Community-driven research on environmental sources of H. pylori infection in arctic Canada

Figures & data

Table 1 Effects of socio-demographic characteristics on H. pylori prevalence odds among 368 community H. pylori project participants, Northwest and Yukon Territories, 2008–2011.

Variable	N	OR	95%CI
Sex
Male	177	1.0
Female	191	1.0	(0.57, 1.8)
Ethnicity
Inuvialuit	173	1.0
Gwich’in	134	0.58	(0.24, 1.3)
Other Aboriginal	16	2.0	(0.36, 11)
Non-Aboriginal	45	0.058	(0.013, 0.26)
Household Size
5+ people	114	1.0
2–4 people	193	0.49	(0.22, 1.1)
1 person	61	0.34	(0.11, 1.0)
Household Income
<$25,000	104	1.0
$25,000–34,999	41	0.66	(0.24, 1.8)
$35,000–49,999	35	1.3	(0.41, 3.9)
$50,000–74,999	80	0.49	(0.22, 1.2)
≥ $75,000	108	0.41	(0.18, 0.95)
Education
Less than High School	193	1.0
High School	57	1.0	(0.46, 2.4)
Trades Certificate	53	0.68	(0.28, 1.7)
College or University	65	1.2	(0.46, 2.9)
Community
Aklavik	227	1.0
Old Crow	89	3.1	(1.2, 8.0)
Tuktoyaktuk	52	0.84	(0.33, 2.1)

Adjusted for age as a cubic spline, sex, ethnicity, income, education, all waterborne and zoonotic exposures, community as a fixed effect, and household as a random effect.

Table 2 Pathways for zoonotic transmission: Exposure prevalence and exposure-specific H. pylori prevalence by community among 368 community H. pylori project participants, Northwest and Yukon Territories, 2008–2011

	Aklavik, NT		Old Crow, YT		Tuktoyaktuk, NT
Variable	Proportion of 227 participants in category n (%)	H. pylori prevalence in category n (%)	Proportion of 89 participants in category n (%)	H. pylori prevalence in category n (%)	Proportion of 52 participants in category n (%)	H. pylori prevalence in category n (%)
Evidence of Mice
No	195 (86)	116 (60)	84 (94)	56 (67)	49 (94)	24 (49)
Yes	32 (14)	23 (72)	5 (6)	5 (100)	3 (6)	3 (100)
Cared for Any Animals/Livestock
No	53 (23)	36 (68)	14 (16)	9 (64)	24 (46)	14 (58)
Yes	174 (77)	103 (59)	75 (84)	52 (69)	28 (54)	13 (46)
Cared for Dogs
No	55 (24)	37 (67)	15 (17)	10 (67)	29 (56)	15 (52)
Yes	172 (76)	102 (59)	74 (83)	51 (69)	23 (44)	12 (52)
Cared for Cats
No	207 (91)	130 (63)	86 (97)	59 (69)	39 (75)	23 (59)
Yes	20 (9)	9 (45)	3 (3.4)	2 (67)	13 (25)	4 (31)
Contact with Animal Innards
No	64 (28)	42 (66)	14 (16)	7 (50)	11 (21)	3 (27)
Yes	163 (72)	97 (60)	75 (84)	54 (72)	41 (79)	24 (59)

Table 3 Pathways for zoonotic transmission: Results of multivariable logistic regression analysis of effects on H. pylori prevalence odds among 368 community H. pylori project participants, Northwest and Yukon Territories, 2008–2011

	Unadjusted Estimates		Model 1 ⌘		Model 2 §
Variable	OR	95%CI	OR	95%CI	OR	95%CI
Evidence of Mice
No	1.0		1.0		1.0
Yes	2.3	(1.1, 5.0)	4.1	(1.2, 14)	4.6	(1.2, 18)
Cared for Any Animals/Livestock
No	1.0		1.0		1.0
Yes	0.84	(0.51, 1.4)	0.78	(0.39, 1.6)	0.82	(0.38, 1.8)
Cared for Dogs
No	1.0		1.0		1.0
Yes	0.94	(0.59, 1.5)	0.76	(0.38, 1.5)	0.72	(0.33, 1.6)
Cared for Cats
No	1.0		1.0		1.0
Yes	0.40	(0.20, 0.81)	1.26	(0.37, 4.3)	1.4	(0.34, 5.4)
Contact with Animal Innards
No	1.0		1.0		1.0
Yes	1.2	(0.74, 1.9)	1.19	(0.57, 2.5)	1.6	(0.70, 3.6)

⌘ Adjusted for age as a cubic spline, sex, ethnicity, income, education, community and household as a random effect

^§ Model 1 plus all waterborne and zoonotic exposures.

Table 4 Pathways for waterborne transmission: Exposure prevalence and exposure-specific H. pylori prevalence by community among 368 community H. pylori project participants, Northwest and Yukon Territories, 2008–2011

	Aklavik, NT		Old Crow, YT		Tuktoyaktuk, NT
Variable	Proportion of 227 participants in category n (%)	H. pylori prevalence in category n (%)	Proportion of 89 participants in category n (%)	H. pylori prevalence in category n (%)	Proportion of 52 participants in category n (%)	H. pylori prevalence in category n (%)
Ever Consumed Untreated Water
No	75 (33)	46 (61)	8 (9)	5 (63)	3 (6)	3 (100)
Yes	152 (67)	93 (61)	81 (91)	56 (69)	49 (94)	24 (49)
Consumed Untreated Water in thePast Year
No	180 (79)	111 (62)	44 (49)	32 (73)	21 (40)	9 (43)
Yes	47 (21)	28 (60)	45 (51)	29 (64)	31 (60)	18 (58)
Contaminated Water (Sewage)
No	169 (74)	103 (61)	58 (65)	45 (78)	37 (71)	18 (49)
Yes	58 (26)	36 (62)	31 (35)	16 (52)	15 (28)	9 (60)

Table 5: Pathways for waterborne transmission: Results of multivariable logistic regression analysis of effects on H. pylori prevalence odds among 368 community H. pylori project participants, Northwest and Yukon Territories, 2008–2011

	Unadjusted Estimates		Model 1 ⌘		Model 2 §
Variable	OR	95%CI	OR	95%CI	OR	95%CI
Ever Consumed Untreated Water
No	1.0		1.0		1.0
Yes	1.1	(0.57, 1.6)	0.44	(0.20, 0.96)	0.36	(0.14, 0.94)
Consumed Untreated Water in the Past Year
No	1.0		1.0		1.0
Yes	0.96	(0.61, 1.5)	0.77	(0.39, 1.5)	0.85	(0.40, 1.8)
Had Sewage Problems
No	1.0		1.0		1.0
Yes	0.83	(0.53, 1.3)	0.48	(0.25, 0.94)	0.49	(0.22, 1.1)

⌘ Adjusted for age as a cubic spline, sex, ethnicity, income, education, community and household as a random effect

^§ Model 1 plus all waterborne and zoonotic exposures

Table 6: Effects of household composition variables on H. pylori prevalence odds among 368 community H. pylori project participants, Northwest and Yukon Territories, 2008–2011

Variable	n	OR ⌘	95%CI
Number of Household Members (per person increase)	368	1.2	0.98, 1.5
Positive Family Member
No	201	1.0
Yes	167	1.2	0.5, 3.0
Number of Children in Home (per person increase)	368	1.4	0.96, 2.2

Figure 1. Random effect of household (SD) relative to the effect of independent variables in the model. Model 1. Household Random Effect (SD): 1.26; 95%CI: 0.70, 2.3 Model 2. Household Random Effect (SD): 1.16; 95%CI: 0.59, 2.3) Model 3. Household Random Effect (SD): 1.11; 95%CI: 0.54, 2.3 Model 4. Household Random Effect (SD): 0.62; 95%CI: 0.96, 4.04 Model 5. Household Random Effect (SD): 0.43; 95%CI: 0.016, 11.3.

Table 7: Sensitivity analysis showing estimates based on different methods for classifying H. pylori infection status of participants with discordant results (n = 368)

	Model 1 ⌘		Model 2 §		Model 3 ϖ		Model 4 ¢
ta	OR	95%CI	OR	95%CI	OR	95%CI	OR	95%CI
Evidence of Mice
No	1.0		1.0		1.0		1.0
Yes	4.6	(1.2, 18)	6.1	(1.5, 25)	4.7	(1.3, 17)	4.1	(1.2, 15)
Cared for Any Animals/Livestock
No	1.0		1.0		1.0		1.0
Yes	0.82	(0.38, 1.8)	1.2	(0.57, 2.6)	0.95	(0.47, 1.9)	0.92	(0.46, 1.9)
Cared for Dogs
No	1.0		1.0		1.0		1.0
Yes	0.72	(0.33, 1.6)	1.2	(0.56, 2.5)	0.88	(0.44, 1.8)	0.85	(0.42, 1.7)
Cared for Cats
No	1.0		1.0		1.0		1.0
Yes	1.4	(0.34, 5.4)	0.81	(0.23, 2.9)	0.98	(0.29, 3.3)	1.02	(0.3, 3.5)
Contact with Animal Innards
No	1.0		1.0		1.0		1.0
Yes	1.6	(0.70, 3.6)	1.2	(0.53, 2.7)	1.5	(0.74, 3.2)	1.5	(0.71, 3.2)
Ever Consumed Untreated Water
No	1.0		1.0		1.0		1.0
Yes	0.36	(0.14,0.94)	0.45	(0.19, 1.1)	0.47	(0.21, 1.1)	0.45	(0.2, 1)
Consumed Untreated Water in the Past Year
No	1.0		1.0		1.0		1.0
Yes	0.85	(0.40, 1.8)	0.87	(0.44, 1.7)	0.73	(0.38, 1.4)	0.76	(0.40, 1.5)
Had Sewage Problems
No	1.0		1.0		1.0		1.0
Yes	0.49	(0.22, 1.1)	0.46	(0.21, 1)	0.49	(0.24, 0.98)	0.55	(0.27, 1.1)

⌘ Discordant results adjusted based on the developed algorithm.

^§ Discordant results re-classified based on culture result.

^ϖ Discordant results re-classified based on histopathology result.

^¢ Discordant results re-classified based on 13C-UBT result.

All models adjusted for age as a cubic spline, sex, ethnicity, income, education, community, all waterborne and zoonotic exposures and household as a random effect

Table 8 Variable definitions and response options for environmental exposures

Variable	Question [Household/Individual Level Variable]	Response Options
Zoonotic Transmission
Mice / Mouse Droppings	Do you ever have problems with mice getting into your house / have you seen mice or mouse droppings in your house? [Household Level]	Yes No Unsure/Missing/ Refused to Answer
Any Animals	Have you yourself ever regularly been the caretaker for one or more animals (such as pets or livestock), doing any of the following: feeding, grooming, cleaning up after, petting or playing with? [Individual Level]	Yes No Unsure/Missing/ Refused to Answer
Dogs	Have you ever been the regular caretaker of a dog? [Individual Level]	Yes No Unsure/Missing/ Refused to Answer
Cats	Have you ever been the regular caretaker of a cat? [Individual Level]	Yes No Unsure/Missing/ Refused to Answer
Animal Innards	Have you ever cleaned fish or game? [Individual Level]	Yes No Unsure/Missing/ Refused to Answer
Waterborne Transmission
Untreated water (ever)	Did you ever, including when you were a child, drink river water that was not treated at the water treatment plant, for example water taken directly from a river, lake or creek? [Individual Level]	Yes No Unsure/Missing/ Refused to Answer
Untreated water (past year)	According to your best estimate, how often in the past 12 months have you consumed: untreated, unboiled river water; melted river or lake ice; or melted snow? [Individual Level]	1 or more times Never Unsure/Missing/ Refused to Answer
Sewage / Contaminated water	Has your household ever had any problems with sewage? [Household Level]	Yes No Unsure/Missing/ Refused to Answer