The contribution of alpha+-thalassaemia to anaemia in a Nigerian population exposed to intense malaria transmission.
The proportion to which alpha-thalassaemia contributes to anaemia in Africa is not well recognized. In an area of intense malaria transmission in South-West Nigeria, haematological parameters of alpha-thalassaemia were examined in 494 children and 119 adults. The -alpha3.7 type of alpha+-thalassaemia was observed at a gene frequency of 0.27. Nine and 36.5% of individuals were homozygous and heterozygous, respectively. P.falciparum-infection was present in 78% of children and in 39% of adults. The alpha-globin genotypes did not correlate with the prevalence of P. falciparum-infection. alpha+-thalassaemic individuals had significantly lower mean values of haemoglobin, mean corpuscular volume, and mean corpuscular haemoglobin than non-thalassaemic subjects. Anaemia was seen in 54. 7% of children with a normal alpha-globin genotype, in 69.9% of heterozygous (odds ratio: 1.99, 95% confidence interval: 1.32-3.00, P = 0.001), and in 88.4% of homozygous alpha+-thalassaemic children (odds ratio: 7.72, 95% confidence interval: 2.85-20.90, P = 0.0001). The findings show that alpha+-thalassaemia contributes essentially to mild anaemia, microcytosis, and hypochromia in Nigeria.
D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000747:Anemia, Hypochromic / Q000453:epidemiology / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D004909:Erythrocyte Indices; D005787:Gene Frequency; D006580:Genetic Carrier Screening; D005838:Genotype; D005914:Globins / Q000235:genetics; D006454:Hemoglobins / Q000032:analysis; D006720:Homozygote; D006801:Humans; D007223:Infant; D016778:Malaria, Falciparum / Q000150:complications* / Q000453:epidemiology / Q000635:transmission; D008875:Middle Aged; D009549:Nigeria / Q000453:epidemiology; D011159:Population Surveillance; D015995:Prevalence; D012307:Risk Factors; D017085:alpha-Thalassemia / Q000097:blood / Q000150:complications* / Q000453:epidemiology / Q000235:genetics*