Changes in caries prevalence in children and young adults of Dutch and Turkish or Moroccan origin in the Netherlands between 1987 and 1993

In 1987, an epidemiological study was started with the aim to evaluate the development of dental health in young people insured by 'Health Insurance Funds'. In The Netherlands, insurance by such funds is compulsory for individuals earning less than some income criterion (in 1995 59,000 Dutch florins) and their families, together approximately 60% of the Dutch population. Dental health care is included in the insurance. Caries data were obtained in subjects aged 5-23 years in 1987, 1990 and 1993. Mean DMFS scores of groups aged 11, 17 or 23 years in 1993 were about 40% lower than in 1987. No significant differences in mean number of dmfs of 5-year-olds in 1987 and 1993 could be observed. A breakdown by country of birth of the mother showed that the difference between indigenous Dutch juveniles and juveniles of Turkish or Moroccan origin depended on year of birth. Caries prevalence of Turkish or Moroccan children born in 1982 or later was higher than that of Dutch children of equal age; no significant difference in DMFS could be demonstrated between ethnic categories in juveniles born in 1976. In cohorts born before 1976, DMFS scores of Turkish/Moroccan juveniles were much lower than those of Dutch juveniles. It is suggested that these opposite trends were caused by the fact that subjects in the youngest cohorts had been born in The Netherlands, while the oldest cohorts spent the first years of their life in those parts of Turkey or Morocco where caries prevalence of children is low. Between 1987 and 1993 caries prevalence in 5-year-old children of Turkish or Moroccan origin decreased significantly.