ABSTRACT:

Introduction:

The adjusted effect of the characteristics of sanitation companies on the provision of fluoridation into public water supply in Brazilian municipalities was evaluated.

Methods:

Cross-sectional and ecological study based on the 2010 Demographic Census, 2008 National Survey on Basic Sanitation (PNSB), and 2010 Atlas of Human Development. The independent variables were the characteristics of utilities and municipalities, and the outcome was the lack of provision of fluoridation. Prevalence ratio was estimated with Poisson regression with robust variance.

Results:

5,565 Brazilian municipalities were included. In the adjusted analysis, the outcome was independently and positively associated to municipalities in the North, Northeast, Central-West and Southeast macro-regions, with coverage rates for water and sewage services below the median value, with less than 10,000 inhabitants, medium and low/very low in human development. Regarding the independent effect of the utilities’ characteristics, they were more likely not to provide fluoridation, all the companies that were not classified as indirect administration of the government or mixed-capital company or mixed-capital company of public character; municipal and intermunicipal (PR=1.21; 95%CI 1.19-1.23); and when the municipal government is the only provider (PR=1.22; 95%CI 1.20-1.25).

Conclusion:

The lack of provision of water fluoridation was greater when the service was mainly provided by municipal administrations and private companies associated or not to public entities, regardless of the characteristics of the municipalities.

Keywords:
Fluoridation; Sewerage enterprises; Multivariate analysis; Ecological studies; Environmental health

INTRODUCTION

Access to fluorides through public water and toothpaste has been considered an important determinant to explain the decline in dental caries since the 1970s in several developed countries¹1. Bratthall D, Hänsel-Petersson G, Sundberg H. Reasons for the caries decline: what do the experts believe? Eur J Oral Sci 1996; 104(4 Pt 2): 416-22. https://doi.org/10.1111/j.1600-0722.1996.tb00104.x
https://doi.org/https://doi.org/10.1111/... .

Data from 2012 indicated that water fluoridation was present in 25 countries, with more than 377 million people affected²2. British Fluoridation Society. One in a million - the facts about water fluoridation [Internet]. Manchester: British Fluoridation Society; 2012 [acessado em 1º fev. 2019]. Disponível em: Disponível em: https://www.bfsweb.org/one-in-a-million
https://www.bfsweb.org/one-in-a-million... . The United States of America, Brazil and Australia are federative republics in which the measure’s coverage, although high, is not homogeneous among states³3. Centers for Disease Control and Prevention. Fluoridation Statistics: 2014 [Internet]. U.S. Department of Health & Human Services, National Water Fluoridation Statistics; 2016 [acessado em 1º fev. 2019]. Disponível em: Disponível em: https://www.cdc.gov/fluoridation/statistics/2014stats.htm
https://www.cdc.gov/fluoridation/statist... ^,44. Frazão P, Narvai PC. Water fluoridation in Brazilian cities at the first decade of the 21st century. Rev Saúde Pública 2017; 51(47). https://doi.org/10.1590/s1518-8787.2017051006372
https://doi.org/https://doi.org/10.1590/... ^,55. Australian Health Policy Collaboration, Australian Dental Association. Australia’s Oral Health Tracker Technical Paper [Internet]. 2018 [acessado em 1º fev. 2019]. Disponível em: Disponível em: https://www.vu.edu.au/sites/default/files/australias-oral-health-tracker-technical-paper.pdf
https://www.vu.edu.au/sites/default/file... . It can be assumed that these differences between regions of the same country are linked to the political-administrative complexity that the relative autonomy of national subunits brings to the provision of sanitation services. Characteristics of municipalities, such as human development index, geographic location between macro-regions and population size seem to be linked to the benefit⁴4. Frazão P, Narvai PC. Water fluoridation in Brazilian cities at the first decade of the 21st century. Rev Saúde Pública 2017; 51(47). https://doi.org/10.1590/s1518-8787.2017051006372
https://doi.org/https://doi.org/10.1590/... ^,66. Peres MA, Fernandes LS, Peres KG. Inequality of water fluoridation in Southern Brazil - the inverse equity hypothesis revisited. Soc Sci Med 2004; 58(6): 1181-9. https://doi.org/10.1016/s0277-9536(03)00289-2
https://doi.org/https://doi.org/10.1016/... ^,77. Gabardo MC, da Silva WJ, Olandoski M, Moysés ST, Moysés SJ. Inequalities in public water supply fluoridation in Brazil: an ecological study. BMC Oral Health 2008; 8: 9. https://doi.org/10.1186/1472-6831-8-9
https://doi.org/https://doi.org/10.1186/... . However, there is no scientific information on the independent effect of other variables, such as the characteristics of sanitation companies in the provision of public health technology.

The environmental conditions for capturing and treating water and the characteristics of the provision of water supply services as a semi-public good, among other aspects, make the activity quite complex⁸8. Abbott M, Cohen B. Productivity and efficiency in the water industry. Util Policy 2009; 17(3-4): 233-44. https://doi.org/10.1016/j.jup.2009.05.001
https://doi.org/https://doi.org/10.1016/... ^,99. Barbosa A, De Lima SC, Brusca I. Governance and efficiency in the Brazilian water utilities: A dynamic analysis in the process of universal access. Util Policy 2016; 43(Part A): 82-96. https://doi.org/10.1016/j.jup.2016.06.013
https://doi.org/https://doi.org/10.1016/... . As a result of the strong market pressure, since the 1980s¹⁰10. Beveridge R, Hüesker F, Naumann M. From post-politics to a politics of possibility? Unravelling the privatization of the Berlin Water Company. Geoforum 2014; 51: 66-74. https://doi.org/10.1016/j.geoforum.2013.09.021
https://doi.org/https://doi.org/10.1016/... ^,1111. Swyngedouw E. Privatising H2O Turning Local Water Into Global Money. JEP 2003; 19(4): 10-33. https://doi.org/10.20446/JEP-2414-3197-19-4-10
https://doi.org/https://doi.org/10.20446... , there has been a gradual investment opening by the private sector in sanitary activities in several countries, based on the promise to increase investment capacity and the efficiency of the sector¹²12. Ouda OKM, Al-Waked RF, Alshehri AA. Privatization of water-supply services in Saudi Arabia: A unique experience. Util Policy 2014; 31: 107-13. https://doi.org/10.1016/j.jup.2014.10.003
https://doi.org/https://doi.org/10.1016/... .

In Brazil, the sanitation sector has undergone several changes throughout its history, and the ownership in the provision of services to the municipal level has been recently defined, which can establish partnerships with public and private entities, relationships in which responsibility can be delegated¹³13. Brasil. Lei nº 11.445, de 5 de janeiro de 2007. Estabelece diretrizes nacionais para o saneamento básico; e dá outras providências. Diário Oficial da União 2007.. Management characteristics may be distinct and specific to each location in the country, with the possibility of direct involvement in the provision of services. Although Law No. 6.050, approved by the National Congress in 1974 in Brazil, made fluoridation mandatory everywhere a water treatment plant exists, creating conditions to universalize access to fluorides, studies have shown that the provision of water fluoridation is extremely unequal, both among macro-regions¹⁴14. Antunes JLF, Narvai PC. Políticas de saúde bucal no Brasil e seu impacto sobre as desigualdades em saúde. Rev Saúde Pública 2010; 44(2): 360-5. https://doi.org/10.1590/S0034-89102010005000002
https://doi.org/https://doi.org/10.1590/... and among municipalities in the country¹⁵15. Silva FB, Frazão P. Sanitation utilities and fluoridation of water supply systems: an ecological study in Brazilian municipalities, 2008-2010. Epidemiol Serv Saúde 2018; 27(4). https://doi.org/10.5123/s1679-49742018000400003
https://doi.org/https://doi.org/10.5123/... . Nonetheless, the significance of the effect of specific variables linked to the concessionaire on the provision of public policy in the presence of characteristics linked to the municipalities, including the Brazilian macro-region to which it belongs, was not further investigated.

Considering the aforementioned aspects, the objective of the present study was to evaluate the adjusted effect of the characteristics of sanitation companies in the provision of fluoridation of public water supply in Brazilian municipalities.

METHODS

STUDY DESIGN

This is a cross-sectional and ecological study, which encompassed all Brazilian municipalities.

DATA SOURCE

The 2010 Demographic Census, 2008 National Survey on Basic Sanitation (PNSB), and 2010 Atlas of Human Development grounded the study.

The Demographic Census is a statistical operation that constitutes a source of information about the population’s life condition in the municipalities¹⁶16. Instituto Brasileiro de Geografia e Estatística. Censo Demográfico 2010 [Internet]. Rio de Janeiro: IBGE; 2010 [acessado em 1º fev. 2019]. Disponível em: Disponível em: https://ww2.ibge.gov.br/home/estatistica/populacao/censo2010/
https://ww2.ibge.gov.br/home/estatistica... . PNSB provides data on basic sanitation conditions in all Brazilian municipalities with the work of public agencies and private companies¹⁷17. Instituto Brasileiro de Geografia e Estatística. Pesquisa Nacional de Saneamento Básico: 2008 [Internet]. Rio de Janeiro: IBGE ; 2010 [acessado em 1º fev. 2019]. Disponível em: Disponível em: https://sidra.ibge.gov.br/pesquisa/pnsb/pnsb-2008
https://sidra.ibge.gov.br/pesquisa/pnsb/... . The Atlas of Human Development is an initiative of the United Nations Development Program (UNDP) that offers human development indicators for Brazilian municipalities and states¹⁸18. Programa das Nações Unidas para o Desenvolvimento. Atlas de Desenvolvimento Humano [Internet]. Programa das Nações Unidas para o Desenvolvimento; 2013 [acessado em 1º fev. 2019]. Disponível em: Disponível em: http://atlasbrasil.org.br/2013/
http://atlasbrasil.org.br/2013/... .

STUDY VARIABLES

The situation of fluoridation in all municipalities in the country was extracted from PNSB 2008, that is, the existence or not of the service in water destined for public supply, regardless of coverage. The outcome was defined by the rate of municipalities without the benefit. The main independent variables were characteristics linked to the sanitation companies, such as the legal nature of companies providing water supply services, the administrative sphere, and the way in which the service is performed¹⁶16. Instituto Brasileiro de Geografia e Estatística. Censo Demográfico 2010 [Internet]. Rio de Janeiro: IBGE; 2010 [acessado em 1º fev. 2019]. Disponível em: Disponível em: https://ww2.ibge.gov.br/home/estatistica/populacao/censo2010/
https://ww2.ibge.gov.br/home/estatistica... . The legal nature variable was broken down into six categories: direct administration of public authority, autarchy, public company, mixed-capital company, public consortium, private company, foundation, and association. Given that 1,848 municipalities had two, three and even four classifications, and to avoid categories with low frequency, the data were organized into six categories:

The administrative sphere variable, originally classified as federal, state, municipal, private, inter-federative and intermunicipal, was also recategorized into five categories:

The service performance form variable indicates who actually works in the provision of the service, maintaining the original classification:

The following characteristics related to the municipalities, from the census, were included: macro-region; demographic size; coverage of the general water distribution network; coverage of the general sewage/rainwater distribution network. The Municipal Human Development Index (MHDI), present in the 2010 Atlas of Human Development, was also used.

The macro-region concerns a political division that has already been used as a relevant variable in a study related to the provision of sanitation services¹⁹19. Rezende S, Wajnman S, De Carvalho JAM, Heller L. Integrando oferta e demanda de serviços de saneamento: análise hierárquica do panorama urbano brasileiro no ano 2000. Eng Sanit Ambient 2007; 12(1): 90-101.. It was categorized according to the division of the Brazilian Institute of Geography and Statistics (IBGE):

The demographic size refers to the total number of residents in the municipality at the time of the Census survey. To describe it, the 2010 population estimates were separated into:

Variables included the coverage of both the general water distribution network and the general sewage/rainwater distribution network because they express the quality of the sanitation service with fluoridation. Both were calculated using the proportion between the number of permanent private households supplied by the general distribution network and the total number of permanent private households in the municipality. For analytical purposes, the classification was made according to the median of the percentage coverage values. The MHDI was inserted as a variable in the study, which is a measure composed of three dimensions (longevity, education, and income) to characterize the degree of development of the municipalities that did not provide fluoridation. The data for 2010 were divided into three categories: very low and low (between 0 and 0.499 and between 0.500 and 0.599); medium (between 0.600 and 0.699); and high and very high (between 0.700 and 0.799 and between 0.800 and 1).

DATA ANALYSIS

The values of the prevalence ratios (PR) and respective 95% confidence intervals (95% CI) were estimated between the outcome and the independent variables with Poisson regression analysis, with robust variance. The hypothesis of the study that guided the multiple analysis was to verify whether the characteristics of the sanitation companies (legal nature, administrative sphere and service performance form) remained or not associated to the outcome, regardless of the characteristics related to the municipalities (coverage of the general distribution network) of water, coverage of the general sewage/rainwater distribution network, demographic size, macro-region and 2010 MHDI. For that, four multiple models were built. In model 1, only variables related to the municipalities were included. In model 2, in addition to those related to the municipalities, the legal nature variable was included in the analysis. In model 3, the legal nature variable was replaced by the administrative sphere and, in model 4, by the service performance form. They were included in the model separately because some categories of variables related to the characteristics of the utilities were associated to each other and the outcome. Stata 12 statistical software was used²⁰20. StataCorp. Stata Statistical Software: Release 12. College Station: StataCorp LP; 2011..

Due to the fact that research uses only census information, of public access, there was no mandatory evaluation by the system of Research Ethics Committees/National Research Ethics Commission, according to the Resolution of the National Health Council (CNS) No. 510, of April 7, 2016.

RESULTS

Among the 5,565 municipalities included in the study, data were missing for the following variables: general water distribution network (n=5), general sewage/rainwater distribution network (n=111), and legal nature, administrative sphere and service performance form (n=4). Table 1 shows the distribution of municipalities according to the characteristics investigated. Among them, 60.2% had fluoridation services, and those belonging to the South and Southeast macro-regions had greater provision of the service. The presence of fluoridation was higher in the upper medians of the variables: coverage of the general water distribution network and sewage coverage. It was also higher in municipalities with a population of over 50,000 inhabitants and in those with very high/high MHDI. The public sector’s role in providing the benefit was noted. State companies, largely represented in the category that included entities characterized as indirectly managed by the public authorities/mixed-capital companies/mixed-capital public entities, and which operate by the association between public entities from different spheres and mixed-capital companies, were responsible for providing water supply services to more than 60% of the municipalities and had higher rates of service provision: 74.9 versus 27.8%, when the concessionaire was a private company. State entities, when added to federal ones in administering the service, also proportionally performed better. On the other hand, when the city council was the only performer, the worst performance was noted.

Table 1 also shows the values of the gross and adjusted effects of the independent variables on the rate of municipalities lacking the benefit. The values of the simple analysis indicate that all categories of variables showed an association with the outcome, except for the Southeast category of the macro-region variable (PR=1.02; 95%CI 0.99-1.04). In the first model of multiple analysis, in which only variables related to the municipalities were included, the associations remained present in all categories, especially municipalities belonging to the Northern macro-region, with a high probability of absence of public policy (PR=1.62; 95%CI 1.58-1.67). Municipalities in the Southeast macro-region, in the presence of the other variables, became significantly associated to the outcome (PR=1.06; 95%CI 1.04-1.09). In Model 2, in which, in addition to the characteristics of the municipalities, the legal nature variable was added, all categories were associated to the outcome, with the exception of “between 10,000 and 50,000 inhabitants” for the demographic size variable (PR=1.01; CI95 % 0.98-1.04), which did not differ in terms of the reference category. Companies classified as “directly managed by public authorities” were more likely not to provide fluoridation (PR=1.25; 95% CI 1.22-1.28), followed by private companies (RP=1.16; 95%CI 1.11-1.20). In the following model, three categories of administrative sphere showed significant associations with the outcome in the presence of covariates linked to the municipalities. Only the category that combined public entities did not differ from the reference category (PR=1; 95%CI 0.98-1.02). Comparing the Simple model and Models 2 and 3, it was observed that the net effect corresponding to the private nature of the legal nature and the administrative sphere, although significant, has lost its magnitude. In the last model, which included the service performance form variable, the category “city council was the only service performer” had a high probability of not providing fluoridation (PR=1.22; 95%CI 1.20-1.25). Just like in Model 2, the category “between 10,000 and 50,000 inhabitants” lost statistical significance. Observing the data of all the adjusted models, the variables related to the sanitation companies and the macro-region variable showed the highest probabilities of not providing fluoridation when compared to the reference categories.

DISCUSSION

This is the first study in a federative republic of three political-administrative levels, which evaluated the net effect of specific variables linked to the concessionaire responsible for water supply on the lack of provision of public fluoridation policy, in the presence of characteristics linked to the municipalities, including the macro-region to which they belong. The study hypothesis was confirmed, that is, the characteristics of the sanitation companies remained positively associated to the provision of fluoridation, regardless of those related to the municipalities.

The process of multiple modeling of the variables verified that, in the comparison with the Brazilian municipalities of the South macro-region, all those belonging to the other macro-regions had a significant probability of not ensuring the population’s access to the benefit, with magnitudes varying between 2 and 9% for the Southeast macro-region, 21 and 32% for the Central-West, 42 and 53% for the Northeast, and 46 and 67% for the North, indicating markedly different patterns of public policy implementation.

Previous studies point out these interregional differences⁷7. Gabardo MC, da Silva WJ, Olandoski M, Moysés ST, Moysés SJ. Inequalities in public water supply fluoridation in Brazil: an ecological study. BMC Oral Health 2008; 8: 9. https://doi.org/10.1186/1472-6831-8-9
https://doi.org/https://doi.org/10.1186/... ^,1414. Antunes JLF, Narvai PC. Políticas de saúde bucal no Brasil e seu impacto sobre as desigualdades em saúde. Rev Saúde Pública 2010; 44(2): 360-5. https://doi.org/10.1590/S0034-89102010005000002
https://doi.org/https://doi.org/10.1590/... . The contribution of the present investigation was to show the strength of the macro-region in the presence of other variables linked to municipalities and concessionaires. The regional inequality of public fluoridation policy seems to follow the history of implementation of essential public services in the Federative Republic of Brazil, such as access to the general water network and the electricity network. This access was marked by an expansion process with clear territorial inequality, in which the North and Northeast macro-regions were only reached by expressive coverage as of the 2000s²¹21. Arretche M. Trajetórias das desigualdades: como o Brasil mudou nos últimos cinquenta anos. São Paulo: Editora Unesp; 2015.. This uneven expansion seems to be primarily linked to the concentration of economic growth in the South and Southeast macro-regions, which was reflected in higher revenue from local governments and investment capacity. The country’s development was marked by inequality in the distribution of wealth and the construction of citizenship rights was unevenly distributed according to the insertion in the formal labor market, with the social benefits linked to the contributions and earnings of workers. The reported inequalities only found political definition for their reduction with the formulation of the Constitution of the Federative Republic of Brazil of 1988 and its resulting fiscal structure, which can be considered recent from the point of view of the universalization of public sanitation services²²22. Arretche M. Federalismo e igualdade territorial: uma contradição em termos? Dados 2010; 53(3): 587-620. https://doi.org/10.1590/S0011-52582010000300003
https://doi.org/https://doi.org/10.1590/... .

Factors such as coverage of water and sewage services remained significantly associated, showing that the lack of access to the benefit was linked to coverage rates for these services below the median value. Nonetheless, the magnitude of the association did not exceed the probability of 10% in any of the models. Given that the economic cost of maintaining water fluoridation in treatment plants would not affect the efficiency of sanitation services provided by companies²³23. Sabbioni G. Efficiency in the Brazilian sanitation sector. Util Policy 2008; 16(1): 11-20. https://doi.org/10.1016/j.jup.2007.06.003
https://doi.org/https://doi.org/10.1016/... , it is legitimate to consider maintaining optimal concentration standards for preventing dental caries as an indication of the quality of treatment services and water distribution under the responsibility of companies²⁴24. Frazão P, Peres MA, Cury JA. Qualidade da água para consumo humano e concentração de fluoreto. Rev Saúde Pública 2011; 45(5): 964-73. https://doi.org/10.1590/S0034-89102011005000046
https://doi.org/https://doi.org/10.1590/... ^,2525. Batabyal AK, Chakraborty S. Hydrogeochemistry and water quality index in the assessment of groundwater quality for drinking uses. WER 2015; 87(7): 607-17. https://doi.org/10.2175/106143015X14212658613956
https://doi.org/https://doi.org/10.2175/... .

Even in the presence of variables linked to municipalities and sanitation companies, medium and low/very low levels of human development remained positively associated to the outcome. As to demographic size, very small municipalities, defined as those with less than 10,000 inhabitants, showed a significant probability of not having the fluoridation service provision. An ecological study that investigated the association between social and economic indicators at the municipal level and the presence of water fluoridation in 252 municipalities in the state of Santa Catarina, Brazil, in 2000, showed that the municipalities that did not offer fluoridation had a lower number of inhabitants and lowest child development rates⁶6. Peres MA, Fernandes LS, Peres KG. Inequality of water fluoridation in Southern Brazil - the inverse equity hypothesis revisited. Soc Sci Med 2004; 58(6): 1181-9. https://doi.org/10.1016/s0277-9536(03)00289-2
https://doi.org/https://doi.org/10.1016/... .

Research involving 5,558 Brazilian municipalities found that fluoridation provision rates were lower in municipalities with less than 10,000 inhabitants and with low/very low MHDI⁴4. Frazão P, Narvai PC. Water fluoridation in Brazilian cities at the first decade of the 21st century. Rev Saúde Pública 2017; 51(47). https://doi.org/10.1590/s1518-8787.2017051006372
https://doi.org/https://doi.org/10.1590/... . The present study corroborates the data in the literature, reinforcing that the service expansion policy should include the specificities of small municipalities and those with medium and low/very low MHDI.

Considering the recent changes in the sector’s regulatory framework in Brazil²⁶26. Scriptore JS, Toneto Júnior R. A estrutura de provisão dos serviços de saneamento básico no Brasil: uma análise comparativa do desempenho dos provedores públicos e privados. Rev Adm Pública 2012; 46(6): 1479-504. https://doi.org/10.1590/S0034-76122012000600004
https://doi.org/https://doi.org/10.1590/... , which expand the possibilities of participation by private companies and give municipalities the right to provide services, the results seem to suggest a complex environment for the expansion of fluoridation in the country. In the present study, the municipalities that had the best results in the provision of fluoridation had its water supply provided by state companies that concentrated greater investment capacity and historical experience in the sector, whereas the lack of access was associated to municipal direct administration and private administration, whether or not combined with public entities. In addition, the economic return that the provision of the service can bring to private companies can make small, low-income municipalities unattractive for private investments²⁷27. Bakker K. Neoliberal versus postneoliberal water: geographies of privatization and resistance. Ann Am Assoc Geogr 2013; 103(2): 253-60. https://doi.org/10.1080/00045608.2013.756246
https://doi.org/https://doi.org/10.1080/... ^,2828. Greiner PT. Social drivers of water utility privatization in the United States: An examination of the presence of variegated neoliberal strategies in the water utility sector. Rur Sociol 2016; 81(3): 387-406. https://doi.org/10.1111/ruso.12099
https://doi.org/https://doi.org/10.1111/... . Thus, in the same way that the universalization of water and sewage services will depend, to a large extent, on the satisfactory performance of the regulatory authority²⁹29. Carvalho AEC, Sampaio LMB. Paths to universalize water and sewage services in Brazil: The role of regulatory authorities in promoting efficient service. Util Policy 2015; 34: 1-10. https://doi.org/10.1016/j.jup.2015.03.001
https://doi.org/https://doi.org/10.1016/... , in view of the results presented, the universalization of access to fluorides through the supply water will depend on the presence of this theme on the political agenda of the sector’s regulatory activities. For this to be achieved, establishing lines of horizontal and vertical coordination of public policy on the fluoridation of water supply systems is of utmost importance.

The data for present research dates to 2008 and 2010. However, information concerns an activity sector (sanitation) whose changes occur in the medium and long term. The fluoridation situation was obtained with a questionnaire applied by IBGE in the entities that provide sanitation services. Such information does not have another source of data to check its validity. There are data missing from some variables in a very small number of municipalities, which does not imply changes in the observed associations. Regardless of the present limitations, the study stands out for covering practically all the municipalities in Brazil, and for including in the analysis important characteristics of the sanitation companies never investigated before.

CONCLUSION

The lack of fluoridation provision was independent and positively associated to municipalities in the North, Northeast, Midwest and Southeast macro regions, with coverage rates for water and sewage services below the median value, with less than 10,000 inhabitants and low and medium level/very low human development. It was higher when the service was mainly provided by municipal administrations and private companies, whether or not associated to public entities, regardless of the characteristics of the municipalities.

References

Publication Dates

History