Original articleThymus Size at 6 Months of Age and Subsequent Child Mortality
Section snippets
Study Site
This study was conducted through the Bandim Health Project (BHP) in Bissau, the capital of Guinea-Bissau in western Africa. In 1978, the BHP implemented a demographic surveillance system in the Bissau suburb known as Bandim I, and later expanded it to neighboring areas.8 The study was performed at the Bandim Health Centre, and the subjects resided mainly in Bandim I and Bandim II.
Subjects and Methods
The subjects participated in a randomized 2-dose measles vaccination trial, in which they received either a measles
Study Population
A total of 923 infants (485 boys and 438 girls) were included in the analyses (Figure 1). The median age at study entry was 6.0 months (range, 5.7 to 6.4 months). The median thymic index was 34.3 (range 10.5 to 71.1 months). The median follow-up in the main analysis was 17 months (interquartile range, 13 to 22 months). Of the 923 children, 767 (83%) were scanned on the same day as they were vaccinated, 44 (5%) were scanned before vaccination, and 112 (12%) after vaccination. At age 7.5 months,
Discussion
Our data provide evidence for a large and independent association between thymus size at age 6 months and subsequent mortality. A larger thymus size was associated with significantly reduced mortality controlled for significant background factors. A doubling of thymus size reduced mortality by about 70%.
Among determinants of smaller thymus size, both living in a house with a zinc roof and not having functioning electricity in the house were significant. We have no explanation as to why these 2
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Funded by the Novo Nordisk Foundation; the Danish Council for Development Research, Science and Technology for Development Programme of the European Community (project IC18-CT95-0011), and the Danish National Research Foundation. The authors have no conflicts of interest to declare.