Age-period-cohort analysis of dentist use in Spain from 1987 to 1997. An analysis based on the Spanish National Health Interview Surveys.

The aim was to determine whether the effects of age, period (from 1987 to 1997), or cohort (birth-cohort) are the most plausible explanations for the variation in dentist utilisation over time in Spain. On the basis of three sequential Spanish National Health Surveys, the trend in the percentage of people visiting the dentist within the previous 3 months was analysed by means of a standard cohort table and by the CLAYTON & SCHIFFLERS method. The percent of people visiting the dentist grew from 13.6% in 1987, to 17.2% in 1997. Visual examination of the cohort table, together with the fit of the age-cohort model, indicates that cohort succession may be the best explanation for the increase. The younger the cohort, the higher the dental visit rate; this relationship was strongest for people born after 1977. The model also indicates that the rates of dental visiting tend to increase up to middle age, and then tend to decrease with age.