Table 2

Unadjusted, matched odds ratios for the occurrence of cryptosporidiosis among patients with AIDS according to exposure to drinking water sources


Cases (n = 49)
Controls (n = 99)


Variable
N
(%)
N
(%)
Odds Ratio
95% CI

Tap water at home






     Never
2
(4)
31
(31)
1.00
Reference
     Sometimes
20
(41)
30
(30)
9.54
2.06, 44.1
     Always
27
(55)
38
(38)
9.78
2.14, 44.7
Tap water outside home






     Never
29
(59)
81
(82)
1.00
Reference
     Sometimes
4
(8)
8
(8)
2.00
0.53, 7.50
     Always
16
(33)
10
(10)
4.20
1.76, 10.0
Tap water compositea






     Lowest exposure
2
(4)
29
(29)
1.00
Reference
     Intermediate exposure
35
(71)
64
(65)
7.08
1.59, 31.4
     Highest exposure
12
(24)
6
(6)
24.3
4.21, 139
Bottled water at home






     Never
25
(51)
38
(38)
1.00
Reference
     Sometimes
24
(49)
40
(40)
0.81
0.37, 1.76
     Always
0
(0)
21
(21)
0.09c
0.03, 0.37
Bottled water outside home






     Never
17
(35)
36
(36)
1.00
Reference
     Sometimes
10
(20)
20
(20)
0.97
0.28, 3.40
     Always
22
(45)
43
(43)
0.75
0.28, 2.06
Bottled water compositeb






     Lowest exposure
11
(22)
17
(17)
1.00
Reference
     Intermediate exposure
38
(78)
70
(71)
0.66
0.26, 1.68
     Highest exposure
0
(0)
12
(12)
0.17c
0.06, 0.83
Filtered municipal water






     Filtered
27
(55)
51
(52)
1.00
Reference
     Mixed
14
(29)
37
(37)
0.75
0.35, 1.58
     Unfiltered
8
(16)
11
(11)
1.36
0.44, 4.16

aLowest = answered never consumed tap water both inside and outside the home; Highest = answered always consumed tap water both inside and outside the home; Intermediate = all other responses bLowest = answered never consumed bottled water both inside and outside the home; Highest = answered always consumed bottled water both inside and outside the home; Intermediate = all other responses cUnmatched, median-unbiased odds ratio estimate and exact 95% confidence intervals calculated directly from the mid-p function based on the hypergeometric model (see methods)

Aragón et al. BMC Public Health 2003 3:2   doi:10.1186/1471-2458-3-2