Table 1.

Demographic characteristics and risk factors associated with P. falciparum seroprevalence

Risk factor	Total		P. falciparum seropositive			Unadjusted			Adjusted
	%n	n	%n	n	%n 95% CI	ORa	95% CI	p value	ORb	95% CI	p-value
Age (years)
2–5	8.8	394	4.6	18	2.9–7.1	0.21	0.12–0.35	<0.001	0.22	0.13–0.38	<0.001
6–15	10.7	481	10	48	7.6–13.0	0.48	0.34–0.69	<0.001	0.52	0.36–0.75	0.001
16–40	45.8	2050	12.8	263	11.5–14.4	0.71	0.58–0.88	0.002	0.71	0.58–0.89	0.002
≥ 41	34.7	1552	17.1	266	15.4–19.1	1			1
Gender
Male	30.3	1357	10.7	145	9.2–12.4	0.67	0.54–0.84	<0.001	0.77	0.62–0.97	0.057
Female	69.7	3120	14.4	450	13.2–15.7	1			1
Education status
Primary and below	49.5	2218	13.6	302	12.3–15.1	1			1
Secondary and above	50.5	2259	13	293	11.7–14.4	0.89	0.73–1.08	0.239	0.72	0.56–0.95	0.018
Employment status
Unemployment	86.7	3881	13.1	508	12.1–14.2	0.36	0.11–1.19	0.094
Some employment	0.5	21	19.1	4	7.67–40.0	1
Full employment	12.8	575	14.4	83	11.8–17.5	0.42	0.12–1.44	0.168
Household IRS between Aug 2014 and Feb 2015
Yes	45.4	2034	11.8	239	10.4–13.2	0.93	0.73–1.18	0.537
No	53.1	2375	14.8	351	13.4–16.3	1
Not sure	1.5	68	7.4	5	3.18–16.1	1.05	0.40–2.81	0.916
Travel outside S. Africa in the past 6 months
Yes	1.5	65	21.5	14	13.3–33.0	1
No	98.5	4412	13.2	581	12.2–14.2	0.63	0.31–1.26	0.190
Outdoor nightime activity last night
Yes	21.1	945	12.4	117	10.4–14.6	1
No	78.9	3532	13.5	478	12.4–14.7	0.90	0.68–1.19	0.464
Household elevation (m)
350–450	41.4	1855	9.1	168	7.8–10.5	0.57	0.32–0.99	0.057
451–550	18.3	818	18.1	148	15.6–20.9	1
551–650	29.0	1296	18.1	235	16.1–20.3	1.06	0.64–1.77	0.823
651–750	11.4	508	8.7	44	6.5–11.4	1.01	0.49–2.08	0.969
Study site
Ba-Phalaborwa	35.3	1580	6.8	107	5.6–8.1	0.23	0.09–0.63	0.004	0.26	0.10–0.74	0.012
Bushbuckridge	64.7	2897	16.9	488	15.5–18.2	1			1
Total	100	4477	13.3	595	12.3–14.3

Seropositivity to either PfAMA-1 and/or PfMSP-1₁₉ across the study sites of Ba-Phalaborwa and Bushbuckridge. Individual level data: age, gender, education status and employment status. Household level data: household IRS between August 2014 and February 2015, travel outside South Africa in the past 6 months, outdoor activity last night and household elevation

^aAdjusted for correlation at the study ward level

^bAdjusted for Age, gender, study site and correlation at the study ward level