Table 2.
Association between different measures of placental malaria and incidence of malaria during infancy
| Infant category | Placental malaria categories (N) | Malaria episodes | Person years of follow-up | Malaria incidencea | Unadjusted | Adjustedb | ||
|---|---|---|---|---|---|---|---|---|
| IRR (95% CI) | p value | IRR (95% CI) | p-value | |||||
| All | No PM (351) | 574 | 327.4 | 1.75 | Reference group | Reference group | ||
| Active PM (78) | 152 | 68.9 | 2.21 | 1.27 (0.99–1.62) | 0.06 | 1.30 (1.00-1.71) | 0.05 | |
| Past PM (mild-mod) (181) | 271 | 157.8 | 1.72 | 0.97 (0.79–1.18) | 0.74 | 0.94 (0.76-1.16) | 0.55 | |
| Past PM (severe) (46) | 91 | 42.5 | 2.14 | 1.22 (0.91–1.63) | 0.19 | 1.28 (0.89-1.83) | 0.18 | |
| Male | No PM (168) | 255 | 154.5 | 1.65 | Reference group | Reference group | ||
| Active PM (45) | 86 | 39.9 | 2.16 | 1.31 (0.93–1.87) | 0.13 | 1.27 (0.87–1.84) | 0.22 | |
| Past PM (mild-mod) (70) | 129 | 77.7 | 1.66 | 0.98 (0.72–1.35) | 0.92 | 1.02 (0.76–1.36) | 0.90 | |
| Past PM (severe) (17) | 49 | 15.3 | 3.20 | 1.87 (1.29–2.71) | 0.001 | 2.17 (1.45–3.25) | <0.001 | |
| Female | No PM (183) | 319 | 172.9 | 1.84 | Reference group | Reference group | ||
| Active PM (33) | 66 | 29.0 | 2.28 | 1.24 (0.89–1.73) | 0.21 | 1.29 (0.87–1.91) | 0.21 | |
| Past PM (mild-mod) (91) | 142 | 80.1 | 1.77 | 0.96 (0.73–1.24) | 0.74 | 0.81 (0.61–1.08) | 0.15 | |
| Past PM (severe) (29) | 42 | 27.1 | 1.55 | 0.85 (0.58–1.24) | 0.40 | 0.74 (0.46–1.20) | 0.22 | |
CI confidence interval, IRR incidence rate ratio, mild-mod mild-moderate, PM placental malaria
aEpisodes of malaria per person year of follow-up
bAdjusted for gravidity, maternal IPTp, maternal parasitaemia at enrolment, and household type
No PM no parasites or pigment detected, active PM parasites detected with or without pigment, past PM (mild-mod) > 0–20% of high-power fields with pigment but no parasites, past PM(severe) > 20%–60% of high-power fields with pigment but no parasites