1http://dx.doi.org/10.20396/bjos.v19i0.8657981 Volume 19 2020 e207981 Original Article 1 Postgraduate Program in Public Health, René Rachou Institute, Oswaldo Cruz Foundation (FIOCRUZ), Brazil. 2 René Rachou Institute, Oswaldo Cruz Foundation (FIOCRUZ), Brazil. Corresponding author: Eduardo José Pereira Oliveira, DDS, MSD, Postgraduate Program in Public Health, René Rachou Institute, Oswaldo Cruz Foundation (FIOCRUZ). Avenida Augusto de Lima, 1715 – Barro Preto. 30.190-002. Belo Horizonte, MG, Brasil. Email: eduardooliveiraacustico@ gmail.com; Phone: +55 35 98868-8867 Received: December 27, 2019 Accepted: May 17, 2020 Oral health-related quality of life among 12-year-olds: results from SB-Minas Gerais Eduardo José Pereira Oliveira1,* , Fabíola Bof de Andrade2 Aim: To assess oral health-related quality of life (OHRQoL) and associated factors among the 12-year-old population of the state of Minas Gerais, Brazil. Methods: Cross-sectional data from the SB-Minas Gerais 2012 study were used. The presence of poor OHRQoL was assessed using the Oral Impact on Daily Performance (OIDP) and its dimensions (physical, psychological and social domains). Independent variables included sociodemographic factors and variables related to the use of dental care and oral health conditions. The association between the outcomes and the independent variables were tested using logistic regression and the results reported as odds ratio with 95% confidence interval. Results: Prevalence of poor OHRQoL was 31.4%; the psychological domain was the most affected (22.6%). Pain and dissatisfaction with oral health were associated with poor OHRQoL on overall OIDP and all its domains. Non-whites had greater poor OHRQoL than whites on overall OIDP and physical domain. Conclusion: Self-perceived oral health and social inequalities were associated with poor OHRQoL. Keywords: Dental health surveys. Oral health. Quality of life. Socioeconomic factors. https://orcid.org/0000-0002-9043-5299 https://orcid.org/0000-0002-3467-3989 2 Oliveira et al. Introduction Poor oral health-related quality of life (OHRQoL) is reported by one-third of 12-year- olds1 and two-fifths of the 15–19-year olds in Brazil2. Its main determinants are socio- economic characteristics, access to dental services2,3 and oral health impairments, such as untreated caries, malocclusion and tooth loss1,4-5. The negative impact of oral health on quality of life can be understood as the bur- den that oral disorders play in daily life, the system of values, and perception of life as a whole within a cultural context and in relation to personal objectives, standards and concerns6. These impairments occur hierarchically7; speech and chewing func- tions are the first dimensions to be affected1,8, next are psychological losses, such as restrictions on smiling9, sleep disorders and anxiety or irritability1. Finally, there may be disadvantages to social life, including association with bullying10,11, disruption of study and restrictions on leisure among children and adolescents1. In the last decades, important advances have been made in the control of oral dis- eases in Brazil, mainly among schoolchildren12,13. These advances may be attributed to the fluoridation of the public water supply14, dissemination of fluoride toothpaste, decrease in sugar consumption12, as well as improvements in living conditions, and the implementation of public policies featured by expansion in health promotion actions13. However, dental caries and incidence of other oral diseases have increased due to the weakening of successful programs and policies15, with those most harmed being the most socially vulnerable16. Similarly, there are inequalities in distribution of poor OHRQoL in Brazil1-3,8,9 and worldwide17. Thus, non-whites2, those in lower levels of income1 and schooling2, and people facing barriers to access dental services1 have been the most affected in their quality of life. Although several studies have identified the determinants of OHRQoL1-5, continuous monitoring of trends and patterns in different contexts shows they are relevant in addressing oral impairments. Studies are lacking that describe OHRQoL determinants among 12-year-olds in Brazilian states3. We performed this study because we recog- nized the importance of these studies in identifying regional variations for planning and setting public health priorities. This study aimed to assess oral health-related quality of life and associated factors in a representative sample of 12-year olds from Minas Gerais state, Brazil. Materials and methods Design, setting and participants A study analyzing observational, secondary data was conducted using data from the last Oral Health Survey performed in Minas Gerais, Brazil (SB-Minas Gerais 2012), including in its capital (Belo Horizonte) and in 60 cities within the state. In 2012, Minas Gerais was the second most populous state in Brazil18. SB-Minas Gerais was con- ducted using probabilistic sampling by multi-stage conglomerates, with proportional probability of participation by size. The sample plan considered the participants’ region of residence, according to factors used for allocating financial resources pro- 3 Oliveira et al. duced by the João Pinheiro Foundation. The cities within the state were classified into quartiles according to economic size and health needs, and the two lower quartiles were grouped in the Interior I domain, representing the municipalities with the low- est relative need for financial resources. The upper quartiles were grouped in Interior II—municipalities with the greatest relative need for financial resources. SB-Minas Gerais was designed to be representative of the State, its capital and the two inte- rior domains at five age groups: 5, 12, 15–19, 35–44, and 65–74 years. Clinical and self-perceived oral health measures, demographic and socioeconomic characteris- tics, access and use of dental services and OHRQoL were investigated19. Data were collected by trained and calibrated dentists, according to World Health Organization criteria20. The minimum level of agreement accepted intra and inter examiners was established with kappa equal to 0.65. More details about the design and sampling have been published elsewhere19,21,22. Of the 1,217 participants aged 12 years, 996 pre- sented complete data for the variables of interest and were included in the analysis, representing 208,763 adolescents from Minas Gerais, Brazil. Variables The dependent variable OHRQoL was evaluated using the Oral Impacts on Daily Per- formances (OIDP) survey. OIDP has three dimensions with a total of nine questions related to daily activities that may be affected by oral conditions in the previous six months. The response options were “no” or “yes” for each of the following activities: 1) physical domain: eat and enjoy food, speak and pronounce clearly, brush teeth, and play sports; 2) psychological domain: sleep and relaxation, smile without embarrass- ment, and maintain the usual emotional state without anxiety or irritability; 3) social domain: study and attend school, and enjoy contact with people (going out, having fun, going to parties, outings)23. Poor OHRQoL was considered for participants who reported difficulty in performing one or more activities for overall OIDP as well as the physical, psychological and social domains. The independent variables included in the analysis were divided into the following blocks: 1) demographic and socioeconomic characteristics: gender; self-declared race / skin color evaluated according to the Brazilian Institute of Geography and Sta- tistics (Instituto Brasileiro de Geografia e Estatística–IBGE) and categorized as white / non-white (black, brown, yellow [Asian]), and indigenous; family income (≤R$500 / R$501–2500 / > R$2500); 2) dental services—time since the last dental appointment (≤1 year / >1 year); type of service used (public / private–including health insurance and covenants); reason for last dental appointment (prevention / other–including pain, extraction, treatment); 3) oral health: presence of untreated caries; dental pain in the last six months; satisfaction with oral health (satisfied–’very satisfied’ and ‘satisfied’) / dissatisfied (‘neither satisfied nor dissatisfied’, ‘dissatisfied’ and ‘very unsatisfied’). Statistical analysis Descriptive analysis was used to estimate relative frequencies, next were bivariate and multiple analyses. In the bivariate analysis, associations between the indepen- dent variables and the outcomes (overall OIDP and its domains –physical, psycholog- ical and social) were tested using the chi-square test with Rao and Scott correction24. 4 Oliveira et al. The association between the outcomes and the independent variables was tested by means of a logistic regression, and the results reported as odds ratio with 95% confidence interval (95% CI). All the variables with a p<0.2 in the bivariate analysis were included in the multiple logistic regression analyses, according to a hierarchical approach25, following the theoretical framework proposed in Figure 1. First, demo- graphic and socioeconomic characteristics (Block 1) were included in the model and adjusted by themselves. The use of dental services (Block 2) was adjusted for demo- graphic and socioeconomic characteristics and for themselves. Finally, the oral health variables (Block 3) were adjusted for demographic and socioeconomic characteris- tics, for the use of dental services and for themselves. All analyses were performed in Stata v. 14.0 software using the survey command, which allows to analyze data from complex samples, incorporating sample weights, stratification processes, conglomeration and study design26. Ethics statement SB- Minas Gerais was ethically conducted based on the Helsinki Declaration. This sur- vey received approval from the Ethics in Research Committee of the Pontifical Catho- lic University of Minas Gerais under protocol number 9,173. Results The 12-year-old children from Minas Gerais were characterized by a predominance of non-whites (59%), and family income ranging from R$501 to R$2,500 (77%). Most par- ticipants had their last dental appointment for reasons other than prevention (63.1%). The prevalence of untreated caries, dental pain in the last six months, and dissatis- Figure 1. Conceptual model used in hierarchical analysis. Demographic & Socioeconomic Characteristics Dental Services Oral Health Outcome Poor Oral Health-Related Quality of Life Satisfaction with oral health Dental painCaries Last dental appointment Reason for consultation Dental Service Sex Skin-color Income 5 Oliveira et al. faction with oral health were 35.3%, 18.1%, and 32.9%, respectively. About 31.4% of participants had at least one negative impact of oral health on quality of life, 22.6% had impacts on psychological domain, and 6.2% on the social domain. In the bivariate analysis, dental services and oral health were associated with poor OHRQoL in over- all OIDP and all its domains. Demographic and socioeconomic characteristics were associated with overall OIDP, physical and psychological domains (Table 1). Table 1. Sample characteristics and bivariate analysis of factors associated with poor oral-related quality of life (OHRQoL) at 12 years. SB-Minas Gerais, 2012 (weighted estimates). Total OIDP Overall Physical Psychological Social % % ORc % ORc % ORc % ORc Total 100 31.4 19.8 22.6 6.2 Demographic and socioeconomic characteristics Sex Men 53.4 28.1 1 18.8 1 20.2 1 5.0 1 Women 46.6 35.1 1.38 20.9 1.14 25.4 1.35 7.6 1.55 Skin-color White 41.0 22.9 1 12.8 1 17.0 1 3.6 1 Non-white 59.0 37.3 2.00** 24.6 2.23** 26.6 1.77* 8.0 2.30 Income ≤R$500 8.4 44.5 1 32.3 1 32.2 1 9.1 1 R$501–R$2,500 77.0 32.0 0.59* 19.1 0.49* 23.5 0.65 7.1 0.76 >R$2,500 14.5 20.8 0.33** 16.3 0.41 12.4 0.30** 0.0 1.00 Dental services Last dental appointment ≤1 year 65.0 29.2 1 18.3 1 21.9 1 5.3 1 >1 year 35.0 35.2 1.33* 22.5 1.29 24.0 1.13 8.0 1.56 Reason for consultation Prevention 36.9 23.4 1 12.0 1 16.2 1 2.0 1 Other 63.1 36.1 1.85** 24.3 2.35** 26.4 1.85** 8.7 4.75** Dental service Public 52.5 32.0 1 20.2 1 23.3 1 7.7 1 Private 47.5 30.7 0.94 19.2 0.93 21.9 0.92 4.6 0.58 Oral health Caries No 64.7 28.3 1 15.8 1 19.8 1 3.5 1 Yes 35.3 37.1 1.49** 27.0 1.97** 27.9 1.57* 11.2 3.46** Dental pain No 81.9 22.1 1 11.4 1 15.3 1 1.3 1 Yes 18.1 73.4 9.71** 58.0 10.80** 55.6 6.92** 28.3 29.52** Satisfaction with oral health Satisfied 67.1 18.9 1 12.3 1 10.9 1 3.0 1 Dissatisfied 32.9 56.8 5.62** 35.1 3.86** 46.6 7.17** 12.7 4.66** Source: SB-Minas Gerais. OIDP: oral impacts on daily performance; ORc: crude odds ratio. * p<0.05; ** p<0,01. 6 Oliveira et al. Table 2 shows the analysis of factors associated with overall OIDP and its domains, after adjustment for demographic and socioeconomic characteristics, dental services and oral health. For overall OIDP and physical domain, the following groups were more likely to have poor OHRQoL: non-white, those with dental pain, and those dissatisfied with their oral health, independently of socioeconomic conditions, dental services and dental care. For the psychological and social domains, after adjustment for multiple variables, subjects with dental pain and dissatisfied with their oral health were more likely to have poor OHRQoL. Table 2. Multiple analysis of factors associated with poor OHRQoL at 12 years. SB-Minas Gerais, 2012 (weighted estimates). OIDP Overall Physical Psycological Social ORa (95%CI) ORa (95%CI) ORa (95%CI) ORa (95%CI) Demographic and socioeconomic characteristics Sex Men 1 - 1 1 Women 1.32 (0.92-1.89) - 1.25 (0.79-1.96) 1.35 (0.70-2.61) Skin-color White 1 1 1 1 Non-white 1.58 (1.06-2.37) 1.72 (1.04-2.84) 1.30 (0.85-1.99) 1.46 0.56-3.85) Income ≤R$500 1 1 1 - R$501–R$2,500 0.71 (0.38-1.32) 0.64 (0.30-1.34) 0.71 (0.44-1.16) - >R$2,500 0.44 (0.18-1.07) 0.73 (0.28-1.94) 0.32 (0.10-1.01) - Dental services Last dental appointment ≤1 year 1 - - 1 >1 year 1.14 (0.81-1.59) - - 1.36 (0.70-2.64) Reason for consultation Prevention 1 1 1 1 Other 1.14 (0.77-1.67) 1.39 (0.91-2.12) 1.09 (0.68-1.75) 2.30 (0.71-7.47) Dental service Public - - - 1 Private - - - 0.88 (0.46-1.67) continue... 7 Oliveira et al. Discussion This was the first study to assess oral health-related quality of life and associated factors in a representative sample of the 12-year-old population of Minas Gerais state, Brazil. One-third of participants at this age had poor OHRQoL, being the psychological domain the most affected. Pain and dissatisfaction with oral health were associated with poor OHRQoL on overall OIDP and all its domains. Non-whites had greater odds of poor OHRQoL for overall OIDP and physical domain. The prevalence of poor OHRQoL at 12 years in Minas Gerais is similar to that presented by other studies conducted with children and adolescents in Brazil1,27 and worldwide28. However, unlike 12-year-old Brazilians (for whom negative impacts on the physical domain prevail)1,8, the psychological domain was the most affected in Minas Gerais. According to Locker and Allen7, OHRQoL is gradually and hierarchically impaired, with physical being the first and social being the last domains to be affected. There is also a gradient of severity ranging from discomfort, pain, disability, impairment and social disadvantage7. Thus, the deterioration of OHRQoL at 12 years in Minas Gerais would be at a more advanced stage than in Brazil. Furthermore, in Brazil1,27, worldwide29,30, and for the State of Minas Gerais, social impacts are the least prevalent, as they rep- resent the final and most severe stage of losses in OHRQoL. In the adjusted models, pain and dissatisfaction with oral health were independently associated with the overall OIDP and all its domains. Similar associations have been reported in other studies for 12-years-olds1 as well as for other age groups2,3,5,6,31,32. Besides being associated with physical losses (such as eating, brushing, speaking and playing sports), pain and dissatisfaction with oral health may trigger psycholog- ical problems such as sleep disorders, irritation and restrictions on smiling. This pro- cess may also be associated with bullying and restrict social life, reaching leisure activities and resulting in school absenteeism11. continuation... Oral health Caries No 1 1 1 1 Yes 0.72 (0.48-1.06) 1.01 (0.69-1.46) 0.77 (0.48-1.25) 1.42 (0.67-3.02) Dental pain No 1 1 1 1 Yes 7.68 (4.97-11.86) 7.81 (4.77-12.79) 5.15 (3.15-8.39) 17.85 (7.99-39.91) Satisfaction with oral health Satisfied 1 1 1 1 Dissatisfied 4.98 (3.16-7.85) 2.74 (1.66-4.52) 6.39 (4.14-9.86) 2.20 (1.04-4.67) Source: SB-Minas Gerais. OIDP: oral impacts on daily performance; ORa: adjusted odds ratio; 95%CI: 95% confidence interval. 8 Oliveira et al. This study showed no independent association between untreated caries and over- all OIDP as well as its domains. Given the effects of dental pain and dissatisfaction with oral health on OHRQoL1,3, one can state that not the cavity itself, but its severity (expressed by pain) and location (which may affect satisfaction, mostly in anterior tooth decay) would result in greater impacts on OHRQoL. However, a study with the 12-year-old Brazilians found an independent association of caries with OIDP in psy- chological and social domains. Cultural, socioeconomic aspects, provision of dental services, distribution and severity of oral diseases in different regions33 may influence the perception of OHRQoL and, hence, the associations found. This reinforces the importance of regional representative studies in detecting different disease patterns and related inequalities. The association between satisfaction with oral health and OHRQoL reported here was also observed for other authors6,31, especially regarding the psychosocial com- ponent33. Indeed, even the prevalence of poor OHRQoL and dissatisfaction with oral health were similar in the population studied. Thus, dissatisfaction with oral health could partially represent poor OHRQoL. On the demographic and socioeconomic characteristics, only skin color was asso- ciated with the overall OIDP and physical domain. This means that non-whites had greater odds of poor OHRQoL, as observed by Colussi et al.27. On the other hand, in the studies performed by Souza et al.1 and Scapini et al.34, socioeconomic inequalities in OHRQoL among adolescents were associated with family income, but not skin color. In another study conducted with adolescents, adults and elderly from the State of São Paulo, Brazil, skin color and income remained associated with poor OHRQoL3. In some scenarios, skin color is able to identify vulnerable social contexts, as non-white indi- viduals are in lower levels of schooling and income as well as have restricted access to dental services in Brazil35. As a consequence, they also present worse oral35 and overall health32. This study has limitations as its cross-sectional design does not allow causal infer- ences. It also has some strengths: this is one of the few representative data of OHRQoL for a Brazilian state3, corroborating the understanding of its determinants and distribution in different regions. In conclusion, the prevalence of poor OHRQoL at the age of 12 years in Minas Gerais is significant. Recent dental pain and dissatisfaction with oral health were associated with overall OIDP and all its domains, and there are inequalities regarding skin color for the physical domain and overall OIDP. Future studies should explore the origins of these inequalities. Strengthening equity in access to dental services, taking into account socioeconomic conditions and the self-perception of individuals may con- tribute to improved OHRQoL. Acknowledgments: SB-Minas Gerais study was supported by State Health Secretar- iat of Minas Gerais, Brazil. EJP Oliveira received a doctoral scholarship from Coorde- nação de Aperfeicoamento de Pessoal de Nível Superior (CAPES). 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