Table 2.

Incidence of hospitalization for malaria and other diseases, by hemoglobin genotype.

Diagnosis,a hemoglobin genotype	No. of episodes	Incidence (no. of episodes/1000 cyfu)	IRR (95% CI)	P
Nonmalaria
All nonmalaria
AA	512	57.83	1
AS	72	47.72	0.84 (0.60–1.17)	.289
Lower respiratory tract infection
AA	271	30.55	1
AS	43	28.50	0.96 (0.63–1.46)	.857
Gastroenteritis
AA	83	9.36	1
AS	8	5.30	0.59 (0.28–1.21)	.150
Malnutrition
AA	11	1.24	1
AS	2	1.33	1.14 (0.17–7.56)	.895
Accidents
AA	24	2.70	1
AS	4	2.65	0.94 (0.31–2.88)	.916
Severe anemia without malarial parasites
AA	18	2.01	1
AS	1	0.66	0.35 (0.05–2.59)	.302
Malaria
All malaria
AA	536	60.42	1
AS	25	16.57	0.25 (0.16–0.39)	<.0001
All severe malaria
AA	191	21.53	1
AS	6	3.98	0.17 (0.07–0.40)	<.0001
Cerebral malariab
AA	34	3.83	1
AS	1	0.66	0.14 (0.02–1.17)	.070
Severe malarial anemia with >10,000 parasites/μLb
AA	48	5.41	1
AS	1	0.66	0.11 (0.01–0.97)	.047
Malaria with convulsions (2 or more seizures during the previous 24 h)b
AA	94	10.60	1
AS	4	2.65	0.23 (0.08–0.67)	.007

NOTE. Admissions to the pediatric ward at Kilifi District Hospital were identified through the birth cohort study. The data on sickle cell trait (HbAS) were collected from 384 children during 1509.9 child-years of follow-up (cyfu), and the data on HbAA were collected from 2271 children during 8871.4 cyfu. Incidence rate ratios (IRRs) were calculated by Poisson regression analysis as described in table 1 but with the additional explanatory variables bed-net usage (by randomization arm), proximity to the nearest health center, and access to the hospital by bus.

^aSee Participants, Materials, and Methods for clinical definitions of the diseases.

^bThese 3 categories are mutually exclusive; the hierarchy for classification was cerebral malaria, severe malarial anemia, and then malaria with convulsions.