Consistent association between hypnotics/sedatives and non-traffic injuries. Results from a national household survey

Highlights

• Few epidemiologic studies have assessed the association between hypnotics and unintentional non-traffic injuries (UNTIs).

• Date from a randomized household pooled sample was used.

• We found a consistent relationship between hypnotics and UNTIs, especially among regular users.

• The strongest association was found for falls among subjects who used hypnotics >=30 days in past year.

• Future longitudinal studies should examine the causal relation between hypnotics use and UNTIs.

Abstract

Aim

To quantify the relationship between patterns of psychostimulants, hypnotics/sedatives and alcohol consumption and the frequency of unintentional non-traffic injuries (UNTIs) requiring medical assistant in Spain.

Methods

We carried out a cross sectional study using a randomized pooled sample from two household surveys on psychoactive drugs use (n = 51,649 subjects aged 15–64 years). We estimated the magnitude of the association between the use of psychostimulants and hypnotics/sedatives in the last 12 months as well as alcohol consumption in the last 30 days with the occurrence of UNTIs in the last 12 months (falls, knocks/bumps and cuts) by building several logistic regression models, which took into account the effect of sociodemographic characteristics and the use of other psychoactive drugs (including cannabis). The presence of interactions between age or gender with drug use was also assessed.

Results

Psychostimulants use was associated with a higher frequency of UNTIs (aOR = 1.24; 95%CI:1.03–1.49). The strongest association was found with cuts (aOR = 1.64; 95%CI:1.10–2.43). An association between hypnotics/sedatives and UNTIs was also found in each type of injury and was higher with regular use (>=30 days) than with non-regular use (<30 days). The age modified the association between hypnotic/sedatives and knocks/bumps, being higher in the 35–64 years group (aOR = 2.34; 95%CI:1.78–3.06) than in the 15–34 years group (aOR = 1.59; 95%CI:1.14–2.21). Regarding alcohol, an increased risk of UNTIs was also observed in all types of UNTIs, even with moderate use, being the association higher for cuts in heavy drinkers (aOR = 2.41; 95%CI:1.63–3.57).

Conclusions

Our results reveal a consistent relationship between hypnotics/sedatives and UNTIs, especially in regular users. Additional research should apply longitudinal designs to establish causal relationships and to gain an in-depth knowledge in this area in order to specific public health interventions.

Introduction

Injuries are one of the main causes of death and disability among people aged under 60 years worldwide (World Health Organization, 2011) and the leading cause of death among children, adolescents and young adults in Europe (EuroSafe, 2013). In 2030, it is expected that mortality due to injuries will reach 10% (World Health Organization, 2015). In Spain, injuries are the leading cause of mortality among people aged from 1 to 39 years (INE, 2016). Furthermore, in developed countries, for each injury-related death, about 30 injured people are hospitalized and over 300 are attended by skilled health staff (Espitia-Hardeman and Paulozzi, 2005).

Health burden related to psychoactive substance abuse or dependence is constantly increasing (by 52% between 1990 and 2010, measured in disability-adjusted life years for illicit drugs, according to Degenhardt et al., 2013). Regarding injuries, an increased risk of road crashes related to driveŕs use of psychoactive drugs has been consistently observed in many previous studies (Dassanayake et al., 2011, European Monitoring Center for Drugs and Drug Addiction, 2014a, Penning et al., 2010). However, there are few studies that assess this association for unintentional non-traffic injuries (UNTIs), a much more frequent subgroup of injuries. Road crash injuries only account for 10% of all hospital treated injuries in the European Union (EuroSafe, 2013). Therefore, UNTIs have a greater impact on social and economic spending due to the higher health costs that they generate.

Previous studies have assessed the association between alcohol and cannabis – the most widely consumed illegal drug in Western countries- and the risk of UNTIs (Barrio et al., 2012, Bogstrand et al., 2011, Gerberich et al., 2003, Vitale and van de Mheen, 2006). However, the association between psychostimulants such as cocaine, amphetamines and ecstasy, and the frequency of UNTIs has not yet been addressed. It is also surprising not to find enough evidence from epidemiologic studies to determine the effects of hypnotics/sedatives consumption on UNTIs, given that in some countries they are more used than cannabis (European Monitoring Center for Drugs and Drug Addiction, 2014b). Toxicological studies reveal a high prevalence of cocaine and benzodiazepines among subgroups of UNTIs populations (Carrigan et al., 2000, McDonald et al., 1999, Perez et al., 2009, Reis et al., 2006) suggesting that this association may exist. For instance, in a recent review, the use of hypnotic and sedatives appears to be related with an increased risk of falls in older people (Park et al., 2015). Although biological plausibility supports this hypothesis, especially for hypnotic/sedative drugs group, it is not easy to isolate the specific effect of chronic psychoactive drug use on the risk of UNTIs from those resulting from confounding factors. Furthermore, the low frequency of use of some subtypes of drugs, limits the power of previous studies to detect these associations. Thus, more epidemiological studies are needed to corroborate the results of experimental studies in a real-life context and to better quantify the excess risk of UNTIs of hypnotic and psychostimulant users in relation to non-users. From a public health perspective, they can also guide policymakers in the promotion of measures to prevent or reduce the risk of UNTIs occurring at work, at home or when performing recreational activities.

Although they do not allow the identification of causal associations, if the sample size is sufficient to account for confounding factors and to detect weak associations precisely enough, cross sectional designs are a useful approach to assess the magnitude of the association between chronic exposures to psychoactive drugs and the frequency of UNTIs. In a previous work by our group using this design, we observed a clear association between cannabis and UNTIs (Barrio et al., 2012).

In the present study, we aim to quantify the relationship between patterns of use of psychostimulants, hypnotics/sedatives as well as alcohol consumption and the frequency of UNTIs in Spain, after adjusting for the confounding effect of sociodemographic characteristics and the use of other drugs and assessing interactions with gender and age.