School academic climate and oral health (tooth loss) in adolescents

physical layout, size, and material resources of a school) [23]. In the educational literature, pos- itive school climate has been related to positive student outcomes, such as higher academic performance [24], better mental health [25], and less bullying [26]. While an association between adolescents’ future planning and academic achievement were reciprocal [27], a posi- tive association between school performance and healthy dietary habits also was found [28]. Accordingly, in the present study, we sought to test one aspect of school climate, viz., the rela- tion between academic climate of educational aspiration and adolescent oral health (as mea- sured by tooth loss). On the other hand, the association between educational aspiration and oral health status could be endogenous, i.e. there may be unobserved characteristics of the individual (such as conscientious personality) that predicts both school performance and oral health. In the pres- ent study we sought to test whether the school academic climate is associated with oral health status, over and above individual characteristics. At the individual level, besides sociodemo- graphic characteristics, clinical variables, lifestyle, self-perception of oral health, and dental anxiety contribute to the explanation of the occurrence of tooth loss. The progression of some clinical variables, such as dental caries and periodontal disease, leads to tooth loss [29]. Self- perception of oral health [30] and dental anxiety are variables related to poor oral health

because it could function as a barrier for using oral health services contributing to tooth loss [31]. Accordingly, we included at the individual level the following variables: sociodemo- graphic characteristics (age, sex, mother’s level of schooling, receiving a family allowance— proxy of poverty), clinical variables (decayed teeth—DMFT 1, and teeth affected by periodon- tal disease—CPI 3), and subjective ratings (self-perception of oral health and dental anxiety). In Brazil, a National High School Examination (ENEM) was introduced at the end of 1998. In 2010 the exam started to be used as a criterion for admission to some public universities and for obtaining scholarships at private universities. High schools are ranked publicly based on student performance–the ENEM league table [32]. However, because the exam is not man- datory for students, only schools with at least 50% participation are ranked in the league table [32, 33]. In the present study, we used the average student participation rates in ENEM as a proxy for the school academic climate. This is a contextual variable, i.e., it is a measure of the average educational aspiration “climate” in each school. This study hypothesized that a school climate characterized by higher educational aspirations is associated with lower incidence of adoles- cent tooth loss. Such schools expose their students to a milieu that instills hope for the future, and hence motivates them to invest in their own health. Materials and methods A cross-sectional study was carried out in Olinda, in the state of Pernambuco, Brazil from Feb-

ruary to June 2018 and from August to October. In 2018, Olinda had a population of 390,000 residents. The parents/guardians of all participants under 18-years-old provided written consent while children also provided written assent. Adolescents over 18-years of age consented by themselves. This research was approved by the Ethics Committee of University of Pernambuco (N. 2.361.780). In 2018, Olinda had 33 state public high schools. Two schools were not included because they held only night classes. Out of the 31 daytime schools, 26 agreed to take part in the study (rate response 83.9%). All students in the 26 schools were invited to participate, and 2,700 returned the questionnaire surveys (overall response rate 37.2%). Almost all classrooms (90.3%) in the involved schools participated in our data collection. PLOS ONE School academic climate and tooth loss in adolescents PLOS ONE | https://doi.org/10.1371/journal.pone.0233505 May 21, 2020 3 / 11