Evaluating the Effect of Socio-Economic Status on DMFT Index in Children Aged 12 in Iran through Zero-Inflated Poisson Regression

The most common index in dental studies is the decayed, missing, or filled teeth (dmft)/DMFT. Risk factor evaluation in order to investigate the significant factors that affect this DMFT in children has an important role in dental epidemiological studies. The aim of this study was to investigate the association between socioeconomic factors and dental caries.

This cross-sectional study was a part of a national survey for assessing the oral health status of Iranian citizens in 2012. The target population was children aged. The data and oral examination results were collected by the clinical examination form and trained calibrated dental group (dentists and hygienists). A zero-inflated Poisson regression model (ZIP) with a random effect was utilized for evaluating the effect of socioeconomic status on DMFT.

In general, 1564 subjects were studied. From the entire subject in this study, the frequency of zero was 4176 (67%). The result of the ZIP model with random effect in zero part showed that socioeconomic status (OR = 1.97; P-value <0.001) had a significant effect on zero DMFT occurrences. The variance component of the random intercept in zero part was significant too (σ2 =17.11, P < 0.001).

The zero-inflatedPoisson model with random effect in zero part was fitted to this data. Children from lower socioeconomic classes experienced more DMFT.