Dog bites: still a problem?

OBJECTIVE: To estimate the incidence of dog bites in the USA and compare it with similar estimates from 1994. DESIGN: Nationally representative cross-sectional, list-assisted, random-digit-dialed telephone survey conducted during 2001-2003. METHODS: Weighted estimates were generated from data collected by surveying 9684 households during 2001-2003 and compared with results from a similar survey conducted in 1994. Estimates for persons aged 15-17 years were extrapolated on the basis of rates for 10-14-year-olds. RESULTS: Whereas the incidence of dog bites among adults remained relatively unchanged, there was a significant (47%) decline in the incidence of dog bites among children compared with that observed in the 1994 survey, particularly among boys and among those aged 0-4 years. Between 2001 and 2003, an estimated 4 521 300 persons were bitten each year. Of these, 885 000 required medical attention (19%). Children were more likely than adults to receive medical attention for a dog bite. Among adults, bite rates decreased with increasing age. Among children and adults, having a dog in the household was associated with a significantly increased incidence of dog bites, with increasing incidence also related to increasing numbers of dogs. CONCLUSIONS: Dog bites continue to be a public health problem affecting 1.5% of the US population annually. Although comparison with similar data from 1994 suggests that bite rates for children are decreasing, there still appears to be a need for effective prevention programs.

Studying "exposure" to firearms: household ownership v access.

BACKGROUND: Firearm ownership has often been used to measure access to weapons. However, persons who own a firearm may not have access to it and conversely, persons who do not own a firearm may be able to access one quickly. OBJECTIVES: To examine whether using firearm ownership is a reasonable proxy for access by describing the demographic characteristics associated with ownership and access. METHODS: Data are from the 1994 Injury Control and Risk Survey, a national, random digit dial survey. Information about household firearm ownership and ready access to a loaded firearm were collected and weighted to provide national estimates. Adjusted odds ratios for three separate models were calculated using logistic regression. RESULTS: A total of 1353 (27.9%) respondents reported both having a firearm in the household and ready access to one. An additional 313 respondents (8.1%) reported having a firearm, but were not able to access these weapons. Another 421 respondents (7.2%) did not have a firearm in or around their home, yet reported being able to retrieve and fire one within 10 minutes. Based on the logistic regression findings, the demographic characteristics of this latter group are quite different from those who report ownership. Those who do not have a firearm, but report ready access to one, are more likely to be ethnic minorities, single, and living in attached homes. CONCLUSIONS: Asking only about the presence of a firearm in a household may miss some respondents with ready access to a loaded firearm. More importantly, those who do not own a firearm, but report ready access to one, appear to be qualitatively different from those who report ownership. Caution should be exercised when using measures of ownership as a proxy for access.

Effectiveness of a state law mandating use of bicycle helmets among children: an observational evaluation.

In spring 1999, the authors evaluated the effectiveness of a 1997 Florida law requiring helmet use by all bicyclists younger than age 16 years. Sixty-four counties in Florida had enacted the bicycle helmet-use law, while the other three counties had opted out. Using a cross-sectional study design, the authors conducted unobtrusive observations at bicycle racks at public elementary schools statewide. Florida children riding bicycles in counties where the state helmet-use law was in place were twice as likely to wear helmets as children in counties without the law. In counties where the state law was in place, 16,907 (79%) of 21,313 riders observed wore a helmet, compared with only 148 (33%) of 450 riders in counties where no such law was in place (crude prevalence ratio = 2.4, 95% confidence interval: 2.1, 2.8). Helmet use by children of all racial groups exceeded 60% under the law. No significant difference in use by gender was found. These data support the positive influence of a law on bicycle helmet use among children. The data reinforce the Healthy People 2010 objective that all 50 states adopt such a law for children in order to increase helmet use and consequently reduce brain injury.

Alcohol consumption and nearly lethal suicide attempts.

We conducted a case-control study of the association between nearly lethal suicide attempts and facets of alcohol consumption; namely, drinking frequency, drinking quantity, binge drinking, alcoholism, drinking within 3 hours of suicide attempt, and age began drinking. Subjects were 13-34 years of age. In bivariable analyses, all measures were associated with nearly lethal suicide attempts. Odds ratios ranged from 2.4 for alcoholism to 7.0 for drinking within 3 hours of attempt. All exposure variables except age began drinking exhibited a J-shaped relationship between alcohol exposure and nearly lethal suicide attempt. After controlling for potential confounders and other measures of alcohol exposure, drinking within 3 hours of attempt remained most strongly (odds ratios > 6) associated. Alcoholism remained significantly associated in most models, but at lower strength.

The influence of geographic mobility on nearly lethal suicide attempts.

Teenagers and young adults are very mobile and mobility has been identified as a potential risk factor for suicidal behavior. We conducted a population-based, case-control study of nearly lethal suicide attempts with 153 cases and 513 controls. Study participants were asked about changing residence over the past 12 months. Results indicate that moving in the past 12 months is positively associated with a nearly lethal suicide attempt (adjusted odds ratio of 2.1, with 95% confidence interval of 1.4-3.3), as are specific characteristics of the move (e.g., frequency, recency, distance, and difficulty staying in touch). These findings confirm and extend prior ecologic research by demonstrating a relationship, at the individual level, between the geographic mobility of adolescents and young adults and nearly lethal suicide attempts.

Characteristics of impulsive suicide attempts and attempters.

Suicide attempts often are impulsive, yet little is known about the characteristics of impulsive suicide. We examined impulsive suicide attempts within a population-based, case-control study of nearly lethal suicide attempts among people 13-34 years of age. Attempts were considered impulsive if the respondent reported spending less than 5 minutes between the decision to attempt suicide and the actual attempt. Among the 153 case-subjects, 24% attempted impulsively. Impulsive attempts were more likely among those who had been in a physical fight and less likely among those who were depressed. Relative to control subjects, male sex, fighting, and hopelessness distinguished impulsive cases but depression did not. Our findings suggest that inadequate control of aggressive impulses might be a greater indicator of risk for impulsive suicide attempts than depression.

Medical conditions and nearly lethal suicide attempts.

Physical illness has been studied as a risk factor for suicidal behavior, but little is known about this relationship among younger persons. We conducted a population-based, case-control study in Houston, Texas, from November 1992 through September 1995. The final sample consisted of 153 case- and 513 control-subjects aged 13 to 34 years. Case patients were identified at hospital emergency departments and met criteria for a nearly lethal suicide attempt. Control subjects were recruited via a random-digit-dial telephone survey. Case patients were more likely than controls to report having any serious medical conditions (crude OR = 3.23; 95% CI = 2.12-4.91). After controlling for age, race/ethnicity, alcoholism, depression, and hopelessness, the adjusted odds ratio for men was 4.76 (95% CI = 1.87-12.17), whereas the adjusted odds ratio for women was 1.60 (95% CI-0.62-4.17), suggesting that young men with medical conditions are at increased risk for nearly lethal suicide attempts. Increased efforts to identify and appropriately refer these patients are needed.

Help-seeking behavior prior to nearly lethal suicide attempts.

The association between help-seeking and nearly lethal suicide attempts was evaluated using data from a population-based, case-control study of 153 13- to 34-year-old suicide attempt case-patients treated at emergency departments in Houston, Texas, and a random sample of 513 control-subjects. Measures of help-seeking included whether the participant sought help for health/emotional problems in the past month, type of consultant contacted, and whether suicide was discussed during the interaction. Overall, friends/family were consulted most frequently (48%). After controlling for potential confounders, case-patients were less likely than control-subjects to seek help from any consultant (OR = 0.5, 95% CI = 0.3-0.8) or a professional (e.g., physician, counselor) consultant (OR = 0.5, 95%CI = 0.29-0.8). Among those who sought help, case-patients were more likely than to discuss suicide (OR = 2.6, 95% CI = 1.2-5.4), particularly with professionals (OR = 11.8, 95% CI = 3.2-43.2). Our findings suggest that efforts to better understand the role of help-seeking in suicide prevention, including help sought from family and friends, deserves further attention.

An unmatched case-control study of nearly lethal suicide attempts in Houston, Texas: research methods and measurements.

This article details the research methods and measurements used in conducting a population-based, case-control study of nearly lethal suicide attempts among persons aged 13-34 years, residing in Houston, Texas. From November 1992 to July 1995, we interviewed 153 case subjects presenting at one of three participating hospital emergency departments and used random digit dialing to identify 513 control subjects residing in the same catchment area in which cases were enlisted. Unlike most research in this area, this study was designed to extend our understanding of suicidal behavior and prevention activities beyond identification and treatment of depression and other mental illnesses. We discuss the overall strengths and weaknesses of our study design and conclude that this methodology is well suited for studying rare outcomes such as nearly lethal suicide.

Lethality of firearm-related injuries in the United States population.

STUDY OBJECTIVE: To characterize differences in the lethality of firearm-related injuries in selected demographic subgroups using national representative data on fatal and nonfatal firearm-related injuries. We also characterize the lethality of firearm-related injuries by intent of injury and anatomic location of the gunshot wound. METHODS: We analyzed case-fatality rates (CFRs) of firearm-related injuries in the United States by using death data from the National Vital Statistics System and data on nonfatal injuries treated in US hospital emergency departments from the National Electronic Injury Surveillance System. National estimates of crude and age-adjusted CFRs are presented by sex, race/ethnicity, age, intent, and primary body part affected. RESULTS: Each year during the study period (July 1992 through December 1995), an estimated 132,687 persons sustained gunshot wounds that resulted in death or treatment in an ED. The overall age-adjusted CFR among persons who sustained firearm-related injuries was 31.7% (95% confidence interval [CI] 27.7 to 35.6). The age-adjusted CFR for persons who were alive when they arrived for treatment in an ED (11. 3%; 95% CI 9.4 to 13.2) was about one third as large as the overall CFR. The age-adjusted CFR varied by sex, race/ethnicity, and age, but these differences depended on intent of injury. For assaultive injuries, the age-adjusted CFR was 1.4 times higher for females (28. 7%) than males (20.6%). For intentionally self-inflicted injuries, the age-adjusted CFR was 1.1 higher for males (77.7%) than females (69.1%). For assaults, the age-adjusted CFR was 1.5 times higher for whites (29.5%) than blacks (19.2%). For assaultive and intentionally self-inflicted injuries among persons 15 years and older, the age-specific CFR increased with age. Persons shot in the head (age-adjusted CFR, 61.0%) were 3.3 times as likely to die as those shot in other body parts (age-adjusted CFR, 18.7%). CONCLUSION: The lethality of firearm-related injuries was influenced strongly by the intent of injury and body part affected. The high lethality of firearm-related injuries relative to other major causes of injury emphasizes the need to continue prevention efforts and efforts to improve access to care and treatment (including emergency medical and acute care services) to reduce the number and increase survivability of firearm-related injuries.

Nonfatal physical violence, United States, 1994.

OBJECTIVES: Most surveillance and research efforts focus on severe violence, especially on homicides. Because less extreme forms of violence may be precursors to more extreme forms, the authors analyzed data from a national survey to describe the extent of nonfatal physical violence in the US. METHODS: The authors generated weighted national estimates from responses to a random-digit-dialed telephone survey. Respondents were asked if they had been "hit, slapped, pushed, or kicked by another person or hit with an object or weapon" in the preceding 12 months. Respondents were also asked how many times such incidents had occurred and, for the last such episode, their relationship with the perpetrator, whether they had been injured, and, if so, whether they had sought medical treatment. RESULTS: The authors estimate that approximately 15 million people, or 8% of the US adult population, experienced nonfatal physical violence, as defined for this study, during a 12-month period. Male gender, the 18-24-year-old age group, never having been married, being out of work or a student, and heavy drinking were associated with a higher likelihood of being assaulted. An estimated 75% of assaults were by a known person and 26% by a stranger. Women were more likely than men to be assaulted by current or former intimate partners; men were more likely than women to be assaulted by strangers. An estimated 18% of incidents resulted in injuries, and an estimated 7% required medical attention. CONCLUSIONS: Nonfatal physical violence is fairly common in the US and may lead to more than one million medical encounters each year.

Injury rates from walking, gardening, weightlifting, outdoor bicycling, and aerobics.

PURPOSE: The objective of this survey was to estimate the frequency of injuries associated with five commonly performed moderately intense activities: walking for exercise, gardening and yard work, weightlifting, aerobic dance, and outdoor bicycling. METHODS: National estimates were derived from weighted responses of over 5,000 individuals contacted between April 28 and September 18, 1994, via random-digit dialing of U.S. residential telephone numbers. Self-reported participation in these five activities in the late spring and summer of 1994 was common, ranging from an estimated 14.5 +/- 1.2% of the population for aerobics (nearly 30 million people) to 73.0 +/- 1.5% for walking (about 138 million people). RESULTS: Among participants, the activity-specific 30-d prevalence of injury ranged from 0.9 +- 0.5% for outdoor bicycle riding to 2.4 +- 1.3% for weightlifting. The estimated number in the 30 d of people injured in the 30 d before their interview ranged from 330,000 for outdoor bicycle riding to 2.1 million for gardening or yard work. Incidence rates for injury causing reduced participation in activity were 1.1 +/- 0.5x100 participantsx30 d for walking, 1.1 +/- 0.4 for gardening, and 3.3 +/- 1.9 for weightlifting. During walking and gardening, men and women were equally likely to be injured, but younger people (18-44 yr) were more likely to be injured than older people (45 + yr). Injury rates were low, yet large numbers of people were injured because participation rates were high. Most injuries were minor, but injuries may reduce participation in these otherwise beneficial activities. CONCLUSIONS: Additional studies to confirm the magnitude of the problem, to identify modifiable risk factors, and to recommend methods to reduce the frequency of such injuries are needed.

Effect of a state law on reported bicycle helmet ownership and use.

OBJECTIVE: To evaluate the effect of a state law on reported bicycle helmet ownership and use. DESIGN: Multistage cluster random-digit-dialing telephone survey. SETTING: Georgia, June through November 1993. PARTICIPANTS: Adults who reported the behavior of bicyclists 4 through 15 years old. INTERVENTION: State law mandating helmet use after July 1, 1993, for all bicyclists aged younger than 16 years. MAIN OUTCOME MEASURES: Bicycle helmet ownership and use. RESULTS: Reported helmet ownership increased from 39% before the law took effect to 57% afterward (+ 46%, P = .06). Reported use increased from 33% before to 52% afterward (+ 58%, P < .05). About 7% of riders changed from "never-wearing" to "always-wearing" behavior. After the law took effect, in those households in which the law was known, 69% of riders owned and 64% used a helmet. By comparison, in those households in which the law was not known, only 30% owned and 25% used a helmet (P < .01). Reported ownership and use were 93% concordant, inversely related to rider age, and directly related to household income. Multivariable analysis indicated that race was an effect modifier of reported helmet ownership and use. In black riders, knowledge of the law appeared to be highly associated with both reported helmet ownership and use but was not significant in white riders. In white riders, though age and income were significantly associated with reported helmet ownership and use. CONCLUSIONS: This law appeared important in increasing reported helmet ownership and use, particularly in black riders. Since knowledge of the law was associated with increased ownership and use, additional publicity about the law might further increase helmet use. Because most riders who owned helmets used them, give-away programs targeting areas of low ownership may also increase use.

Injuries from falls on playgrounds. Effects of day care center regulation and enforcement.

OBJECTIVES: To measure the incidence of playground fall injuries among children attending licensed US day care centers and to evaluate how injury incidence varies with center characteristics and with the regulatory and enforcement climate in which centers operate. DESIGN: Telephone surveys of directors of day care centers and enforcement agencies and review of written day care regulations. SETTING: Probability sample of licensed day care centers in 50 states and the District of Columbia. PARTICIPANTS: Children attending day care centers with playgrounds. MAIN OUTCOME MEASURES: Medically attended playground fall injuries. RESULTS: Among the 1740 day care centers studied, a weighted total of 89.2 injuries occurred during the 2-month study period (0.25/100,000 child-hours in day care). The most important risk factor for injury was height of the tallest piece of climbing equipment on the playground in both bivariate (P = .01) and multivariate (P = .02) analyses. Neither regulations addressing playground safety or playground surfaces nor enforcement patterns were associated with lower injury rates. CONCLUSIONS: Additional effort is needed to develop and evaluate regulations and enforcement that reduce injury risks for children while minimizing burden on day care centers. In the meantime, limiting climbing equipment heights may reduce playground injury rates.

The compliance of licensed US child care centers with national health and safety performance standards.

The American Public Health Association and the American Academy of Pediatrics recently published health and safety guidelines for child care centers. A survey was conducted to determine the extent to which practices in US child care centers are reflective of these guidelines. Compliance with 16 guidelines ranged from 19.5% to 98.6%, varied considerably by state, and was not consistently associated with selected center characteristics. Prevention efforts should focus on practices for which compliance is low and on those that have the greatest disease- and injury-reducing potential.

The effect of adult belt laws and other factors on restraint use for children under age 11.

We used data from 11 states (5,449 respondents) to examine the association between self-reported consistent use of occupant restraints for children under 11 years of age and presence of adult belt-use laws while controlling for other factors. Self-reported safety belt use by adults, age of youngest child in the household (child restraint use decreased with increasing age), and adult educational attainment were significant predictors of child restraint use; respondent age, race/ethnicity, sex, marital status, household income, and employment status were not. Adult and child occupant restraint use was higher in states with an adult safety belt law than in states without such a law.

Bicycle helmet use by adults: the impact of companionship.

Most of the nearly 1,000 fatal bicycle-related injuries annually could be prevented if riders used safety helmets. Helmet use by adult bicyclists has received relatively little attention because educational campaigns to promote helmet use generally focus on children. Helmet use by adult and child bicyclists at 120 suburban and rural sites in three Maryland counties was observed on two Saturdays in 1990-91 during an evaluation of the impact of a mandatory helmet law. Concordance or discordance of helmet use within various groups of bicyclists--adults only, adults with children, and children only--was recorded. Helmet use among 2,068 adult bicyclists was 49 percent, 51 percent, and 74 percent in the three counties. In two counties combined, 52 percent (365 of 706) of solo adult bicyclists wore helmets compared with only 5 percent (5 of 94) of solo child bicyclists (P < .001). Helmet use or nonuse was concordant among 87 percent of 277 adult-adult pairs, 94 percent of 50 child-child pairs, and 91 percent of 32 adult-child pairs of bicyclists observed. Concordance rates of helmet use or nonuse were similarly high among pairs of adult bicyclists of the same or mixed sexes. These data are consistent with the concept that both adults and children tend to adopt the helmet-wearing behaviors of their companions. Public health efforts focused on adults should encourage helmet use by adult bicyclists both to prevent head injuries and to provide a role model for children.

Bicycle helmet use among Maryland children: effect of legislation and education.

Although bicycle helmets are effective in preventing head injuries, use of helmets among children remains infrequent. In response to the bicycling deaths of two children, Howard County, Maryland, became the first US jurisdiction to mandate use of bicycle helmets for children. Schoolchildren were lectured by police about the law before its enactment. Prelaw and postlaw helmet use was observed in Howard County and two control counties: Montgomery (which sponsored a community education program) and Baltimore County (no helmet activities). Prelaw crude helmet use rates for children were 4% (95% confidence interval [CI] 0% to 10%) for Howard, 8% (95% CI 3% to 13%) for Montgomery, and 19% (95% CI 5% to 33%) for Baltimore. Postlaw rates were 47% (95% CI 32% to 62%), 19% (95% CI 11% to 27%), and 4% (95% CI 0 to 11%), respectively. The rate of bicycle helmet use by Howard County children is now the highest documented for US children. A similar increase in helmet use among children younger than 16 years nationwide could prevent about 100 deaths and 56,000 emergency-department-treated head injuries annually. Physicians and other health professionals should consider proposing and supporting the Howard County approach in their communities.

The relation of computer-based measures of sperm morphology and motility to male infertility.

We investigated the relation between various sperm characteristics, including morphometric parameters, and impaired fertility among 596 men who participated in a national study. Semen was collected and processed by using a standardized protocol, and sperm measurements were made using a computer-aided sperm analysis instrument. We defined infertility in two ways: (1) the inability to father a child after trying for a year or longer, and (2) the number of children fathered. We found that all measures of sperm motion were decreased among men with impaired fertility. After adjustment for the other motion parameters and various potential confounders, however, only the percentage of progressive cells was associated with infertility. One morphometric parameter, the mean length/width ratio, was consistently associated with both measures of infertility, even after adjustment for potential covariates. This measure was also strongly associated with infertility among various subgroups defined by poor sperm concentration, motility, and morphology. The sperm length/width ratio appears to be an important correlate of infertility in males.

Semen characteristics of Vietnam veterans.

As part of an epidemiologic study of the health status of a randomly selected group of Vietnam veterans, we measured the semen characteristics of 324 Vietnam veterans and compared them with a similar group of 247 veterans who did not serve in Vietnam. The participation rate was 81% in both groups. Measurements of sperm concentration, movement characteristics, and head dimensions were performed, using the Cellsoft computer-assisted semen analysis system. We found that Vietnam veterans had significantly (p less than 0.05) lowered mean sperm concentrations (64.8 x 10(6) sperm/mL for Vietnam veterans vs 79.8 x 10(6) sperm/mL for non-Vietnam veterans), and Vietnam veterans were twice as likely to have sperm concentrations less than or equal to 20 million/mL (odds ratio = 2.7, 95% confidence interval = 1.3-5.7). Vietnam veterans also had a significantly lowered mean proportion of morphologically normal sperm heads (57.9% vs 60.8%), with significantly longer mean major axis length and head circumference. The proportion of motile cells, velocity, linearity, amplitude of lateral head displacement, and beat frequency were not different between the two groups. Despite differences in sperm characteristics, Vietnam and non-Vietnam veterans reported fathering similar numbers of children.