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Table 1 Demographic characteristics and risk factors associated with P. falciparum seroprevalence

From: Serology reveals heterogeneity of Plasmodium falciparum transmission in northeastern South Africa: implications for malaria elimination

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       
  1. 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
  2. aAdjusted for correlation at the study ward level
  3. bAdjusted for Age, gender, study site and correlation at the study ward level