Study objective: This investigation compared the Significant Caries Index (SiC) with alternative summary measures of caries prevalence, designed to highlight high-risk communities and examined the implications of their use in health policy and planning in Wales.
Design: Data from the 2001 BASCD survey of 7,412, 12-year-old Welsh children were used in this analysis. As an alternative to the 33% cut-off value utilised in the SiC, the mean DMFT of children with the 10, 20 and 25% highest caries scores were calculated for 22 local health board areas, as was the mean DMFT for the whole population, %DMFT >0, and the mean for those with DMFT >0, >1, >2, and >3.
Setting: Examinations for the childhood epidemiology programme took place in Welsh secondary schools.
Participants: 12-year-old children examined in the 2000/01 survey.
Main results: The mean DMFT for the whole population was 1.31, and the mean DMFT of those with caries was 2.56. The mean DMFT for SiC 33%, 25%, 20% and 10% was: 3.39, 3.85, 4.28, and 5.31 respectively. When local health board areas were ranked according to mean DMFT score at different percentage cut-off points, variation in rank order was observed, the greatest difference in rank order being 6. Furthermore, when compared with summaries based on DMFT scores traditionally used in Wales, even greater rank differences were noted (up to 14 places).
Conclusions: Rank order of geographical area is influenced by the definition of the index chosen when describing high risk populations using a variety of caries indices. This has implications for health policy planning and resource allocation.