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Table 2 Rates of uncomplicated malaria, non-malarial febrile episodes and severe events (hospital admission or death), by genotype

From: Effect of α+-thalassaemia on episodes of fever due to malaria and other causes: a community-based cohort study in Tanzania

Event

Normal

(αα/αα)

Heterozygotes

(-α/αα)

Homozygotes

(-α/-α)

All episodes of malaria

      

   Incidence (n/child-years)

3.10

(812/262)

2.89

(622/215)

2.83

(136/48)

   Hazard ratio, crude

1.00

Reference

0.93

[0.80-1.06]

0.92

[0.73-1.14]

   Hazard ratio, adjusted †

1.00

Reference

0.93

[0.82-1.06]

0.91

[0.73-1.14]

   Episodes with parasitaemia > 5,000/μL (1,249)

1.00

Reference

0.94

[0.81-1.10]

0.89

[0.67-1.17]

   Episodes with parasitaemia > 10,000/μL (1,119)

1.00

Reference

0.95

[0.81-1.11]

0.91

[0.68-1.22]

   Episodes with parasitaemia > 100,000/μL (263)

1.00

Reference

0.94

[0.69-1.29]

0.98

[0.57-1.69]

   Episodes with haemoglobin concentration < 80 g/L (178)

1.00

Reference

1.25

[0.86-1.84]

2.65

[1.71-4.10]

1 st episodes of malaria

      

   Incidence (n/child-years)

3.08

(257/84)

2.66

(199/75)

3.44

(49/14)

   Incidence rate ratio

1.00

Reference

0.86

[0.71-1.04]

1.12

[0.81-1.52]

   Hazard ratio, crude

1.00

Reference

0.90

[0.75-1.09]

1.10

[0.81-1.49]

   Hazard ratio, adjusted †

1.00

Reference

0.89

[0.74-1.08]

1.06

[[0.78-1.44]

All episodes of non-malarial fever

      

   Incidence (n/child-years)

1.64

(431/262)

1.72

(370/215)

1.82

(87/48)

   Hazard ratio, crude

1.00

Reference

1.04

[0.85-1.28]

1.10

[0.82-1.49]

   Hazard ratio, adjusted ¶

1.00

Reference

1.00

[0.84-1.19]

0.98

[0.73-1.36]

All hospital admissions or deaths §

      

   Incidence (n/child-years)

0.15

(39/262)

0.10

(21/215)

0.19

(9/48)

   Hazard ratio, crude

1.00

Reference

0.66

[0.38-1.14]

1.26

[0.56-2.89]

   Hazard ratio, adjusted ¶

1.00

Reference

0.57

[0.33-0.98]

0.89

[0.36-2.24]

  1. Values between brackets indicate (cases), (cases/child-year) or [95% CIs].
  2. † Adjusted for experimental intervention (indicated by dummies), mosquito net use, distance between homestead and research clinic, height-for-age z-score and Plasmodium infection at baseline. There was no evidence of an interaction between genotype and experimental intervention.
  3. ¶ Adjusted for age class, experimental intervention (dummies), distance between homestead and research clinic, height-for-age z-score and Plasmodium infection at baseline.
  4. § Hospital admissions or deaths (of which two occurred outside hospital) for infection-related causes, excluding events due to trauma, poisoning or burns (one case occurred in a child for whom the genotype could not be determined).