viernes, 18 de mayo de 2012

Drowning — United States, 2005–2009

Weekly
May 18, 2012 / 61(19);344-347

Drowning is a leading cause of unintentional injury death worldwide, and the highest rates are among children (1). Overall, drowning death rates in the United States have declined in the last decade; however, drowning is the leading cause of injury death among children aged 1–4 years (2,3). In 2001, approximately 3,300 persons died from unintentional drowning in recreational water settings, and an estimated 5,600 were treated in emergency departments (EDs) (4). To update information on the incidence and characteristics of fatal and nonfatal unintentional drowning in the United States, CDC analyzed death certificate data from the National Vital Statistics System and injury data from the National Electronic Injury Surveillance System – All Injury Program (NEISS-AIP) for 2005–2009. The results indicated that each year an average of 3,880 persons were victims of fatal drowning and an estimated 5,789 persons were treated in U.S. hospital EDs for nonfatal drowning. Death rates and nonfatal injury rates were highest among children aged ≤4 years; these children most commonly drowned in swimming pools. The drowning death rate among males (2.07 per 100,000 population) was approximately four times that for females (0.54). To prevent drowning, all parents and children should learn survival swimming skills. In addition, 1) environmental protections (e.g., isolation pool fences and lifeguards) should be in place; 2) alcohol use should be avoided while swimming, boating, water skiing, or supervising children; 3) lifejackets should be used by all boaters and weaker swimmers; and 4) all caregivers and supervisors should have training in cardiopulmonary resuscitation.
Death certificate data for 2005–2009 were obtained from the National Vital Statistics System.* Fatal unintentional drowning was defined as any death for which the underlying cause recorded on death certificates was one of the following International Classification of Diseases, 10th Revision codes: W65–W74, V90, or V92. By international standards, boating-related drowning (V90 and V92) is classified as transportation-related death.† Boating-related deaths are presented in this report as a subcategory to allow for international comparison, although most boating in the United States is not for transportation.
Data on nonfatal drowning were gathered from NEISS-AIP, which is operated by the U.S. Consumer Product Safety Commission. NEISS-AIP collects data annually on approximately 500,000 initial visits for all types of injuries treated in U.S. EDs.§ Data are drawn from a nationally representative subsample of 66 hospitals out of 100 NEISS hospitals selected as a stratified probability sample of hospitals in the United States and its territories; the hospitals have a minimum of six beds and a 24-hour ED.
Nonfatal cases included those classified as having a precipitating or immediate cause of "drowning/near-drowning," a diagnosis of "submersion," or the mention of "drown" or "submersion" in the comment field. To collect and classify nonfatal cases in a manner similar to deaths, case narratives were reviewed and intentional and motor vehicle crash–related drownings were excluded. Persons who were dead on arrival or who died in the ED also were excluded. Each case was assigned a sample weight on the basis of the inverse probability of selection; these weights were summed to provide national estimates. National estimates were based on 605 patients treated for nonfatal drowning at NEISS-AIP hospital EDs during 2005–2009. Confidence intervals were calculated using statistical software to account for the complex sample design. Because of the small sample size, percentages of nonfatal injuries for location by age group were based on unweighted data and thus are not nationally representative.
Drowning was examined by age group, sex, race/ethnicity, location, disposition (e.g., treated and released, hospitalized or transferred), day of week, and month of year when possible. Persons identified as Hispanic might be of any race. Persons identified as white, black, or other race all were non-Hispanic. Rates were calculated using U.S. Census bridged-race intercensal population estimates.¶ Significant differences (p<0.05) between rates were determined using a t-test for nonfatal drowning rates and a z-test for death rates.
During 2005–2009, overall, an average of 3,880 persons died from unintentional drowning (including boating incidents) annually in the United States (1.29 deaths per 100,000 population) (Table). Rates were highest among children aged ≤4 years (2.55), and the death rate for males (2.07) was nearly four times that for females (0.54). The death rate for blacks (1.40) was significantly higher than the overall death rate (1.29), and the death rate for Hispanics was significantly lower (1.19). Racial/ethnic disparity in drowning death rates was greatest among children aged 5–14 years (blacks, 1.34; Hispanics, 0.46; and whites, 0.48). Approximately half (51.1%) of fatal drownings occurred in natural bodies of water. From 2005 to 2009, death rates declined significantly from 1.34 per 100,000 to 1.25 (p=0.002).
During 2005–2009, an estimated 5,789 persons on average were treated annually in U.S. EDs for nonfatal drowning (Table). Children aged ≤4 years accounted for 52.8% of the ED visits, and children aged 5–14 years accounted for 17.5%. Males accounted for 60.2% of nonfatal drowning patients, and 50.2% of the ED patients required hospitalization or transfer for further care. In addition, of nonfatal drowning injuries among those aged ≥15 years, 21.8% were associated with alcohol use.
Nonfatal (45.5%) and fatal (37.1%) incidents occurred most commonly on weekends and during June–August, 57.5% and 46.7%, respectively. Among children aged ≤4 years, 50.1% of fatal incidents and 64.6% of nonfatal incidents occurred in swimming pools (Figure). Drownings in natural water settings increased with increasing age group. Incidents in bathtubs accounted for approximately 10% of both fatal and nonfatal drownings and were most common among children aged ≤4 years.

Reported by

Orapin C. Laosee, PhD, Association of Southeast Asian Nations Institute for Health Development, Mahidol Univ, Nakhonpathom, Thailand. Julie Gilchrist, MD, Rose A. Rudd, MSPH, Div of Unintentional Injury Prevention, National Center for Injury Prevention and Control, CDC. Corresponding contributor: Julie Gilchrist, jrg7@cdc.gov, 770-488-1178.

Editorial Note

In the United States, children aged 1–4 years continue to have the highest drowning death rates, and those rates are higher than the rates for all other causes of death in that age group except congenital anomalies (3). Other groups at greater risk for drowning include males, who account for approximately 80% of fatal drowning victims, and blacks, whose drowning death rate is 9% higher than that of the overall population (and, among those aged 5–14 years, 116% higher than the overall population) (4,5). Males might be at greater risk because they are more likely to overestimate their swimming ability, choose higher risk activities, or more commonly use alcohol (6). Blacks might be at greater risk because they often lack survival swimming skills (7,8).
Age, race/ethnicity, sex, and socioeconomic factors have been associated with lack of swimming ability among urban children (7). Swimming skills have been promoted as a means to reduce drowning risk, although concerns have been raised that initiating swimming lessons in young children might increase their risk for drowning (9). Teaching basic survival skills (e.g., ability to right oneself after falling into water, proceed a short distance, and float or tread water) to children aged ≥4 years in Bangladesh significantly reduced drowning rates (10). Furthermore, formal swimming lessons have been shown to reduce the risk for fatal drowning among children aged 1–4 years in the United States and China and might also reduce risk among older age groups (9). Other effective interventions include bystander cardiopulmonary resuscitation, four-sided pool fencing that separates the pool from the house and yard, and use of lifejackets (1,9).
Death certificates and ED records lack critical pieces of information, such as details on the victim's activities and swimming ability, the body of water, weather conditions, health conditions, use of life jackets, type and functionality of fences or barriers, supervision type and quality (e.g., impaired), presence of lifeguards, and whether cardiopulmonary resuscitation was performed by a bystander. These data are needed to better understand drowning incidents, design interventions, and track their effectiveness. Among children aged <18 years, these data could be obtained by full implementation and analysis of data from the National Child Death Review Case Reporting System.** This system, managed by the National Center for Child Death Review in Okemos, Michigan, could provide data compiled by state and local teams to more completely describe drowning circumstances. Currently, 40 states voluntarily submit data to the system, and a public use data set is available to researchers through application to the center.
The findings in this report are subject to at least three limitations. First, whereas fatalities occurring in EDs were excluded from the nonfatal data presented, NEISS-AIP does not provide information on outcomes after hospitalization; therefore, data for fatal and nonfatal drownings might not be mutually exclusive. Second, some unintentional drownings might have been classified as undetermined and some homicides or suicides as unintentional. Finally, the extent of exposure to recreational water settings might vary by age, sex, season, level of swimming skill, or other factors; however, these data were not available. As a result, rates are population-based and do not account for exposure.
Parents and caregivers of children, and participants in and supervisors of activities in or near water, should be aware of drowning hazards, use appropriate prevention strategies, and be prepared with life-saving skills in the event of emergencies. Additional information regarding drowning risk factors and prevention strategies is available at http://www.cdc.gov/homeandrecreationalsafety/water-safety/index.html and at http://www.cdc.gov/safechild.

References

Peden M, Oyegbite K, Ozanne-Smith J, et al, eds. World report on child injury prevention. Geneva, Switzerland: World Health Organization; 2008. Available at http://www.who.int/violence_injury_prevention/child/injury/world_report/report/en/index.html . Accessed May 10, 2012.
CDC. Vital signs: unintentional injury deaths among persons aged 0–19 years—United States, 2000–2009. MMWR 2012;61:270–6.
CDC. Web-Based Injury Statistics Query and Reporting System (WISQARS). Atlanta, GA: US Department of Health and Human Services, CDC; 2012. Available at http://www.cdc.gov/injury/wisqars/index.html.
CDC. Nonfatal and fatal drownings in recreational water settings—United States, 2001–2002. MMWR 2004;53:447–52.
Nasrullah M, Muazzam S. Drowning mortality in the United States, 1999–2006. J Community Health 2011:36;69–75.
Howland J, Hingson R, Mangione TW, Bell N, Bak S. Why are most drowning victims men? Sex differences in aquatic skills and behaviors. Am J Public Health 1996;86:93–6.
Irwin CC, Irwin R L, Ryan T D, Drayer J. Urban minority youth swimming (in)ability in the United States and associated demographic characteristics: toward a drowning prevention plan. Inj Prev 2011;15:234–9.
Gilchrist J, Sacks JJ, Branche CM. Self-reported swimming ability in US adults, 1994. Public Health Rep 2000;115:110–1.
Weiss J. Technical report: prevention of drowning. Pediatrics 2010;126:e253–62.
Rahman A, Rahman F, Hossain J, Talab A, Scarr J, Linnan M. Survival swimming—effectiveness of SwimSafe in preventing drowning in mid and late childhood. Presented at the World Conference on Drowning Prevention, Danang, Vietnam, May 11, 2011.