Estimation of age specific incidence rates of childhood burns from a prevalence survey of burn scars

Objectives - This paper describes two methods of estimating the age specific incidence rates of childhood burns from a prevalence survey of burn scars. Methods - A prevalence survey of burn scars was carried out in 1992 on 15 742 Ghanaian children aged 5 years or less. Nine hundred and fifty five (6.1%) of these children had scars from burn, and for 630 (66%) of these children, additional information about the burn incident, including the child's age at the time of the burn, was obtained from the mother two to three months later. Thirty four per cent of mothers of children with burn scars were not interviewed due to absence, relocation, or inaccessibility. Age specific incidence rates of burns were estimated for eight age groups using two methods. In method I, the number of incident cases of burns for each age group were estimated from the burn scars by subtracting the estimated contribution of scars from burns that had occurred at earlier ages. In method II, the estimate was based on the mother's recall of the age of the child at the time of the burn. Results - Slightly different results were obtained with the two methods, and problems were noted with both methods. Conclusion - We recommend the use of these methods for estimating age specific incidence rates from retrospective population surveys for health conditions which result in long term residual markers.