Table 3. Multivariable logistical regression model of risk factors for malaria infection in Zambezia province.

Factors		OR*(95%CI)	Wald P-value	Adjusted P-value*
Age groups of children (years)
1–3		1
4–6		1.3(1.1–1.5)	= 0.01
7–9		1.4(1.1–1.7)	= 0.016
10–15		1.3(1.0–1.6)	= 0.056
Children with current fever
No		1
Yes		1.2(1.0–1.5)	= 0.076
Living in IRS houses and sleeping under ITN
No IRS & not sleeping under ITN		1
IRS & sleeping under ITN		0.5(0.3–0.7)	= 0.001
IRS & not sleeping under ITN		0.6(0.4–0.9)	= 0.018
No IRS & sleeping under ITN		1.2(0.9–1.8)	= 0.238	0.009
Size of household in which children live
1–4 people	1
5–7 people	1.6(1.3–2.0)		<0.0001
8–15 people	1.6(1.3–2.1)		= 0.001	0.0022
Children of parents with different level of education
None	1
Primary/secondary	0.6(0.5–0.7)		<0.0001
Tertiary	0.4(0.3–0.6)		<0.0001	<0.0001
Children living in household with different wealth index (SES)
1st quartile (poorest)	1
2nd quartile	0.9(0.7–1.2)		= 0.50
3rd quartile	0.9(0.7–1.3)		= 0.723
4th quartile (wealthiest)	0.5(0.4–0.7)		<0.0001
Roof material of house in which children live
Without grass roof	1
With grass roof	1.7(1.3–2.4)		= 0.002
Children living in household with pig
No pig	1
Own pig(s)	3.2(2.1–4.9)		<0.0001
Year of survey
2006	1
2007	1.4(1.0–2.1)		= 0.047
2008	0.4(0.3–0.7)		= 0.003

OR* adjusted for age, year of survey and wealth index. Estimates of OR* for covariates not related with farm animals were done with pig variable in the model.

*P-value derived from Wald test adjusted for the combine effect of categories in the variable.