Accident Analysis and Prevention 66 (2014) 114–119
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Impact of road safety interventions on traffic-related occupational injuries in Spain, 2004–2010 María López-Ruiz a,b,∗ , José Miguel Martínez a,b , Katherine Pérez a,c,d , Ana M. Novoa c,d , Aurelio Tobías e , Fernando G. Benavides a,b,f a
CIBER Epidemiología y Salud Pública (CIBERESP), Spain Center for Research in Occupational Health, Universitat Pompeu Fabra, Spain c Agència de Salut Pública de Barcelona, Spain d Institut d’Investigació Biomédica (IIB Sant Pau), Spain e Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Spain f IIS IMIM - Parc Salut Mar, Spain b
a r t i c l e
i n f o
Article history: Received 5 April 2013 Received in revised form 20 December 2013 Accepted 14 January 2014 Keywords: Evaluation Occupational health Injury prevention
a b s t r a c t Objectives: To evaluate the impact of road safety interventions, including the penalty point system (PPS) and the reformed Spanish penal code (RPC), on traffic-related occupational injuries in Spain. Methods: The study design was an interrupted time-series with a comparison group. The study group had traffic-related, occupational injuries incurred during working and commuting hours; the comparison group had non-traffic-related injuries incurred at the work site. A negative binomial regression model was used to determine the relative risk (RR) of sustaining occupational injuries for the post-intervention periods compared to the non-intervention period. Results: Non-fatal, traffic-related injuries did not significantly change after the PPS and RPC implementations, except for those occurred in commuting hours, which increased significantly after the PPS. On the other hand, after the RPC, fatal, traffic-related injuries decreased significantly during working hours (0.79; 95%CI 0.65 to 0.97) and commuting hours (RR: 0.63; 95%CI:0.56 to 0.72), although fatal, non-traffic-related injuries also decreased at the work site. Conclusions: Road safety interventions did not clearly affect traffic-related occupational injuries in Spain. Specific occupational risk factors could influence the occurrence of those injuries. © 2014 Elsevier Ltd. All rights reserved.
1. Introduction 1.1. Overview of the problem Occupational and road traffic injuries are important problems in public health (Hamalainen, 2009; World Health Organization, 2009), but in recent years, they have decreased in middle-high income countries, particularly fatal injuries (Benavides et al., 2005; World Health Organization, 2009). In Spain the incidence of nonfatal occupational injuries per 1,000 workers decreased from 84 in 2000 to 45 in 2009 (Benavides et al., 2011); moreover, the number of road traffic injuries decreased between 2001 and 2011 by around 23% for non-fatal and 63% for fatal injuries (Dirección General de Tráfico, 2012). However, the absolute number of these types of
∗ Corresponding author at: Center for Research in Occupational Health, Universitat Pompeu Fabra, Department of Experimental and Health Sciences PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Barcelona, Spain. Tel.: +34 933160872. E-mail address: [email protected] (M. López-Ruiz). 0001-4575/$ – see front matter © 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.aap.2014.01.012
injuries remains unacceptably high. In Spain, there were 580,434 non-fatal and 716 fatal occupational injuries in 2011 (Ministerio de Empleo and Seguridad Social, 2013), and 115,627 non-fatal and 2060 fatal road traffic injuries in 2011 (Dirección General de Tráfico, 2012). Many occupational injuries involve traffic collisions. In fact, the number of traffic-related occupational injuries (both commuting and during working hours) has tended to remain stable or even increased over the last decade. For example, in middle-high income countries, like France, the percentage of traffic-related occupational injuries remained at around 10% from 1997 to 2006 for all traffic-related injuries (Charbotel et al., 2010). In Spain, in 2010, 10% (65,446) of all occupational injuries and one in three fatal occupational injuries were traffic-related (De Vicente et al., 2012). Also, in Catalonia (Spain), the incidence for non-fatal, traffic-related, occupational injuries remained around 50 per 10,000 workers from 2004 to 2010 (Departament d’Empresa i Ocupació, 2013). Consequently, the burden of traffic-related occupational injuries has increased, considering the percentage of these injuries among the total number of occupational injuries. For instance, among all
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non-fatal, commuting occupational injuries that occurred between 2004 and 2010, the percentage of traffic-related injuries increased from 55% to 59%. 1.2. Road safety interventions The decreasing trend in road traffic injuries in Spain has been attributed to the effectiveness of road safety interventions promoted since 2004 (Dirección General de Tráfico, 2006; Novoa et al., 2011b; Izquierdo et al., 2011). For example, the penalty point system (PPS) was introduced in July 2006. The PPS applies points against the driving licence for traffic-related violations. Also, the reformed Spanish penal code (RPC) was introduced in December 2007; it criminalised several road offenses, including speeding, drunk driving, and driving without a licence. The PPS achieved around 11% and 9% reductions in serious road traffic injuries in men and women, respectively (Novoa et al., 2010). The RPC resulted in a 7% reduction in the number of males involved in injury collisions; thus, an estimated 13,891 road traffic injuries in men were prevented by 2009 (Novoa et al., 2011a). 1.3. Hypothesis and objective Although road safety interventions are mentioned in public policies on road safety for preventing general traffic injuries, the impact of these interventions on traffic-related occupational injuries has not been evaluated. We hypothesized that these road safety interventions should also effectively reduce traffic-related occupational injuries. Thus, the objective of this study was to evaluate the impact of two road safety interventions (the PPS and the RPC) on trafficrelated, occupational injuries in Spain between 2004 and 2010. 2. Material and methods 2.1. Study design and population The study design was an interrupted time-series with a comparison group (Biglan et al., 2000). The study population included all salaried workers in Spain between 2004 and 2010 that were covered by social security occupational injury benefits, excluding business owners, public employees, and self-employed workers. The study group comprised salaried workers that had sustained traffic-related occupational injuries. The injuries must have caused the loss of at least one workday and resulted from a collision with a motor vehicle on a public road. Injuries incurred at the worksite were excluded. The selected injuries were most susceptible to the studied road safety interventions. The comparison group comprised salaried workers that had sustained non-traffic-related occupational injuries that had occurred at the work site. These injuries must have caused the loss of at least one workday. They were not expected to be influenced by the studied road safety interventions. 2.2. Sources of information The number of occupational injuries associated with at least one lost workday was determined from records from the Labour Administration (Ministerio de Empleo and Seguridad Social, 2013), which collects all the occupational injuries that have occurred in workers in Spain. The total number of workers in the active population was estimated from the Spanish labour survey (Instituto Nacional de Estadística, 2012). This survey includes around 180,000 people and then is weighted to obtain a representative sample of all workers.
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2.3. Study period Throughout the study period, from 2004 to 2010, we considered three different time periods, based on the road safety interventions. First, the non-intervention period (NI) included the first trimester of 2004 to the second trimester of 2006. Then, we considered two post-intervention periods. One began with the introduction of the PPS, and included the third trimester of 2006 to the fourth trimester of 2010 (LEY, 2005). The other began with the introduction of the RPC, and included the first trimester of 2008 to the last trimester of 2010 (LEY ORGÁNICA, 2007). 2.4. Variables The dependent variable was the trimester incidence rate of occupational injuries. The injuries were traffic-related for the study group and non-traffic-related for the comparison group. To determine the effect of the two interventions, the explanatory variables (PPS and RPC) were set as follows. The PPS variable was set to 0 during the NI period, and it was set to 1 from the third trimester of 2006 to the fourth trimester of 2010. The RPC variable was set to 0 from the start of the NI period to the first trimester of 2008, and then it was set to 1 until the last trimester of 2010. The stratification variables included the severity of the injury (fatal or non-fatal) and the time when the injury occurred (during working hours or commuting hours). Therefore, the analysis was made separately for these variables. 2.5. Statistical analysis Trimestrial incidence rates were calculated as the ratio of the number of occupational injuries to the number of salaried workers. The ratio is expressed per 10,000 or per 1,000,000 workers for nonfatal or fatal occupational injuries, respectively. The relative risk (RR) of sustaining an occupational injury in the post-intervention periods, compared to the NI period, was calculated with the 95% confidence interval. RR was estimated for each outcome assuming a negative binomial distribution (Long, 1997) on yt , the number of occupational injuries in the tth trimester (t = 1,. . ., 28), according to the following log-linear formula: log (E[yt ]) = ˇ0 + ˇ1 PPS + ˇ2 RPC + log (Nt ) where PPS is the PPS variable, RPC the RPC variable, and Nt is the number of workers in the tth trimester. Therefore, the RR for the PPS period was estimated as exp(ˇ1 ), and the RR for the RPC period was estimated as exp(ˇ2 ). All analyses were conducted with the R statistic program (Development Core Team, 2014), with the ‘glm.nb’ R function. 3. Results 3.1. General description of the data The number of non-fatal occupational injuries included in the analysis was 5,591,648. Of these, 468,582 were traffic-related injuries (112,888 during working hours and 355,694 during commuting hours), and 5,123,066 were non-traffic-related injuries that occurred at the work site. (Table 1) The fatal injuries included 6,571 occupational injuries. Of these, 2,734 were traffic-related injuries (1,002 and 1,732 in working and commuting hours, respectively), and 3,837 were non traffic-related injuries that occurred at the work site. (Table 1) The total number of salaried workers in the active population analysed was 110,834,882, between 2004 and 2010.
n
529 875 490 747 501 775 465 674 366 672 281 532 260 471 292 180 295 50 291 64 303 37 218 35 170 29 163 21
61.9 38.1 85.5 14.5 82.0 18.0 89.1 10.9 86.2 13.8 85.4 14.6 88.6 11.4 77.4 22.6 74.0 26.0 73.7 26.3 64.6 35.4 63.1 36.9 56.8 43.2 55.0 45.0 195 57 151 53 157 56 153 84 147 86 105 80 94 77
% n % n
Total Commuting hours Working hours
3.2. Occupational injury trends Among the non-fatal occupational injuries, we examined the trimestrial incidence rates over the entire study period. Between the first trimester of 2004 and the last trimester of 2010, the incidence of non-traffic-related injuries that occurred at the work site decreased from 144.3 to 72.1 per 10,000 workers. Over the same period, the incidences of traffic-related injuries remained stable at around 2.5 and 7.5 per 10,000 workers for injuries that occurred during working and commuting hours, respectively (Fig. 1). Among the fatal injuries, the incidences decreased for all types of occupational injuries analysed. The incidence decreased from 11.8 to 5.9 per 1,000,000 workers for non-traffic-related injuries that occurred at the work site. The incidence decreased from 3.5 to 1.6 and from 4.5 to 2.4 per 1,000,000 workers for traffic-related injuries that occurred during working and commuting hours, respectively (Fig. 2).
6.2 93.8 1.4 98.6 7.5 92.5 7.4 92.6 0.2 99.8 1.4 98.6 0.8 99.2
% n
42 638 9 644 53 655 44 553 1 551 6 423 3 373 6.8 93.2 7.3 92.7 7.1 92.9 8.5 91.5 9.2 90.8 10.0 90.0 10.2 89.8
%
53.8 46.2 55.2 44.8 54.4 45.6 63.9 36.1 64.5 35.5 62.3 37.7 61.3 38.7 43,829 37,575 49,174 39,947 49,457 41,503 61,511 34,743 57,051 31,415 48,782 29,533 45,890 28,995
63,176 862,452 69,789 885,598 69,887 917,337 85,563 921,100 79,048 782,328 67,378 609,772 63,338 557,210
n % n
38.9 61.1 40.4 59.6 39.9 60.1 43.3 56.7 42.0 58.0 39.3 60.7 35.9 64.1 14,408 22,597 15,680 23,133 15,354 23,137 19,320 25,344 18,096 24,947 15,480 23,897 14,550 25,965 2010
2009
2008
2007
2006
2005
n
0.6 99.4 0.6 99.4 0.6 99.4 0.5 99.5 0.5 99.5 0.6 99.4 0.6 99.4
% n
4,939 802,280 4,935 822,518 5,076 852,697 4,732 861,013 3,901 725,966 3,116 556,342 2,898 502,250 Traffic Non traffic Traffic Non traffic Traffic Non traffic Traffic Non traffic Traffic Non traffic Traffic Non traffic Traffic Non traffic
Working hours At the work site
%
Total Commuting hours
2004
Fatal
At the work site
3.3. Occupational injury risk
Non fatal
Table 1 Number and percentage of traffic-related and non-traffic-related occupational injuries (n, %), by fatal and non-fatal injuries and time when the injury occurred. Spain, 2004–2010.
37.7 62.3 39.6 60.4 39.3 60.7 40.8 59.2 35.3 64.7 34.6 65.4 35.6 64.4
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%
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We examined the risk of sustaining a non-fatal occupational injury after the interventions. The PPS intervention did not significantly affect the risk of sustaining a non-fatal, traffic-related injury that occurred during working hours (RR: 1.07; 95%CI: 0.99−1.16). However, it was associated with a significant increase in the risk of sustaining non-fatal, traffic-related injuries that occurred during commuting hours (RR: 1.10; 95%CI: 1.02−1.20). The RPC did not significantly affect the non-fatal, traffic-related injuries. A significant decrease in non-fatal, non-traffic-related injuries that occurred at the work site was found after the RPC (RR: 0.73; 95%CI: 0.66−0.81). (Table 2) We examined the risk of sustaining a fatal occupational injury after the interventions. Both the PPS and the RPC interventions were associated with decreases in the risk of fatal injuries. The decrease in risk was not statistically significant for traffic-related, fatal injuries after the PPS intervention; but significant after the RPC intervention (RR: 0.79; 95%CI: 0.65−0.97 for working hours, and RR: 0.63; 95%CI: 0.56−0.72 for commuting hours). A significant decrease in fatal, non-traffic-related injuries was found after both interventions. (Table 2) 4. Discussion Our results showed that road safety interventions did not have a clear effect on traffic-related occupational injuries in Spain. We found that, after the PPS or RPC interventions, the risk of sustaining a traffic-related occupational injury during working or commuting hours did not decrease significantly from that observed in the NI period. After the RPC intervention, the risk of sustaining fatal, traffic-related occupational injuries decreased significantly, but the risk of sustaining fatal, non-traffic-related injuries at the work site also decreased. The reduction in non-traffic-related occupational injuries could be attributed to the introduction (since 2000) of specific, occupational preventive interventions called ‘Preferential Action Plans’ (an intervention for preventing occupational injuries, developed by Spanish regional governments). These plans are focused on companies with high incidence rates of occupational injuries (López-Ruiz et al., 2013). Furthermore, the risk of fatal, traffic-related occupational injuries, both during work and commuting hours, may have decreased after the RPC intervention due to the economic crisis, which began in 2008. The economic crisis may have had a positive effect on reducing the number of fatal traffic injuries (Stuckler et al., 2009). In Spain, risk factors related to road traffic injuries, such as law violations, alcohol and drugs, distraction, speeding and seat belt
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Non traffic 160 140 120 100 80 60 40 20 0 1T
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th
Note. 1T, 2T, 3T, and 4T indicate the 1 to 4 trimesters of the year. Fig. 1. Trimestrial incidence rates of non-fatal occupational injuries per 10,000 workers, including (top) non-traffic-related injuries (incurred at the work site) and (bottom) traffic-related injuries (incurred during working and commuting hours). Spain, 2004–2010.
use, among others, have been decreasing in recent years (Dirección General de Tráfico, 2012). These risk factors are common to all traffic injuries (including occupationally-related) and could influence the incidence of traffic-related occupational injuries. In fact, these risk factors have decreased due to the road safety interventions
analysed (Novoa et al., 2010, 2011b), and also the improvement of infrastructure, vehicle fleet and driver behavior (Dirección General de Tráfico, 2012). Although these components equally affect the entire population, our results showed that trends in traffic-related occupational injuries have not decreased.
Table 2 Occupational injuries before (non intervention) and after traffic interventions (penalty points system and reformed Spanish penal code), including fatal and non-fatal, traffic-related and non-traffic-related, occupational injuries in Spain, 2004–2010.
Non fatal
Traffic
Fatal
Non traffic Traffic Non traffic
Working hours Commuting hours At the work site Working hours Commuting hours At the work site
Non intervention (1T 2004–2T 2006)
Penalty points system (3T 2006–4T 2010)
Reformed penal code (1T 2008–4T 2010)
Mean rate
RR
Mean rate
RR (95%CI)
Mean rate
RR (95%CI)
2.5 7.8 135.2 2.8 4.8 10.4
1.00 1.00 1.00 1.00 1.00 1.00
2.7 8.6 127.5 2.3 4.6 9.0
1.07 (0.99; 1.16) 1.10 (1.02; 1.20)* 0.94 (0.84; 1.05) 0.81 (0.67; 1.00) 0.96 (0.85; 1.08) 0.87 (0.76; 0.99)*
2.5 8.0 93.6 1.8 2.9 7.1
0.94 (0.87; 1.02) 0.93 (0.86; 1.01) 0.73 (0.66; 0.81)* 0.79 (0.65; 0.97)* 0.63 (0.56; 0.72)* 0.78 (0.68; 0.89)*
Note: 1T, 2T, 3T, and 4T indicate the 1st to 4th trimesters of the year. Values represent the mean rates per 10,000 workers for non-fatal or per 1,000,000 workers for fatal occupational injuries. RR: relative risk; 95%CI: 95% confidence interval. * p-value < 0.05
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Non traff traffic ic 14 12 10 8 6 4 2 0 1T
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Note. 1T, 2T, 3T, and 4T indicate the 1st to 4th trimesters of the year. Fig. 2. Trimestrial incidence rates of fatal occupational injuries per 1,000,000 workers, including (top) non-traffic-related injuries (incurred at the work site) and (bottom) traffic-related injuries (incurred during working and commuting hours) in Spain, 2004–2010.
Alternatively, specific occupational risk factors may strongly influence the incidence of traffic-related occupational injuries. Thus, road safety interventions may not be sufficient to lower the risk for occupational injuries. A previous systematic review pointed out that many studies have focused on driver-related risk factors for traffic-related injuries, like alcohol or speeding; but occupationrelated factors for traffic-related injuries have been neglected. For instance, traffic-related occupational injuries have been associated with extended shifts, sleepiness, occupational stress, or time spent driving, among other factors (Robb et al., 2008). Significant associations have also been found between the risk of trafficrelated occupational injuries and difficult working conditions, like inflexible work schedules, lack of consecutive rest-days, difficulties in communicating with superiors, low seniority, low educational level, strenuous jobs, and physical constraints at work (Fort et al., 2010; Chiron et al., 2008; Mitchell et al., 2004). Further research is needed in order to assess this alternative hypothesis. Moreover, it is possible that our results would have changed if we had had information on some of the occupational risk factors mentioned above. Therefore, another hypothesis to be tested in future studies
would be that if we remove the effect of these risk factors associated to traffic-related occupational injuries, PPS and RPC interventions could have a positive impact on this kind of injuries. It is also possible that our results would have changed if we had information on some of these risk factors. Another hypothesis to be tested would be that if we remove the effect of occupational risk factors affecting road traffic injuries, interventions might be effective. 4.1. Limitations and strengths A primary limitation of this study was that it was based on administrative data from the labour administration. This data did not include traffic information, like the type of vehicle, type of road user, the number of people injured in the collision, etc. The only information related to traffic was whether the accident was due to a collision with a motor vehicle and whether it occurred on a public road. Also, the exhaustiveness of the data was unknown, although we assumed that the information was complete, because workers are required to declare and register the accident before they can
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receive occupational injury benefits. As we mentioned, the registry did not include public employees (approximately 1.5 million workers in 2011 (Muface, 2012)) or self-employed workers (around 2 million in 2011 (Ministerio de Empleo and Seguridad Social, 2011)); this fact might have introduced a selection bias. However, road safety interventions affect all workers equally, independent of their employment conditions; therefore, we assumed that this selection did not affect the results. Another possible limitation is the selection of the comparison group: there may be different etiological factors which affect the types of injuries of the comparison group and the intervention groups. But we have chosen for the comparison group the non-traffic-related occupational injuries that occurred at the work site, firstly, because they are not expected to be influenced by the studied road safety intervention (as they are not related to traffic). Secondly, because they were the most similar type of injuries since they are related to work, although they occurred in different places. Due to the ecological design of the study, it is important to consider the ecological fallacy (Schwartz, 1994). However, our study has assessed the impact of two policy interventions at the population level. In this sense, the interrupted time-series design is one of the most useful studies to assess the impact of a policy intervention (Gil-González et al., 2009). Finally, we could not stratify by sex or age, due to the lack of convergence in the statistical models of stratified analyses. This study had several strengths, including the large number of records and the study design with a comparison group. This was the first study, to our knowledge, that evaluated road safety interventions in relation to occupational injuries. Finally, this research was a worthy exercise that could promote cooperation between traffic and labour authorities. 5. Conclusions After a decade of successful implementation of road traffic and occupational injury prevention programs in Spain (Novoa et al., 2011b; Benavides et al., 2011), our results showed mixed effects on the risk of sustaining traffic-related occupational injuries. Therefore, future research and preventive efforts should be focused on working conditions that could potentially have stronger effects on road safety. A first step in that direction could be to improve the exchange of information between Labour and Traffic Administrations. The occupational injury record should include details like the type of vehicle, the type of road user, etc. Conversely, the road traffic injury record should include details like the type of job, the contract, working hours, etc. Moreover, private and public companies and their preventive services play a key role in managing employee working conditions. Thus, it may be necessary to motivate companies to develop plans for preventing traffic-related occupational injuries (European Agency for Safety and Health at Work, 2010) that apply to both commuting and working hours. Finally, these preventative plans should focus on workers whose real workplace is a vehicle. The effectiveness of these interventions should be evaluated in future research. Acknowledgements We acknowledge David Martos Moral and Juan Miguel Mouat Silva for their useful contributions to our study. References Benavides, F.G., Benach, J., Martínez, J.M., Gonzalez, S., 2005. Description of fatal occupational injury rates in five selected European Union countries: Austria, Finland, France, Spain and Sweden. Saf. Sci. 43 (8), 497–502, http://dx.doi.org/10.1016/j.ssci.2005.04.005.
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Novoa, A.M., Perez, K., Santamarina-Rubio, E., Mari-Dell’Olmo, M., Ferrando, J., Peiro, R., Tobias, A., Zori, P., Borrell, C., 2010. Impact of the penalty points system on road traffic injuries in Spain: a time-series study. Am. J. Public Health 100 (11), 2220–2227, http://dx.doi.org/10.2105/AJPH. 2010.192104. Robb, G., Sultana, S., Ameratunga, S., Jackson, R., 2008. A systematic review of epidemiological studies investigating risk factors for work-related road traffic crashes and injuries. Inj. Prev. 14, 41–48, http://dx.doi.org/10.1136/ ip.2007.016766. Stuckler, D., Basu, S., Suhrcke, M., Coutts, A., McKee, M., 2009. The public health effect of economic crises and alternative policy responses in Europe: an empirical analysis. Lancet 374 (9686), 315–323, http://dx.doi.org/10.1016/ S0140-6736(09)61124-7. Schwartz, S., 1994. The fallacy of the ecological fallacy: the potential misuse of a concept and the consequences. Am. J. Public Health 84 (5), 819–824. 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Accident Analysis and Prevention journal homepage: www.elsevier.com/locate/aap
Impact of road safety interventions on traffic-related occupational injuries in Spain, 2004–2010 María López-Ruiz a,b,∗ , José Miguel Martínez a,b , Katherine Pérez a,c,d , Ana M. Novoa c,d , Aurelio Tobías e , Fernando G. Benavides a,b,f a
CIBER Epidemiología y Salud Pública (CIBERESP), Spain Center for Research in Occupational Health, Universitat Pompeu Fabra, Spain c Agència de Salut Pública de Barcelona, Spain d Institut d’Investigació Biomédica (IIB Sant Pau), Spain e Institute of Environmental Assessment and Water Research (IDAEA), Spanish Council for Scientific Research (CSIC), Spain f IIS IMIM - Parc Salut Mar, Spain b
a r t i c l e
i n f o
Article history: Received 5 April 2013 Received in revised form 20 December 2013 Accepted 14 January 2014 Keywords: Evaluation Occupational health Injury prevention
a b s t r a c t Objectives: To evaluate the impact of road safety interventions, including the penalty point system (PPS) and the reformed Spanish penal code (RPC), on traffic-related occupational injuries in Spain. Methods: The study design was an interrupted time-series with a comparison group. The study group had traffic-related, occupational injuries incurred during working and commuting hours; the comparison group had non-traffic-related injuries incurred at the work site. A negative binomial regression model was used to determine the relative risk (RR) of sustaining occupational injuries for the post-intervention periods compared to the non-intervention period. Results: Non-fatal, traffic-related injuries did not significantly change after the PPS and RPC implementations, except for those occurred in commuting hours, which increased significantly after the PPS. On the other hand, after the RPC, fatal, traffic-related injuries decreased significantly during working hours (0.79; 95%CI 0.65 to 0.97) and commuting hours (RR: 0.63; 95%CI:0.56 to 0.72), although fatal, non-traffic-related injuries also decreased at the work site. Conclusions: Road safety interventions did not clearly affect traffic-related occupational injuries in Spain. Specific occupational risk factors could influence the occurrence of those injuries. © 2014 Elsevier Ltd. All rights reserved.
1. Introduction 1.1. Overview of the problem Occupational and road traffic injuries are important problems in public health (Hamalainen, 2009; World Health Organization, 2009), but in recent years, they have decreased in middle-high income countries, particularly fatal injuries (Benavides et al., 2005; World Health Organization, 2009). In Spain the incidence of nonfatal occupational injuries per 1,000 workers decreased from 84 in 2000 to 45 in 2009 (Benavides et al., 2011); moreover, the number of road traffic injuries decreased between 2001 and 2011 by around 23% for non-fatal and 63% for fatal injuries (Dirección General de Tráfico, 2012). However, the absolute number of these types of
∗ Corresponding author at: Center for Research in Occupational Health, Universitat Pompeu Fabra, Department of Experimental and Health Sciences PRBB, C/Doctor Aiguader 88, 08003 Barcelona, Barcelona, Spain. Tel.: +34 933160872. E-mail address: [email protected] (M. López-Ruiz). 0001-4575/$ – see front matter © 2014 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.aap.2014.01.012
injuries remains unacceptably high. In Spain, there were 580,434 non-fatal and 716 fatal occupational injuries in 2011 (Ministerio de Empleo and Seguridad Social, 2013), and 115,627 non-fatal and 2060 fatal road traffic injuries in 2011 (Dirección General de Tráfico, 2012). Many occupational injuries involve traffic collisions. In fact, the number of traffic-related occupational injuries (both commuting and during working hours) has tended to remain stable or even increased over the last decade. For example, in middle-high income countries, like France, the percentage of traffic-related occupational injuries remained at around 10% from 1997 to 2006 for all traffic-related injuries (Charbotel et al., 2010). In Spain, in 2010, 10% (65,446) of all occupational injuries and one in three fatal occupational injuries were traffic-related (De Vicente et al., 2012). Also, in Catalonia (Spain), the incidence for non-fatal, traffic-related, occupational injuries remained around 50 per 10,000 workers from 2004 to 2010 (Departament d’Empresa i Ocupació, 2013). Consequently, the burden of traffic-related occupational injuries has increased, considering the percentage of these injuries among the total number of occupational injuries. For instance, among all
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non-fatal, commuting occupational injuries that occurred between 2004 and 2010, the percentage of traffic-related injuries increased from 55% to 59%. 1.2. Road safety interventions The decreasing trend in road traffic injuries in Spain has been attributed to the effectiveness of road safety interventions promoted since 2004 (Dirección General de Tráfico, 2006; Novoa et al., 2011b; Izquierdo et al., 2011). For example, the penalty point system (PPS) was introduced in July 2006. The PPS applies points against the driving licence for traffic-related violations. Also, the reformed Spanish penal code (RPC) was introduced in December 2007; it criminalised several road offenses, including speeding, drunk driving, and driving without a licence. The PPS achieved around 11% and 9% reductions in serious road traffic injuries in men and women, respectively (Novoa et al., 2010). The RPC resulted in a 7% reduction in the number of males involved in injury collisions; thus, an estimated 13,891 road traffic injuries in men were prevented by 2009 (Novoa et al., 2011a). 1.3. Hypothesis and objective Although road safety interventions are mentioned in public policies on road safety for preventing general traffic injuries, the impact of these interventions on traffic-related occupational injuries has not been evaluated. We hypothesized that these road safety interventions should also effectively reduce traffic-related occupational injuries. Thus, the objective of this study was to evaluate the impact of two road safety interventions (the PPS and the RPC) on trafficrelated, occupational injuries in Spain between 2004 and 2010. 2. Material and methods 2.1. Study design and population The study design was an interrupted time-series with a comparison group (Biglan et al., 2000). The study population included all salaried workers in Spain between 2004 and 2010 that were covered by social security occupational injury benefits, excluding business owners, public employees, and self-employed workers. The study group comprised salaried workers that had sustained traffic-related occupational injuries. The injuries must have caused the loss of at least one workday and resulted from a collision with a motor vehicle on a public road. Injuries incurred at the worksite were excluded. The selected injuries were most susceptible to the studied road safety interventions. The comparison group comprised salaried workers that had sustained non-traffic-related occupational injuries that had occurred at the work site. These injuries must have caused the loss of at least one workday. They were not expected to be influenced by the studied road safety interventions. 2.2. Sources of information The number of occupational injuries associated with at least one lost workday was determined from records from the Labour Administration (Ministerio de Empleo and Seguridad Social, 2013), which collects all the occupational injuries that have occurred in workers in Spain. The total number of workers in the active population was estimated from the Spanish labour survey (Instituto Nacional de Estadística, 2012). This survey includes around 180,000 people and then is weighted to obtain a representative sample of all workers.
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2.3. Study period Throughout the study period, from 2004 to 2010, we considered three different time periods, based on the road safety interventions. First, the non-intervention period (NI) included the first trimester of 2004 to the second trimester of 2006. Then, we considered two post-intervention periods. One began with the introduction of the PPS, and included the third trimester of 2006 to the fourth trimester of 2010 (LEY, 2005). The other began with the introduction of the RPC, and included the first trimester of 2008 to the last trimester of 2010 (LEY ORGÁNICA, 2007). 2.4. Variables The dependent variable was the trimester incidence rate of occupational injuries. The injuries were traffic-related for the study group and non-traffic-related for the comparison group. To determine the effect of the two interventions, the explanatory variables (PPS and RPC) were set as follows. The PPS variable was set to 0 during the NI period, and it was set to 1 from the third trimester of 2006 to the fourth trimester of 2010. The RPC variable was set to 0 from the start of the NI period to the first trimester of 2008, and then it was set to 1 until the last trimester of 2010. The stratification variables included the severity of the injury (fatal or non-fatal) and the time when the injury occurred (during working hours or commuting hours). Therefore, the analysis was made separately for these variables. 2.5. Statistical analysis Trimestrial incidence rates were calculated as the ratio of the number of occupational injuries to the number of salaried workers. The ratio is expressed per 10,000 or per 1,000,000 workers for nonfatal or fatal occupational injuries, respectively. The relative risk (RR) of sustaining an occupational injury in the post-intervention periods, compared to the NI period, was calculated with the 95% confidence interval. RR was estimated for each outcome assuming a negative binomial distribution (Long, 1997) on yt , the number of occupational injuries in the tth trimester (t = 1,. . ., 28), according to the following log-linear formula: log (E[yt ]) = ˇ0 + ˇ1 PPS + ˇ2 RPC + log (Nt ) where PPS is the PPS variable, RPC the RPC variable, and Nt is the number of workers in the tth trimester. Therefore, the RR for the PPS period was estimated as exp(ˇ1 ), and the RR for the RPC period was estimated as exp(ˇ2 ). All analyses were conducted with the R statistic program (Development Core Team, 2014), with the ‘glm.nb’ R function. 3. Results 3.1. General description of the data The number of non-fatal occupational injuries included in the analysis was 5,591,648. Of these, 468,582 were traffic-related injuries (112,888 during working hours and 355,694 during commuting hours), and 5,123,066 were non-traffic-related injuries that occurred at the work site. (Table 1) The fatal injuries included 6,571 occupational injuries. Of these, 2,734 were traffic-related injuries (1,002 and 1,732 in working and commuting hours, respectively), and 3,837 were non traffic-related injuries that occurred at the work site. (Table 1) The total number of salaried workers in the active population analysed was 110,834,882, between 2004 and 2010.
n
529 875 490 747 501 775 465 674 366 672 281 532 260 471 292 180 295 50 291 64 303 37 218 35 170 29 163 21
61.9 38.1 85.5 14.5 82.0 18.0 89.1 10.9 86.2 13.8 85.4 14.6 88.6 11.4 77.4 22.6 74.0 26.0 73.7 26.3 64.6 35.4 63.1 36.9 56.8 43.2 55.0 45.0 195 57 151 53 157 56 153 84 147 86 105 80 94 77
% n % n
Total Commuting hours Working hours
3.2. Occupational injury trends Among the non-fatal occupational injuries, we examined the trimestrial incidence rates over the entire study period. Between the first trimester of 2004 and the last trimester of 2010, the incidence of non-traffic-related injuries that occurred at the work site decreased from 144.3 to 72.1 per 10,000 workers. Over the same period, the incidences of traffic-related injuries remained stable at around 2.5 and 7.5 per 10,000 workers for injuries that occurred during working and commuting hours, respectively (Fig. 1). Among the fatal injuries, the incidences decreased for all types of occupational injuries analysed. The incidence decreased from 11.8 to 5.9 per 1,000,000 workers for non-traffic-related injuries that occurred at the work site. The incidence decreased from 3.5 to 1.6 and from 4.5 to 2.4 per 1,000,000 workers for traffic-related injuries that occurred during working and commuting hours, respectively (Fig. 2).
6.2 93.8 1.4 98.6 7.5 92.5 7.4 92.6 0.2 99.8 1.4 98.6 0.8 99.2
% n
42 638 9 644 53 655 44 553 1 551 6 423 3 373 6.8 93.2 7.3 92.7 7.1 92.9 8.5 91.5 9.2 90.8 10.0 90.0 10.2 89.8
%
53.8 46.2 55.2 44.8 54.4 45.6 63.9 36.1 64.5 35.5 62.3 37.7 61.3 38.7 43,829 37,575 49,174 39,947 49,457 41,503 61,511 34,743 57,051 31,415 48,782 29,533 45,890 28,995
63,176 862,452 69,789 885,598 69,887 917,337 85,563 921,100 79,048 782,328 67,378 609,772 63,338 557,210
n % n
38.9 61.1 40.4 59.6 39.9 60.1 43.3 56.7 42.0 58.0 39.3 60.7 35.9 64.1 14,408 22,597 15,680 23,133 15,354 23,137 19,320 25,344 18,096 24,947 15,480 23,897 14,550 25,965 2010
2009
2008
2007
2006
2005
n
0.6 99.4 0.6 99.4 0.6 99.4 0.5 99.5 0.5 99.5 0.6 99.4 0.6 99.4
% n
4,939 802,280 4,935 822,518 5,076 852,697 4,732 861,013 3,901 725,966 3,116 556,342 2,898 502,250 Traffic Non traffic Traffic Non traffic Traffic Non traffic Traffic Non traffic Traffic Non traffic Traffic Non traffic Traffic Non traffic
Working hours At the work site
%
Total Commuting hours
2004
Fatal
At the work site
3.3. Occupational injury risk
Non fatal
Table 1 Number and percentage of traffic-related and non-traffic-related occupational injuries (n, %), by fatal and non-fatal injuries and time when the injury occurred. Spain, 2004–2010.
37.7 62.3 39.6 60.4 39.3 60.7 40.8 59.2 35.3 64.7 34.6 65.4 35.6 64.4
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%
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We examined the risk of sustaining a non-fatal occupational injury after the interventions. The PPS intervention did not significantly affect the risk of sustaining a non-fatal, traffic-related injury that occurred during working hours (RR: 1.07; 95%CI: 0.99−1.16). However, it was associated with a significant increase in the risk of sustaining non-fatal, traffic-related injuries that occurred during commuting hours (RR: 1.10; 95%CI: 1.02−1.20). The RPC did not significantly affect the non-fatal, traffic-related injuries. A significant decrease in non-fatal, non-traffic-related injuries that occurred at the work site was found after the RPC (RR: 0.73; 95%CI: 0.66−0.81). (Table 2) We examined the risk of sustaining a fatal occupational injury after the interventions. Both the PPS and the RPC interventions were associated with decreases in the risk of fatal injuries. The decrease in risk was not statistically significant for traffic-related, fatal injuries after the PPS intervention; but significant after the RPC intervention (RR: 0.79; 95%CI: 0.65−0.97 for working hours, and RR: 0.63; 95%CI: 0.56−0.72 for commuting hours). A significant decrease in fatal, non-traffic-related injuries was found after both interventions. (Table 2) 4. Discussion Our results showed that road safety interventions did not have a clear effect on traffic-related occupational injuries in Spain. We found that, after the PPS or RPC interventions, the risk of sustaining a traffic-related occupational injury during working or commuting hours did not decrease significantly from that observed in the NI period. After the RPC intervention, the risk of sustaining fatal, traffic-related occupational injuries decreased significantly, but the risk of sustaining fatal, non-traffic-related injuries at the work site also decreased. The reduction in non-traffic-related occupational injuries could be attributed to the introduction (since 2000) of specific, occupational preventive interventions called ‘Preferential Action Plans’ (an intervention for preventing occupational injuries, developed by Spanish regional governments). These plans are focused on companies with high incidence rates of occupational injuries (López-Ruiz et al., 2013). Furthermore, the risk of fatal, traffic-related occupational injuries, both during work and commuting hours, may have decreased after the RPC intervention due to the economic crisis, which began in 2008. The economic crisis may have had a positive effect on reducing the number of fatal traffic injuries (Stuckler et al., 2009). In Spain, risk factors related to road traffic injuries, such as law violations, alcohol and drugs, distraction, speeding and seat belt
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Non traffic 160 140 120 100 80 60 40 20 0 1T
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th
Note. 1T, 2T, 3T, and 4T indicate the 1 to 4 trimesters of the year. Fig. 1. Trimestrial incidence rates of non-fatal occupational injuries per 10,000 workers, including (top) non-traffic-related injuries (incurred at the work site) and (bottom) traffic-related injuries (incurred during working and commuting hours). Spain, 2004–2010.
use, among others, have been decreasing in recent years (Dirección General de Tráfico, 2012). These risk factors are common to all traffic injuries (including occupationally-related) and could influence the incidence of traffic-related occupational injuries. In fact, these risk factors have decreased due to the road safety interventions
analysed (Novoa et al., 2010, 2011b), and also the improvement of infrastructure, vehicle fleet and driver behavior (Dirección General de Tráfico, 2012). Although these components equally affect the entire population, our results showed that trends in traffic-related occupational injuries have not decreased.
Table 2 Occupational injuries before (non intervention) and after traffic interventions (penalty points system and reformed Spanish penal code), including fatal and non-fatal, traffic-related and non-traffic-related, occupational injuries in Spain, 2004–2010.
Non fatal
Traffic
Fatal
Non traffic Traffic Non traffic
Working hours Commuting hours At the work site Working hours Commuting hours At the work site
Non intervention (1T 2004–2T 2006)
Penalty points system (3T 2006–4T 2010)
Reformed penal code (1T 2008–4T 2010)
Mean rate
RR
Mean rate
RR (95%CI)
Mean rate
RR (95%CI)
2.5 7.8 135.2 2.8 4.8 10.4
1.00 1.00 1.00 1.00 1.00 1.00
2.7 8.6 127.5 2.3 4.6 9.0
1.07 (0.99; 1.16) 1.10 (1.02; 1.20)* 0.94 (0.84; 1.05) 0.81 (0.67; 1.00) 0.96 (0.85; 1.08) 0.87 (0.76; 0.99)*
2.5 8.0 93.6 1.8 2.9 7.1
0.94 (0.87; 1.02) 0.93 (0.86; 1.01) 0.73 (0.66; 0.81)* 0.79 (0.65; 0.97)* 0.63 (0.56; 0.72)* 0.78 (0.68; 0.89)*
Note: 1T, 2T, 3T, and 4T indicate the 1st to 4th trimesters of the year. Values represent the mean rates per 10,000 workers for non-fatal or per 1,000,000 workers for fatal occupational injuries. RR: relative risk; 95%CI: 95% confidence interval. * p-value < 0.05
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Non traff traffic ic 14 12 10 8 6 4 2 0 1T
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Note. 1T, 2T, 3T, and 4T indicate the 1st to 4th trimesters of the year. Fig. 2. Trimestrial incidence rates of fatal occupational injuries per 1,000,000 workers, including (top) non-traffic-related injuries (incurred at the work site) and (bottom) traffic-related injuries (incurred during working and commuting hours) in Spain, 2004–2010.
Alternatively, specific occupational risk factors may strongly influence the incidence of traffic-related occupational injuries. Thus, road safety interventions may not be sufficient to lower the risk for occupational injuries. A previous systematic review pointed out that many studies have focused on driver-related risk factors for traffic-related injuries, like alcohol or speeding; but occupationrelated factors for traffic-related injuries have been neglected. For instance, traffic-related occupational injuries have been associated with extended shifts, sleepiness, occupational stress, or time spent driving, among other factors (Robb et al., 2008). Significant associations have also been found between the risk of trafficrelated occupational injuries and difficult working conditions, like inflexible work schedules, lack of consecutive rest-days, difficulties in communicating with superiors, low seniority, low educational level, strenuous jobs, and physical constraints at work (Fort et al., 2010; Chiron et al., 2008; Mitchell et al., 2004). Further research is needed in order to assess this alternative hypothesis. Moreover, it is possible that our results would have changed if we had had information on some of the occupational risk factors mentioned above. Therefore, another hypothesis to be tested in future studies
would be that if we remove the effect of these risk factors associated to traffic-related occupational injuries, PPS and RPC interventions could have a positive impact on this kind of injuries. It is also possible that our results would have changed if we had information on some of these risk factors. Another hypothesis to be tested would be that if we remove the effect of occupational risk factors affecting road traffic injuries, interventions might be effective. 4.1. Limitations and strengths A primary limitation of this study was that it was based on administrative data from the labour administration. This data did not include traffic information, like the type of vehicle, type of road user, the number of people injured in the collision, etc. The only information related to traffic was whether the accident was due to a collision with a motor vehicle and whether it occurred on a public road. Also, the exhaustiveness of the data was unknown, although we assumed that the information was complete, because workers are required to declare and register the accident before they can
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receive occupational injury benefits. As we mentioned, the registry did not include public employees (approximately 1.5 million workers in 2011 (Muface, 2012)) or self-employed workers (around 2 million in 2011 (Ministerio de Empleo and Seguridad Social, 2011)); this fact might have introduced a selection bias. However, road safety interventions affect all workers equally, independent of their employment conditions; therefore, we assumed that this selection did not affect the results. Another possible limitation is the selection of the comparison group: there may be different etiological factors which affect the types of injuries of the comparison group and the intervention groups. But we have chosen for the comparison group the non-traffic-related occupational injuries that occurred at the work site, firstly, because they are not expected to be influenced by the studied road safety intervention (as they are not related to traffic). Secondly, because they were the most similar type of injuries since they are related to work, although they occurred in different places. Due to the ecological design of the study, it is important to consider the ecological fallacy (Schwartz, 1994). However, our study has assessed the impact of two policy interventions at the population level. In this sense, the interrupted time-series design is one of the most useful studies to assess the impact of a policy intervention (Gil-González et al., 2009). Finally, we could not stratify by sex or age, due to the lack of convergence in the statistical models of stratified analyses. This study had several strengths, including the large number of records and the study design with a comparison group. This was the first study, to our knowledge, that evaluated road safety interventions in relation to occupational injuries. Finally, this research was a worthy exercise that could promote cooperation between traffic and labour authorities. 5. Conclusions After a decade of successful implementation of road traffic and occupational injury prevention programs in Spain (Novoa et al., 2011b; Benavides et al., 2011), our results showed mixed effects on the risk of sustaining traffic-related occupational injuries. Therefore, future research and preventive efforts should be focused on working conditions that could potentially have stronger effects on road safety. A first step in that direction could be to improve the exchange of information between Labour and Traffic Administrations. The occupational injury record should include details like the type of vehicle, the type of road user, etc. Conversely, the road traffic injury record should include details like the type of job, the contract, working hours, etc. Moreover, private and public companies and their preventive services play a key role in managing employee working conditions. Thus, it may be necessary to motivate companies to develop plans for preventing traffic-related occupational injuries (European Agency for Safety and Health at Work, 2010) that apply to both commuting and working hours. Finally, these preventative plans should focus on workers whose real workplace is a vehicle. The effectiveness of these interventions should be evaluated in future research. Acknowledgements We acknowledge David Martos Moral and Juan Miguel Mouat Silva for their useful contributions to our study. References Benavides, F.G., Benach, J., Martínez, J.M., Gonzalez, S., 2005. Description of fatal occupational injury rates in five selected European Union countries: Austria, Finland, France, Spain and Sweden. Saf. Sci. 43 (8), 497–502, http://dx.doi.org/10.1016/j.ssci.2005.04.005.
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