Environmental chemical exposures among Greenlandic children in relation to diet and residence

Figures & data

Figure 1. Map of Greenland with study areas marked

Figure 2. Flowchart of participants

Table 1. Characteristics of children included in the study

	N	Median (25^th–75^th percentile)			n/N	(%)
Age (years)	367	10.0 (9.1; 10.5)	Sex	Girls	176/367	(48.0)
Height (cm)	345	138 (132; 144.5)	Standardised weight	Normal	251/345	(72.8)
				Overweight	72/345	(20.9)
Weight (kg)	345	34 (30; 40)		Obese	22/345	(6.4)
BMI (kg/m^2)	345	17.9 (16.6; 20.1)	Breastfed	<6 months	94/341	(27.6)
				6–12 months	77/341	(22.6)
Greenlandic food (days/week)	245	2 (1; 3)		>1 year	170/341	(49.9)
Mercury (μg/L blood)	333	3.83 (1.92; 5.62)	Older siblings	0	109/344	(31.7)
				1	106/344	(30.8)
ΣPCB (μg/g lipid)	338	0.26 (0.16; 0.50)		≥2	129/344	(37.5)
PFHxS (ng/mL serum)	338	0.69 (0.54; 0.93)	Younger siblings	0	151/342	(44.2)
				1	134/342	(39.2)
PFOS (ng/mL serum)	338	8.68 (6.52; 12.23)		≥2	57/342	(16.7)
PFOA (ng/mL serum)	338	2.28 (1.89; 2.88)	Smokers in household		248/345	(71.9)
PFNA (ng/mL serum)	338	1.40 (1.09; 1.95)	Indoor smoking		64/328	(19.5)
PFDA (ng/mL serum)	338	0.49 (0.24; 0.80)	Residence	Nuuk	86/367	(23.5)
				Maniitsoq	34/367	(9.3)
				Sisimiut	68/367	(18.6)
				Ilulissat	102/367	(27.6)
				Aasiaat	23/367	(6.3)
				Qeqertarsuaq	11/367	(3.0)
				Qasigiannguit	18/367	(4.9)
				Tasiilaq	25/367	(6.8)

Figure 3. Traditional Greenlandic food consumption by area. Information about diet was not available for children from Sisimiut, Aasiaat and Qasigiannguit

Table 2. Pearson’s correlation coefficients for the log-transformed environmental exposures

	Mercury	ΣPCB	PFHxS	PFOS	PFOA	PFNA
ΣPCB	0.4131
PFHxS	0.5760	0.6466
PFOS	0.6159	0.5515	0.8412
PFOA	0.1626	0.2489	0.3535	0.4141
PFNA	0.5898	0.4998	0.7987	0.8850	0.5270
PFDA	0.5779	0.3917	0.6596	0.6919	0.5264	0.7181

Table 3. Per cent difference in mercury, ΣPCB, and PFASs with potential predictors. For total numbers in subgroups see Table 1

		Mercury	ΣPCB	PFHxS	PFOS	PFOA	PFNA	PFDA
		% difference (95% CI)	% difference (95% CI)	% difference (95% CI)	% difference (95% CI)	% difference (95% CI)	% difference (95% CI)	% difference (95% CI)
		N = 333	N = 338	N = 338	N = 338	N = 338	N = 338	N = 338
Residence (reference: Nuuk)	Maniitsoq	109.4 (57.6; 178.1)	144.7 (75.5; 241.0)	38.0 (17.7; 61.8)	48.5 (24.5; 77.2)	13.7 (1.0; 27.9)	52.8 (30.2; 79.2)	60.4 (32.2; 94.5)
	Sisimiut	4.5 (−17.9; 33.0)	54.6 (19.2; 100.6)	−6.0 (−15.7; 4.8)	3.3 (−9.2; 17.6)	−15.7 (−22.2; −8.6)	−4.5 (−15.2; 7.6)	−63.0 (−67.5; −57.8)
	Ilulissat	99.4 (60.2; 148.2)	85.4 (42.6; 141.0)	10.1 (−1.1; 22.6)	38.6 (22.4; 56.9)	29.0 (18.6; 40.3)	30.4 (16.9; 45.5)	59.5 (39.3; 82.7)
	Aasiaat	43.0 (−2.0; 108.8)	64.8 (2.0; 166.2)	−0.2 (−14.6; 16.8)	37.2 (9.6; 71.7)	13.3 (0.2; 28.2)	26.4 (3.2; 55.0)	−57.8 (−65.6; −48.1)
	Qeqertarsuaq	309.3 (172.0; 516.1)	67.3 (7.0; 161.4)	33.6 (8.0; 65.1)	80.1 (43.5; 125.9)	5.8 (−8.4; 22.2)	29.9 (7.4; 57.1)	95.3 (51.5; 151.7)
	Tasiilaq	298.1 (185.3; 455.3)	814.9 (500.5; 1293.9)	231.4 (158.1; 325.5)	158.3 (99.1; 234.9)	9.1 (−3.4; 23.1)	111.7 (63.8; 173.7)	144.4 (91.0; 212.8)
	p	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001	<0.001
		N = 333	N = 338	N = 338	N = 338	N = 338	N = 338	N = 338
Age (years)		−1.9 (−9.5; 6.3)	2.3 (−6.7; 12.2)	2.6 (−1.8; 7.1)	1.2 (−3.5; 6.1)	−8.8 (−11.5; −6.1)	−1.7 (−5.8; 2.6)	−22.1 (−27.0; −17.0)
		N = 333	N = 338	N = 338	N = 338	N = 338	N = 338	N = 338
Sex (reference: Boys)	Girls	−17.0 (−31.0; −0.2)	−9.5 (−26.8; 11.8)	−4.0 (−13.6; 6.7)	−9.5 (−18.7; 0.9)	3.3 (−3.5; 10.5)	−9.2 (−17.6; 0.2)	−7.2 (−21.4; 9.6)
		N = 309	N = 314	N = 314	N = 314	N = 314	N = 314	N = 314
Breastfed (reference: <6 months)	6–12 months	−23.2 (−41.5; 0.8)	23.0 (−9.6; 67.2)	−4.6 (−18.8; 12.2)	−5.2 (−19.4; 11.6)	−0.4 (−9.3; 9.4)	−7.1 (−19.9; 7.8)	−3.4 (−24.7; 23.9)
	>1 year	−3.6 (−22.9; 20.3)	102.2 (57.5; 159.7)	11.6 (−1.1; 26.1)	8.6 (−5.0; 24.1)	6.4 (−2.5; 16.0)	4.5 (−7.4; 18.0)	10.9 (−9.7; 36.3)
	p trend	0.99	<0.001	0.04	0.16	0.13	0.35	0.26
		N = 328	N = 333	N = 333	N = 333	N = 333	N = 333	N = 333
Standardised weight (reference: Normal)	Overweight	−9.1 (−28.2; 15.1)	−43.8 (−56.6; −27.3)	−5.4 (−16.5; 7.2)	−6.5 (−18.1; 6.9)	0.4 (−8.4; 10.0)	1.1 (−10.5; 14.3)	−1.0 (−20.0; 22.4)
	Obese	4.4 (−32.2; 60.6)	−66.0 (−77.0; −50.1)	−9.2 (−23.7; 8.1)	−8.9 (−23.6; 8.7)	−7.7 (−17.3; 3.0)	−8.5 (−21.7; 6.9)	−19.4 (−42.7; 13.4)
	p trend	0.73	<0.001	0.21	0.19	0.43	0.58	0.35
		N = 314	N = 319	N = 319	N = 319	N = 319	N = 319	N = 319
Older siblings (reference: 0)	1	29.0 (0.9; 64.7)	−4.7 (−29.4; 28.7)	5.7 (−8.6; 22.3)	8.8 (−6.2; 26.3)	0.1 (−8.3; 9.2)	8.8 (−4.8; 24.3)	4.0 (−16.2; 29.0)
	≥2	8.7 (−12.7; 35.4)	1.8 (−21.9; 32.8)	5.6 (−7.1; 20.1)	5.0 (−8.0; 19.7)	3.6 (−5.0; 12.9)	5.5 (−6.2; 18.7)	−4.6 (−21.9; 16.5)
	p trend	0.54	0.87	0.41	0.51	0.41	0.40	0.61
		N = 313	N = 318	N = 318	N = 318	N = 318	N = 318	N = 318
Younger siblings (reference: 0)	1	−4.2 (−22.3; 18.2)	16.1 (−7.4; 45.5)	1.0 (−10.0; 13.3)	−3.2 (−14.3; 9.3)	4.9 (−2.8; 13.2)	−2.8 (−13.1; 8.7)	2.5 (−15.0; 23.5)
	≥2	6.5 (−19.0; 40.2)	32.7 (−6.8; 89.0)	7.9 (−9.3; 28.4)	−4.4 (−19.0; 12.9)	0.1 (−9.2; 10.4)	0.2 (−13.3; 15.7)	−3.7 (−25.1; 23.9)
	p trend	0.80	0.08	0.42	0.54	0.68	0.89	0.86
		N = 311	N = 316	N = 316	N = 316	N = 316	N = 316	N = 316
Smokers in household (reference: No)	Yes	−14.0 (−30.4; 6.2)	−1.7 (−21.9; 23.7)	−10.8 (−21.3; 1.2)	−13.9 (−24.0; −2.4)	−0.9 (−7.8; 6.6)	−9.8 (−19.4; 1.0)	−11.5 (−26.7; 6.7)
		N = 295	N = 300	N = 300	N = 300	N = 300	N = 300	N = 300
Indoor smoking (reference: No)	Yes	−15.2 (−32.5; 6.4)	−4.0 (−24.4; 22.1)	−10.9 (−20.0; −0.7)	−9.2 (−19.1; 1.9)	−1.6 (−8.8; 6.3)	−8.8 (−18.1; 1.6)	−25.3 (−39.8; −7.3)
		N = 231	N = 236	N = 236	N= 236	N = 236	N = 236	N = 236
Greenlandic food (days/week)		18.4 (10.0; 27.5)	17.4 (8.3; 27.4)	8.4 (4.0; 12.9)	10.6 (6.4; 14.9)	3.2 (0.6; 5.8)	8.5 (4.4; 12.7)	12.1 (7.8; 16.6)

Table 4. Per cent difference in mercury, ΣPCB, and PFASs with potential predictors – adjusted for area of residence. For total numbers in subgroups see Table 1

		Mercury	ΣPCB	PFHxS	PFOS	PFOA	PFNA	PFDA
		% difference (95% CI)	% difference (95% CI)	% difference (95% CI)	% difference (95% CI)	% difference (95% CI)	% difference (95% CI)	% difference (95% CI)
		N = 333	N = 338	N = 338	N = 338	N = 338	N = 338	N = 338
Age (years)		−2.2 (−10.7; 7.2)	−11.7 (−20.2; −2.2)	−0.8 (−5.3; 3.8)	−0.9 (−6.2; 4.7)	−5.1 (−8.3; −1.8)	−2.0 (−6.8; 3.0)	−3.3 (−8.9; 2.7)
		N = 333	N = 338	N = 338	N = 338	N = 338	N = 338	N = 338
Sex (ref: Boys)	Girls	−15.9 (−28.2; −1.4)	−4.5 (−20.2; 14.3)	−1.1 (−8.8; 7.3)	−7.8 (−16.0; 1.3)	3.1 (−2.8; 9.5)	−7.7 (−15.3; 0.5)	−6.9 (−15.3; 2.4)
		N = 309	N = 314	N = 314	N = 314	N = 314	N = 314	N = 314
Breastfed (reference: <6 months)	6–12 months	−23.2 (−40.4; −1.0)	25.7 (−1.6; 60.5)	−8.2 (−18.8; 3.7)	−4.7 (−17.4; 9.9)	2.1 (−6.4; 11.2)	−6.8 (−18.4; 6.5)	−11.4 (−23.7; 2.9)
	>1 year	−9.0 (−26.0; 11.8)	102.2 (61.9; 152.4)	8.9 (−1.7; 20.6)	6.8 (−5.2; 20.3)	7.3 (−0.7; 15.9)	3.1 (−7.6; 15.2)	0.5 (−10.8; 13.2)
	p trend	0.55	<0.001	0.05	0.20	0.06	0.44	0.70
		N = 328	N = 333	N = 333	N = 333	N = 333	N = 333	N = 333
Standardised weight (reference: Normal)	Overweight	−4.2 (−22.4; 18.3)	−38.8 (−51.1; −23.3)	−2.4 (−11.8; 7.9)	−3.0 (−13.9; 9.3)	2.1 (−5.6; 10.4)	3.8 (−6.9; 15.8)	0.7 (−10.7; 13.7)
	Obese	21.1 (−17.9; 78.7)	−57.1 (−69.7; −39.5)	3.4 (−12.6; 22.4)	0.6 (−13.0; 16.3)	−8.7 (−15.6; −1.3)	−0.9 (−13.7; 13.7)	−12.0 (−26.8; 5.7)
	p trend	0.63	<0.001	0.99	0.75	0.43	0.70	0.39
		N = 314	N = 319	N = 319	N = 319	N = 319	N = 319	N = 319
Older siblings (reference: 0)	1	28.9 (5.1; 58.1)	−6.6 (−27.1; 19.6)	4.8 (−5.8; 16.6)	7.6 (−4.5; 21.3)	1.6 (−6.2; 10.2)	8.9 (−2.6; 21.7)	13.9 (0.4; 29.3)
	≥2	0.6 (−16.8; 21.7)	−9.4 (−28.6; 14.9)	3.1 (−7.0; 14.2)	0.2 (−10.7; 12.3)	3.9 (−4.1; 12.5)	2.2 (−7.8; 13.3)	3.3 (−8.5; 16.6)
	p trend	0.92	0.41	0.59	0.96	0.34	0.74	0.68
		N = 313	N = 318	N = 318	N = 318	N = 318	N = 318	N = 318
Younger siblings (reference: 0)	1	−12.3 (−26.9; 5.3)	3.2 (−15.7; 26.2)	−4.0 (−12.6; 5.5)	−8.6 (−17.9; 1.9)	2.7 (−4.2; 10.1)	−7.6 (−16.5; 2.1)	−5.5 (−15.7; 5.8)
	≥2	−8.2 (−28.3; 17.5)	0.9 (−23.3; 32.7)	−6.9 (−17.1; 4.5)	−15.3 (−25.8; −3.3)	0.5 (−7.6; 9.4)	−8.7 (−19.5; 3.6)	−8.5 (−18.8; 3.2)
	p trend	0.30	0.88	0.19	0.01	0.72	0.09	0.13
		N = 311	N = 316	N = 316	N = 316	N = 316	N = 316	N = 316
Smokers in household (reference: No)	Yes	−14.9 (−29.1; 2.1)	3.3 (−14.8; 25.2)	−7.7 (−15.6; 0.9)	−13.0 (−21.5; −3.6)	−2.2 (−8.2; 4.3)	−9.1 (−17.5; 0.2)	−12.3 (−20.8; −2.9)
		N = 295	N = 300	N = 300	N= 300	N = 300	N = 300	N = 300
Indoor smoking (reference: No)	Yes	−8.5 (−25.5; 12.3)	3.3 (−16.5; 27.7)	−3.1 (−11.1; 5.8)	−4.3 (−13.6; 6.0)	2.4 (−4.2; 9.5)	−4.5 (−13.4; 5.3)	−5.7 (−15.7; 5.3)
		N = 231	N = 236	N = 236	N = 236	N = 236	N = 236	N = 236
Greenlandic food (days/week)		13.4 (5.7; 21.6)	13.4 (5.5; 21.8)	7.5 (4.1; 11.0)	8.1 (4.3; 12.1)	2.0 (−0.7; 4.8)	7.0 (3.3; 10.8)	9.0 (5.2; 13.1)

Table 5. Explanatory power for models containing different sets of predictors using all cases and complete cases

		Mercury		ΣPCB		PFHxS		PFOS		PFOA		PFNA		PFDA
	Cases	All/complete		All/complete		All/complete		All/complete		All/complete		All/complete		All/complete
	N	333	194	338	194	338	194	338	194	338	194	338	194	338	194
Area	R-squared	0.27	0.28	0.30	0.33	0.41	0.42	0.27	0.31	0.24	0.13	0.24	0.26	0.68	0.31
	N	231	194	236	194	236	194	236	194	236	194	236	194	236	194
Greenlandic food	R-squared	0.09	0.09	0.06	0.07	0.06	0.06	0.08	0.08	0.02	0.02	0.07	0.07	0.10	0.10
	N	231	194	236	194	236	194	236	194	236	194	236	194	236	194
Area and Greenlandic food	R-squared	0.33	0.33	0.37	0.37	0.46	0.47	0.33	0.36	0.13	0.13	0.28	0.30	0.33	0.36
Area, age, sex, breastfeeding, standardised weight, younger siblings, smokers in household, and Greenlandic food	N	194	194	199	194	199	194	199	194	199	194	199	194	199	194
	R-squared	0.37	0.37	0.54	0.54	0.49	0.49	0.40	0.39	0.19	0.18	0.33	0.32	0.40	0.39