title: Cohort effects in the prevalence of caries in child populations in Tanzania.
abstract: In 1984, a four-year mixed-longitudinal study of oral health was begun in Morogoro Town and Morogoro District, Tanzania. Its main goal was to detect a possible upward trend in prevalence of caries in child cohorts in this developing country. The sample consisted of 722 seven- to nine-year-olds in 1984, 833 seven- to 11-year-olds in 1986, and 989 seven- to 13-year-olds in 1988. Mixed-longitudinal studies provide the opportunity for application of the Age-Period-Cohort analysis. On the basis of external information, either age and/or cohort and/or period effects can thus be isolated. Apart from significant age and period effects, a cohort effect was found, indicating that the prevalence of caries has decreased in these child populations between 1984 and 1988.
authors.affiliation: Department of Cariology, University of Nijmegen, The Netherlands.
authors.forename: J E
authors.initials: JE
authors.lastname: Frencken
authors.forename: M A
authors.initials: MA
authors.lastname: Van 't Hof
authors.forename: G J
authors.initials: GJ
authors.lastname: Truin
authors.forename: B S
authors.initials: BS
authors.lastname: Lembariti
authors.forename: K G
authors.initials: KG
authors.lastname: König
mesh_terms: D000293:Adolescent; D000704:Analysis of Variance; D002648:Child; D015331:Cohort Studies; D004245:DMF Index; D003731:Dental Caries / Q000453:epidemiology*; D004037:Diet, Cariogenic; D005457:Fluoridation; D006801:Humans; D008137:Longitudinal Studies; D015995:Prevalence; D015203:Reproducibility of Results; D013636:Tanzania / Q000453:epidemiology