Impact of a Government Income Support Program on the OHRQoL and orthodontic treatment need. A case-control study

This study aimed to assess the impact of a Government Income Support Program in orthodontic treatment need and on adolescents' oral health-related quality of life (OHRQoL). A population-based, matched case-control study involving 309 adolescents aged 11-14 years was conducted in the northeast of Brazil (Bahia, Brazil). The case group (with impact on OHRQoL) and the control group (no impact on OHRQoL) were matched by age and sex (p>0.05) at a ratio of 2: 1 (206 controls: 103 cases). Impact on the adolescent's OHRQoL was assessed using the Brazilian version of the Child Perceptions Questionnaire (CPQ11-14). Families who received Bolsa Família determined their participation in Government's Income Support Program. The Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC) determined the orthodontic treatment need. The data were analyzed using conditional logistic regression (p≤0.05; 90%CI). The results showed that 96.1% of adolescents in the case group and 89.3% of adolescents in the control group present orthodontic treatment need. Adolescents with a negative impact on OHRQoL are 2.75 (90%CI: 1.12-6.72) times more likely to present orthodontic treatment need than the control group. The exposure factor to Government Income Support Program did not affect the adolescent's OHRQoL. However, adolescents reported a negative impact of orthodontic treatment need in their OHRQoL.


Introduction
Currently, aiming to favor quality of life (Coelho & Melo, 2017;Ribas-Prado et al., 2016), several developing countries have used income support programs to reduce poverty and social inequality (Monnerat et al., 2007;Oliveira et al., 2011a;Roque et al., 2015;Almeida e Silva, 2016). In Brazil, such strategy is performed through social assistance programs such as the Bolsa Família (Sperandio e Priore et al., 2015), which is considered the most extensive income support program directed to families in poverty or extreme poverty conditions (Brasil, 2018).
The Bolsa Familia Program presents conditionalities in the fields of education and health. Thus, it aims to ensure nutritional improvements and good health conditions and promote children and adolescents' access and maintenance in schools (Brasil, 2018). Studies have been performed to assess the impact of this Program on the quality of life, health, and nutrition of individuals, showing controversial results (Coelho & Melo, 2017;Ribas-Prado et al., 2016;Monnerat et al., 2007;Oliveira et al., 2011a;Almeida e Silva, 2016;Sperandio e Priore et al., 2015;Brasil, 2018;Oliveira et al., 2011b;Uchimura et al., 2012;Ferreira e Magalhães, 2017;Sperandio et al., 2017;Suzart e Ferreira, 2018;Carvalho et al., 2014).
Understanding the association of clinical factors (Fernandes et al., 2013;Bulgareliet al., 2018) and socioeconomic status with an individual's quality of life may contribute to assessing more vulnerable groups, guiding health programs, and providing a better cost-effectiveness relationship of oral health policies (Piovesan et al., 2010;Scapini et a., 2013). The oral health promotion strategies should include subjective, social, and environmental aspects in planning, action, and assessment (Piovesan et al., 2010).
In this sense, the literature presents no reports on the impact of income distribution programs on OHRQoL.
Thus, the hypothesis studied is that adolescents whose families benefit from a Government Income Support Program (Bolsa Família) have more access to services, lower orthodontic treatment need, and lower impact on OHRQoL. Therefore, this study aimed to assess the impact of a Government Income Support Program in the orthodontic treatment need and on adolescent's OHRQoL.

Methodology
The Human Research Ethics Committee (#57990516.2.0000.5385) previously approved this study, performed according to the STROBE statement.
This case-control study included a population-based consisting of 309 adolescents aged between 11 and 14 years enrolled at public schools in Ilhéus, Brazil. Ilhéus is a seaside city located in Brazil's northeast region and is divided into ten administrative health districts. The average monthly income is approximately US$ 110 per capita, and the Human Development Index is 0.690.
Adolescents whose parents did not sign the Informed Consent Form, presenting previous or current orthodontic or orthopedic treatment, and who were not intellectually fit to answer the questionnaire were excluded from the study. The minimum sample size for this study was calculated based on test power of 80%, standard error of 5.0%, and estimated 63.5% and 37% prevalence rates of orthodontic treatment need in case and control groups, respectively. These characteristics were determined in a pilot study, and the individuals (n = 30) were not included in the main sample. Considering two controls for each case, the minimum sample size to satisfy the requirements was 103 cases and 206 controls (Pereira, 2018;Koche, 2011).

Training and calibration
The training and calibration exercise consisted of two phases (theoretical and clinical). The theoretical stage involved a discussion on the diagnostic criteria of malocclusion. An orthodontics specialist (gold standard) coordinated this phase, instructing the researcher on conducting the examination. The clinical phase was performed in a school selected randomly and not belonging to the main sample. The dentist examined 50 adolescents selected previously, aged between 11 and 14 years.
The weighted Kappa was calculated based on the Dental Health Component of the Index of Orthodontic Treatment Need (IOTN-DHC). The inter-examiner agreement was tested by comparing the examiner with the gold standard (K = 0.92).

Collection of clinical data
The clinical examination was performed in the schools after receiving the signed Informed Consent Form.
Orthodontic treatment need was defined according to the IOTN-DHC (Brook PH & Shaw, 1989). Using a scale that ranges from Grade 1 to Grade 5, the IOTN-DHC assesses need, missing teeth (including congenital absence and impacted teeth), overjet (positive or negative), posterior and anterior crossbite, crowding, overbite, and anterior and posterior open bite.
Although all changes were assessed, only the most severe was used as a base to determine treatment need. For data analysis, the IOTN-DHC was dichotomized in no/little need (grades 1, 2, and 3) and with need (4 and 5) (Mandall et al., 2000).

Collection of non-clinical data
The non-clinical data were assessed by the oral health-related quality of life (OHRQoL) instrument directed to adolescents and by the questionnaire on sociodemographic data answered by the parents and/or guardians. health-related quality of life (OHRQoL) of adolescents (Jokovic et al., 2002;Jokovic et al., 2006;Barbosa et al., 2009). CPQ11-14 includes 16 multiple choice questions referring to the period of three months before the assessment and it is divided into four domains: oral symptoms, functional limitations, emotional well-being, and social well-being. The total score of the CPQ11-14 is obtained by adding the response scores: 0 = never, 1 = rarely, 2 = sometimes, 3 = frequently, and 4 = always.
Scores ≥25 set a negative impact on OHRQoL and scores <25 set the absence of impact on OHRQoL (Barbosa et al., 2009;Torres et al., 2009).
The outcome variable of "impact on the OHRQoL of adolescents" was used to define cases and controls. Thus, 103 (33.3%) adolescents with impact of OHRQoL were eligible for the case group and 206 (66.7%) adolescents without impact on OHRQoL were eligible for the control group. Cases and controls were matched by age and sex at a 2:1 ratio.

Data analysis
Frequency distributions were used to characterize the sample and demonstrate the distribution of the CPQ11-14 item levels. Case and control groups were matched for the variables age and sex, selecting two adolescents of the control group for each case randomly and maintaining the ratio of 1: 2 (103 cases: 206 controls). The chi-square test analyzed the pairing between case and control groups for the variable of sex, and Student's t-test analyzed it for the variable of age.
Case and control groups were analyzed for orthodontic treatment need (with or without need) and participation in an income distribution program (yes or no), using conditional logistic regression models and estimating odds ratio with the 90% confidence interval. All analyses were performed in the R software (R Foundation for Statistical Computing, Vienna, Austria). Table 1 showed no significant difference between case and control groups regarding sex and age of the adolescents (p>0.05). Table 2 presents the association among participation in income distribution programs, orthodontic treatment need, and impact on OHRQoL. There was no significant difference between case and control groups regarding the income distribution program (p>0.05). Thus, the exposure factor of the income distribution program did not affect the adolescent's OHRQoL.

Results
Adolescents of the case group are 2.75 (90%CI: 1.12-6.72) times more likely to present orthodontic treatment need than the control group. Thus, the orthodontic treatment need factor affected OHRQoL.

Discussion
Quality of life-related to oral health (OHRQoL) is affected by different factors, which may be clinical and represented by oral diseases or socioeconomic determinants, such as financial conditions; therefore, it is essential to understand such association (Bulgareliet al., 2018;Dimberg et al., 2015;Paula et al., 2017). The importance of our study lies in the fact that it is the first case-control study to investigate the impact of the Brazilian Government Income Support Program associated with orthodontic treatment need on adolescent's OHRQoL.
The main finding of the present study was that exposure to Government Income Support Program did not affect the OHRQoL of adolescents. Such results reject our hypothesis and show the impact of orthodontic treatment need on the adolescent's OHRQoL and corroborate the previous literature (Fernandes et al., 2013;Piovesan et al., 2010;Scapini et a., 2013;Sardenberg et al., 2013;Dawoodboy et al., 2013;Sun et al., 2018;Dalaie et al., 2018;Paula et al., 2017;Kavaliauskienè et al., 2018;Vedovello et al., 2016), which shows an association between clinical aspects and OHRQoL.
A potential explanation for these findings is that adolescents receiving the benefit and presenting malocclusion do not have access to orthodontic treatment, negatively affecting their daily lives. Previous studies (Teixeira et al., 2018;Oliveira et al. 2013b) show the presence of inequities in dental care, considering that young people with low economic conditions (public school, unemployment, participants of Bolsa Familia Program) useless dental care, although they have more significant needs.
As for socioeconomic aspects, the results presented in the literature are still controversial, considering some studies confirm the influence on OHRQoL (Piovesan et al., 2010;Scapini et a., 2013;Sardenberg et al., 2013;Locker, 2007;Apaza-Ramos et al., 2015), and others deny it (Sun et al., 2018;Kavaliauskienè et al., 2018;Firmino et al., 2016). To assess the socioeconomic context, in the present study, the Government Income Support Program-Bolsa Familia initiated in 2003 was considered an exposure factor (Brasil, 2018). Thus, the participation in the program did not result in improved access to orthodontic treatment for the population studied, which may justify our findings-the literature suggests (Oliveira et al. 2013b) incorporating oral health care in the conditionalities of the Bolsa Familia Program to decrease inequities.
Studies have been performed to assess the impact of this program on the quality of life, health, and nutrition of individuals. The results are still questionable, considering some studies showed nutritional improvement (Coelho e Melo, 2017;Oliveira et al., 2011b;Sperandio et al., 2017) which was not satisfactory in others (Sperandio e Priore et al., 2015;Ferreira e Magalhães, 2017;Suzart e Ferreira, 2018). However, it is unanimous that offering the benefit to the families is insufficient, and emphasizing nutritional and health education is required. Moreover, studies indicate that the conditionalities of the program bring users closer to health services (Monnerat et al., 2007;Oliveira et al., 2011a;Almeida e Silva, 2016;Suzart e Ferreira, 2018;Carvalho et al., 2014) providing countries with significant advances in this sector (Roque et al., 2015).
Regarding psychological health and quality of life, the findings remain controversial (Ribas-Prado et al., 2016;Almeida e Silva, 2016). However, even with the program's limitations, as it is often considered the only family income, it has reflected positively in the lives of families in poverty conditions.
The limitation of this study is related to the retrospective nature of the case-control design. A longitudinal study is suggested to assess the impact of the income distribution program on OHRQoL over time. Finally, our findings are highlighted for contributing to understanding the factors affecting the OHRQoL of adolescents. Thus, a future hypothesis to be investigated is access to the health services of the families participating in the program.

Conclusion
The Government Income Support Program (Bolsa Família) did not affect the adolescent's OHRQoL. However, adolescents reported a negative impact of the need for orthodontic treatment on their OHRQoL. Thus, it is suggested that the socioeconomic and clinical factors, that are related to OHRQoL, be comprehensively evaluated and considering the individual's context.