Sample dimensioning in epidemiological surveys based on the change of the dental caries prevalence and their implications in the costs / Dimensionamento de amostra em levantamentos epidemiologicos baseado na mudança da prevalencia de carie dentaria e suas implicações nos custos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2007

RESUMO

The objective of the present study was to analyze how the prevalence and the distribution of dental caries in schoolchildren influence the size of the necessary sample in epidemiological surveys and, consequently, in the costs for the completion of similar ones for public services. Secondary data of two medium load municipal districts in São Paulo state were used. 12-year-old age children were examined. 1,449 schoolchildren from Bauru were examined during 1976, 1984, 1990, 1994, and 2001. 1,763 were examined in Piracicaba during 2001 and 2005. The samples were dimensioned according to the average and standard deviation obtained in the studies. The amostral error was set (d) to 1, 2, 5 and 10% of the average. After the dimensioning of the samples, the costs for the dental caries surveys were estimated considering the real prices of the materials and labor, including the following items: permanent material, consumption material, and human resources. In both municipal districts, the increased necessity was verified in the size of the samples due to the decrease of the prevalence of the dental caries and increase in the variability among the schoolchildren. Considering the amostral error of 10% in Bauru, the variation in the size of the sample would be 119 in 1976 to 1,118 in 2001. In Piracicaba this variation would be from 954 to 1,252 during 2001 and 2005, respectively. In relation to the costs for completion of the epidemiological survey in Bauru were estimated US$ 182,00 in 1976 and US$ 1.706,00 in 2001. In Piracicaba, the values were US$ 1.456,00 in 2001 and US$ 1.910,00 in 2005. The stated values refer to the operational cost, because, in both municipal districts, an additional fixed cost of US$ 561,00 regarding the permanent material was estimated. It is ended that the decrease of the prevalence of the dental caries determined the need of an increase in the size of the samples and, as a result, the increase in costs and time for completion of the surveys.

ASSUNTO(S)

epidemiologia public health epidemiology saude coletiva

ACESSO AO ARTIGO

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