Age as a risk factor for severe Plasmodium falciparum malaria in nonimmune patients.

In this nationwide, cross-sectional study, we evaluated the influence of age and other factors that affect clinical outcome of Plasmodium falciparum malaria in nonimmune patients. Of 135 patients with P. falciparum malaria, 84 (62%) were < 40 years old, and only 5% of the patients in this age group developed severe malaria, compared with 18% of the subjects who were > or =40 years of age (odds ratio, 4.29); moreover, all deaths occurred in the latter group. Male subjects did not differ from female subjects with regard to severity of disease.