英文版mm4719

U.S. DEPARTMENT OF HEALTH AND HUMAN SERVICES 385 World No-Tobacco Day 386 Selected Cigarette Smoking Initiation and Quitting Behaviors Among High School Students 389 Cholera Outbreak among Rwandan Refugees 391 Lightning-Associated Deaths 394 Plesiomonas shigelloides and Salmonella serotype Hartford Infections Associated with a Contaminated Water Supply TM May 22, 1998 / Vol. 47 / No. 19 World No-Tobacco Day — May 31, 1998 Tobacco use is one of the most important determinants of human health trends worldwide (1 ). The annual rate of 3 million deaths attributed to tobacco use will reach approximately 10 million by 2025. Globally, if current trends continue, more than 200 million persons who are currently children and teenagers will die from tobacco-related illnesses (1 ). In many countries, tobacco use is increasing among young persons, and the age of smoking initiation is declining. Most smokers begin smoking during their teen- age years. If young persons do not use tobacco before age 20 years, they are un- likely to initiate use as adults (2 ). The theme for this year’s World No-Tobacco Day, to be held May 31, is “Growing up Without Tobacco.” The World Health Organization (WHO) encourages govern- ments, communities, organizations, schools, families, and persons to focus on the increasing epidemic of tobacco-related morbidity and mortality, to take strong ac- tions to prevent nicotine addiction in young persons, to protect nonsmokers from the dangers of environmental tobacco smoke, and to provide effective youth- oriented smoking-cessation programs. WHO will provide press releases, fact sheets, a poster, and an advisory kit on comprehensive measures to reduce tobacco use. Additional information about World No-Tobacco Day 1998 is available from WHO’s World-Wide Web site http://www.who.ch/programmes/psa/toh.htm, from the WHO regional office of the Americas, telephone (202) 861-3200, or from CDC’s Office on Smoking and Health, National Center for Chronic Disease Prevention and Health Promotion, telephone (770) 488-5705; World-Wide Web site http://www.cdc.gov/tobacco. References 1. Peto R, Lopez A, Boreham J, Thun M, Heath C Jr. Mortality from smoking in developed countries, 1950–2000: indirect estimates from national vital statistics. Oxford, England: Ox- ford University Press, 1994. 2. World Health Organization. World No-Tobacco Day, 31 May 1998 [Advisory kit]. Geneva, Switzerland: World Health Organization, 1998. Selected Cigarette Smoking Initiation and Quitting Behaviors Among High School Students — United States, 1997 Smoking Initiation and Quitting Behaviors — ContinuedThe continuum of smoking behavior among children and adolescents can be de- scribed in stages of preparation, trying, experimentation, regular smoking, and nico- tine dependence or addiction (1 ). Persons who have smoked can discontinue at any stage, but quitting becomes more difficult as smokers progress through the contin- uum and become increasingly dependent on nicotine (1,2 ). Nicotine addiction is char- acterized by a physiologic need for nicotine, including a tolerance for nicotine, withdrawal symptoms if an attempt is made to quit, and a high probability of relapse after quitting (1 ). To determine the prevalence of selected cigarette smoking initiation and quitting behaviors among youth, CDC analyzed data from the 1997 Youth Risk Behavior Survey (YRBS). Findings indicate that among U.S. high school students in 1997, 70.2% had tried cigarette smoking. Among students who had ever tried cigarette smoking, 35.8% went on to smoke daily. Among those who had ever smoked daily, 72.9% had ever tried to quit smoking and 13.5% were former smokers. YRBS, a component of CDC’s Youth Risk Behavior Surveillance System (3 ), bienni- ally measures the prevalence of priority health risk behaviors among youth through representative national, state, and local surveys. The 1997 national YRBS used a three- stage cluster-sample design to obtain a representative sample of 16,262 students in grades 9–12 in the 50 states and the District of Columbia. The school response rate was 79%, the student response rate was 87%, and the overall response rate was 69%. Data were weighted to provide national estimates, and SUDAAN®* was used to calcu- late standard errors for determining 95% confidence intervals (CIs). Students com- pleted a self-administered questionnaire that included questions about lifetime and current cigarette use, ever-daily cigarette use, and attempts to quit smoking. Lifetime smokers were defined as students who had ever tried smoking cigarettes, even one or two puffs. Current smokers were defined as students who smoked cigarettes on ≥1 of the 30 days preceding the survey. Ever-daily smokers were defined as students who reported that they had “ever smoked cigarettes regularly, that is, at least one cigarette every day for 30 days.” Quit attempts were determined from the question “Have you ever tried to quit smoking cigarettes?” Former cigarette smokers were defined as ever-daily smokers who were not current smokers. The number of persons from racial/ethnic groups other than non-Hispanic black, non-Hispanic white, and Hispanic was too small for meaningful analysis. The prevalence of lifetime smoking was 70.2% (95% CI=±1.9) overall and did not vary by sex, race/ethnicity, or grade in school (Table 1). More than one third of stu- dents (35.8%) who had tried cigarette smoking reported ever smoking daily (Table 1). Ever-daily smoking was highest among white students (41.7%), followed by Hispanic students (24.5%), and black students (14.9%). Almost three fourths (72.9% [95% CI=±2.7]) of ever-daily smokers had tried to quit smoking (Table 1). Among ever-daily smokers, females (77.6%) were more likely than males (68.7%) and white students (76.0%) were more likely than Hispanic students (61.9%) to report ever having tried to quit. Among ever-daily smokers, 13.5% were former smokers (Table 1). *Use of trade names and commercial sources is for identification only and does not imply endorsement by CDC or the U.S. Department of Health and Human Services. 386 MMWR May 22, 1998 Reported by: Office on Smoking and Health, and Div of Adolescent and School Health, National Center for Chronic Disease Prevention and Health Promotion, CDC. Editorial Note: As with other drug addictions, nicotine dependence is a progressive, chronic, and relapsing disorder (1 ). The optimal public health strategy is to prevent tobacco use completely or to intervene as early in the smoking behavior continuum as possible. Once adolescents have established a pattern of regular use, their behavior is usually compelled by nicotine dependence as well as social factors. Efforts are needed to help youth break the cycle of addiction and prevent the disability and death associ- ated with tobacco use. Initiation and quitting behaviors suggest areas for intervention and research. For example, the incidence of lifetime ever smoking among adolescents declined in the mid-1970s and early 1980s, but increased from 1991 to 1994 (4 ), suggesting that this TABLE 1. Percentage of high school students* who reported selected cigarette smoking initiation and quitting behaviors, by sex, race/ethnicity, and grade — United States, Youth Risk Behavior Survey, 1997 Lifetime smokers† Lifetime smokers who have ever smoked daily§ Ever-daily smokers who have ever tried to quit smoking¶ Former smokers** Category % (95% CI††) % (95% CI) % (95% CI) % (95% CI) Sex Male 70.9 (±1.9) 34.7 (±2.6) 68.7 (± 5.5) 13.0 (±3.0) Female 69.3 (±2.6) 37.1 (±4.1) 77.6 (± 2.6) 14.0 (±3.4) Race/Ethnicity§§ White, non-Hispanic 70.4 (±2.3) 41.7 (±2.4) 76.0 (± 2.3) 13.4 (±3.4) Black, non-Hispanic 68.4 (±4.4) 14.9 (±2.6) 64.8 (± 9.0) 16.9 (±6.0) Hispanic 75.0 (±2.7) 24.5 (±3.5) 61.9 (± 8.3) 14.3 (±5.4) Grade 9 67.7 (±5.1) 35.7 (±5.3) 66.1 (±11.5) 17.8 (±4.1) 10 70.0 (±3.9) 34.9 (±4.5) 77.3 (± 5.7) 14.6 (±5.6) 11 68.8 (±3.1) 37.1 (±4.4) 73.2 (± 6.2) 10.0 (±3.7) 12 73.7 (±4.1) 35.5 (±3.9) 74.4 (± 4.2) 12.4 (±2.9) Total 70.2 (±1.9) 35.8 (±2.6) 72.9 (± 2.7) 13.5 (±2.8) *N=16,262. †Ever tried cigarette smoking, even one or two puffs. §Ever tried cigarette smoking, even one or two puffs, and have ever smoked at least one cigarette every day for 30 days. ¶Have ever smoked at least one cigarette every day for 30 days and have ever tried to quit smoking. Excludes data from 55 students who reported that they had never tried to quit, but did not smoke on any of the 30 days preceding the survey. **Have ever smoked at least one cigarette every day for 30 days and did not smoke on any of the 30 days preceding the survey. Excludes data from 55 students who reported that they had never tried to quit, but did not smoke on any of the 30 days preceding the survey. ††Confidence interval. §§Numbers for racial groups other than whites and blacks were too small for meaningful analysis. Vol. 47 / No. 19 MMWR 387 Smoking Initiation and Quitting Behaviors — Continued behavior is modifiable. Cigarette advertising and promotion, smoking by adults and older siblings, access to cigarettes, price of cigarettes, peer pressure, and the degree of exposure to effective counteradvertising and school-based prevention programs can influence patterns of initiation (1,2 ). The findings in this report are consistent with previous studies that indicate ap- proximately 33%–50% of persons who try smoking cigarettes escalate to regular pat- terns of use (1 ). The 1990–1992 National Comorbidity Survey estimated that 23.6% of persons aged 15–24 years who ever used cigarettes progressed to the final stage in the smoking behavior continuum (i.e., nicotine dependence). This conversion rate (i.e., from any use to dependence) was similar to conversion rates for use of cocaine (24.5%) and heroin (20.1%) (5 ). Although indicators of dependence increase with the frequency of smoking among youth, many less-than-daily smokers experience symp- toms of nicotine withdrawal when they attempt to quit (6 ). Differences described in this report in the rate of conversion from trying a cigarette to daily use may explain some of the racial/ethnic differences in current smoking prevalence estimates among youth (7,8 ). Black adolescents who try cigarette smok- ing may experience greater social disapproval regarding their smoking behavior than white adolescents (8 ). Among ever-daily smokers, white students were more likely than Hispanics students and female students were more likely than male students to have attempted to quit smoking during high school. Investigation of the influence of early quit attempts on long-term success is needed. The findings in this report are subject to at least three limitations. First, these data apply only to youth who attend high school and, therefore, are not representative of all persons in this age group. In 1996, 6% of persons aged 16–17 years were not en- rolled in a high school program and had not completed high school (7 ). Second, more detailed measures of cessation (i.e., current interest in quitting, recent quit attempts, and longest time abstinent from cigarettes) could not be examined because they were not included in the survey. Third, a cross-sectional survey can measure only the preva- lence of various stages in the smoking behavior continuum. Transitions through the stages of smoking behavior are best studied with a longitudinal research design. Most young persons who smoke regularly are already addicted to nicotine, and the experience of addiction is similar to that among adults (1 ). Although approximately 70% of adolescent smokers regret ever starting (9 ), success rates have been low in the few cessation programs designed for young persons that have reported quit rates at follow-up (13%) (10 ). Adolescents are difficult to recruit for formal cessation pro- grams and, when enrolled, are difficult to retain in the programs (1 ). In September 1997, CDC conducted the first Workgroup on Youth Tobacco Use Cessation to discuss strategies to stimulate research on tobacco-use cessation programs. Tobacco-use ces- sation programs are being evaluated in schools, health-maintenance organizations, and state health departments and feature adolescent team competitions, pharma- cologic agents, telephone counseling, and cooperative learning. Evaluations of these efforts will assist in developing tobacco-use cessation programs for youth that can be used nationwide. References 1. US Department of Health and Human Services. Preventing tobacco use among young people: a report of the Surgeon General. Atlanta, Georgia: US Department of Health and Human Serv- ices, Public Health Service, CDC, 1994. 388 MMWR May 22, 1998 Smoking Initiation and Quitting Behaviors — Continued 2. National Cancer Institute. Strategies to control tobacco use in the United States: a blueprint for public health action in the 1990s. Bethesda, Maryland: US Department of Health and Human Services, National Institutes of Health, 1991; NIH publication no. 92-3316. (Smoking and to- bacco control monograph no. 1). 3. Kolbe LJ, Kann L, Collins JL. Overview of the Youth Risk Behavior Surveillance System. Public Health Rep 1993;108(suppl 1):2–10. 4. Substance Abuse and Mental Health Services Administration. Preliminary results from the 1996 National Household Survey on Drug Abuse. Rockville, Maryland: US Department of Health and Human Services, Substance Abuse and Mental Health Services Administration, Office of Applied Studies, 1997; DHHS publication no. (SMA)97-3149. 5. Anthony JC, Warner LA, Kessler RC. Comparative epidemiology of dependence on tobacco, alcohol, controlled substances and inhalants: basic findings from the National Comorbidity Survey. Exper and Clin Psychopharm 1994;2:244–68. 6. CDC. Reasons for tobacco use and symptoms of nicotine withdrawal among adolescent and young adult tobacco users—United States, 1993. MMWR 1994;43:745–50. 7. CDC. Tobacco use among high school students—United States, 1997. MMWR 1998;47:229–33. 8. US Department of Health and Human Services. Tobacco use among U.S. racial/ethnic minority groups—African Americans, American Indians and Alaska Natives, Asian Americans and Pa- cific Islanders, and Hispanics: a report of the Surgeon General. Atlanta, Georgia: US Department of Health and Human Services, Public Health Service, CDC, 1998. 9. George H. Gallup International Institute. Teen-age attitudes and behaviors concerning tobacco: report of findings. Princeton, New Jersey: George H. Gallup International Institute, 1992. 10. Sussman DS, Lichtman K, Ritt A, Pallonen U. Effects of 34 adolescent tobacco use cessation and prevention trials on regular users of tobacco products. Substance Use and Misuse 1998 (in press). Smoking Initiation and Quitting Behaviors — Continued Cholera Outbreak among Rwandan Refugees — Democratic Republic of Congo, April 1997 Cholera — ContinuedIn April 1997, a cholera outbreak occurred among 90,000 Rwandan refugees resid- ing in three temporary camps between Kisangani and Ubundu, Democratic Republic of Congo (formerly Zaire). Médecins Sans Frontières (MSF) established two referral medical centers and a cholera treatment center in these camps. Personnel from MSF, Zairean nongovernmental organizations (NGOs), and the Office of the United Nations High Commissioner for Refugees (UNHCR) implemented morbidity and mortality sur- veillance to monitor refugee health status. This report presents the findings of the surveillance system and indicates this outbreak was characterized by a higher death rate than that observed in previous cholera outbreaks in refugee populations. The daily number of deaths in the camps was obtained from Zairean Red Cross Society volunteers, who were responsible for burying bodies in mass graves. During March 30–April 20, 1997, a total of 1521 deaths were recorded, most of which occurred outside of health-care facilities. The daily crude mortality rate (CMR) ranged from seven to 14 per 10,000 population; the average daily CMR during this period was 9.9 per 10,000 population. Active identification and referral for treatment of cholera cases was initiated by hiring Rwandan community health workers who were familiar with the refugees in their section of the camps. Cholera was defined as sudden onset of watery diarrhea resulting in dehydration. Clinical characteristics included vomiting (60% of patients), moderate to severe dehydration (50%–70%), and fever >99.5 F (>37.5 C) (<20%). Vol. 47 / No. 19 MMWR 389 Smoking Initiation and Quitting Behaviors — Continued During April 4–19, 1997, a total of 545 persons with cholera were admitted to the cholera treatment center (attack rate: 0.9%); 67 (12.3%) died. Most deaths in the treat- ment center occurred during the night when MSF health-care workers were absent. According to MSF personnel, most patients with cholera were severely malnourished and suffered from concurrent health problems (e.g., malaria or acute respiratory ill- nesses). Most (80%) persons with cholera were aged ≥5 years. Cholera cases also oc- curred among health-care workers at the cholera-treatment center. Three of seven stool specimens tested from patients with watery diarrhea were positive for Vibrio cholerae O1, biotype El Tor, serotypes Inaba or Ogawa. Cholera-control interventions included filtration and chlorination of the camps’ water systems, health education, and construction and maintenance of latrines. Treat- ment of cholera patients by intravenous and oral rehydration therapy was instituted by MSF (1,2 ). The overall evaluation of cholera control measures was not possible because of the dispersion of the refugees by unidentified armed forces on April 21, 1997. Reported by: F Matthys, Médecins Sans Frontières Belgium, Brussels, Belgium. S Malé, Z Labdi, Office of the United Nations High Commissioner for Refugees, Geneva, Switzerland. Interna- tional Emergency and Refugee Health Program, National Center for Environmental Health; and an EIS Officer, CDC. Editorial Note: The findings in this report indicate that the implementation of a rapid surveillance system facilitated recognition of the need for increased health-care serv- ices and appropriate intervention strategies. Timely surveillance using simple case definitions is crucial to targeting interventions during the emergency phase of refugee situations. During emergency situations, CMR (normally <0.5 per 10,000 population per day in developing countries) is the most specific indicator of health status in refugee popula- tions (3 ). The CMR among refugees in this outbreak was 9.9. This rate was substan- tially higher than that in Tingi-Tingi (a temporary settlement of Rwandan refugees in the Democratic Republic of Congo) in 1997 (2.5 per 10,000 per day) (4 ); lower than in Goma in July 1994 (34–54 per 10,000 per day) (5 ); and similar to those in refugee camps in Thailand in 1979 (10.6 per 10,000 per day) and Somalia in 1980 (10.1 per 10,000 per day) (3 ). The situation in the Democratic Republic of Congo demonstrates the importance of immediate and unrestricted access to displaced populations by the international com- munity if local authorities do not have the means or the political will to assist in emer- gency situations. The case-fatality ratio for cholera in this outbreak was substantially higher than that observed in previous outbreaks of cholera in refugee camps (3,4 ). Case-fatality ratios of ≤1% are expected if adequate rehydration services are available (1 ). Several factors accounted for the high mortality among the refugees in this out- break. First, the refugees had been without adequate food, shelter, or access to health care during the preceding 5 months. In addition, the location of the camps assigned by local authorities was far from the nearest villages (4–50 miles [7–82 km] from Kisan- gani) and the only transport available for relief personnel and supplies was a railway l