Table 3.

Risk of LBW associated with placental malaria

Placenta malaria prevalence	Prevalence of LBW		Prevalence ratio	Infected attributable fraction	Population-attributable fraction
	Placenta malaria	No Placenta malaria
27.89 (738/2646)	21.0 (152/723)	13.7 (259/1892)	1.535	34.87	12.99

The prevalence ratio (Pr) is the proportion of infected women with LBW divided by the proportion of uninfected women with LBW. The infected attributable fraction is the percentage of infected women with LBW that is due to malaria [(Pr − 1)/pr]. The population-attributable fraction is the percentage of LBW cases that are due to malaria infection: [PM(Pr − 1)]/{1 + [PM(Pr − 1)]} where PM is the proportion with placental malaria infection