Impact of Non-Weighting in the Analysis of Data Obtained from Complex Samples

Abstract Objective: To compare the estimates obtained, considering or not the weighting data. Material and Methods: Secondary data from the Oral Health Survey of the State of São Paulo (SBSP2015) was used for calculation of mean estimates, standard errors of the mean and confidence intervals (CI) for the DMFT index and components (decayed, lost and filled), in the age group of 35-44 years. Multiple logistic regression models were estimated, considering or not the weighting from the sampling plan (p<0.05). Results: It was observed that the estimates of the DMFT index and the carious component did not vary much when the design was considered or not (1.1% and 2.0%, respectively). However, the data referring to the lost and filled component showed greater differences between the values of the means. The averages fluctuated up and down by up to 6.7% for weighted versus unweighted analyses. The standard error was underestimated in the unweighted analysis and the confidence interval showed variations. Differences between the regression models obtained by the weighted and unweighted analysis of the data were detected. Conclusion: Although weighted and unweighted models presented differences of less than 10% in estimates of the mean, confidence intervals, as well as statistical inferences, were different. Thus, weighting should be applied in the population base data analysis collected by sampling with complex designs.

Factors associated with the need for a complete denture in one arch or both arches among the elderly population

Abstract: This study aimed to identify factors associated with the need for complete dentures in one dental arch or both, among the elderly population. The cross-sectional household study was conducted with a representative sample of elderly people (65 years or older) in the state of São Paulo, Brazil, in 2015. The dependent variable was the need for complete dentures (in one arch or both), and independent variables were socioeconomic and demographic conditions, social capital, self-perception of oral health and access to dental services. Simple and multinomial logistic regression models tested effect measures (p < 0.05). A total of 5,948 elderly people participated. Results indicated that those with greater chances of needing a complete denture in one arch were male (OR = 1.54; CI95%:1.04-2.29), with fewer household goods (OR = 2.25; CI95%:1.50-3.38), lower monthly household income: R$501-1500 (OR = 3.44; CI95%:1.27-9.35), R$1501-2500 (OR = 4.11; CI95%:1.50-11.27), R$2501-4500 (OR = 2.76; CI95%:1.10-6.95), self-reported need for a complete denture (OR = 4.75; CI95%:3.08-7.35), ≥3 years since last dental appointment (OR = 1.80; CI95%:1.06-3.05), and dissatisfaction with last dental appointment (OR = 1.80; CI95%:1.06-3.05). There were more chances of the need for complete dentures in both arches among older elders (OR = 1.44; CI95%:1.06-1.88), with lower monthly household income: R$ < 501 (OR = 4.45; CI95%:1.71-11.60), R$501-1500 (OR = 4.01; CI95%:2.14-7.51), R$1501-2500 (OR = 2.95; CI95%:1.64-5.32), < 3 years of education (OR = 1.45; CI95%:1.13-1.85), feeling unhappy (OR = 2.74; CI95%:1.35-5.57), self-reported need for a complete denture (OR = 8.48; CI95%:5.75-12.50), dissatisfaction with their mouth (OR = 2.38; CI95%:1.64-3.46), ≥3 years since last dental appointment (OR = 4.28; CI95%:2.85-6.43), and dissatisfaction with last dental appointment (OR = 4.28; CI95%:2.85-6.43). The several dimensions of the determinants of the need for a complete denture reflect the influence of both demographic and socioeconomic aspects, social capital, self-perception of oral health and access to dental services.