Comparison of four composite deprivation indices and two census variables in predicting dental caries in 12-year-old children in Wales.

OBJECTIVE To compare the explanatory power of four composite indices of social economic status in their ability to predict dental caries experience. BASIC RESEARCH DESIGN A secondary analysis of Welsh BASCD survey data using ward aggregated dental data, census variables and composite measures of deprivation. CLINICAL SETTING Examinations took place in schools. PARTICIPANTS All 12-year-old children examined in the 1996/97 survey. MAIN OUTCOME MEASURES The explanatory variables were Jarman index, Welsh Underprivileged Area score (WUPA), Carstairs and Townsend indices and the outcome measure was mean DMFT. RESULTS The amount of the mean DMFT explained by the explanatory variables ranged from 62.9% with Welsh Underprivileged Area score (WUPA) in Bro Taf Health Authority to 4.2% with the Jarman index in Dyfed-Powys health authority. Of the constituent parts of the composite variables only the percentage with no car appeared in the 'top three' variables in all but one of six models. CONCLUSIONS The composite indices explained very different amounts of the variation in mean DMFT between the different health authorities. It would be unwise to rely on any one as a method of predicting which sections of the population would be likely to have dental disease.