Prevalence and natural history of otitis media with perforation in Maori school children.

New Zealand Maoris are one of five ethnic groups in developed countries known to have a high rate of ear disease, including perforation of the eardrum (CSOM). It is a strongly held belief by otolaryngologists whose practice dates back to the 1960's that the prevalence of CSOM in Maori children is gradually falling. Despite the obvious practical implications this change has not yet been documented. The aim of the study was to compare the prevalence of CSOM in two surveys conducted in 1978 and 1987 of children living in a North Island Maori community. A second aim was to examine the natural history of CSOM in these children. The raw data from the 1978 study were reviewed. Of 134 children aged 4-13, 12 had CSOM. In 1987 the same age group yielded 12 children out of 250 with CSOM. The prevalence of CSOM fell from 9 per cent to 4 per cent. The incidence of new perforations in 1987 was 1.3 per cent per child per year. It is concluded there has been a fall in the rate of CSOM, although otitis media remains a significant problem for these children. The probability of a perforation healing was influenced by whether or not the perforation had been observed before: at least 35 per cent of perforations seen for the first time healed, but none of the perforations seen on two occasions healed spontaneously. It was concluded that perforation of the eardrum can be managed conservatively at first.