Current trends and update on injury prevention.

Injuries are a major and growing public health problem, a leading cause of death and disabilities among people aged 1-44 years around the world. Each year, 5.8 million people die from injuries, accounting for 10% of the world's deaths. Road traffic injuries (RTIs), self-inflicted injuries and violence are the top three leading causes of all injury deaths, while RTIs, falls and drowning are the top three leading causes of unintentional injury death. In many high-income countries, trends of injury death have been decreasing as a result of prevention measures. In contrast, trends in low- and middle-income countries have been rising. In this article, we review the prevention strategies for RTIs, violence, falls and drowning developed over decades to disseminate the knowledge and inform health care providers, especially acute care physicians, about the importance of injury prevention.

INTRODUCTION

Injuries are the leading cause of death and disability among children and young adults around the world.[1] Injury is a physical damage to the body, resulting from various kinds of energy (mechanical, thermal, electrical, chemical or radiant) in amounts that exceed the threshold of physiological tolerance, or from the absence of essentials (such as heat or oxygen). Injury can be categorized into unintentional [i.e. road traffic injuries (RTIs) and drowning] and intentional (i.e. suicide, homicide).[2] In this article, we review the current prevention strategies to encourage and inform health care providers about the importance of this area. Approximately 5.8 million people die from injuries each year, accounting for 10% of the world's deaths. Globally, the three leading causes of death from injuries are RTIs (23%), self-inflicted injuries (15%) and violence (11%) [Figure 1]. For unintentional injuries, RTIs are the leading cause of death, followed by falls and drowning[13] [Table 1].

Figure 1

Causes of injury deaths (source: Global Burden of Disease, 2004)

Table 1

Leading causes of death by age group, both sexes

The consequence of injuries is not only death. Millions of people die from injuries and substantial numbers of people are left with either temporary or permanent disabilities. An estimated 16% of all disabilities globally are caused by injuries.[13] The effects of injuries are both emotional and financial, impacting individual, family and friends along with the entire nation. The costs derive from the cost of treatment, non-medical expenditure and loss of productivity of the individual and family members who need to take time off from work to care for patients. For example, RTIs have been estimated to cost US$ 518 billion globally, of which US$ 65 billion is accounted for by low-income countries (LICs). Approximately 1% of gross national product (GNP) in LICs, 1.5% in middle-income countries (MICs) and 2% in high-income countries (HICs) are attributed to costs of RTIs.[34]

Injuries have been traditionally thought of as accidents or random events. This has resulted in a global neglect of this area of public health. However, injuries are preventable by changing the environment, individual behavior, product, social norms, legislation and governmental and institutional policies to reduce or eliminate risks and increase protective factors.[5]

ROAD TRAFFIC INJURIES

An RTI is any injury secondary to crashes originating, terminating or involving a vehicle partially or fully on a public highway.[2] RTIs are a huge and growing public health problem. In 2004, reported RTIs killed 1.3 million people worldwide, accounted for 2.2% of global deaths and ranked as the ninth leading cause of death. It is predicted to rise in rank to become the fifth leading cause of death by 2030 [Table 2]. More than 50% of road traffic deaths occur among young adults aged between 15 and 44 years and the mortality rate for males is almost three times greater than that for females.[1346] Ninety percent of RTIs occur in low- and middle-income countries (LMICs) which have only half of the world's registered vehicles. Almost half of the global RTI deaths are vulnerable road users (cyclists, pedestrians and motorcycle riders) and 48% are car occupants.[1346] In 2005, the United Nations adopted third Sunday of November as the “World Day of Remembrance of Road Traffic Victims” in order to acknowledge the road traffic victims and their families.

Table 2

Leading causes of death: Comparison of causes in 2004 and predicted causes in 2030

Motorcyclists

Motorcycles are an important, but also a dangerous means of transportation in LMICs. Motorcyclists have the highest risk for injury and death in a motor vehicle crash among all vehicle users. Motorcyclists are found to be 37 times more likely to die in a motor vehicle crash than passenger car occupants and 9 times more likely to be injured.[7] In most countries in Southeast Asia, motorized two- and three-wheelers account for more than 60% of registered vehicles. In Vietnam, motorcycle injuries account for 59% of road traffic injuries.[8] The most common site of all motorcycle related injuries is lower extremity (30–70%), while head injuries are the leading cause of death in motorcycle crashes.[9] Alcohol is a major risk factor for fatal motorcycle crashes. The effects of alcohol on motorcycle riding skills can be observed at blood alcohol concentration (BAC) as low as 0.05 g/dl. Not only does alcohol impair the riding performance but also intoxicated motorcyclists are less likely to wear a helmet.[710]

Prevention: Motorcycle helmets were found to reduce the risk of death by 42% and the risk of head injury by 69%.[11] However, motorcycle helmets are underused. In China, 72.6% of drivers and 34.1% of passengers are reported using helmets.[12] In Vietnam, the prevalence of helmet use ranges from 23.3 to 30%.[13] One study from Pakistan reports that approximately 56% of motorcyclists wear helmets.[14] It has been suggested that legislation might increase helmet use among people. One study from Vietnam showed that helmet use increased from 27 to 99% and the risk of road traffic head injuries and death decreased by 16 and 18%, respectively, as a result of motorcycle helmet legislation.[15] Motorcyclists of age 25 years or more, having a higher education and higher income are more likely to wear a helmet.[12-14] Asia Injury Prevention (AIP) foundation is a non-profit organization that works to reduce the rate of RTIs and fatalities in LMICs by creating public-private partnerships, as well as developing and implementing traffic safety education programs. In 2009, the AIP foundation together with the World Bank Global Road Safety Facility introduced an international campaign, the Global Helmet Vaccine Initiative, to promote motorcycle helmet wearing in LMICs in Africa, Asia and Latin America (AIP).[16]

Bicyclists

The bicycle is a recreational vehicle in HICs, especially for children and young adults; but in LMICs, bicycles are used for necessary modes of transportation. In HICs, the United States for instance, there were 716 deaths and almost 500,000 injuries treated due to bicycle crashes in 2008. Children aged 5–14 years have the highest bicycle-related injury rate.[17] In LMICs such as China, bicycle-related deaths account for 30% of all road traffic deaths. In India, 12–21% of road traffic deaths occur among bicyclists.[4] Extremities and head/neck region are the primary parts affected by bicycle-related injuries.[1819] Brain injuries are the most common cause of bicycle-related death.[2021] Risk factors of serious injuries are collision with motor vehicle, self-reported speed of >15 mph, age of <6 and >39 years.[22]

Prevention: Studies from HICs suggest that bicycle helmets can reduce the risk of head, and brain injury by 63–88% in all ages. Injury to the upper and mid face areas can also be reduced by 65%.[23] Even in the United States, only half of the children (48%) always wear helmets, whereas 29% are reported to never wear their helmet.[24] Factors associated with helmet use are race, ethnicity, child age, household income, household education, and helmet law status.[25] A Canadian study demonstrated that the bicycle-related mortality rate in children, 1–15 years of age, significantly decreased by 52% after helmet legislation.[26] There are no data from LMICs.

Pedestrians

In the United States, 2008 data show that 4378 pedestrians were killed and 69,000 pedestrians were injured in road traffic crashes.[27] Globally, children aged 5-14 years are at a maximum risk of pedestrian related injuries. In LMICs, child pedestrians comprise 30–40% of all road traffic deaths as the road is a shared space for driving, walking, cycling and playing for children.[28] Risk factors for child pedestrian injury are male, younger age, belonging to low income family, high volume of traffic, high vehicle speed, high street vendor density and absent lane demarcations.[2930]

Prevention: One systematic review of 15 randomized controlled trials (RCTs) of pedestrian safety education showed that safety education can improve the children's knowledge and change the road crossing behavior, but there is no evidence on pedestrian injury.[31] Speed is a major risk factor for road crashes and severity of injuries from crashes. The probability of pedestrian death from road crashes increases significantly when the speed is over 30 km/h.[28] In The United Kingdom, 20 mph speed zones, as part of traffic calming, have been established since 1986. It has been shown that road casualties reduce by 40% and have the greatest effect in children aged 0-15 years.[32] Alcohol does not affect only drivers but also impacts pedestrians. According to National Highway Safety Traffic Administration (NHSTA) data, in 2008, 48% of pedestrian deaths in traffic crashes in the United States were alcohol related.[27] Mobile phone use is another risk factor. Studies have shown that both drivers and pedestrians who talk on mobile phone while driving or crossing the road are at increased risk due to cognitive distraction.[33-36]

Most pedestrian fatalities occur in low-light conditions.[27] Hence, interventions that improve pedestrian visibility to drivers may reduce road traffic accidents. A recent Cochrane Database of Systematic review which investigated the effect of light on road traffic crashes involved 17 controlled before–after studies (not RCTs) from HICs, demonstrating that street lighting can prevent road traffic crashes, injuries and fatalities. The risk of crash, injury-crash and fatal-crash reduced by 55, 22 and 66%, respectively.[37] One review of 42 studies comparing driver detection of pedestrians or cyclists with or without visibility aids revealed that fluorescent materials in yellow, red and orange improved drivers detection of pedestrians and cyclists during the daytime. For nighttime visibility, flashing lights and retro-reflective materials in red or yellow, particularly those with a “biomotion” configuration increased pedestrian detection.[38]

Occupants

Alcohol consumption impairs cognitive ability and decision-making skills of the driver. In 2008, 11,773 people died in alcohol-impaired driving crashes, accounting for 32% of the total motor vehicle traffic fatalities in the United States.[39] In LMICs, 33–69% of drivers who were fatally injured were positive for blood alcohol and alcohol was found in 8-29% of the injured drivers.[28] Some driving skills are impaired in most of the drivers at BAC as low as 0.02 g/dl. The risk of involvement in any crash increases significantly with BAC at 0.04 g/dl or higher.[40] Therefore, the WHO recommendation for a blood alcohol concentration limit for driving is 0.05 g/dl or less for the general population and 0.02 g/dl for young drivers (20 years and younger).[7]

Prevention: Protective devices include seat belts and airbags. Seat belts prevent ejection and reduce the frequency and severity of occupant's contact with the vehicle's interior during crashes, while airbags only reduce the frequency and severity of occupant's contact. Lap-shoulder belts, when used correctly, can reduce fatalities by 72% in frontal collision.[41] Airbags alone can reduce mortality by 63%.[41] Airbags are most effective when used together with seat belts, which can reduce the mortality by more than 80% in frontal collision.[41] The use of child restraints can reduce the risk of deaths during traffic collision by 71% in infants and 54% in children aged 1–4 years.[42]

In the United States, the observed seat belt use rate in 2008 was 83%, and among fatally injured passenger vehicle occupants, 55% of those killed were not restrained.[42] In China, the prevalence of seat belt use for drivers varies from 30 to 66%, while less than 10% of front seat passengers wore seat belts.[43] The prevalence of seat belt use in China increased by 12% due to the interventions adopted from HICs which included enhanced police training and enforcement, social marketing, and health education.[44] There are no other data from LMICs.

Guidelines developed by the American Academy of Pediatrics[45] and the National Highway Traffic Safety Administration[46] for child passenger safety suggest that infants should ride rear-facing in an infant seat or convertible seat in the backseat as long as possible until they have reached the height or weight limit for the particular seat or at least 1 year of age and weigh 20 pounds. The safest position for children seats is in the center rear. The risk of injury is 43% lower compared to the right outbound position, whereas the front seat is the least safe.[47]

When children have outgrown the rear-facing seats, they should sit facing forward in children seats in the backseat until they reach the upper weight or height limit. Then, children should change to a booster seat secured to the backseat when around 4 years of age or weigh around 40 pounds, until he or she is 4‘9“ in height, i.e. when they are around 8–12 years old. Children in belt positioning booster (BPB) seats are 45% less likely to sustain injuries compared to those in seat belts.[48] In China, the BPB use increased from 15.5 to 85.5% as a result of knowledge-plus-motivation video, designed for US audience, translated into Mandarin.[49]

Violence

WHO defines violence as “The intentional use of physical force or power, threatened or actual, against oneself, another person, or against a group or community, that either results in or has a high likelihood of resulting in injury, death, psychological harm, maldevelopment or deprivation”.[50] In 2004, around 1.6 million people died due to violence worldwide, with a significant proportion (1.5 million) reported from LMICs.[1]

Intimate partner violence

Intimate partner violence (IPV) refers to behavior within an intimate relationship that causes physical, sexual or psychological harm, including acts of physical aggression, sexual coercion, psychological abuse and controlling behaviors.[50] The prevalence of IPV ranges between 15 and 71%, and LICs tend to have higher rates.[51] Risk factors of IPV can be categorized into four levels: individual, relationship, community and societal factors.[5052] Risk factors for perpetrators are young age, alcohol use, depression, personality disorders, hostility, low income, low education and having experienced violence as a child. Relationship factors are marital conflict or instability, poor family functioning, and male dominance. Community factors are poverty, weak community sanction against IPV. Societal factors include traditional gender norms and social norms supportive of violence. Risk factors for victims are the same as and/or associated with those for perpetrators: young age, low income, low education, depression and alcohol use.

Studies from both HICs and LMICs show that 40–70% of female murder victims are killed by their boyfriends or husbands.[5053] In 2007, 64% of female homicides in the United States were committed by intimate partner or a family member.[54]

The most common injuries are minor, such as scratches and bruises, while more serious types of injuries such as deep lacerations, broken bones or bullet wounds are less common.[55] In the long term, IPV can result in chronic health problems such as neurological deficit, seizures, chronic pain, gastrointestinal symptoms, sexually transmitted diseases, pregnancy, sexual dysfunction and psychiatric problems including depression, posttraumatic stress disorder, suicidal thoughts, and alcohol abuse.[56-58]

Prevention: Primary prevention aims to prevent IPV before it occurs. Strategies include educational interventions targeting young people to change individual attitudes, risk-taking behaviors. The Safe Dates Program, an RCT investigating the effects of school- and community-based programs on the prevention of dating violence among adolescents, has shown that physical and sexual violence rates were reduced and mediating variables were positively changed.[59] Secondary prevention aims to detect or identify IPV in early stages. Reports from the US Preventive Services Task Force and the Canadian Task Force for preventive Health Prevention and Treatment of Violence against women concluded that there was insufficient evidence to recommend for or against routine screening of adult women for IPV.[6061]

Tertiary prevention focuses on long-term care such as rehabilitation. A recent review of 10 RCTs found that intensive advocacy interventions (12 hours or more duration) were effective in reducing physical abuse, but the effects on emotional abuse, depression, quality of life and psychological distress were equivocal.[62] A meta-analysis of 22 controlled batterer intervention program studies found that overall effects of batterer intervention program were in a small range.[63] There are explanations why perpetrator's programs have modest effects, for instance, unidentified or untreated psychological conditions, and substance use. Studies have shown that alcoholism treatment, either individual or couples-based, reduced intimate partner violence in both male-to-female and female-to-male violence.[64]

Youth violence

Youth violence is violence involving people between the ages of 10 and 29 years. In 2000, it was estimated that 199,000 youths died as a result of violence around the world. Africa and Latin America are the two regions of the world that have the highest rates of youth homicide, while western Europe and parts of Asia and the Pacific have the lowest rates.[50] Risk factors for youth violence are categorized into four types: individual, family, peer/school and environmental/community.[506566] Individual risk factors are male gender, history of early aggression, low IQ, substance use and exposure to media violence. Family risk factors are low socioeconomic status, poor parent-child relations, poor family functioning. Peer/school risk factors are academic failure, and gang membership. Environment or community risk factors are crime, neighborhood drugs, community disorganization and access to firearm. Protective factors are safeguards which help prevent or reduce the chance of young people from becoming violent. For this instance, individual/family protective factors are high IQ, higher grades, connectedness with parents and other adults.[6768]

Prevention: Primary prevention aims to prevent the onset of violence by reducing or changing risk of youth violence. Secondary and tertiary prevention aims to reduce violence in young people at risk or who already have demonstrated violence. Prevention strategies should target all levels: individual, relationship, community and societal level. Strategies at individual level aim to increase protective factors associated with individual skills, attitudes and beliefs. Strategies targeted at relationship level attempt to affect relationships of young people with others. Strategies targeting community level are those that attempt to modify community risk factors. Interventions that change the social and cultural environment to reduce violence are societal approaches.[50] Blueprints for violence and prevention are a US violence prevention initiative to identify the violence prevention programs that are effective. The Blueprints has evaluated over 800 programs and reported 11 model programs and 19 promising programs.[69] The examples of model programs are Life Skills Training (LST), the Midwestern Prevention Project, the Olweus Bullying Prevention Program and the Multi-System Therapy (MST).[69]

Strategies such as individual counseling, peer counseling/peer mediation and gang prevention programs have not been shown to be effective in reducing youth violence or risk factors for youth violence.[50]

FALLS

A fall is an event which results in a person coming to rest inadvertently on the ground or floor or other lower level. Unintentional falls and fall-related injury are major public health problems among older people. Each year, approximately 424,000 people die from falls worldwide. Over 80% of fall-related deaths occur in LMICs.[70] The incidence of falls varies among countries. The prevalence of falls in community-living Chinese Hong Kong is 26.4%.[71] Approximately 30% of people aged 65 years or more fall each year and it increases up to 40% for people aged over 75 years.[7072] Approximately 40–60% of falls lead to injuries, 10% result in serious injuries and 5% being fracture.[70] Most common fractures are hip fractures and fractures of upper extremities.[73] Falls also have psychological impacts. People who have fallen may develop a fear of falling which leads to a restriction in physical and mental performance and increase the risk of falling.[74] Risk factors for falls can be classified as intrinsic and extrinsic. Intrinsic factors are increasing age, history of falls, female sex, use of medications such as sedatives/hypnotics, benzodiazepines, psychotropic, or diuretics, arthritis, impaired mobility and altered gait, cognitive impairment, or visual impairment. Extrinsic or environmental factors are environmental hazard, footwear and inappropriate walking aids.[73-78]

Prevention: Many studies and reviews reported that exercise, vitamin D supplement, expedited first eye cataract surgery, multifactorial interventions and gradual withdrawal of psychotropic medication are effective in falls reduction. Exercise reduces the rate of falling by 17%. Different types of exercise that target two or more of the components such as strength, balance, flexibility or endurance are effective in reducing both the rate of falling and the risk of fall. Effective exercise includes exercise in supervised group, individually prescribed exercise at home or Tai Chi.[7980] Vitamin D at a dose of 700–1000 IU/day also has been found to reduce the risk of falling by 19%.[81] Expedited first eye cataract surgery has been reported to reduce the rate of falling by 34% compared to routine cataract surgery.[82] Multifactorial interventions are found to be effective in reducing the rate of falls but not the risk of falling.[79] A prescribing modification program for primary care physicians reduced the risk of falling, and gradual withdrawal of psychotropic medication reduces the rate of falls.[79] However, studies have failed to demonstrate the effectiveness of some interventions such as cardiac pacing[83] and home safety interventions.[79]

DROWNING

Drowning is defined as the process of experiencing respiratory impairment from submersion/immersion in liquid. Drowning outcomes are classified as death, morbidity and no morbidity by the World Congress on Drowning and World Health Organization in 2002.[84] Each year, more than 175,000 children and teenagers die from drowning, which makes drowning the second leading cause of unintentional injury death for children under the age of 18 years.[28] Ninety-seven percent of unintentional drowning deaths occur in LMICs.[84] Children under 5 years of age have the highest drowning mortality rate worldwide.[288586] Drowning of most of the children, younger than 1 year of age, occurs in bathtubs or buckets.[87] More than 50% of drowning among children aged 1–4 years in HICs occurs in swimming pools,[87] whereas most drowning occurs in natural bodies of water in rural areas in LMICs.[278688] Globally, males have higher rates of drowning than females at all ages, except in infants where females have a higher rate of drowning than males.[8485]

Prevention: Drowning mostly occurs when the child is inadequately supervised or unsupervised.[87-89] A study from Bangladesh showed that child supervision can be increased by using supervision tools such as a playpen and a door barrier.[90] A pilot study from Bangladesh demonstrated that a drowning prevention program can be developed by using low-cost local resources involving the community. The prevention measures included three facets: i) increased child supervision by creating drowning-safe homes and establishing community crθches, ii) heightened water safety culture by formation of village committees, conduction of courtyard and social autopsy meetings with communities, and iii) providing basic first response skills to the community. This study also showed that the program was well accepted, feasible and sustainable to the community.[91] Lack of pool barrier or inadequate fencing is another risk factor for drowning. A meta-analysis in 2000 showed that pool fencing significantly reduced the risk of drowning.[92] A study from the European Association for Consumer Representation in Standardization (ANEC) indicated that the most effective barrier was 1.2 m high, inclining at an angle toward the climbers.[93] A systematic review in 2004 revealed that alcohol was detected in blood of 30–70% of persons who drowned while being involved in recreational aquatic activities in HICs. Moreover, 10–30% of drowning deaths could be attributed to alcohol use.[94] People with epilepsy also have a greater risk of drowning. The risk is approximately 15–19 fold greater compared to the general population. Bathtubs and pools are major submersion sites for children with epilepsy.[9596]

Currently, the American Academy of Pediatrics recommends that swimming lessons should be given to children of age 4 years or older.[97] However, recent case-control studies from the United States and China demonstrated that children under 4 years of age may be benefited from the swimming lessons. The risk of drowning was found to reduce by 88% among children aged 1–4 years who had formal swimming lessons.[8998] The International Task Force on Prevention of Open Water Drowning established the guidelines for individual and families[99] [Table 3]. The International Drowning Research Centre-Bangladesh (IDRC-B) is a child drowning research center, working to enhance and improve drowning-related research, as well as developing drowning prevention strategies and affordable prevention packages for application in LMICs.

Table 3

International Open Water Drowning Prevention Guidelines

For those interested in injury and violence prevention, Centers for Disease Control and Prevention (CDC)'s National Center for Injury Prevention and Control (NCIPC or CDC's injury center) and Society for the Advancement of Violence and Injury Research (SAVIR) are excellent resources for injury and violence prevention information and research. The Bangladesh Center of Injury Prevention and Research, Bangladesh (CIPRB) provides information on injury prevention for LMICs.

SUMMARY

Injuries are a major and growing public health problem. Injury deaths have been increasing in many LMICs over the past 20 years. Without prevention efforts, by the year 2030, injuries will be the fifth leading cause of death worldwide. Injuries cause not only loss of life but also long-term disabilities and other consequences including economic burden for individuals, families and communities. In HICs, prevention strategies are better established and proven to be effective, resulting in a continuously decreasing number of deaths and disabilities from injuries. However, in many LMICs, people are not aware of injuries as a problem, there is a paucity of injury data, and little to no information on injury prevention measures has been disseminated. Injuries can only be effectively prevented by active collaboration between stakeholders from international, national, and local communities, and individuals to address the problems, create prevention strategies and policies.