8, 112.5)	< 0.05
	Income – household
	Q1 (0-$35 000)	121.8 (107.4, 138.1)
	Q2 ($36 000-$60 000)	117.4 (107.6, 128.1)	NS
	Q3 ($61 000-$99 000)	87.8 (76.4, 100.9)	< 0.01
	Q4 ($100 000-$500 000)	102.3 (84.5, 124.0)	NS
	Occupational status
	Yes	93.4 (84.9, 102.7)
	No	150.4 (132.1, 171.3)	< 0.0001
	Breastfed at least 1 baby
	Yes	110.2 (94.9, 127.9)
	No	139.3 (117.1, 165.6)	< 0.05
	Egg and egg dish consumption
	Low (0.00–1.00)	110.3 (96.7, 125.8)
	Medium (1.30–2.00)	110.0 (97.9, 123.6)	NS
	High (2.50–28.00)	96.8 (86.9, 107.8)	< 0.05
	Fish consumption
	Low (0.00–1.00)	89.7 (81.7, 98.4)
	Medium (1.02–2.02)	105.0 (96.3, 114.5)	< 0.05
	High (2.04–15.50)	130.6 (110.0, 155.0)	< 0.01
	Liver consumption
	None	93.8 (85.7, 102.7)
	Yes	128.9 (114.2, 145.4)	< 0.0001
p,p'-DDE	Sex
	Male	134.6 (110.9, 163.3)
	Female	172.3 (141.0, 210.6)	< 0.01
	Age
	20–39	94.8 (77.1, 116.6)
	40–59	168.4 (137.9, 205.7)	< 0.001
	60–79	292.0 (248.3, 343.5)	< 0.001
	Region of birth
	North America	116.0 (104.7, 128.5)
	Europe	229.5 (178.2, 295.4)	< 0.01
	South Asia	1639.0 (590.7, 4547.2)	< 0.01
	East/Southeast Asia	793.9 (429.9, 1466.2)	< 0.001
	Other	328.2 (259.0, 416.0)	< 0.001
	Ethnic origin
	Caucasian	125.1 (111.3, 140.5)
	All Other	453.4 (265.2, 774.9)	< 0.001
	Education – household
	< Secondary school graduation	291.0 (204.4, 414.3)
	Secondary school graduation	189.8 (140.4, 256.6)	NS
	Some post-secondary	111.0 (84.8, 145.4)	< 0.01
	Post-secondary graduation	139.5 (114.6, 169.9)	< 0.01
	Income – household
	Q1 (0-$35 000)	221.0 (156.5, 312.1)
	Q2 ($36 000-$60 000)	163.8 (137.0, 195.8)	NS
	Q3 ($61 000-$99 000)	122.8 (97.0, 155.5)	< 0.05
	Q4 ($100 000-$500 000)	127.6 (103.4, 157.5)	< 0.05
	Occupational status
	Yes	128.8 (107.9, 153.8)
	No	253.5 (191.4, 335.5)	< 0.0001
	Smoking status
	Daily	121.0 (107.5, 136.0)
	Occasionally	130.1 (86.9, 195.0)	NS
	Not at all	162.6 (132.0, 200.3)	< 0.01
	Liver consumption
	None	129.4 (108.1, 155.0)
	Yes	196.3 (163.2, 236.1)	< 0.0001

CI = confidence interval; DDE = dichlorodiphenyldichloroethylene; GM = geometric mean; NA = not available; NS = not significant; PCB = polychlorinated biphenyl

* Plasma concentrations adjusted for serum lipids.

** Adjusted for multiple comparisons. Other pairwise comparisons are presented in Supplementary Material, Table S8.

Table 4. Factors associated with lipid-adjusted plasma concentrations of ∑PCBs and p,p’-DDE based on multiple linear regression analysis (CHMS, Cycle 1).

	Transformed β (95% CI)*	Untransformed β (95% CI)**	p value	N	R^2	Model p value
∑PCBs
Age (increase of 1 year)	0.03 (0.03, 0.04)	1.03 (1.03, 1.04)	0.000
Region of Birth (vs. N. America)
Europe	0.38 (0.08, 0.69)	1.46 (1.08, 1.99)	0.019
All 0ther	0.06 (−0.09, 0.22)	1.06 (0.91, 1.25)	0.387
Fish (vs. low)				1653	58.1%	0.0000
Medium	0.01 (−0.08, 0.09)	1.01 (0.92, 1.09)	0.901
High	0.26 (0.14, 0.37)	1.30 (1.15, 1.45)	0.001
Liver (vs. none)
Yes	0.11 (0.03, 0.19)	1.12 (1.03, 1.21)	0.010
p,p’-DDE
Sex (vs. male)
Female	0.21 (0.07, 0.34)	1.23 (1.07, 1.40)	0.006
Age (increase of 1 year)	0.03 (0.03, 0.04)	1.03 (1.03, 1.04)	0.000
Region of birth (vs. N. America)
Other than N. America	0.51 (0.24, 0.78)	1.67 (1.27, 2.18)	0.002
Household education (vs. < than SS graduation)				1580	47.0%	0.0001
SS Graduation	−0.06 (−0.32, 0.19)	0.94 (0.73, 1.21)	0.604
Some Post-Secondary	−0.26 (−0.59, 0.08)	0.77 (0.55, 1.08)	0.118
Post-Secondary Graduation	−0.24 (−0.47, −0.01)	0.79 (0.63, 0.99)	0.040
Ethnic origin (vs. caucasian)
Non-caucasian	1.03 (0.44, 1.62)	2.80 (1.55, 5.05)	0.003

CI = confidence interval; DDE = dichlorodiphenyldichloroethylene; PCB = polychlorinated biphenyl

* Transformed β was calculated from natural log transformed lipid-adjusted plasma concentration.

** Untransformed β is the multiple change of lipid-adjusted plasma concentration compared with the reference category. A multiple of < 1 lowers and > 1 increases lipid-adjusted plasma concentration.

Figure 2. Comparison of PCB and p,p’-DDE concentrations with levels of concern.

Table 5. Comparison with selected international surveys.

		CHMS Cycle 1 (2007–2009)* GM (95% CI)	US NHANES (2003–04)** GM (95% CI)	ENNS (2006–2007)*** GM (95% CI)	BIOAMBIENT.ES^****, ***** (2009–2010) GM	GerES III (1998)****** GM (95% CI)
PCB-138	Wet Weight (µg/L)	0.06 (0.05, 0.07) (N = 1668)	-	-	-	0.42 (0.41, 0.43) (N = 2823)
	Lipid Adjusted (µg/kg lipid)	10.13 (8.92, 11.51) (N = 1666)	17.7(16.5–19.0) PCB-138 + 158 (N = 1298)	70.8 (64.4, 77.7) (N = 386)	31.89**** (N = 1880)	-
PCB-153	Wet Weight (µg/L)	0.11 (0.09, 0.13) (N = 1668)	-	-	-	0.68 (0.66, 0.70) (N = 2818)
	Lipid Adjusted (µg/kg lipid)	18.31 (15.83, 21.16) (N = 1666)	23.7 (22.3, 25.1) (N = 1300)	113.3 (102.1, 125.7) (N = 386)	43.61**** (N = 1880)	-
PCB-180	Wet Weight (µg/L)	0.09 (0.08, 0.10) (N = 1668)	-	-	-	0.44 (0.42, 0.45) (N = 2822)
	Lipid Adjusted (µg/kg lipid)	15.21 (13.52, 17.11) (N = 1666)	19.0 (17.9, 20.1) (N = 1298)	93.7 (83.1, 105.5) (N = 386)	55.97**** (N = 1880)	-
p,p’-DDE	Wet Weight (µg/L)	0.91 (0.76, 1.09) (N = 1668)	-	-	-	1.33 (1.28, 1.38) (N = 2290, West Germany) 3.37 (3.11, 3.64) (N = 534, East Germany)
	Lipid Adjusted (µg/kg lipid)	152.05 (127.03, 182.00) (N = 1666)	268 (217, 332) (N = 1368)	118 (102, 136) (N = 386)	158.8***** (149.8–168.4) (N = 934)	-
Study population and analytical considerations	Population	20–79 years	20 years and older	18–74 years	18–65 years (occupied population)	18–69 years
	Matrix	Plasma	Serum	Serum	Serum	Whole blood
	Lipid adjustment	Serum total lipids, calculated using equation by Bernert et al. 2007*******	Serum total lipids, calculated using equation by Bernert et al. 2007*******; serum specific gravity also accounted for in the adjustment.	Serum total lipids, calculated using equation by Akins, 1989********	Serum total lipids, calculated using equation by Bernert et al. 2007*******	N/A
	LODs/LOQs	PCBs: 0.01 ug/L DDE: 0.05 ug/L	PCB 180: 0.4 ng/g lipid; PCB 138/158: 0.4 ng/g lipid; PCB 153: 1.1 ng/g lipid; DDE: 7.8 ng/g lipid	PCBs: LOD 0.002 μg/L LOQ 0.006 μg/L; DDE: LOD 0.002 LOQ 0.006	PCB 138 and PCB153: 0.01 μg/L 0.59 ng/g lipid PCB180: 0.005 μg/L 0.29 ng/g lipid*****; DDE: 0.03 μg/L******	PCBs 0.1 μg/L DDE: 0.1 μg/L
	Imputation	LOD/2	LOD/√2	Imputation varied based on per cent detection, and used LOD, LOQ or both	PCBs: LOQ/2***** DDE: LOQ/√2******	LOQ/2

CHMS = Canadian Health Measures Survey; CI = confidence interval; DDE = dichlorodiphenyldichloroethylene; ENNS = Etude Nationale Nutrition Sante (French National Nutrition and Health Survey); FLEHS = Flemish Environment and Health Survey; GerES = German Environmental Survey; GM = geometric mean; GSD = geometric standard deviation; LOD = limit of detection; LOQ = limit of quantification; NHANES = National Health and Nutrition Examination Survey; PCB = polychlorinated biphenyl; SD = standard deviation

* As reported in the Report on Human Biomonitoring of Environmental Chemicals in Canada (Health Canada 2010)

** As reported in the Fourth National Report on Human Exposure to Environmental Chemicals by US Centre for Disease Control (CDC, 2009)

*** As reported in the Exposition de la population française aux substances chimiques de l’environnement. Tome 2 – Polychlorobiphényles (PCB-NDL). Pesticides (accessed at the URL http://opac.invs.sante.fr/index.php?lvl=notice_display&id=11441 on March 22 2017)

**** As reported by Huetos et al. (2014)

***** As reported by Ramos et al. (2016)

****** As reported by Becker et al. (2002

******* Equation 1: Total Lipids (g/L) = 2.27 X total cholesterol (g/L) + triglycerides (g/L) + 0.623

******** Equation 2: Lipides totaux = 1,677 X (cholestérol total – cholestérol libre) + cholestérol libre + triglycérides + phospholipides

Table 6. Comparison with Canadian historical data.

Analyte	Study	Period of Sampling	Age Group (years)	Sex	Statistic	Concentration (µg/kg lipid)
PCB-138	Canadian Study of Health and Aging*	1991–2002	65+	-	Median	42.2
	CHMS**	2007–09	60–79	-	Median	21.63
	Quebec***	1994–1997	52 (± 10, SD)	Females	GM	35.4
	CHMS**	2007–09	20–79	Females	GM	10.13
PCB-153	Canadian Study of Health and Aging*	1991–2002	65+	-	Median	73.6
	CHMS**	2007–09	60–79	-	Median	43.43
	Quebec***	1994–1997	52 (± 10, SD)	Females	GM	51
	CHMS**	2007–09	20–79	Females	GM	18.31
PCB-180	Canadian Study of Health and Aging*	1991–2002	65+	-	Median	60.5
	CHMS**	2007–09	60–79	-	Median	41.23
	Quebec***	1994–1997	52 (± 10, SD)	Females	GM	31.1
	CHMS**	2007–09	20–79	Females	GM	15.21
Aroclor 1260 (5.2 x ([PCB138] + [PCB153])	Non-Eaters of Great Lakes Fish****	1992	18–64	Male	GM	442.5
	CHMS**	2007–09	20–79	Male	GM	148.43
	Non-Eaters of Great Lakes Fish****	1992	18–64	Female	GM	426.0
	CHMS**	2007–09	20–79	Female	GM	152.67
p,p’-DDE	Canadian Study of Health and Aging****	1991–2002	65+	-	Median	716
	CHMS**	2007–09	60–79	-	Median	269.54
	Non-Eaters of Great Lakes Fish****	1992	18–64	Male	GM	292.8
	CHMS**	2007–09	20–79	Male	GM	134.6
	Non-Eaters of Great Lakes Fish****	1992	18–64	Female	GM	359.8
	CHMS**	2007–09	20–79	Female	GM	172.3

CHMS = Canadian Health Measures Survey; DDE = dichlorodiphenyldichloroethylene; GM = geometric mean; PCB = polychlorinated biphenyl;

SD = standard deviation

* Medehouenou et al. (2011)

** Health Canada (2010)

*** Demers et al. (2002)

**** Kearney et al. (1999)

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