Injuries caused by road traffic crashes (RTCs) have a major impact on morbidity, mortality and premature disability. According to the World Health Organisation (WHO), every year there are over 1.2 million deaths due to this cause around the world, 20 to 50 million persons sustain injuries, and more than 5 million remain disabled for life.1 RTCs cause disability in the short and long term, are the 9th leading cause in the world of disability-adjusted life years (DALYs) and generate 41.2 million years of healthy life lost, thus accounting for 2.7% of the total worldwide.2–5It is estimated that there are 3.8 million disabled persons in Spain. Accidents are the 3rd leading cause of disability and account for 9% of all disability; within this category, RTCs rank second after occupational accidents.6

Despite the appreciable reduction in traffic accident figures observed in this country from 2000 onwards,7 the resulting injuries continue generating a substantial disease burden, with a great impact on the country's social and economic spheres. RTCs generate premature mortality,8 continue to be the leading specific cause of death in the 15-34 year age group, and are the leading (in men) and 2nd leading cause (in women) of years of potential life lost.9

On investigating the effects on RTC-injury victims, analysis of disability can provide a complementary view of this event and furnish the necessary information for the prevention and control of RTCs, and so minimise the risk of premature death, disability and sequelae. Road traffic disability (RTD) is an important indicator of the severity of such accidents, and allows for assessment of related temporary or permanent disability, loss of autonomy, individual development disorders, family involvement and the ensuing social burden.10

The aim of this study was thus to provide a first-ever estimate of the magnitude and distribution of disability caused by RTCs in Spain, and to describe the RTC-disabled population by reference to basic socio-demographic variables, as well as the types of RTC-related disability and their main socio-economic and health profiles.

In 2008, the prevalence of RTD in Spain was 2.1 per 1000 inhabitants; injuries were the fourth cause of disability and within these, traffic accidents ranked second.

Table 1 shows the distribution of RTD by socio-demographic variables. In comparison with persons aged 16 to 30 years, the odds ratio (OR) of having RTD was higher in the 31-64 year age group and particularly among those aged 31 to 45 years, with an OR of 2.8 (95% CI: 1.7-4.6). There were no statistically significant differences by sex or nationality. Subjects with a secondary education had a higher OR than did those with a primary education or lower (OR=1.3; 95% CI: 1.1-1.7); and married (OR=0.6; 95% CI: 0.5-0.8) and widowed persons (OR=0.5; 95% CI: 0.3-0.8) had a significantly lower OR than did singletons. Nevertheless, there was an interaction between sex and marital status statistically significant: the comparison of married men versus single showed an OR of 0.4 (CI: 0.2-0.5) while women had an OR of 1.7 (1.4-2.8). A breakdown by occupation showed that persons with RTD were more likely to be “unfit for work, without any type of allowance” (OR= 19.5; 95% CI: 11.3-33.7) or “receiving different types of pensions” (OR= 12.7; 95% CI: 8.6-18.7); only 24% were gainfully employed. Persons with household incomes of €1,500 to < €3,000 per month had an OR=0.5 (95% CI: 0.3-0.8) as compared to those with monthly family incomes below €500. Apart from sex and marital status we did not find other statistically significant interactions between sex and sociodemographic variables.

Figure 1 depicts age at disability onset. Seven out of ten persons affected by RTD reported onset of disability before the age of 45 years. The disability onset curve showed an inflection point at age 16 years in both sexes, with onset of disability occurring before the age of 28 years in half of all men and before the age of 40 years in women. This difference of approximately 10 years in RTD onset between men and women remained in evidence up to age 65 years.

Figure 1.

Age at onset of disability caused by road traffic crashes among individuals aged 16 and over. Spain, 2008.. Cumulative percentage by sex.

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Table 2 describes the type of disability. Mobility, domestic life and self-care were the most frequent types of disability in all disabled persons, and were significantly higher in the case of RTD regarding to other causes of disability (mobility OR=3.1; p<0.001; domestic life OR=1.8; p<0.001; self-care OR=1.3; p=0.046). Hearing (p<0.001), communication (p<0.040), learning (p<0.005) and interaction/interpersonal relationship (p<0.008) disability, were meaningfully lower in the RTD-persons.

Table 3 shows health and social conditions with respect to disability. Although 68.8% of RTD-sufferers perceived their health status as fair or poor, this percentage was not significant in comparison with the OCD category. Subjects with RTD had a greater need of health/social services (OR=1.5; p=0.003), required more technical aids (OR=1.4; p=0.014), and experienced more problems with private transportation (OR=1.6; p<0.001) and moving around outside the home (OR=1.6; p<0.001).

In terms of economic conditions (Table 4), close on 50% of all disabled persons were the primary household earners, with no difference between the RTD and OCD categories. RTD caused major changes in economic activity due to the onset or worsening of disability among persons who were gainfully employed (OR=2.4; p<0.001). Health reasons were the most frequent cause for leaving work; disability-related early retirement was higher among persons in the RTD than among those in the OCD category, but this difference was not significant. No differences were observed in terms of disability-related expenditure and the main items to which such expenditure was allocated.

In Spain, RTCs generate two disabled persons per 1,000 population over the age of 15 years. This prevalence rate is lower when compared to data published by other developed countries 10,14–16 but higher in relation to recent Chinese studies,17,18 despite the fact that such information displays important differences in methods, data-sources and type of population analysed. This lower prevalence could be related to the decrease in RTCs with victims, and the ensuing decrease in serious injuries (-43%) in the period 1998-2007.7,9

Although statistics and previously published studies agree on the fact that the greatest number of road accident-related deaths, injuries and disabilities affect young/middle-aged men,1,3,5,9,17–19the profile of the RTD-sufferer in Spain coincides only in terms of age because our study failed to found any significant differences by sex.

As compared to the general population, RTD-sufferers in Spain have a low socio-economic status (worse educational level; lower proportion engaged in gainful employment; high percentage receiving permanent disability retirement or other pensions, unfit for work, and living in the lowest-income households).6 This situation makes them a vulnerable population, with important disadvantages in social aspects: indeed, the socio-economic inequalities in traffic injuries and fatalities have been reported by previous studies,4,17,18,20–23 where the risk of road traffic injuries and fatalities has been shown to be higher among disadvantaged groups with less education,24,25 unskilled occupations,26 lower income27,28 or lower socio-economic status in general.23,28 RTD might thus be aggravating socio-economic disadvantages already present in the population affected, owing -among other things- to important changes in economic activity due to the onset or worsening of disability, health reasons and disability-related early retirement.

Traffic crashes cause 14% more mobility-related disability than do other causes. This could be explained by the type of injury suffered, in that this mainly gives rise to osteoarticular impairments affecting the lower limbs and spinal cord, in line with previous results which show that the musculoskeletal support system, essentially the legs and pelvis, is the region most affected by RTCs.29–31 Assuming that RTCs can generate major injuries and limitations almost immediately, age at disability onset was presumed to be close to the date of the accident, so that our results would suggest that over half of all disabled persons had their accident before the age of 35 years; this figure reinforces and matches previous data, which define the most vulnerable population group as being young adults.1,3,5,9,19,32. However, this information should be interpreted in the context of the age distribution of the sample, where around one in two people have less than fifty years old.

Persons with disability have a considerably more negative self-reported health status than that of the general population6, and this situation holds true for disability caused by RTCs. This condition, taken together with their low socio-economic status, reinforces the idea that socio-economic circumstances, more than other known risk factors, create major differences in health status.33

As Pereda et al. point out, “disabled persons have more need of medical consultation and health/social services than does the general population because they are a group with greater health problems.“6 RTD generates a major need for these types of services/consultation in a group with few technical aids and personal care, which could indicate their degree of involvement and dependence. The RTD-sufferer receives more financial benefits or compensation which could be due to the role of compulsory third-party insurance and indemnity payable to traffic accident victims under the Spanish Motor Vehicle Civil Liability Insurance Act.34 The accessibility and commuting problems of the disabled in Spain have been previously described, with these being shown to be more frequent in the older population (age >65 years).6 RTD-sufferers have a greater risk of experiencing these, a situation that may exacerbate their high degree of mobility-related disability, thereby increasing their level of dependence and limiting their activities in and outside the home.

Although there were no important differences in the expenditure generated by disability, the items of expenditure relating to adaptations, transport, commuting, schooling and housing were the most important in RTD. It would thus seem vital to analyse the social cost of disability caused by RTCs.

Previous studies have ascertained that there is an increased risk of disability following an RTC,16,35 and our results could be suggesting that this risk is especially important in a younger segment of the population. This study was undertaken using a different data source, in order to provide a new view of the problem, complement the information currently available and support the relevance of RTD as a public health problem. Notwithstanding this, there continues to be little scientific information on the subject, and the research that has been conducted indicates a lack of homogeneity in the data sources and the methods applied, which hinders comparisons at an international level.

This study has several limitations and strengths. Among its limitations, the EDAD2008 is a specific survey of disability, which unfortunately does not explore the causes of disability in detail and so does not allow for the characteristics of road traffic crashes to be known. Using the currently available format, information cannot be linked with other RTC databases in order to supplement our existing data. Although the analyses were performed using a complex sample design, it is nevertheless possible that some of the multiple comparisons may have proved significant by chance. Among the study's strengths is the large size and representativeness of the adult population of the country as a whole.

To conclude, prevalence of RTD in Spain is lower than in other developed countries, with middle-aged and socio-economically underprivileged population being at greatest risk. The disadvantages observed in basic socio-economic characteristics, health/social conditions and economic activity make such persons a particularly vulnerable group, with high needs in terms of social and health-care support.

Miguel Angel Negrín

R Palmera-Suárez, T López-Cuadrado, R Fernández-Cuenca and I Galán have contributed to the concept and design of the project. J Almazán-Isla and E Alcalde-Cabero have contributed to the collection, review, standardization and appropriateness of databases. R Palmera-Suárez, T López-Cuadrado and I Galán collaborated on the analyses, interpreting the results and writing the article. R Palmera-Suárez, T López-Cuadrado and I Galán had access to all data and are responsible for the overall content. All authors reviewed and approved the final version.

This study was supported by a grant from the Mutua Madrileña Foundation.

None declared