OBJECTIVE. The objective of this study was to present a detailed examination of unintentional injuries in infants ≤12 months of age treated in emergency departments.
METHODS. We conducted a retrospective analysis of data for infants ≤12 months of age from the National Electronic Surveillance System-All Injury Program for 2001–2004. Sample weights provided by the National Electronic Surveillance System-All Injury Program were used to make national estimates.
RESULTS. An estimated 1314000 injured infants were treated in US emergency departments for nonfatal unintentional injuries during the 4-year period of 2001–2004, ∼1 infant every 1.5 minutes. Falls were the leading cause of nonfatal unintentional injuries for infants. Overall, the patients were more likely to be male (55.2%) than female (44.8%). Contusions/abrasions were the leading diagnosis overall (26.7%). Contusion/abrasion, laceration, hematoma, foreign-body, and puncture injuries occurred most frequently to the head or neck region. More than one third of fractures (37.2%) were to the arm or hand. Bed was the product most frequently noted as being involved in the injury event for every age except 2 and 12 months (car seat was the most frequently noted product at 2 months of age, and stairs were top ranked at 12 months). Product rank changed markedly as age increased.
CONCLUSIONS. The influences of the social environment, the physical environment, and products change as infants mature in the first year of life; this was substantiated in our study by the shift in the relative importance of products involved in injuries according to month of age. The concept that aspects of safety must adapt in anticipation of developmental stage is critical.
Infancy represents a unique period of childhood regarding injury risk and prevention. The first year of life is a time of rapid developmental changes, when daily activities depend almost entirely on the caregiver. Injuries to infants represent a complex interplay between environment, developmental stage, and parental knowledge, skill, and abilities.1–4 Unintentional injuries are a significant cause of death and morbidity in the first year of life. A total of 1052 infants in the United States sustained fatal unintentional injuries in 2004.5 In 2000, the total lifetime costs of nonfatal injuries among children 0 to 4 years of age were more than $12 billion.6 Rates of pediatric injuries have been reported in 3-month intervals for children on the basis of California data7 and for infants as a single group on the basis of national data.8 Detailed studies of unintentional injuries among infants have focused largely on specific products (eg, bathtub seats,9 strollers/shopping carts,10,11 infant carriers,12 or high chairs13). Other work has focused on a particular cause of injury (eg, falls14 or burns15) or a particular diagnosis (eg, head injuries16,17).
Previous work has not fully explored this period of rapid change in human development. This study begins to fill this gap by analyzing data from an ongoing, national, emergency department (ED)-based surveillance system, the National Electronic Injury Surveillance System-All Injury Program (NEISS-AIP). This study presents a detailed examination of the estimates, causes, and outcomes of unintentional injuries among infants ≤12 months of age treated in EDs. Using data from 2001 through 2004, the study describes external causes of injuries and products related to injuries according to month of age and demonstrates a shifting trajectory of risk during the first year of life.
Data were acquired from the 2001–2004 NEISS-AIP, which is a stratified probability sample of hospitals having ≥6 beds and providing 24-hour emergency services in the United States or its territories. The NEISS-AIP is a collaborative effort between the Centers for Disease Control and Prevention National Center for Injury Prevention and Control and the US Consumer Product Safety Commission. Data are collected daily from each participating hospital. The NEISS-AIP defines a nonfatal injury as bodily harm resulting from exposure to an external force or substance (mechanical, thermal, electrical, chemical, or radiant) or submersion. The NEISS-AIP was described in more detail in previously published reports18,19 and has been used to study a broad range of injuries at the national level.20–22 Data elements included age (in months), body part injured, cause, diagnosis, case disposition, gender, a brief narrative, location of injury event, and product involvement.
Cases were selected if the age of the child was ≤12 months and the injury was listed as unintentional. The NEISS-AIP codes up to 2 products that were involved in an injury incident. “Product” in this system is broadly defined, to encompass consumer products (eg, cribs or infant walkers) and other objects that are involved in injury events (eg, floors, walls, or stairs). For this analysis, product codes were made comparable across years of the data system. No product was listed as being involved in the injury event for 16.3% of the cases, and 21.2% of the cases noted 2 products involved. When 2 products were coded, they could be listed in any order. All product code combinations were reviewed; if the first product coded was a landing surface (eg, floor or rug) and a second product was noted (eg, walker or car seat), then the second product was designated as the first product. The first product code was then used for analyses. It should also be noted that, although motor vehicles, insect bites, and animal bites are coded as products in the NEISS-AIP, they are not included in the product table because estimates of these events (ie, motor vehicle crash, noncanine bite or sting, or dog bite) could be ascertained directly from the cause of injury table.
Expanded cause definitions for the NEISS-AIP are available online (www.cdc.gov/ncipc/wisqars/nonfatal/definitions.htm). Some causes were combined in this study because actual case numbers were small. For example, the “other transportation” category here includes the NEISS-AIP causes of “other transportation,” “pedal cycle,” and “pedestrian.” These categories cover events such as injury to a person boarding or riding in or on all transport vehicles involved in a collision with another vehicle, pedestrian, or animal that are not covered under the category “motor vehicle occupant.” They include transport such as railway, water, and animal-drawn conveyances. The “other specified” category includes the NEISS-AIP categories of “other specified,” “machinery,” “gunshot,” and “natural/environmental.” Examples include injuries from electric current, electrocution, explosive blast, fireworks, machinery, or firearm gunshot. Patients who were transferred to another medical facility were combined with those who were hospitalized because both dispositions indicated a need for a higher level of care.
Analyses were conducted according to month of age. It should be noted that the data system classifies the 1-month-old group as infants 0 to 7 weeks of age and the 12-month-old group as infants 48 to 55 weeks of age; the remaining cases are grouped in 4-week intervals. Because population estimates according to month of age were not available, denominators for the crude rates were derived for comparisons. We used monthly birth cohort data from 2000 to estimate the 1-month cohort. Then, infant mortality data were used to calculate the number of deaths in that cohort. This number was subtracted from the 1-month-old cohort to estimate the number of surviving infants for the 2-month-old cohort. This process of calculating the surviving infants was repeated for the remaining monthly cohorts. Crude rates are presented as cases per 100000 infants.
All estimates were weighted. A sample weight is calculated by the Consumer Product Safety Commission for each injured person treated at an NEISS-AIP hospital, on the basis of the inverse of the probability of selection of that hospital in each stratum. In addition, sample weights were poststratified according to the annual number of ED visits over time. The adjustment applied to the basic NEISS-AIP weight is the ratio of the known total number of ED visits in the population (from the most recent hospital database) to the estimate of the total ED visits based on the sample of NEISS-AIP hospitals.23 Analyses were conducted by using SPSS (SPSS Inc, Chicago, IL) complex samples to account for the sampling design. Computation of proportions included 95% confidence intervals (CIs).
Leading Causes of Nonfatal Unintentional Injuries
During the 4-year period (2001–2004), 30505 injured infants were reported to the NEISS-AIP. These injuries represent an estimated 1314000 injured infants nationally. Consequently, an estimated 328500 infants are seen annually in EDs for nonfatal unintentional injuries, or ∼1 infant every 1.5 minutes (Table 1).
Falls were the leading cause of nonfatal unintentional injuries for infants, accounting for one half of the total and bringing nearly 170000 infants to EDs annually. “Struck by or against” was the second leading cause of nonfatal unintentional injuries among infants treated in EDs (>44000 annually), and fire or burn injuries were ranked third (>17000 annually). Struck by or against is defined in the NEISS-AIP as an injury resulting from being struck, striking, or being crushed by a human, animal, or inanimate object (excluding vehicles and machinery). Examples of these injuries include common household items (eg, toy or iron) being dropped on infants, fingers or toes being caught in doors or toys, and infants being poked by an object (eg, toy or straw).
Although relatively few children were treated for nonfatal drowning injuries (>600 annually), just less than one half (47.6% [95% CI: 24.8%–71.5%]) were hospitalized. For comparison, on average, 3.4% of all infants seen for unintentional injuries were hospitalized. Other causes with above-average hospitalization rates included inhalation/suffocation injuries (11.2% [95% CI: 6.9%–17.6%]), motor vehicle occupant injuries (9.5% [95% CI: 5.7%–15.4%]), foreign body injuries (8.8% [95% CI: 6.5%–11.9%]), poisoning injuries (7.5% [95% CI: 5.1%–10.9%]), fire and burn injuries (5.1% [95% CI: 3.7%–7.0%]), and other transport injuries (4.5% [95% CI: 2.2%–9.3%]).
Overall, the patients were more likely to be male (55.2% [95% CI: 54.5%–55.8%]) than female (44.8% [95% CI: 44.1%–45.5%]). The causes of injury were similar between male and female patients (Table 1), except that female infants (3.6% [95% CI: 2.9%–4.5%]) were significantly more likely than male infants (2.0% [95% CI: 1.7%–2.4%]) to present with overexertion injuries. Overexertion is defined in the NEISS-AIP as working the body or a body part too hard, causing damage to muscle, tendon, ligament, cartilage, joint, or peripheral nerve (eg, common cause of strains, sprains, and twisted ankles). Among infants, this category primarily represents subluxations or dislocations (eg, nursemaid's elbow/radial head subluxation).
Falls made up approximately one half of the nonfatal unintentional injuries at each month of age (Table 2). Struck by or against was the second leading cause of nonfatal unintentional injuries treated in EDs among infants at every month of age. There were some notable shifts in the proportions attributable to some causes according to month of age. For example, the proportion of cut or pierce injuries increased from 1.8% (95% CI: 1.2%–2.8%) among 1-month-old infants to 4.1% (95% CI: 3.5%–4.6%) among 12-month-old infants. In addition, proportions of fire or burn, foreign body, and bite or sting injuries were greater among older infants than among younger infants. Although there was variability according to cause, generally injury rates increased and hospitalization rates decreased according to month of age.
Diagnoses and Body Parts Injured
Table 3 examines the leading diagnoses according to the body part injured. Leading diagnoses for which the body part was not relevant (aspiration, ingestion, poisoning, and concussion) are not listed according to body part but the overall proportions are listed. Diagnoses with few cases (<1% of all cases; eg, avulsion, hemorrhage, amputation, and electric shock) were excluded from Table 3. Contusion/abrasion, laceration, hematoma, foreign body and puncture injuries occurred most frequently to the head or neck region. More than one third of fractures (37.2% [95% CI: 32.3%–42.4%]) were to the arm or hand. Thermal burns occurred largely to the arm or hands, whereas scald burns were distributed across body regions.
Contusions or abrasions were the leading diagnosis overall (26.7% [95% CI: 23.2%–30.6%]) and for every month of age except 12 months (lacerations were ranked first for 12-month-old infants). Although it is not shown in Table 3, the proportion of contusions/abrasions decreased from 37.5% (95% CI: 30.4%–45.1%) of the injuries for 2-month-old infants to 19.8% (95% CI: 17.3%–22.5%) of the injuries for 12-month-old infants. The proportion attributable to lacerations increased with age; 8.1% (95% CI: 6.4%–10.2%) of the injuries among 1-month-old infants were diagnosed as lacerations, compared with 27.6% (95% CI: 25.0%–30.3%) for 12-month-old infants.
Products Involved in Unintentional Injuries
Bed was the most frequently noted product involved in the injury event for every month of age except 2 months and 12 months (Table 4). Narrative comments reported infants falling, rolling, or sliding off the bed. Ranks of other products changed markedly as the month of age increased. For example, injuries involving car seats (excluding motor vehicle crash-related events) ranked 1, 2, or 3 up to 6 months of age and then dropped out of the top 10. Injuries from events such as falling out of a car seat (eg, unsecured infant lurching forward out of the seat) or a car seat falling with the secured infant (eg, such as off a grocery cart) accounted for >10% of all product-related injuries for 2- and 3-month-old infants.
Injuries related to infant walkers ranked in the top 10 for months 6 to 10, peaking in month 8 as the fourth-ranked product. An estimated 971 infants 8 months of age were seen in EDs each year for infant walker-related injuries. Stairs ranked in the top 10 for every month of age but rose in rank as infant mobility increased. Narrative comments suggested that these injuries were sustained when a caregiver carrying the infant fell on the stairs or were independent falls of the infant down the stairs (or rolling down the stairs). Stroller-related injuries seemed to peak between 2 and 4 months and dropped from the top 10 ranking after 9 months.
To our knowledge, this study is the first to report national estimates of injuries among infants according to month of age. Every 1.5 minutes, an infant 0 to 12 months of age is seen in an ED for a nonfatal unintentional injury. Falls are the leading cause of injuries at every month of age. Our results set the stage for future research on injury prevention during an infant's first year of life. Application of an ecological model of life course development to prevention suggests that the safety of infants during the first 12 months depends primarily on 2 factors, namely, adequate parenting and safe environments (home and community).3 Strong emotional bonds between infant and caregiver, high caregiver awareness, appropriate parental or caregiver supervision, knowledge and use of home safety measures, absence of home hazards, positive reinforcement to promote safe behaviors, environmental protection, and home visitation programs are likely to reduce the risk of injury among infants.24
Our study shows the need for better understanding of the connection between these factors and an infant's developmental stage. As noted by Sleet and Mercy,24 the influences of the social environment, the physical environment, and products change as the individual develops. This is substantiated here, given the shift in the relative importance of products according to month of age. The involvement of stairs in injury events increased with age and is likely related to independent mobility and access to stairs. The circumstances of the injuries could be explored further to examine the role of independent mobility. For example, although beds figure prominently in injuries at every month of age, the circumstances of the injury event are likely to change substantially (for example, rolling off the bed versus climbing on the bed and falling off). The concept that aspects of safety must adapt in anticipation of developmental stage is critical.
Although the difference was smaller than the difference between boys and girls at older ages, this study showed that, even among infants, boys were more likely to be injured than girls; rates of lacerations were slightly higher for boys than for girls and those of dislocations were slightly higher for girls than for boys. Although Powell and Tanz8 did not find significant differences in overall injury rates according to gender, the NEISS-AIP sample used in our analysis was substantially larger than the National Hospital Ambulatory Medical Care Survey they used. Other studies found that larger proportions of male infants were treated for injuries at hospital EDs, compared with female infants.16,25 Our findings lend support to the idea that gender differences at this young age are related to parenting practices and injury risk.16 Previous work with toddlers suggested that parents' communication and redirection strategies varied according to the gender of child and this might serve to shape and to promote gender differences in risk-taking.26,27 In addition, the average male infant is more active than the average female infant.28 Boys tend to reach some developmental milestones earlier than girls, including standing with support and crawling independently.29 These factors may have an effect on injury risk, especially if parents are not anticipating developmental changes. Parents need to be aware of such developmental indicators, including reach, strength, activity level, curiosity, and dexterity, and also must be aware of new injury risks as these change with age.4
Our analyses of product-related injuries support and expand previous work.30,31 Other reports detailed the type and severity of injuries sustained by young children with products such as car seats, high chairs, and strollers.11–13 The present study demonstrates that, although beds are prominent across the first year of life, the remaining products associated with injuries fluctuate in the top 10 ranking. These results vary with changes in mobility, product use, parenting, and environment during the first year of life. The costs of product-related injuries are not inconsequential. Zaloshnja et al30 found that 24% of home injury costs for infants were related to injuries involving beds.
Although some infant products (eg, cribs) must meet mandatory standards designed to enhance safety, caregivers should be aware that these standards do not eliminate all hazards. Although cribs must meet mandatory standards designed to prevent deaths from falls or entrapment, caregivers play a role in their proper use and maintenance. For example, they need to be diligent in keeping the crib sides raised and secured when they leave the infant in the crib. Anticipating developmental stages is critical in preventing the first rollover from turning into a fall. Infants should not be left alone on tables or beds, even for a brief moment. Stair gates need to be installed properly and latched to prevent access to the stairs. Recent work suggests that a substantial proportion of staircases cannot accommodate stair gates, which suggests a need for improved housing codes or gate designs.32
Given that the useful life of some products can extend for years, caregivers should exercise caution in selecting products that were previously owned, by making certain that they meet any current Consumer Product Safety Commission guidelines and that they are not part of a product recall. Products should be used according to the manufacturer's instructions. Certain products should not be used. For example, the American Academy of Pediatrics discourages the use of infant walkers and has called for a ban on the manufacture and sale of any with wheels33; stationary activity centers are a safer alternative. Infant products, however, should not be seen as a replacement for appropriate supervision.
The results of this study are subject to limitations. First, the NEISS-AIP includes only injuries treated in hospital EDs and excludes those treated in homes, physicians' offices, or outpatient clinics. Therefore, our results underestimate total injuries and may not be representative of all injuries sustained by infants, although the system is likely to capture the more-serious injuries. Approximately 31% of injured children <15 years of age are seen in EDs; the remaining 69% are seen in primary care offices, surgical specialty offices, medical specialty offices, and outpatient departments.5 Therefore, the number of infants medically treated for injuries each year may approach 1 million. Second, the NEISS-AIP provides only national estimates and not state or local estimates. Causes and circumstances of infant injuries may vary according to community and location because of differences in home and community environments and practices. Third, the NEISS-AIP does not provide detailed sociodemographic information, which limited our ability to analyze key factors such as socioeconomic status and family structure. Finally, narratives in some records provided little or incomplete information (eg, incomplete coding of product involvement); hence, described circumstances of the injury event sometimes were vague.
An infant's risk of injury is influenced by social and physical environments and products, which change as the infant matures during the first year of life. This observation is substantiated by this study, which shows a shift in the relative importance of products as infants grow older. Previous studies on the home environment found serious deficiencies in the presence and use of home safety devices.34,35 Although creating a safe environment is important (eg, properly installing stair gates), this alone is not sufficient. Parental knowledge of developmental motor milestones is often lacking.36 Therefore, interventions must consider enhancing the knowledge of milestones (eg, through physician anticipatory guidance regarding mobility changes), use of home safety devices (eg, installation of stair gates), and behavior changes (eg, promoting consistent stair gate use).
- Accepted September 6, 2007.
- Address correspondence to Karin A. Mack, PhD, Centers for Disease Control and Prevention, National Center for Injury Prevention and Control, Division of Unintentional Injury Prevention, 4770 Buford Hwy NE, Mail Stop F62, Atlanta, GA 30341. E-mail:
The findings and conclusions in this report are those of the authors and do not necessarily represent the official position of the Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry.
The authors have indicated they have no financial relationships relevant to this article to disclose.
What's Known on this Subject
Previous studies of unintentional injuries among infants focused largely on specific products (eg, bathtub seats, strollers/shopping carts, infant carriers, or high chairs), particular causes of injury (eg, falls or burns), or a particular diagnosis (eg, head injuries).
What This Study Adds
This is the first study to report comprehensively on injuries among infants according to month of age. The influences of the social environment, the physical environment, and products change as infants mature in the first year of life.
- ↵Mercy J, Sleet D, Doll L. Developmental factors and injuries to children and youth. In: Liller K, ed. Injury Prevention for Children and Adolescents: Research, Practice and Advocacy. Washington, DC: American Public Health Association; 2006:1–14
- ↵Centers for Disease Control and Prevention. Web-based Injury Statistics Query and Reporting System (WISQARS). Available at: www.cdc.gov/ncipc/wisqars. Accessed August 10, 2007
- ↵Finkelstein E, Corso P, Miller T. The Incidence and Economic Burden of Injuries in the United States. New York, NY: Oxford; 2006
- ↵Agran P, Anderson C, Winn D, Trent R, Walton-Haynes L, Thayer S. Rates of pediatric injuries by 3-month intervals for children 0 to 3 years of age. Pediatrics.2003;111 (6). Available at: www.pediatrics.org/cgi/content/full/111/6/e683
- ↵Powell E, Tanz R. Adjusting our view of injury risk: the burden of nonfatal injuries in infancy. Pediatrics.2002;110 (4):792–796
- ↵Thompson K. The role of bath seats in unintentional infant bathtub drowning deaths. Med Gen Med.2003;5 (1):36
- ↵Vilke G, Stepanski B, Ray L, Lutz M, Murrin P, Chan T. 9-1-1 responses for shopping cart and stroller injuries. Pediatr Emerg Care.2004;20 (10):660–663
- ↵Powell E, Jovtis E, Tanz R. Incidence and description of stroller-related injuries to children. Pediatrics.2002;110 (5). Available at: www.pediatrics.org/cgi/content/full/110/5/e62
- ↵Drago D. Kitchen scalds and thermal burns in children five years and younger. Pediatrics.2005;115 (1):10– 16
- ↵Arbogast K, Margulies S, Christian C. Initial neurologic presentation in young children sustaining inflicted and unintentional fatal head injuries. Pediatrics.2005;116 (1):180– 184
- ↵McGeehan J, Annest J, Vajani M, Bull M, Agran P, Smith G. School bus-related injuries among children and teenagers in the United States, 2001–2003. Pediatrics.2006;118 (5):1978– 1984
- Shults R, Wiles S, Vajani M, Helmkamp J. All-terrain vehicle-related nonfatal injuries among young riders: United States, 2001–2003. Pediatrics.2005;116 (5). Available at: www.pediatrics.org/cgi/content/full/116/5/e608
- ↵Schroeder T, Ault K. NEISS All Injury Program: Sample Design and Implementation. Washington, DC: US Consumer Product Safety Commission; 2001
- ↵Sleet D, Mercy J. Promotion of safety, security, and well-being. In: Bornstein M, Davidson L, Keyes C, Moore K, eds. Well-being: Positive Development Across the Life Course. Mahwah, NJ: Erlbaum; 2003:81–98
- ↵Chiaviello CT, Christoph RA, Bond GR. Stairway-related injuries in children. Pediatrics.1994;94 (5):679– 681
- ↵Pollack-Nelson C, Drago DA. Hazards associated with common nursery products. In: Liller K, ed. Injury Prevention for Children and Adolescents. Washington, DC: American Public Health Association; 2006:65–90
- ↵Stone K, Eastman E, Gielen A, et al. Home safety in inner cities: prevalence and feasibility of home safety product use in inner city housing. Pediatrics.2007;120 (2). Available at: www.pediatrics.org/cgi/content/full/120/2/e346
- ↵American Academy of Pediatrics, Committee on Injury and Poison Prevention. Injuries associated with infant walkers. Pediatrics.2001;108 (3):790– 792. Available at: http://aappolicy.aappublications.org/cgi/content/full/pediatrics;108/3/790
- ↵Chen L, Gielen A, McDonald E. Validity of self reported home safety practices. Inj Prev.2003;9 (1):73– 75
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