Table 2.

Univariate logistic regression analysis of risk factors associated with a positive malaria rapid diagnostic test

Explanatory variable		Total tested	Malaria positive	Malaria positivity (%)	Odds ratio (95% CI)	P-value	P-trend
Individual factors
Gender (N = 80,532)	Female	41,623	2103	5.1	1.0
	Male	38,909	1714	4.4	0.9 (0.8–0.9)	< 0.001
Age group (N = 80,275)	≥ 45 years	9207	181	2.0	1.0		< 0.001
	35–44 years	9016	266	3.0	1.5 (1.2–1.8)	< 0.001
	25–34 years	11,816	580	4.9	2.5 (2.1–2.9)	< 0.001
	15–24 years	16,887	838	5.0	2.6 (2.2–3.1)	< 0.001
	5–14 years	21,948	1311	6.0	3.2 (2.7–3.7)	< 0.001
	< 5 years	11,401	642	5.6	2.9 (2.5–3.4)	< 0.001
Self-reported fever in last two weeks (N = 73,273)	No	70,384	2151	3.1	1.0
	Yes	2889	1354	46.9	32.1 (29.3–35.1)	< 0.001
History of travel during last 30 days (N = 76,970)	No	55,267	2103	3.8	1.0		< 0.001
	Within Zanzibar	2360	66	2.8	0.8 (0.6–0.9)	0.027
	Outside Zanzibar	19,343	1506	7.8	2.3 (2.1–2.4)	< 0.001
Number of household members who travelled outside Zanzibar (N = 82,021)	None	48,966	1751	3.6	1.0		< 0.001
	1	10,977	503	4.6	1.4 (1.3–1.6)	< 0.001
	≥ 2	22,078	1569	7.1	2.3 (2.1–2.5)	< 0.001
Slept under an LLIN the previous night (N = 74,119)	No	29,316	1658	5.7	1.0
	Yes	44,803	1864	4.2	0.7 (0.6–0.7)	< 0.001
Household factors
Net access (N = 80,202)a	No access	15,756	922	5.9	1.0		< 0.001
	< 80%	24,071	1344	5.6	0.9 (0.8–1.0)	0.058
	≥ 80%a	40,375	1492	3.7	0.6 (0.6–0.7)	< 0.001
IRS in the last 12 months (N = 82,021)	No	21,934	1173	5.3	1.0
	Yes	60,087	2650	4.4	0.8 (0.7–0.9)	< 0.001
Geographical factors
Zone (N = 82,021)	Pemba	20,777	880	4.2	1.0
	Unguja	61,244	2943	4.8	1.2 (1.0–1.4)	0.019
Total weekly rainfall for previous 9 weeks (N = 82,021)	Increments of 10 mm				1.0 (0.9–1.0)	0.757

CI, confidence interval; LLIN, long-lasting insecticidal net; IRS, indoor residual spraying of households with insecticide

^aHousehold level access to LLIN (universal coverage ≥ 80%)