Deprivation, urbanisation and Perthes' disease in Northern Ireland

It has been suggested that Perthes' disease is more prevalent in urban area s, and that the risk increases with deprivation. We present the findings of a preliminary analysis of Perthes' disease in Northern Ireland, which is s hown to have one of the highest national annual rates of incidence in the w orld (11.6 per 100 000), Of the 313 children diagnosed over a seven-year pe riod, 311 were allocated to the enumeration districts of the 1991 census, t hus allowing the incidence to be calculated using both spatial and non-spat ial aggregation. The cases were grouped according to the size of the settle ment from highly urbanised to open countryside and by level of area depriva tion. While the incidence of Perthes' disease was found to be associated wi th indicators of the level of deprivation for areas, there was no evidence to suggest that there was an increased risk in urban areas; the highest rat e was found in the most deprived rural category.