Prospective validation of a standardized questionnaire for estimating childhood mortality and morbidity due to pneumonia and diarrhoea.

This paper reports the validation of a 'best-judgement' standardised questionnaire using guidelines and algorithms developed by an expert working group conducted in Nicaragua between 1995 and 1997. Prospective hospital data, including standardised medical recording of selected signs and symptoms, laboratory and radiographic test results and physician diagnoses were collected for children < 5 years admitted with any serious life-threatening condition in 3 study hospitals. The mothers or caregivers of the children were later traced and interviewed using the 'best-judgement' questionnaire. Interviews were completed 1-22 months after admission to hospital for 1115 children (400 who died during the stay in hospital and 715 who were discharged alive). The cause of death or admission to hospital was determined by an expert algorithm applied to hospital data. A similar procedure was used to derive the cause using the answers to questions from interviews. Hospital causes were compared with interview causes and sensitivity and specificity calculated, together with the estimated cause-specific fraction for diarrhoea and pneumonia. Multiple diagnoses were allowed; 378 children in the sample (104 deaths, 274 survivors) had a reference diagnosis of diarrhoeal illness, and 506 (168 deaths, 338 survivors) a reference diagnosis of pneumonia. When results for deaths and survivors in all age groups were combined, the expert algorithms had sensitivity between 86% and 88% and specificity between 81% and 83% for any diarrhoeal illness; and sensitivity between 74% and 87% and specificity between 37% and 72% for pneumonia. Algorithms tested in previous validation studies were also applied to data obtained in this study, and the results are compared. Despite less than perfect sensitivity and specificity, reasonably accurate estimates of the cause-specific mortality and morbidity fractions for diarrhoea were obtained, although the accuracy of estimates in other settings using the same instrument will depend on the true cause-specific fraction in those settings. The algorithms tested for pneumonia did not produce accurate estimates of the cause-specific fraction, and are not recommended for use in community settings.

Does intelligence account for the link between maternal literacy and child survival?

The strong and consistent correlation between maternal education and child health is now well known, and numerous studies have shown that wealth and income cannot explain the link. Policy-makers have therefore assumed that the relationship is causal and explicitly advocate schooling as a child health intervention. However, there are other factors which could account for the apparent effect of maternal education on child morbidity and mortality, one of which is intelligence. This paper examines the effect of maternal intelligence on child health and looks at the degree to which it can explain the literacy associations with child survival and risk of malnutrition. The data are from a retrospective cohort study of 1294 mothers and their 7475 offspring, of whom 454 were women who had learned to read and write as adults in Nicaragua's literacy programme, 457 were illiterate, and 383 had become literate as young girls attending school. The women's intelligence was tested using Raven's Coloured Progressive Matrices. Acquisition of literacy was strongly related to intelligence. Statistically significant associations with maternal literacy were found for under five mortality, infant mortality, and the risk of low mid-upper-arm circumference (MUAC) for age, before and after controlling for a wide range of socio-economic factors. Under five, child (one to four years), infant and post-neonatal mortality plus the risk of low height for age were significantly correlated with intelligence, but only with infant and under mortality rates did the association remain significant after controlling for socio-economic factors. A significant interaction between intelligence and literacy for under five mortality was due to literacy having a strong effect in the women of low intelligence, and a negligible effect among those of high intelligence. This study provides evidence that intelligence is an important determinant of child health among the illiterate, and that education may have the greatest impact on child health for mothers of relatively low intelligence.