Effect of α + -thalassaemia on episodes of fever due to malaria and other causes: a community-based cohort study in Tanzania
Abstract Background It is controversial to what degree α + -thalassaemia protects against episodes of uncomplicated malaria and febrile disease due to infections other than Plasmodium . Methods In Tanzania, in children aged 6-60 months and height-for-age z-score < -1.5 SD (n = 612), rates of feve...
| Published in: | Malaria Journal |
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| Main Authors: | , , , , , , , |
| Format: | Article in Journal/Newspaper |
| Language: | English |
| Published: |
BMC
2011
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| Subjects: | |
| Online Access: | https://doi.org/10.1186/1475-2875-10-280 https://doaj.org/article/d78832979fc94bffb70c1c8332cfffe9 |
| Summary: | Abstract Background It is controversial to what degree α + -thalassaemia protects against episodes of uncomplicated malaria and febrile disease due to infections other than Plasmodium . Methods In Tanzania, in children aged 6-60 months and height-for-age z-score < -1.5 SD (n = 612), rates of fevers due to malaria and other causes were compared between those with heterozygous or homozygotes α + -thalassaemia and those with a normal genotype, using Cox regression models that accounted for multiple events per child. Results The overall incidence of malaria was 3.0/child-year (1, 572/526 child-years); no differences were found in malaria rates between genotypes (hazard ratios, 95% CI: 0.93, 0.82-1.06 and 0.91, 0.73-1.14 for heterozygotes and homozygotes respectively, adjusted for baseline factors that were predictive for outcome). However, this association strongly depended on age: among children aged 6-17 months, those with α + -thalassaemia experienced episodes more frequently than those with a normal genotype (1.30, 1.02-1.65 and 1.15, 0.80-1.65 for heterozygotes and homozygotes respectively), whereas among their peers aged 18-60 months, α + -thalassaemia protected against malaria (0.80, 0.68-0.95 and 0.78, 0.60-1.03; p-value for interaction 0.001 and 0.10 for hetero- and homozygotes respectively). No effect was observed on non-malarial febrile episodes. Conclusions In this population, the association between α + -thalassaemia and malaria depends on age. Our data suggest that protection by α + -thalassaemia is conferred by more efficient acquisition of malaria-specific immunity. |
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