Table 4 Social and geographic factors associated with WASH insecurity variables among 586 PWID in Tijuana-San Diego metropolitan area in 2020–2021

Variable

Level

WASH insecurity indicator (%)

RR

95% CI

aRR

95% CI

Basic drinking water insecurity

City of residence

San Diego

8.1

Tijuana

15.8

1.96

1.23, 3.12*

1.68

1.02, 2.76*

Housing status

Permanent housing

5.7

Sheltered homelessness

16

2.83

1.43, 5.58*

2.4

1.18, 4.90*

Unsheltered homelessness

12.4

2.2

1.16, 4.17*

2.03

1.07, 3.86*

Basic sanitation insecurity

City of residence

San Diego

68.5

Tijuana

77.2

1.13

1.02, 1.25*

1.07

0.97, 1.18

Housing status

Permanent housing

53.3

Sheltered homelessness

60.8

1.14

0.94, 1.38

1.13

0.93, 1.37

Unsheltered homelessness

92.4

1.73

1.52, 1.98*

1.68

1.48, 1.92*

Basic hand hygiene insecurity

City of residence

San Diego

53.4

Tijuana

79.7

1.49

1.33, 1.68*

1.45

1.28, 1.64*

Housing status

Permanent housing

54.7

Sheltered homelessness

62.4

1.14

0.95, 1.37

0.98

0.81, 1.18

Unsheltered homelessness

69.1

1.26

1.09, 1.46*

1.15

0.99, 1.34

Bathing insecurity

City of residence

San Diego

50.3

Tijuana

62.4

1.24

0.07, 1.44

1.21

1.06, 1.39*

Housing status

Permanent housing

37.7

Sheltered homelessness

45.6

1.21

0.93, 1.56

1.21

0.94, 1.57

Unsheltered homelessness

73.1

1.94

1.60, 2.34*

1.84

1.52, 2.22*

Improved water for cleaning wounds/abscesses insecurity

City of residence

San Diego

8.9

Tijuana

8.4

0.95

0.54, 1.65

0.85

0.49, 1.48

Housing status

Permanent housing

4.2

Sheltered homelessness

7.3

1.71

0.70, 4.19

1.93

0.78, 4.76

Unsheltered homelessness

13.3

3.13

1.54, 6.40*

3.12

1.55, 6.29*

Improved water for preparing drugs insecurity

City of residence

San Diego

8.6

Tijuana

9.9

1.15

0.68, 1.95

1.11

0.65, 1.88

Housing status

Permanent housing

5.2

Sheltered homelessness

5.6

1.08

0.43, 2.71

1.13

0.44, 2.86

Unsheltered homelessness

14.1

2.71

1.41, 5.20*

2.58

1.36, 4.89*