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Table 2 Minimal logistic generalized linear mixed model describing risk factors for malaria among 9172 RDT-tested occupants of 2822 households in Dar es Salaam, Tanzania, surveyed between March 2010 and May 2012, for whom valid values of all significant variables were recorded

From: The epidemiology of residual Plasmodium falciparum malaria transmission and infection burden in an African city with high coverage of multiple vector control measures

Variable

Proportion (n)

Odds ratio [95 % CI]

P

Live in one of the original 15 Urban Malaria Control Programme (UMCP) study wards

New study ward

68.8 (7693)

1.00 [NA]

NA

Old UMCP study ward

31.2 (3494)

1.30 [1.02, 1.65]

0.033

Education of head of household

Any

96.8 % (8882)

1.00 [NA]

NA

None

3.2 % (290)

1.90 [1.34, 2.71]

0.00035

Sex

Female

63.9 % (5864)

1.00 [NA]

NA

Male

36.1 % (3308)

1.16 [1.03, 1.33]

0.020

Window screening a and the proportion of potential vector biting exposure occurring indoors (Ï€ i ) b

Unscreened or screened but lowest π i tercile

34.1 % (3132)

1 [NA]

NA

Screened and middle or highest π i tercile

65.9 % (6040)

0.71 [0.62, 0.82]

0.0000036

Living in a ward with or without active larvicide application

No larviciding

69.2 % (7744)

1.00 [NA]

NA

Granule application managed by contractorc

11.9 % (1329)

1.29 [0.78, 2.13]

0.325

Granule application managed by Ministry of Health & Social Welfare (MoHSW)

4.9 % (551)

0.26 [0.12, 0.56]

0.00040

Pre-diluted liquid application managed by MoHSWc

14.0 % (1563)

0.96 [0.67,1.37]

0.836

Individual use of a bed net the previous night

Didn’t use any bed net

19.4 % (1773)

[NA]

NA

Used an untreated bed net

29.8 % (2736)

1.29 [1.03, 1.60]

0.023

Used a long-lasting insecticidal net (LLIN)

50.8 % (4663)

1.42 [1.16, 1.74]

0.00063

Population-wide LLIN use d

Increase in coverage by final round

From 51.0 to 71.2 %

0.80 [0.69, 0.91]

0.0013

Recent travel history over last month

Had not slept away from home

79.8 % (7322)

1.00 [NA]

NA

Slept away from home at least once

20.2 % (1850)

0.69 [0.54, 0.88]

0.0024

Anopheles gambiae density e among households lacking window screening a only

One mosquito caught per trap per night

Continuum

6.99 [1.12, 43.7]

0.037

Age group c

Under 5 years

16.7 (1873)

1.00 [NA]

NA

5–14 years

18.4 (2062)

1.06 [0.86, 1.32]

0.542

15–24 years

22.6 (2526)

1.16 [0.95, 1.44]

0.143

25–34 years

18.2 (2040)

0.97 [0.77, 1.21]

0.776

35 years and above

24.0 (2686)

1.01 [0.82, 1.24]

0.947

  1. NA Not applicable
  2. aBased on exploratory analysis as described in the main text, with glass, completely screened with no holes and completely screened with holes classified as adequately-screened and protective, whereas unscreened, torn or only partially screened were all classified as inadequately screened
  3. bSee Fig. 8 for a description of the behavioural characteristics of the three terciles of this index of the proportion of human exposure to mosquitoes which occurs indoors and can be prevented with indoor vector control measures [74, 75, 106–109]
  4. cExcluded from the final model because non-significant, but presented here for illustrative purposes
  5. dAssociation with community-level mean LLIN scale-up, captured by fitting city-wide mean reported LLIN use the previous night as a continuous covariate, so the odds ratio presented is that estimated based on community-wide usage in the last round of1 surveys (71.2 %) versus the first (51.0 %)
  6. ePresented here for illustrative purposes but excluded from the final mode, because reducing vector density is an intermediate outcome of both bed net use and larvicide application, so inclusion confounds evaluation of these vector control measures. Incorporated into the model as a square root-transformed continuous variable so the odds ratio presented represents that estimated for any area with an Anopheles gambiae density of one mosquito per tent trap per night compared with a location where none were detected by tent trapping. To get this threshold in context, the highest density of An. gambiae recorded was only slightly lower than this (Fig. 6)