Factor

% seronegativity

P*

Relative

risk

Lower

limit

Upper limit

High SES

Low SES

Parents income

71.4

32.3

<0.05

2.2

1.7

2.8

Source of water

70.5

28.3

<0.05

2.5

2.8

3.4

Residential area

66.9

30.2

<0.05

2.2

1.6

3.0

Parents level of education

72.7

20.0

<0.05

3.6

2.4

5.6

Crowded household

70.4

36.7

<0.05

1.9

1.5

2.4

Age

73.2

34.6

<0.05

3.8

2.8

5.8