Reviews of evidence regarding interventions to reduce alcohol-impaired driving

BACKGROUND

Alcohol-related motor vehicle crashes are a major public health problem, resulting in 15,786 deaths and more than 300,000 injuries in 1999. This report presents the results of systematic reviews of the effectiveness and economic efficiency of selected population-based interventions to reduce alcohol-impaired driving.

METHODS

The Guide to Community Preventive Services's methods for systematic reviews were used to evaluate the effectiveness of five interventions to decrease alcohol-impaired driving, using changes in alcohol-related crashes as the primary outcome measure.

RESULTS

Strong evidence was found for the effectiveness of .08 blood alcohol concentration laws, minimum legal drinking age laws, and sobriety checkpoints. Sufficient evidence was found for the effectiveness of lower blood alcohol concentration laws for young and inexperienced drivers and of intervention training programs for servers of alcoholic beverages. Additional information is provided about the applicability, other effects, and barriers to implementation of these interventions.

CONCLUSION

These reviews form the basis of the recommendations by the Task Force on Community Preventive Services presented elsewhere in this supplement. They can help decision makers identify and implement effective interventions that fit within an overall strategy to prevent impaired driving.

Methods for conducting systematic reviews of the evidence of effectiveness and economic efficiency of interventions to reduce injuries to motor vehicle occupants

BACKGROUND

Motor vehicle occupant injury prevention is included in the Guide to Community Preventive Services because of the enormous health impact of these largely preventable injuries. This article describes the methods for conducting systematic literature reviews of interventions for three key injury prevention strategies: increasing child safety seat use, increasing safety belt use, and decreasing alcohol-impaired driving.

METHODS

Systematic review methods follow those established for the Guide to Community Preventive Services and include: (1) recruiting a systematic review development team, (2) developing a conceptual approach for selecting interventions and for selecting outcomes that define the success of the interventions, (3) defining and conducting a search for evidence of effectiveness, (4) evaluating and summarizing the body of evidence of effectiveness, (5) evaluating other potential beneficial and harmful effects of the interventions, (6) evaluating economic efficiency, (7) identifying implementation barriers, (8) translating the strength of the evidence into recommendations, and (9) identifying and summarizing research gaps.

RESULTS

The systematic review development team evaluated 13 interventions for the three strategic areas. More than 10,000 titles and abstracts were identified and screened; of these, 277 met the a priori systematic review inclusion criteria. Systematic review findings for each of the 13 interventions are provided in the accompanying articles in this supplement.

CONCLUSION

The general methods established for conducting systematic reviews for the Guide to Community Preventive Services were successfully applied to interventions to reduce injuries to motor vehicle occupants.

Reviews of evidence regarding interventions to increase the use of safety belts

BACKGROUND

The use of safety belts is the single most effective means of reducing fatal and nonfatal injuries in motor vehicle crashes. If all motor vehicle occupants consistently wore safety belts, an estimated 9553 deaths would have been prevented in 1999 alone.

METHODS

The Guide to Community Preventive Services's methods for systematic reviews were used to evaluate the effectiveness of three interventions to increase safety belt use. Effectiveness was assessed on the basis of changes in safety belt use and number of crash-related injuries.

RESULTS

Strong evidence was found for the effectiveness of safety belt laws in general and for the incremental effectiveness of primary safety belt laws relative to secondary laws. Strong evidence for the effectiveness of enhanced enforcement programs for safety belt laws was also found. Additional information is provided about the applicability, other effects, and barriers to implementation of these interventions.

CONCLUSIONS

These reviews form the basis of the recommendations by the Task Force on Community Preventive Services presented elsewhere in this supplement. They can help decision makers identify and implement effective interventions that fit within an overall strategy to increase safety belt use.

Reviews of evidence regarding interventions to increase use of child safety seats

BACKGROUND

In 1998, nearly 600 child occupants of motor vehicles aged younger than 4 years died in motor vehicle crashes. Yet approximately 29% of children aged 4 years and younger do not ride in appropriate child safety seat restraints, which, when correctly installed and used, reduce the need for hospitalization in this age group by 69% and the risk of death by approximately 70% for infants and by 47% to 54% for toddlers (aged 1 to 4 years).

METHODS

The systematic review development team reviewed the scientific evidence of effectiveness for five interventions to increase child safety seat use. For each intervention, changes in the use of child safety seats or injury rates were the outcome measures evaluated to determine the success of the intervention. Database searching was concluded in March 1998. More than 3500 citations were screened; of these citations, 72 met the inclusion criteria for the reviews.

RESULTS

The systematic review process identified strong evidence of effectiveness for child safety seat laws and distribution plus education programs. In addition, community-wide information plus enhanced enforcement campaigns and incentive plus education programs had sufficient evidence of effectiveness. Insufficient evidence was identified for education-only programs aimed at parents, young children, healthcare professionals, or law enforcement personnel.

CONCLUSIONS

Evidence is available about the effectiveness of four of the five interventions we reviewed. This scientific evidence, along with the accompanying recommendations of the Task Force elsewhere in this supplement, can be a powerful tool for securing the resources and commitment required to implement these strategies.

Data collection instrument and procedure for systematic reviews in the Guide to Community Preventive Services. Task Force on Community Preventive Services

INTRODUCTION

A standardized abstraction form and procedure was developed to provide consistency, reduce bias, and improve validity and reliability in the Guide to Community Preventive Services: Systematic Reviews and Evidence-Based Recommendations (the Guide).

DATA COLLECTION INSTRUMENT

The content of the abstraction form was based on methodologies used in other systematic reviews; reporting standards established by major health and social science journals; the evaluation, statistical and meta-analytic literature; expert opinion and review; and pilot-testing. The form is used to classify and describe key characteristics of the intervention and evaluation (26 questions) and assess the quality of the study's execution (23 questions). Study procedures and results are collected and specific threats to the validity of the study are assessed across six categories (intervention and study descriptions, sampling, measurement, analysis, interpretation of results and other execution issues).

DATA COLLECTION PROCEDURES

Each study is abstracted by two independent reviewers and reconciled by the chapter development team. Reviewers are trained and provided with feedback.

DISCUSSION

What to abstract and how to summarize the data are discretionary choices that influence conclusions drawn on the quality of execution of the study and its effectiveness. The form balances flexibility for the evaluation of papers with different study designs and intervention types with the need to ask specific questions to maximize validity and reliability. It provides a structured format that researchers and others can use to review the content and quality of papers, conduct systematic reviews, or develop manuscripts. A systematic approach to developing and evaluating manuscripts will help to promote overall improvement of the scientific literature.

Pediatric head injuries and deaths from bicycling in the United States

OBJECTIVE

To estimate the potential benefit of increasing bicycle helmet use among children and adolescents in the United States.

DESIGN

All bicycle-related deaths (Multiple Cause-of-Death Public Use Data Tapes, 1989 through 1992) and bicycle-related injuries treated in sampled emergency departments (National Electronic Injury Surveillance System, 1989 through 1993) were used to calculate traumatic brain injury-associated death and head injury rates per 1,000,000 US residents. Preventable injuries and deaths were estimated by calculating the population-attributable risk of head injury due to nonuse of bicycle helmets.

PATIENTS

US residents aged 0 through 19 years who were injured or who died as a result of a bicycle crash.

RESULTS

An average of 247 traumatic brain injury deaths and 140,000 head injuries among children and adolescents younger than 20 years were related to bicycle crashes each year in the United States. As many as 184 deaths and 116,000 head injuries might have been prevented annually if these riders had worn helmets. An additional 19,000 mouth and chin injuries were treated each year. The youngest age groups had the highest proportions of both head and mouth injuries.

CONCLUSION

There continues to be a need to advocate for greater use of bicycle helmets, particularly among young children. Helmet design changes should be considered to prevent mouth injuries.

Incidence of mild and moderate brain injury in the United States, 1991

The 1991 National Health Interview Survey was analysed to describe the incidence of mild and moderate brain injury in the United States. Data were collected from 46 761 households and weighted to reflect all non-institutionalized civilians. The report of one or more occurrences of head injury resulting in loss of consciousness in the previous 12 months was the main outcome measure. Each year an estimated 1.5 million non-institutionalized US civilians sustain a non-fatal brain injury that does not result in institutionalization, a rate of 618 per 100,000 person-years. Motor vehicles were involved in 28% of the brain injuries, sports and physical activity were responsible for 20%, and assaults were responsible for 9%. Medical care was sought by 75% of those with brain injury; 14% were treated in clinics or offices, 35% were treated in emergency departments, and 25% were hospitalized. The risk of medically attended brain injury was highest among three subgroups: teens and young adults, males, and persons with low income who lived alone. The incidence of mild and moderate brain injury in the United States is substantial. The National Health Interview Survey is an important national source of current outpatient brain-injury data.

The role of heightened surveillance in an outbreak of Escherichia coli O157.H7

After instituting laboratory screening for Escherichia coli O157.H7, a Connecticut hospital isolated the organism from four persons in September 1993. As a result, an outbreak of E. coli O157.H7 associated with a country club was detected. The club had served hamburger from the same shipment at two picnics. Attendees of two picnics were interviewed, stool cultures were obtained from symptomatic persons, and the remaining hamburger was cultured. Twenty (22%) of 89 persons who ate hamburger became ill, compared with 1 of 60 who did not eat hamburger (relative risk = 13.5, 95% confidence interval 3.2-56.3). Among persons who ate hamburgers, illness was strongly associated with eating hamburger that was not thoroughly cooked (P < 0.001). All 20 samples from 5 remaining boxes of patties yielded E. coli O157.H7. Isolates from hamburger and case-patients were indistinguishable by pulsed-field gel electrophoresis. Heightened surveillance can rapidly identify outbreaks and may mitigate their impact. However, continued review of food safety issues is necessary if E. coli O157.H7 outbreaks are to be prevented.

The first reported outbreak of diarrheal illness associated with Cyclospora in the United States

OBJECTIVE

To investigate and characterize the epidemiology of a diarrheal outbreak associated with a potentially new pathogen, Cyclospora species (previously referred to as Cyanobacteria [blue-green algae]-like bodies).

DESIGN

Three retrospective cohort studies supported by laboratory studies, environmental investigation, and community surveillance.

SETTING

A hospital in Chicago.

PARTICIPANTS

Housestaff physicians and hospital administrative staff.

MEASUREMENTS

Identification of clinical features associated with illness and potential risks for acquisition of infection.

RESULTS

Illness was characterized by watery diarrhea, abdominal cramping, decreased appetite, and low-grade fever. Symptoms typically occurred in a distinctive cycle of remissions and exacerbations lasting up to several weeks. Stool cultures and examinations for known ova and parasites were negative. Microscopic examination of stool specimens from 11 ill persons showed many spherical bodies, 8 to 10 microns in diameter, that were identified as Cyclospora organisms. The organisms disappeared by 9 weeks after onset of illness in the 7 patients from whom follow-up specimens were obtained. Epidemiologic studies implicated tap water from a physicians' dormitory as the most likely source of the outbreak. Environmental investigation suggested that stagnant water in a storage tank may have contaminated the water supply after a pump failure.

CONCLUSIONS

This is the first reported outbreak of diarrhea associated with Cyclospora in the United States. Cyclospora may be a human enteric pathogen able to produce bouts of acute and relapsing diarrhea, and it should be considered in assessments of patients with unexplained, prolonged diarrheal illness.

Fighting as a marker for multiple problem behaviors in adolescents

PURPOSE

Behaviors that put adolescents at risk frequently occur together. To help identify high-risk adolescents, we analyzed a national, self-reported behavior survey of high school students to assess the suitability of fighting as a marker for students with multiple problem behaviors.

METHODS

A cross-sectional cluster survey of 11,631 U.S. high school students in 1990 was used to compare the prevalence of recent problem behaviors among all students and those who fight.

RESULTS

One (8%) of every 12 students was in a fight during the 30 days before the survey. Reported problem behaviors were prevalent among fighters: during the previous 12 months, 24% attempted suicide; during the previous 30 days, 26% carried a firearm, 13% used cocaine, and 39% drove a motor vehicle while intoxicated; during the previous 3 months 41% had two or more sex partners; and 45% had sexual intercourse and did not use a condom the last time they had sex. Of all students, fighters accounted for 22% of those who reported attempting suicide, 49% carrying a firearm, 46% using cocaine, 18% driving while intoxicated, 25% having sex with multiple partners, and 11% not using condoms. Three or more of these six problem behaviors were reported by 26% of the fighters. The problem behaviors were all positively correlated, and the first principal component accounted for 35% of the total variation among the individual variables.

An outbreak of cryptosporidiosis from fresh-pressed apple cider

BACKGROUND

Recent waterborne outbreaks have established Cryptosporidium as an emerging enteric pathogen, but foodborne transmission has rarely been reported. In October 1993, an outbreak of cryptosporidiosis occurred among students and staff attending a 1-day school agricultural fair in central Maine.

DESIGN

Environmental/laboratory investigation and cohort study.

PARTICIPANTS

Attendees of the fair and their household members.

MAIN OUTCOME MEASURES

Clinical or laboratory-confirmed cryptosporidiosis. Clinical cryptosporidiosis was defined as 3 days of either diarrhea (three loose stools in a 24-hour period) or vomiting.

RESULTS

Surveys were completed for 611 (81%) of the estimated 759 fair attendees. Among attendees who completed the survey, there were 160 (26%) primary cases. Cryptosporidium oocysts were detected in the stools of 50 (89%) of 56 primary and secondary case patients tested. The median incubation period was 6 days (range, 10 hours to 13 days); the median duration of illness was 6 days (range, 1 to 16 days). Eighty-four percent of primary case patients had diarrhea and 82% had vomiting. Persons drinking apple cider that was hand pressed in the afternoon were at increased risk for cryptosporidiosis (154 [54%] of 284 exposed vs six [2%] of 292 unexposed; relative risk, 26; 95% confidence interval, 12 to 59). Cryptosporidium oocysts were detected in the apple cider, on the cider press, and in the stool specimen of a calf on the farm that supplied the apples. The secondary household transmission rate was 15% (53/353).

CONCLUSIONS

This is the first large cryptosporidiosis outbreak in which foodborne transmission has been documented. It underscores the need for agricultural producers to take measures to avoid contamination of foodstuffs with infectious agents common to the farm environment.

Boilerbaisse: an outbreak of methemoglobinemia in New Jersey in 1992

BACKGROUND

On October 20, 1992, > 40 children from one elementary school visited the school nurse due to the acute onset of blue lips and hands, vomiting, and headache during and after the school lunch periods. Forty-nine children were seen by physicians that day and 14 were hospitalized. Laboratory analysis revealed methemoglobinemia in many of the children. All recovered in 36 hours.

OBJECTIVE

A case-control study was supplemented by environmental and laboratory investigations to determine the outbreak source.

METHODS

Cases were selected based on the laboratory diagnosis of methemoglobinemia (methemoglobin level > 2%). Children whose methemoglobin levels were missing or < 2% were excluded from analysis. Controls were obtained by selecting every third name from a school roster. The parents of 29 students who met the case definition and 52 controls were interviewed.

RESULTS

All 29 cases and 33% (17/52) of the controls ate soup during the school lunch (odds ratio undefined, lower 95% confidence limit 16.1). Two pots of soup were prepared from ready-to-serve cans, which were diluted with water and enriched with a commercially prepared flavor enhancer. The school's boiler, dormant during the previous 5 months, was restarted on the morning of the outbreak. The boiler also served as a tankless hot water heater. Laboratory analysis of the soup identified abnormally high quantities of nitrite (459 ppm) and sodium metaborate, major components of the boiler water treatment solution. Undiluted soup from the same lot had 2.0 ppm nitrites; the flavor enhancer had 2.2 ppm nitrites. Nitrites were present in the hot potable water system (4 to 10 ppm) and absent in the cold potable water system.

CONCLUSIONS

This outbreak of methemoglobinemia due to nitrite poisoning was traced to soup contaminated by nitrites in a boiler additive. Nitrites are ubiquitous and potentially hazardous inorganic ions. Extreme caution should be used when the possibility for toxic human exposure to nitrites exists.

Household-acquisition of measles and illness severity in an urban community in the United States

Studies from developing countries suggest that persons with household-acquired (HA) measles are at greater risk of severe illness than persons with community-acquired (CA) infection. Reported measles cases occurring among Milwaukee residents from May 1989 to June 1990 were used to assess whether household-acquisition was a risk factor for severe measles in the United States. A case was classified as HA if onset of rash occurred 7-18 days after onset of rash in another case in the same household. Hospitalization rates were similar for 128 patients with HA measles (27%) and for 1004 patients with CA measles (26%). Multiple logistic regression was used to evaluate the association between hospitalization and household-acquisition after controlling for socioeconomic status, measles vaccination history, age, race, and date of onset of rash. Patients with HA measles were no more likely to be hospitalized than patients with CA measles (odds ratio 0.9, 95% confidence interval 0.6, 1.5). HA measles cases were not more severe than CA measles cases during this urban outbreak in the United States.

Tuberculosis in a correctional facility

BACKGROUND

After the identification of five suspected cases of tuberculosis (TB) in a Nassau County (New York) jail during a 3-week period, an epidemiologic investigation was begun to document the number of cases of TB infection and disease associated with the jail, the characteristics of current or former inmates with TB disease, and the factors contributing to TB transmission in the jail.

METHODS

The county TB register was matched against the inmate files of the jail. Medical records from hospitals, the health department, and the jail were then reviewed. All inmates in the jail were skin tested during a mass screening.

RESULTS

From January 1, 1988, through March 16, 1990, of 205 TB cases in the county, 49 (24%) were associated with the jail. Forty of the cases occurred among current or former inmates, one in a corrections officer, and eight among community contacts of inmates. The 40 inmates with TB were predominantly nonwhite (75%), unmarried (80%) men (90%), with a median age of 32 years. Twenty-three (58%) had a history of injecting drug use, and 14 (35%) were known to be seropositive for the human immunodeficiency virus. Thirty (75%) of the inmates had culture-confirmed pulmonary TB. Five (29%) of 17 Mycobacterium tuberculosis isolates had the same phage type and DNA fingerprint, which was consistent with transmission of infection within the jail. The mass screening revealed that 374 (20%) of 1855 inmates were tuberculin positive.

CONCLUSIONS

Without an effective program of TB control, jails can act as reservoirs of disease for inmates and staff, and for the community into which the inmates are released.

Sensitivity of multiple-cause mortality data for surveillance of deaths associated with head or neck injuries

PROBLEM/CONDITION

Multiple-cause mortality data was assessed as a source of information for surveillance of deaths associated with head or neck injuries.

REPORTING PERIOD COVERED

1985-1986 DESCRIPTION OF SYSTEM: Data on causes of death were abstracted from death certificates in New Mexico and coded according to criteria of the International Classification of Diseases, Ninth Revision (ICD-9). Deaths with an external cause-of-death (E) code as the underlying cause of death and one or more head or neck injury nature-of-condition (N) codes as contributing causes of death were considered head or neck injury deaths. These data were compared with data for head or neck injury deaths obtained from computerized records from the New Mexico Office of the Medical Investigator (OMI). Data for alcohol or drug use were abstracted from both systems.

RESULTS

Of the 699 head or neck injury deaths coded by the New Mexico OMI system in 1985-1986, 536 were identified as head or neck injury deaths in multiple-cause mortality data (sensitivity = 76.7%). Firearms were the leading cause of head or neck injury deaths, followed by motor vehicles. Multiple-cause mortality data contained alcohol codes for only 3.7% of OMI records with blood alcohol concentrations > or = 0.10 mg/dL and contained drug codes for none of the OMI records with positive toxicology tests for drugs.

INTERPRETATION

The sensitivity of multiple-cause mortality data was relatively high for surveillance of head and neck injury deaths.(ABSTRACT TRUNCATED AT 250 WORDS)

Exposure to environmental tobacco smoke among Missouri children

Childhood exposure to environmental tobacco smoke (ETS) increases the risk of lower respiratory infections (e.g., bronchitis and pneumonia), exacerbates childhood asthma, and increases the prevalence of fluid in the middle ear. Using self-reported telephone survey data, we examined the attitudes and practices of Missouri residents related to ETS exposure of children. Ninety-five percent of all respondents believed that ETS exposure is harmful to children and the percentage was similar for households with children (96%) and without children (94%). ETS was present in 42% of households and the percentage was similar for households with children (41%) and without children (44%). Childhood exposure to ETS remains a problem in Missouri, despite widespread awareness of the hazards. More active intervention is needed to reduce ETS exposure in the home.

Surface-specific fall injury rates on Utah school playgrounds

The purpose of this study was to estimate surface-specific rates of fall injuries on school playgrounds. Playground injuries related to falls from climbing equipment and the surfaces involved were identified from injury reports for 1988 to 1990 from 157 Utah elementary schools. Enrollment data and playground inspections were used to estimate student-years spent over each surface. The fall injury rates per 10,000 student-years were asphalt, 44; grass, 12; mats, 16; gravel, 15; and sand, 7. These data did not show that impact-absorbing surfaces reduce fall injuries on playgrounds better than grass. Improved field studies are needed to guide policy decisions for playground surfacing.

Motorcycle helmet-use laws and head injury prevention

OBJECTIVE

To rebut criticism of a previous study of motorcycle helmet-use laws through reanalysis with improved measures of exposure, stratification for regional differences in crash risk, and addressing of total motorcycle-related mortality and the grounds for targeting motorcyclists for helmet-use laws.

DESIGN

Death certificate-based correlational study of motorcycle-related deaths and motorcycle helmet-use laws.

POPULATION STUDIED

United States resident deaths from 1979 through 1986.

RESULTS

Regardless of the denominator used (resident population, motorcycle registrations, or motorcycle crashes), states with full helmet-use laws had consistently lower head injury-associated death rates than states without such laws, even when stratified by region. Total motorcycle-related mortality, however, was similar between law groups. On a registration or crash basis, motorcyclists who died in crashes had a fivefold to sixfold higher risk of head injury than those who died using any other type of motor vehicle.

CONCLUSION

Full helmet-use laws were consistently associated with lower rates of head injury-associated death. While disagreement remains on the acceptability of the legislative approach, the scientific basis for motorcycle helmet-use laws as a head injury prevention tool appears sound.

Bicycle-associated head injuries and deaths in the United States from 1984 through 1988. How many are preventable?

OBJECTIVE

To estimate the potential benefits from more widespread bicycle safety helmet use.

DESIGN

Review of death certificates and emergency department injury data for 1984 through 1988. Categorization of deaths and injuries as related to bicycling and head injury. Using relative risks of 3.85 and 6.67 derived from a case-control study and varying helmet usage from 10% to 100%, population attributable risk was calculated to estimate preventable deaths and injuries.

SETTING

Entire United States.

MAIN OUTCOME MEASURES

Numbers of US residents coded as dying from bicycle-related head injuries, numbers of persons presenting to emergency departments for bicycle-related head injuries, and numbers of attributable bicycle-related deaths and head injuries.

MAIN RESULTS

From 1984 through 1988, bicycling accounted for 2985 head injury deaths (62% of all bicycling deaths) and 905,752 head injuries (32% of persons with bicycling injuries treated at an emergency department). Forty-one percent of head injury deaths and 76% of head injuries occurred among children less than 15 years of age. Universal use of helmets by all bicyclists could have prevented as many as 2500 deaths and 757,000 head injuries, ie, one death every day and one head injury every 4 minutes.

CONCLUSIONS

Effective community-based education programs and legislated approaches for increasing bicycle safety helmet usage have been developed and await only the resources and commitment to reduce these unnecessary deaths and injuries.

Shigellosis in Kentucky, 1986 through 1989

A marked increase in the number of cases of shigellosis was reported in Kentucky in 1988. To examine reasons for this increase, we reviewed the 389 cases of shigellosis reported from 1986 through 1989. Ninety-three percent (285/305) of cases due to known species were due to Shigella sonnei. Sixty-two percent (243/389) of cases occurred in children less than 10 years of age. The annual incidence for blacks (6.8 cases per 100,000) was nearly four times that for whites (1.8 per 100,000). The increased number of cases in 1988 was due to outbreaks in five areas of the state, which accounted for 85% (200/234) of the cases. Three of the five outbreaks involved day-care centers. The primary mode of transmission appeared to be person-to-person; there was no evidence of a common source of infection from food or water. To prevent future outbreaks, cases of shigellosis need to be reported promptly to ensure appropriate investigation and control by local health departments.

The epidemiology of Lyme disease in Kentucky, 1985-1990

Lyme Disease has become the most common vector-borne disease in the United States. To assess the extent of the disease in Kentucky, all case reports were reviewed for 1985-1990. A total of 51 cases met the current case definition. Epidemiologic features were similar to those reported nationally. Although the recognized tick vectors for Lyme Disease have still not been identified in Kentucky, physicians should educate their patients on the risk of Lyme Disease and measures to prevent tick bites. Reporting cases of Lyme Disease will continue to be important so that trends in the disease's occurrence in Kentucky can be monitored.

Head injury--associated deaths from motorcycle crashes. Relationship to helmet-use laws

A review of US mortality data from 1979 to 1986 identified 15,194 deaths and nearly 600,000 years of potential life lost before age 65 years that were associated with head injuries from motorcycle crashes. White males from 15 to 34 years of age accounted for 69% of the deaths. The rate of motorcycle-related deaths associated with head injury declined modestly between 1979 and 1986 (19% using rates based on resident population and 8% based on motorcycle registrations). Population-based rates adjusted for age, sex, and race in states with partial or no motorcycle helmet-use laws were almost twice those in states with comprehensive helmet-use laws. Two states that weakened their helmet-use laws from comprehensive to partial during the study period had increases in motorcycle-related head injury death rates (184% and 73%), and one state that strengthened its law from partial to comprehensive had a decline in its death rate (44%). Head injury death rates based on motorcycle registrations were also lowest in states with comprehensive helmet-use laws. Since helmets reduce the severity of nonfatal head injuries in addition to lowering the rate of fatal injuries, we urge the adoption and enforcement of comprehensive motorcycle helmet-use legislation.

Changing epidemiology of mumps and its impact on university campuses

The reported incidence of mumps has declined dramatically since licensure of the live attenuated mumps vaccine in the United States in 1967, particularly in young children. Because administration of the vaccine was not widely practiced during the first decade it was available, there is now a cohort of teenagers and young adults who are relatively underimmunized. Reported mumps cases in this cohort increased substantially during 1986 to 1987. Mumps outbreaks at three Illinois universities, from which 123 clinical cases were reported between September 1986 and May 1987, were investigated. Meningeal involvement was reported in 17% of case-patients, orchitis occurred in 19% of 64 men, 6% of patients were hospitalized, and direct health care costs were estimated at $264 per case and more than $32,000 for the three outbreaks combined. The risk of mumps illness was greater for students less than 20 years of age (relative risk [RR] = 2.1, 95% confidence interval [CI] = 1.4, 3.1); students residing in dormitories (RR = 2.7, 95% CI = 1.6, 4.6); and out-of-state students (RR = 1.8, 95% CI = 1.0, 3.0). Because the available data suggest that mumps in college-aged persons is due chiefly to a failure to vaccinate susceptible persons, colleges and universities should become one major focus of mumps prevention activities to reduce susceptibility in this high-risk population.

An outbreak of furunculosis among high school athletes

Furuncles (boils) are common among teenagers; however, few outbreaks have been documented. We investigated an outbreak of furuncles that occurred among male athletes of a Kentucky high school during the 1986 to 1987 school year. The overall attack rate was 25% (31/124). The risk of developing a furuncle increased two to three times in those who had skin injury. Athletes who sustained abrasions more than twice per week (P less than 0.01), who had a cut that required bandaging (P = 0.01), or had an unspecified injury causing a missed practice or game (P = 0.04) were at increased risk. The risk of developing furunculosis did not appear to be related to contact with formites, but rather, to contact with furuncles. Although athletes shared common areas (showers, locker rooms, practice areas, the attack rates for varsity football (36%) and varsity basketball (33%) were four times greater than for nonvarsity teams (P less than 0.01). Players who had a friend with a furuncle were more than twice as likely to also have had a furuncle (P less than 0.01). Exposure to furuncles appeared to increase the risk of furunculosis independently of reported skin injury. Control and prevention should, therefore, focus on both reducing skin injury and reducing exposure to furuncles, rather than attempting to sterilize inanimate objects.

Head injury-associated deaths in the United States from 1979 to 1986

Review of US mortality data from 1979 to 1986 identified 315,328 deaths associated with head injury, which represented 2% of all deaths, 26% of injury deaths, and an annualized head injury-associated death rate of 16.9 per 100,000 residents. Motor vehicles (57%), firearms (14%), and falls (12%) were the most frequent causes. Death rates peaked at 15 to 24 years of age and at 75 years or older, with the younger group most affected by motor vehicles (77%) and the older group by falls (43%). Although blacks and whites had similar death rates overall, age- and cause-specific rates varied considerably. The rate of head injury-associated death for males was three times that of females. Rates for head injury-associated death plateaued after declining in the early 1980s. Physicians can play an important role in primary prevention of head injury through careful prescribing of medications, patient counseling, and advocacy of proved interventions such as motor vehicle-occupant restraints. use, we observed 9827 children riding bicycles at sites in high-, middle-, and

The Will Rogers phenomenon. Stage migration and new diagnostic techniques as a source of misleading statistics for survival in cancer

We found that a cohort of patients with lung cancer first treated in 1977 had higher six-month survival rates for the total group and for subgroups in each of the three main TNM stages (tumor, nodes, and metastases) than a cohort treated between 1953 and 1964 at the same institutions. The more recent cohort, however, had undergone many new diagnostic imaging procedures. According to the "old" diagnostic data for both cohorts, the recent cohort had a prognostically favorable "zero-time shift." In addition, by demonstrating metastases that had formerly been silent and unidentified, the new technological data resulted in a stage migration. Many patients who previously would have been classified in a "good" stage were assigned to a "bad" stage. Because the prognosis of those who migrated, although worse than that for other members of the good-stage group, was better than that for other members of the bad-stage group, survival rates rose in each group without any change in individual outcomes. When classified according to symptom stages that would be unaltered by changes in diagnostic techniques, the two cohorts had similar survival rates.

Capillarity and blood flow of transplanted skeletal muscles of cats

After transplantation, skeletal muscle fibers and the microvasculature degenerate and then regenerate. The structural and functional characteristics of autografted muscle change with time and ultimately stabilize. Capillarity, blood flow, or fatigability was measured in control (total n = 22) and in autografted (total n = 42) extensor digitorum longus muscles of cats. From 10 to 180 days after transplantation, the capillaries per square millimeter in peripheral areas of autografts averaged 65% of control, and from 180 to 518 days, 45% of control. Resting blood flow in autografts increased eventually from total ischemia at the time of transplantation to values 400% of control. After 400 days, resting blood flow returned to control values. The blood flow of autografts increased in response to twitch stimulation, reaching maximal value (24.4 +/- 1.4 ml . 100 g-1 . min-1) at 1 twitch . s-1 . The maximal blood flow of autografts was comparable to the submaximal blood flow at 1 twitch . s-2 of controls and was 30% of the maximal flow of controls obtained at 4 twitches . s-1. The maximal blood flow in autografts did not increase from 80 to 460 days. When stimulated with repetitive twitches, autografts fatigued more rapidly than controls.