In Sweden, children and adolescents with two foreign-born parents constitute 17% of all children in the Swedish population.

AIMS: The aims of this thesiswere to collect knowledge of the prevalence of gingivitis, caries and caries associated variables, in the 3-, 5-, 10- and 15-year age groups with two foreign born parents compared with their counterparts with Swedish-born parents in a ten-year perspective (Study I). To investigate the prevalence of caries and caries-associated variables in 15-year-olds in relation to foreign backgrounds and to examine differences in the prevalence of caries in adolescents with foreign backgrounds according to their length of residence in Sweden (StudyII).

MATERIAL AND METHODS: In 1993 and 2003, cross-sectional studies with random samples of individuals in the age groups of 3, 5, 10 and 15 years were performed in Jönköping, Sweden. The oral health status of all individuals was examined clinically and radiographically. The children or their parents also answered a questionnaire about their attitudes to, and knowledge of, teeth and oral health care habits. The final study sample comprised 739 children and adolescents, 154 with two foreign-born parents (F cohort) and 585 with two Swedish-born parents (S cohort) (Study I). In Study II, all 15-year-olds(n=143) at one school in the city of Jönköping were asked to participate in the study. The final sample comprised 117 individuals, 51 with foreign-born parents and 66 with Swedish-born parents. All the individuals were interviewed using a structured questionnaire with visualisation e.g. food packages, sweets and snacks. Information about DFS was collected from case records at the Public Dental Service.

RESULTS: In both 1993 and 2003, more 3- and 5-yearolds in the S cohort were caries free compared with the F cohort. In 1993, dfs was higher among 3- and 5-year-olds in the F cohort (p<0.01) compared with the S cohort. In 2003, dfs/DFS was statistically significantly higher in all age groups among children and adolescents in the F cohort compared with the S cohort. In 2003, the odds ratio of being exposed to dental caries among 10- and 15-year-olds in the F cohort, adjusted for gender and age, was more than six times higher (OR=6.3, 95% CI:2.51-15.61; p<0.001) compared with the S cohort (Study I). Fifteen-year-olds born in Sweden with foreign-born parents, or who had arrived before one year of age, had a caries prevalence similar to that of adolescents with Swedish-born parents, whereas children who had immigrated to Sweden after seven years of age had a caries prevalence that was two to three times higher (p <0.06) (Study II). Both in 1993 and 2003, the mean of the percentage of tooth sites with plaque and gingivitis was numerically higher in all age groups in individuals with foreign backgrounds compared with Swedish background, except between the 15-year-olds (Study I).

CONCLUSIONS: The decrease in caries prevalence, in a ten-year perspective, was less among children and adolescents with foreign-born parents compared with children and adolescents with Swedish-born parents. In 2003, there was statistically significantly more caries in all age groups among children and adolescents with foreign-born parents compared with children and adolescents with Swedish-born parents. Children who immigrated to Sweden at age seven or later had a two to three times higher caries prevalence compared with their Swedish counterparts. The odds ratio for being exposed to dental caries was almost six times higher for 10- and 15-year olds with foreign-born parents compared with their Swedish counterparts. The intake of carbohydrate-rich food was higher among 15-year olds with foreign backgrounds compared to those with Swedish background. There is an obvious need to improve the promotion of oral health care programmes among children and adolescents with foreign-born parents.

AIM: The overall aim of this thesis was to study culture as an oral health determinant for dental caries and gingivitis in children living in Jönköping, Sweden, in relation to children living in Da Nang, Vietnam.

MATERIALS AND METHODS: In 1993 and 2003, cross-sectional studies with clinical examinations and questionnaires were performed in Jönköping, Sweden, with a random sample of 130 children from each of four age groups; 3, 5, 10 and 15 years. The final study sample comprised 739 children, 154 (21%) with two foreign-born parents and 585 (79%) with two Swedish-born parents (Paper I). In 2000, all 15-year-olds (n=143) at one school in Jönköping, Sweden, were asked to participate in a questionnaire study connected to clinical data. The final sample comprised 117 individuals, 51 (44%) with foreign-born parents and 66 (56%) with Swedish-born parents (Paper II). In 2008, a cross-sectional study with clinical examinations and questionnaires was performed in Da Nang, Vietnam with 840 randomly selected children, 210 in each of four age groups; 3, 5, 10 and 15 years. The final sample comprised 745 individuals (Papers III and IV).

RESULTS: In 2003, the mean number of decayed (initial and manifest) and filled tooth surfaces was significantly higher in all age groups in children with foreign-born parents compared with children with Swedish-born parents. The gap between children with foreign-born parents and Swedish-born parents increased over the ten-year period from 1993 to 2003. The odds ratio of dental caries development among 10- and 15-year-old children with foreign-born-parents was more than six times higher than for their counterparts with Swedish-born parents (Paper I). Fifteen-year-olds born in Sweden of foreignborn parents and those who had immigrated before one year of age had a caries prevalence similar to 15-year-olds with Swedish-born parents, whereas the caries prevalence in children who had immigrated to Sweden after 7 years of age was 2-3 times higher (Paper II). Among the 3- and 5-year-olds in Vietnam, 98% suffered from dental caries, compared with 91% of 10- and 15-year-olds (Paper IV). The distribution of the most frequent values of decayed and filled primary tooth surfaces (dfs) in 5-year-olds was 16–20, and of decayed and filled permanent tooth surfaces (DFS) in 15-year-olds was 1–5. The maximum dfs was 76–80, and significant numbers of children had dfs between 20 and 50. The percentage of tooth sites with plaque and gingivitis was higher for children in all age groups with foreign-born parents compared with children with Swedish-born parents, except among the 15-year-olds in 2003. In Vietnam, the prevalence of plaque and gingivitis was high in all age groups, especially in 10- and 15-year-olds. Fifteen-yearolds in Sweden with foreign-born parents had a higher intake of snack products between principal meals compared with 15-year-olds with Swedish-born parents (Paper II). In Sweden, most children in all age groups brushed their teeth themselves or with help from their parents twice or more than twice a day (Paper I). Among 3- and 5-year-olds in Vietnam, about half of the parents reported that their children brushed their teeth themselves or with help from parents twice or more than twice a day (Paper III). All 3-year-olds and 99% of 5-year-olds in Sweden brushed their teeth with fluoride toothpaste (Paper I). Among 15-year-olds in Sweden with foreign-born parents, 88% reported that they brushed their teeth with fluoride toothpaste at least twice a day compared with 98% of 15-year-olds with Swedish-born parents (Paper II). In Vietnam, 44–78% of the children used fluoride toothpaste for toothbrushing and 51% consumed sweets between principal meals at least once a day (Paper III). Sweetened milk was the most common source of this sugar intake for the 3- and 5-year-olds (Paper III).

CONCLUSIONS: Culture is an important oral health determinant for dental caries and gingivitis in children. There is an urgent need to improve oral health care promotion and preventive programmes for children with foreign-born parents in Sweden, but also a great need for such programmes for children in Vietnam.

SYFTE: Det övergripande syftet med denna avhandling var att studera kultur som en oral bestämningsfaktor för karies och gingivit hos barn boende i Jönköping, Sverige, i relation till barn boende i Da Nang, Vietnam.

MATERIAL OCH METOD: Under 1993 och 2003 utfördes två epidemiologiska tvärsnittsstudier i Jönköping med ett slumpmässigt urval av individer i åldersgrupperna 3, 5, 10 och 15 år. Samtliga individers orala hälsa undersöktes kliniskt och röntgenologiskt. Barnen, eller deras föräldrar, svarade även på ett frågeformulär avseende sociodemografi, attityder till och kunskaper om tänder samt munhälsovanor. Totalt omfattade studien 739 barn och ungdomar, 154 med två utrikes födda föräldrar och 585 med två svenskfödda föräldrar (Paper I). I en annan studie inbjöds 143 15-åringar på en kommunal skola i Jönköping att delta (Paper II). Av dessa deltog 117 personer; 51 med två utrikes födda föräldrar och 66 med två svenskfödda föräldrar. Alla ungdomar intervjuades med hjälp av ett strukturerat frågeformulär där kostfrågor förtydligades med visualisering, dvs exempel på förpackningar och varor. Information om karies (DFS) samlades in från journaler från Folktandvården, Landstinget i Jönköpings län. Under 2008 genomfördes en epidemiologisk tvärsnittsstudie i Da Nang, Vietnam med 840 slumpmässigt utvalda barn, 210 individer i åldersgrupperna 3, 5, 10 och 15 år, där det slutliga urvalet omfattade 745 individer. Samtliga individers orala hälsa undersöktes kliniskt. Barnen, eller deras föräldrar, svarade även på ett frågeformulär avseende sociodemografi, attityder till och kunskaper om tänder samt munhälsovanor (Papers III och IV)

RESULTAT: År 2003 var antalet karierade och fyllda tandytor (dfs/DFS) statistiskt signifikant högre i alla åldersgrupper hos svenska barn med två utrikes födda föräldrar jämfört med barn med två svenskfödda föräldrar och klyftan mellan barn med utländsk bakgrund och barn med svensk bakgrund ökade under tioårsperioden 1993-2003. Risken för att utsättas för karies bland 10- och 15-åringar med utländsk bakgrund var mer än sex gånger högre jämfört med 15-åringar med svensk bakgrund (Paper I). Femtonåringar födda i Sverige med två utrikes födda föräldrar som hade kommit till Sverige före ett års ålder, hade en kariesprevalens som liknade den hos 15-åringar med svenskfödda föräldrar, medan barn som hade invandrat till Sverige efter sju år ålder hade en 2-3 gånger högre kariesprevalens (Paper II). Bland 3- och 5-åringar i Vietnam hade 98 % karies, hos 10- och 15-åringar var motsvarande siffra 91 % (Paper IV). De mest frekventa värdena av antalet kariesskadade och fyllda tandytor på primära tänder hos barn i 5-års-ålder var 16-20, och de mest frekventa värdena av kariesskadade och fyllda tandytor på permanenta tänder hos barn i åldern 15 år var 1-5. De maximala värdena av kariesskadade och fyllda primära tandytor var 76-80, och det fanns ett stort antal barn med mellan 20 och 50 skadade och fyllda primära tandytor. Procentandelen tandytor med plack och gingivit var numeriskt högre i alla åldersgrupper i Sverige hos barn med utländsk bakgrund jämfört med barn med svensk bakgrund, utom mellan 15-åringar år 2003. I Vietnam var förekomsten av plack och gingivit mycket hög i alla åldersgrupper och i synnerhet hos 10- och 15-åringar. I Sverige borstade de flesta av barnen i alla åldersgrupper sina tänder själva eller med hjälp av sina föräldrar två eller mer än två gånger per dag (Paper I). Bland 3- och 5-åringar i Vietnam rapporterade ungefär hälften av föräldrarna att barnen borstade tänderna själva eller med hjälp av föräldrar två eller mer än två gånger per dag (Paper III). Alla 3-åringar och 99 % av 5-åringar i Sverige borstade tänderna med fluortandkräm (Paper I). Bland 15-åringar med utländsk bakgrund uppgav 88 % att de borstade tänderna med fluortandkräm minst två gånger om dagen jämfört med 98 % av 15-åringarna med svensk bakgrund (Paper II). I Vietnam borstade 44 %-78 % av barnen tänderna med fluortandkräm (Paper III). Femtonåringar i Sverige med utländsk bakgrund hade ett högre intag av sötsaker mellan huvudmåltider jämfört med ungdomar med svensk bakgrund (Paper II). I Vietnam konsumerade 51 % av barnen sötsaker mellan huvudmåltiderna minst en gång om dagen. Sötad mjölk var den vanligaste källan till detta sockerintag för 3- och 5-åringar (Paper III).

SLUTSATSER: Kultur är en viktig bestämningsfaktor för karies och gingivit hos barn. Det finns ett överhängande behov av att förbättra promotion och preventionsprogram avseende oral hälsa bland barn i Sverige med utrikes födda föräldrar men också ett stort behov för barnen i Vietnam.