ABSTRACT:

Objective:

To assess the impact of 2008 Public Law number 11,705, also known as Dry Law (DL-08), on mortality from road traffic accidents (RTA), in each of the 27 Brazilian Federative Units (BFUs).

Methods:

Ecological study of interrupted time series with RTA data from 2002 to 2015, totalizing 168 months. Data were obtained from the Mortality Information System, the Brazilian Institute of Geography and Statistics, and from the National Traffic Department. Autoregressive integrated moving average (ARIMA) models were adjusted to assess the impact of DL-08 in each BFUs.

Results:

After the implementation of the DL-08, there was a significant decrease in mortality from RTA in the state of Santa Catarina (pre DL-08 = 2.60 ± 0.30 and post DL-08 = 2.32 ± 0.35; p < 0.001) and in the Federal District (pre DL-08 = 2.22 ± 0.40 and post DL-08 = 1.76 ± 0.35; p = 0.002), a significant increase in mortality in the states of Acre, Amazonas, Rondônia, Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe and Mato Grosso, and a stability in the other states. The sensitivity analysis conducted over a shorter time series with 24 months showed results similar to those obtained with the 168-month series for most of the 27 BFUs.

Conclusion:

The DL-08 had a heterogeneous impact on mortality from traffic accidents on BFUs.

Keywords:
Interrupted time series analysis; Accidents traffic; Time series studies. Ecological studies

INTRODUCTION

Traffic accidents (TA) are a relevant public health problem. They account for about 1.35 million deaths per year worldwide, being the eighth leading cause of death in the general population and the leading cause of death among people aged 5 to 29 years¹1. World Health Organization. Global status report on road safety 2018 [Internet]. Genebra: World Health Organization; 2018 [acessado em 6 ago. 2020]. Disponível em: Disponível em: https://www.who.int/violence_injury_prevention/road_safety_status/2018/en/
https://www.who.int/violence_injury_prev... . Furthermore, most TAs occur in low- and middle-income countries, where their cost can reach 2.9% of the Gross Domestic Product (GDP)²2. Wijnen W, Stipdonk H. Social costs of road crashes: An international analysis. Accid Anal Prev 2016; 94: 97-106. http://dx.doi.org/10.1016/j.aap.2016.05.005
https://doi.org/http://dx.doi.org/10.101... .

In Brazil, data from the 2013 National Health Survey show that 3.1% of the Brazilian population were involved in TAs with bodily injuries within a 12-month interval³3. Instituto Brasileiro de Geografia e Estatística (IBGE). Coordenação de Trabalho e Rendimento. Pesquisa nacional de saúde: 2013: acesso e utilização dos serviços de saúde, acidentes e violências: Brasil, grandes regiões e unidades da federação [Internet]. Rio de Janeiro: IBGE, 2015 [acessado em 6 ago. 2020]. Disponível em: Disponível em: https://biblioteca.ibge.gov.br/visualizacao/livros/liv94074.pdf
https://biblioteca.ibge.gov.br/visualiza... , which places TA as the second cause with the highest proportion of years of life lost due to external causes in Brazil⁴4. Campos MR, von Doellinger V dos R, Mendes LV, Costa M de F, Pimentel TG, Schramm JM. Morbidity and mortality associated with injuries: results of the Global Burden of Disease study in Brazil, 2008. Cad Saúde Pública 2015; 31(1): 121-36. http://dx.doi.org/10.1590/0102-311x00191113
https://doi.org/http://dx.doi.org/10.159... .

The effects of alcohol consumption on the occurrence of TAs are well described in the literature. Alcohol is known to delay the reaction to a stimulus, alter alertness, visual acuity, performance in tasks that involve divided attention and the ability to judge⁵5. Calinescu T, Adminaite D. Progress in reducing drink driving in Europe [Internet]. Bruxelas: European Safety Research Council, 2018 [acessado em 6 ago. 2020]. Disponível em: Disponível em: https://etsc.eu/wp-content/uploads/report_reducing_drink_driving_final.pdf
https://etsc.eu/wp-content/uploads/repor... ^,66. Liu YC, Ho CH. Effects of different blood alcohol concentrations and post-alcohol impairment on driving behavior and task performance. Traffic Inj Prev 2010; 11(4): 334-41. http://dx.doi.org/10.1080/15389581003747522
https://doi.org/http://dx.doi.org/10.108... ^,77. Zhao X, Zhang X, Rong J. Study of the Effects of Alcohol on Drivers and Driving Performance on Straight Road. Math Probl Eng 2014. http://dx.doi.org/10.1155/2014/607652
https://doi.org/http://dx.doi.org/10.115... . Furthermore, studies show that alcohol intake is associated with a higher risk of injuries and death from TA⁸8. Cherpitel CJ, Witbrodt J, Korcha RA, Ye Y, Monteiro MG, Chou P. Dose-response relationship of alcohol and injury cause: effects of country-level drinking pattern and alcohol policy. Alcohol Clin Exp Res 2019; 43(5): 850-6. http://dx.doi.org/10.1111/acer.13986
https://doi.org/http://dx.doi.org/10.111... ^,99. Taylor B, Rehm J. The relationship between alcohol consumption and fatal motor vehicle injury: high risk at low alcohol levels. Alcohol Clin Exp Res 2012; 36(10): 1827-34. http://dx.doi.org/10.1111/j.1530-0277.2012.01785.x
https://doi.org/http://dx.doi.org/10.111... . In Brazil, Damacena et al.¹⁰10. Damacena GN, Malta DC, Boccolini CS, Souza Júnior PRB, Almeida WS, Ribeiro LS, et al. Consumo abusivo de álcool e envolvimento em acidentes de trânsito na população brasileira, 2013. Ciên Saúde Coletiva 2016; 21(12): 3777-86. http://dx.doi.org/10.1590/1413-812320152112.25692015
https://doi.org/http://dx.doi.org/10.159... showed that alcohol consumption is associated with TA even when the effects of age, sex, education, skin color and marital status are considered. Evidence of the harmful effects of alcohol presented in the world literature helps to understand why 45 countries currently have restrictive laws on alcohol and driving¹1. World Health Organization. Global status report on road safety 2018 [Internet]. Genebra: World Health Organization; 2018 [acessado em 6 ago. 2020]. Disponível em: Disponível em: https://www.who.int/violence_injury_prevention/road_safety_status/2018/en/
https://www.who.int/violence_injury_prev... , including Brazil.

In Brazil, Law No. 11,705, of June 19, 2008, popularly known as Dry Law (DL-08), was one of the measures adopted by the Brazilian government to reduce morbidity and mortality from TA. In force since June 20, 2008, the DL-08 penalizes the driver caught driving under the influence of alcohol or any psychoactive substance with the suspension of the right to drive for 12 months across Brazilian territory, in addition to fines and administrative sanctions¹¹11. Brasil. Lei nº 11.705, de 19 de junho de 2008. Altera a Lei nº 9.503, de 23 de setembro de 1997, que ‘institui o Código de Trânsito Brasileiro’, e a Lei nº 9.294, de 15 de julho de 1996. Diário Oficial da União [Internet] 20 jun. 2008 [acessado em 6 ago. 2020]. Disponível em: Disponível em: http://www.planalto.gov.br/ccivil_03/_ato2007-2010/2008/lei/L11705.htm
http://www.planalto.gov.br/ccivil_03/_at... .

Several studies have investigated the impact of DL-08 on TA mortality in Brazil. Malta et al.¹²12. Malta DC, Soares Filho AM, Montenegro MMS, Mascarenhas MDM, Silva MMA, Lima CM, et al. Análise da mortalidade por acidentes de transporte terrestre antes e após a Lei Seca - Brasil, 2007-2009. Epidemiol Serv Saúde 2010; 19(4): 317-28. http://dx.doi.org/10.5123/S1679-49742010000400002
https://doi.org/http://dx.doi.org/10.512... did this by comparing the overlapping confidence intervals of the standardized rate of mortality from TA before and after DL-08, using aggregated data from one year before and one year after the law implementation. The authors reported a significant reduction (-7.4%) in the standardized rate of mortality from TA in Brazil and also stated that this reduction occurred heterogeneously across states. Andreuccetti et al.¹³13. Andreuccetti G, Carvalho HB, Cherpitel CJ, Ye Y, Ponce JC, Kahn T, et al. Reducing the legal blood alcohol concentration limit for driving in developing countries: a time for change? Results and implications derived from a time series analysis (2001-2010) conducted in Brazil: Reducing blood alcohol limits for driving. Addiction 2011; 106(12): 2124-31. http://dx.doi.org/10.1111/j.1360-0443.2011.03521.x
https://doi.org/http://dx.doi.org/10.111... showed that DL-08 was responsible for a significant reduction in the rate of mortality from TA by 7.2% and 16.0% in the state of São Paulo and capital, respectively. Abreu et al.¹⁴14. Abreu AMM, Jomar RT, Thomaz RGF, Guimarães RM, Lima JMB, Figueiró RFS. Impacto da lei seca na mortalidade por acidentes de trânsito. Rev Enferm UERJ 2012; 20(1): 21-6., in a descriptive study in the city of Rio de Janeiro, compared the months of July 2007 (pre-DL-08) and July 2008 (post-DL-08) and reported a reduction of 12.9% in mortality from TA. In 2017, Klabunde et al.¹⁵15. Klabunde FC, Ghizzo Filho J, Freitas PF, Nazário NO. Impacto da lei seca na taxa de mortalidade por acidentes de trânsito, Santa Catarina, entre 2005 e 2011 [impact of alcohol prohibition in the death rate from traffic accidents, in Santa Catarina, from 2005 to 2011]. Arq Catarin Med 2017; 46(2): 108-17. compared pre- and post-DL-08 TA mortality for the state of Santa Catarina and reported a significant reduction in the overall rate. More recently, Abreu et al.¹⁶16. Abreu DROM, Souza EM, Mathias TAF. Impacto do Código de Trânsito Brasileiro e da Lei Seca na mortalidade por acidentes de trânsito [Impact of the Brazilian Traffic Code and the Law Against Drinking and Driving on mortality from motor vehicle accidents]. Cad Saúde Pública 2018; 34(8): e00122117. http://dx.doi.org/10.1590/0102-311x00122117
https://doi.org/http://dx.doi.org/10.159... , in a segmented regression with yearly data for the state of Paraná between 1980 and 2014, observed a decrease in mortality among drivers in general and pedestrians after DL-08.

Despite the relevance of studies already carried out, the effect of DL-08 has not yet been evaluated by models that simultaneously incorporate autocorrelation, seasonality, confounders and cointerventions in all states. Thus, TA mortality described by closer-to-reality and regionalized models can provide more accurate estimates of the impact of DL-08, contributing to traffic management in the country. Therefore, the aim of this study was to assess the impact of DL-08 on mortality from TA in the 27 Brazilian Federation Units (UF), between January 2002 and December 2015.

METHODS

This study conducted an interrupted time-series analysis (ITSA) to assess mortality from TA that occurred monthly in each of the 27 Brazilian FUs between 2002 and 2015, in which 168 months were included, being 78 months before DL-08 (January 2002 to June 2008) and 90 after DL-08 (July 2008 to December 2015).

The studied outcome was the mortality coefficient due to TA observed monthly in each FU. Deaths whose underlying causes were coded in categories V01 to V89 were used for calculation, representing land transport accidents in Chapter XX (External Causes of Morbidity and Mortality) of the tenth revision of the International Classification of Diseases (ICD-10).

Three sources of information were used to collect data: Mortality Information System¹⁷17. Brasil. TabNet Win32 3.0: Mortalidade [Internet]. [acessado em 10 nov. 2017]. Disponível em: Disponível em: http://tabnet.datasus.gov.br/cgi/deftohtm.exe?sim/cnv/obt10br.def
http://tabnet.datasus.gov.br/cgi/deftoht... for the monthly number of deaths from TA; Brazilian Institute of Geography and Statistics (IBGE)¹⁸18. Brasil. Projeção da população [Internet]. [acessado em 15 nov. 2017]. Disponível em: Disponível em: https://www.ibge.gov.br/apps/populacao/projecao/
https://www.ibge.gov.br/apps/populacao/p... to collect the annual population projection; and the National Traffic Department (DENATRAN)¹⁹19. Brasil. Estatísticas: frota de veículos [Internet]. [acessado em 25 nov. 2017]. Disponível em: Disponível em: https://antigo.infraestrutura.gov.br/component/content/article/115-portaldenatran/8552-estat%C3%ADsticas-frota-de-ve%C3%ADculos-denatran.html
https://antigo.infraestrutura.gov.br/com... for information about the monthly vehicle fleet.

The intervention studied was DL-08, which was established in Brazil on June 20, 2008. Two co-interventions were also considered: the implementation of the Emergency and Emergency Medical Service (SAMU), according to Ordinance 5,055 of April 27, 2004 (SAMU-2004), and its reformulation according to Ordinance of the Ministry of Health 1,010 of May 21, 2012 (SAMU-2012).

Regressors considered were:

A model of the type Zt = µ + w0It + Xtβ + Nt was adjusted for each FU, with µ being a constant, Z_t the TA mortality coefficient in month t (t=1...168), w ₀ the impact of DL-08, I_t a binary variable equal to 0 when t ≤ 78 and equal to 1 when t > 78, X_t is the regressor matrix and N_t a residual series belonging to the autoregressive integrated moving average ARIMA (p,d,q). To identify the residual N_t series and to verify the assumptions of homoscedasticity and stationarity, the 78 pre-DL-08 observations were grouped into 13 clusters containing six observations in temporal sequence.

Homoscedasticity was verified with a scatter plot between means and standard deviations of the clusters. In the presence of heteroscedasticity, a Box-Cox transformation was applied to the data.

Stationarity was verified by comparing the series:

In case of doubt about which of the three series was stationary, the increased Duckey-Fuller test was applied, and its regression equation was determined based on the number of significantly non-null partial ACF.

The orders p and q were determined by comparing models with different orders p and q in relation to the value of the Akaike information criterion (AIC). The need for a constant in the model was verified with the t test for H0: µ = 0. The adequacy of the model was evaluated by graphic inspection of residuals using the ACF function, partial ACF function and residual histogram, and by the Ljung-Box test. Analyses were performed using the TSA, lmtest and AID packages of the R software, version 3.4.2.

RESULTS

Table 1 shows the estimates of the impact of DL-08 on traffic mortality, in each FU, based on the time series with 168 months, being 78 months before DL-08 and 90 months after DL-08, adjusted by cointerventions and regressors. A significant decrease in mortality from TA after DL-08 was observed only in the state of Santa Catarina (w^0 = -0.08; p < 0.001) and in the Federal District (w^0 = -0.08; p = 0.002). There was also a significant increase in mortality from TA after DL-08 in 12 Brazilian states: Acre (w^0 = 0.22; p = 0.005), Amazonas (w^0 = 0.08; p = 0.030) and Rondônia (w^0 = 0.71 ; p < 0.001) in the North region; Alagoas (w^0 = 0.31; p = 0.008), Ceará (w^0 = 0.35; p < 0.001), Maranhão (w^0 = 0.22; p = 0.004), Paraíba (w^0 = 0.13; p < 0.001), Pernambuco (w^0 = 0.30; p < 0.001), Piauí (w^0 = 0.34; p = 0.007), Rio Grande do Norte (w^0 = 0.25; p < 0.001) and Sergipe (w^0 = 0.30; p < 0.001) in the Northeast region; and Mato Grosso (w^0 = 0.41; p < 0.001) in the Mid-west region. In the other FUs, mortality from TA after DL-08 remained stable when compared to the pre-DL-08 period. The quality of adjusted models was evaluated using residuals and the Ljung-Box test, which did not indicate a failure in the white noise assumption for the residuals in all FUs.

Table 2 shows the sensitivity analysis performed to compare the results of the original 168-month time series with the results of the shorter 48-month time series, 24 months pre-DL-08 and 24 months post-DL-08. Among the 27 UF, the impact of DL-08 (w^0) was significant, having presented the same direction in both time series of six UF (Santa Catarina, Federal District, Rondônia, Pernambuco, Sergipe and Mato Grosso), while w^0 was not significant in both the time series of 10 UF (Amapá, Pará, Roraima, Bahia, Mato Grosso do Sul, Espírito Santo, Minas Gerais, Rio de Janeiro, São Paulo and Rio Grande do Sul), w^0 had the same direction with significant p value only in the longer time series in five FUs (Acre, Ceará, Maranhão, Paraíba and Rio Grande do Norte), w^0 presented opposite directions and significant p value only in the longer time series in three FUs (Amazonas, Alagoas and Piauí), w^0 had the same direction and significant p value only in the shorter time series in two FUs (Goiás and Paraná) and, finally, w^0 presented opposite directions between series and significant p value only in the shorter series in one FU (Tocantins).

DISCUSSION

This study found that the DL-08 was not enough to reduce TA mortality in all FUs. After DL-08 implementation, mortality from TA decreased significantly in two states (Santa Catarina and Distrito Federal), decreased non-significantly in five states (Amapá, Rio de Janeiro, São Paulo, Paraná and Rio Grande do Sul), increased non-significantly in eight states (Roraima, Pará, Tocantins, Bahia, Goiás, Mato Grosso do Sul, Minas Gerais and Espírito Santo) and increased with statistical significance in 12 states (Amazonas, Acre, Rondônia, Maranhão, Piauí, Ceará, Rio Grande do Norte, Paraíba, Pernambuco, Alagoas, Sergipe and Mato Grosso).

Although interventions that regulate and penalize drinking and driving are among the most effective to reduce mortality from TA²⁰20. Lefio A, Bachelet VC, Jiménez-Paneque R, Gomolán P, Rivas K. A systematic review of the effectiveness of interventions to reduce motor vehicle crashes and their injuries among the general and working populations. Rev Panam Salud Publica 2018; 42: e60. http://dx.doi.org/10.26633/RPSP.2018.60
https://doi.org/http://dx.doi.org/10.266... , this study pointed out a significant decrease in mortality from TA after DL-08 in only two of the 27 FUs.

To explain this divergence, factors associated with TA deaths should be considered, particularly vehicle fleet, behavior of drivers, functioning of the national traffic system and traffic engineering interventions, traffic municipalization process and adherence to health policies and actions, which may have evolved differently between states.

As for the vehicle fleet, the study showed a direct linear correlation between the fleet growth rate and the magnitude of the DL-08 effect (w^0) between FUs (r = 0.55; p = 0.003; Spearman’s correlation). Thus, FUs with high positive variations in the number of automotive vehicles between 2002 and 2015 had higher values of w^0, which indicates that the effect of DL-08 may have lost strength in FUs whose population acquired more vehicles. The high interest in purchasing vehicles is described in the literature. Carvalho and Pereira²¹21. Carvalho CHR, Pereira RHM. Gastos das famílias brasileiras com transporte urbano público e privado no Brasil: uma análise da POF 2003 e 2009 [Internet]. Brasília: Instituto de Pesquisa Econômica e Aplicada, 2012 [acessado em 6 ago. 2020]. Disponível em: Disponível em: https://www.ipea.gov.br/portal/images/stories/PDFs/TDs/td_1803.pdf
https://www.ipea.gov.br/portal/images/st... showed that families spend, on average, five times more on private transportation than on public transportation. Public transport has been increasingly ignored and this has an impact on urban mobility. From 1992 to 2012, commuting time between residence and workplace increased on average by 6.4% in Brazil²²22. Pero V, Stefanelli V. A questão da mobilidade urbana nas metrópoles brasileiras. Rev Econ Contemp 2015; 19(3): 366-402. http://dx.doi.org/10.1590/198055271932
https://doi.org/http://dx.doi.org/10.159... .

With regard to behaviors associated with mortality from TA, such as those described by Nascimento and Menandro²³23. Nascimento AS, Menandro PRM. Bebida Alcoólica e Direção Automotiva: relatos de policiais militares sobre a “Lei Seca”. Psicol Ciênc Prof 2016; 36(2): 411-25. http://dx.doi.org/10.1590/1982-370300067201
https://doi.org/http://dx.doi.org/10.159... -alcohol and drug consumption, high-speed driving, disobedience to traffic rules and overestimation of driving skills-, the prevalence may have evolved differently depending on state during the period of this study. The same may have occurred with non-behavioral factors associated with mortality from TA, such as those mentioned by Almeida et al.²⁴24. Almeida RL, Bezerra Filho JG, Braga JU, Magalhães FB, Macedo MC, Silva KA. Man, road and vehicle: risk factors associated with the severity of traffic accidents. Rev Saude Publica 2013; 47(4): 718-31. https://doi.org/10.1590/S0034-8910.2013047003657
https://doi.org/https://doi.org/10.1590/... and Lima et al.²⁵25. Lima IMO, Figueiredo JC, Morita PA, Gold P. Fatores condicionantes da gravidade dos acidentes de trânsito nas rodovias brasileiras [Internet]. Brasília: Instituto de Pesquisa Econômica e Aplicada ; 2008 [acessado em 6 ago. 2020]. Disponível em: Disponível em: https://www.ipea.gov.br/portal/images/stories/PDFs/TDs/td_1344.pdf
https://www.ipea.gov.br/portal/images/st... -age of the fleet, degree of urban development, traffic engineering conditions and meteorological conditions-, which may also have evolved differently between UFs.

Another possible explanation for the variability of estimates w^0 is the complexity of the National Traffic System (NTS). In each UF, the NTS is composed of a State Traffic Council (CETRAN), a Traffic Department (DETRAN), a Roads and Highways Department (DER), military police and an administrative appeals and infractions board (JARI)²⁶26. Brasil. Lei nº 9.503 de 23 de setembro de 1997. Institui o Código Brasileiro de Trânsito. Brasil; 1997.. Each of these bodies has complex structures made up of directors, superintendencies and management boards. Thus, it is possible that the quality of intra- and inter-organizational integrations is not the same in all 27 FUs.

Another factor that can explain the heterogeneity of values is the process of municipalization of traffic, which has been occurring at an unequal speed between the states. DENATRAN data reveal that, in the state of Tocantins, 5% of the municipalities are integrated into the NTS, while in Rio Grande do Sul this percentage reaches 97%. Many managers resist the idea of municipalizing the traffic of their municipalities for financial reasons²⁷27. Marques EV, Machado MA. Identificação dos fatores relevantes na decisão da alocação dos recursos econômicos visando um trânsito seguro. Rev Adm Pública 2010; 44(6): 1379-404. https://doi.org/10.1590/S0034-76122010000600006
https://doi.org/https://doi.org/10.1590/... , even though it is something positive²⁸28. Queiroz MS, Oliveira PC. Acidentes de trânsito: uma visão qualitativa no Município de Campinas, São Paulo, Brasil [Traffic accidents: a qualitative approach from Campinas, São Paulo, Brazil]. Cad Saúde Pública 2002; 18(5): 1179-87. https://doi.org/10.1590/s0102-311x2002000500010
https://doi.org/https://doi.org/10.1590/... .

The different degrees of adherence of FUs to health policies and actions can also explain the heterogeneity in values. The SAMU-a relevant component of the National Emergency Care Policy-represents an important advance in the fight against morbidity and mortality associated with emergencies in Brazil²⁹29. Teles AS, Coelho TCB, Ferreira MPS, Scatena JHG. Serviço de Atendimento Móvel de Urgência (SAMU) do Estado da Bahia: subfinanciamento e desigualdade regional [Mobile Emergency Care Service (SAMU): underfunding and regional inequality]. Cad Saúde Colet 2017; 25(1): 51-7. https://doi.org/10.1590/1414-462x201700010188
https://doi.org/https://doi.org/10.1590/... . Despite its relevance, Machado et al.³⁰30. Machado CV, Salvador FG, O’Dwyer G. Mobile Emergency Care Service: analysis of Brazilian policy. Rev Saúde Pública 2011; 45(3): 519-28. https://doi.org/10.1590/s0034-89102011005000022
https://doi.org/https://doi.org/10.1590/... show that the scope of SAMU varies from state to state. In July 2009, the proportion of the population covered by SAMU ranged from 21% (in Espírito Santo) to 100% (in the Federal District and Santa Catarina). Other important policies in the fight against TA, such as the National Policy for the Reduction of Morbimortality from Accidents and Violence of 2001 and the National Policy for Health Promotion of 2006, may also have been conducted differently between FUs.

Finally, differences in road structures, in the operationalization of traffic engineering and in the assertiveness of works over the years between FUs can also contribute to the variability observed.

The results of the sensitivity analysis obtained over the shorter time series of 24 months suggest that, in the states of Santa Catarina, Distrito Federal, Rondônia, Pernambuco, Sergipe and Mato Grosso, there was a significant decrease or increase in mortality from TA after DL-08 in the short term and extended to the long term. In the states of Acre, Ceará, Maranhão, Paraíba and Rio Grande do Norte, a possible effect of the time series size on the power of the tests in adjusted models must be considered. In the states of Amazonas, Alagoas and Piauí, the effect of DL-08 may have been important only in the short term, with the historical trend of increased mortality from TA prevailing, while in the state of Paraná, DL-08 may have lost efficiency over time. However, the possibility that DL-08 has maintained its long-term efficiency in the state of Paraná cannot be ruled out, but other factors associated with mortality from TA have increased in the long-term.

The possible biases of this study were discussed using the instrument Risk Of Bias In Non-randomised Studies of Interventions (ROBINS-I)³¹31. Sterne JAC, Hernán MA, Reeves BC, Savovic J, Berkman ND, Viswanathan M, et al. ROBINS-I: a tool for assessing risk of bias in non-randomised studies of interventions. BMJ 2016; 355. https://doi.org/10.1136/bmj.i4919
https://doi.org/https://doi.org/10.1136/... .

We believe that the risk of confounding bias is low because DL-08 is a federal law, which submits any driver to its rules regardless of their predictors of mortality from TA.

In this study, for selection bias, one would need:

As for the risk of bias in the classification of interventions, we believe that this risk is null because there was no possibility that the inhabitants of all 27 states were classified as not exposed to DL-08 when it was in force, nor they were considered exposed to DL-08 before its validity.

In this study, with aggregated data from all FUs, the problem of missing data is discussed in the context of international emigration. Data from the 2010 Demographic Census indicate that the percentage of people who moved to other countries ranged from 0.06% in Piauí to 0.57% in Goiás. Therefore, the percentage of people who leave Brazil is insufficient to impact the estimates of monthly mortality coefficients for TA. Thus, we believe the risk of bias due to lost data is low or null.

In addition, this study has advantages over previous work on the impact of DL-08¹²12. Malta DC, Soares Filho AM, Montenegro MMS, Mascarenhas MDM, Silva MMA, Lima CM, et al. Análise da mortalidade por acidentes de transporte terrestre antes e após a Lei Seca - Brasil, 2007-2009. Epidemiol Serv Saúde 2010; 19(4): 317-28. http://dx.doi.org/10.5123/S1679-49742010000400002
https://doi.org/http://dx.doi.org/10.512... ^,1313. Andreuccetti G, Carvalho HB, Cherpitel CJ, Ye Y, Ponce JC, Kahn T, et al. Reducing the legal blood alcohol concentration limit for driving in developing countries: a time for change? Results and implications derived from a time series analysis (2001-2010) conducted in Brazil: Reducing blood alcohol limits for driving. Addiction 2011; 106(12): 2124-31. http://dx.doi.org/10.1111/j.1360-0443.2011.03521.x
https://doi.org/http://dx.doi.org/10.111... ^,1414. Abreu AMM, Jomar RT, Thomaz RGF, Guimarães RM, Lima JMB, Figueiró RFS. Impacto da lei seca na mortalidade por acidentes de trânsito. Rev Enferm UERJ 2012; 20(1): 21-6.^,1515. Klabunde FC, Ghizzo Filho J, Freitas PF, Nazário NO. Impacto da lei seca na taxa de mortalidade por acidentes de trânsito, Santa Catarina, entre 2005 e 2011 [impact of alcohol prohibition in the death rate from traffic accidents, in Santa Catarina, from 2005 to 2011]. Arq Catarin Med 2017; 46(2): 108-17.^,1616. Abreu DROM, Souza EM, Mathias TAF. Impacto do Código de Trânsito Brasileiro e da Lei Seca na mortalidade por acidentes de trânsito [Impact of the Brazilian Traffic Code and the Law Against Drinking and Driving on mortality from motor vehicle accidents]. Cad Saúde Pública 2018; 34(8): e00122117. http://dx.doi.org/10.1590/0102-311x00122117
https://doi.org/http://dx.doi.org/10.159... . This is the first study to investigate the effect of DL-08 in all FUs using a statistical intervention model that simultaneously considers ACF in monthly observations, seasonality and the following confounding variables: number of Saturdays and Sundays per month, evolution of vehicle fleet in each UF and co-interventions that represent the implementation of SAMU, according to Ordinance 5,055 of April 27, 2004 (SAMU-2004), and its reformulation in the Ministry of Health Ordinance 1,010 of 21 of May 2012 (SAMU-2012).

Time limits for pre- and post-DL-08 periods were determined based on Penfold and Zhang³²32. Penfold RB, Zhang F. Use of interrupted time series analysis in evaluating health care quality improvements. Acad Pediatr 2013; 13(6 Supl.): S38-44. https://doi.org/10.1016/j.acap.2013.08.002
https://doi.org/https://doi.org/10.1016/... , who recommend at least eight observations before and eight observations after an intervention. However, considering that our model would include several regressors and that the TA mortality time series showed great variability in some FUs, we decided to expand our time limit from January 2002 to December 2015 (n = 168 months), expanding the recommended by Penfold and Zhang³²32. Penfold RB, Zhang F. Use of interrupted time series analysis in evaluating health care quality improvements. Acad Pediatr 2013; 13(6 Supl.): S38-44. https://doi.org/10.1016/j.acap.2013.08.002
https://doi.org/https://doi.org/10.1016/... .

However, this study has some limitations:

Unfortunately, data on the annual prevalence of alcohol consumption were not found for all 27 FUs. One possibility would be to use data from the Surveillance of Risk Factors and Protection for Chronic Diseases by Telephone Survey (Vigitel), which provides an estimate of proportion of the number of adults who abused alcohol. However, the first edition of Vigitel is from 2006 (therefore, it does not cover the period of our study-2002 to 2015). Also, these data represent the capitals of each UF only, not the UF as a whole.

In summary, after DL-08 there was a significant decrease in mortality from TA only in the state of Santa Catarina and in the Federal District. This heterogeneity may stem from factors associated with death from TA such as change in vehicle fleet, change in behavior of vehicle drivers, functioning of the national traffic system, municipalization of traffic management and variable adherence to health policies and actions, which evolved unevenly between the FUs.

ACKNOWLEDGEMENTS

We would like to thank the employees of the Collective Health Research Unit (UPeSC) of the Botucatu Medical School, UNESP.

References

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