Population-Based HIV Impact Assessments Survey Methods, Response, and Quality in Zimbabwe, Malawi, and Zambia

BACKGROUND

The population-based HIV impact assessment (population-based HIV impact assessments) surveys are among the first to estimate national adult HIV incidence, subnational prevalence of viral load suppression, and pediatric HIV prevalence. We summarize the survey methods implemented in Zimbabwe, Malawi, and Zambia, as well as response rates and quality metrics.

METHODS

Each cross-sectional, household-based survey used a 2-stage cluster design. Survey preparations included sample design, questionnaire development, tablet programming for informed consent and data collection, community mobilization, establishing a network of satellite laboratories, and fieldworker training. Interviewers collected demographic, behavioral, and clinical information using tablets. Blood was collected for home-based HIV testing and counseling (HBTC) and point-of-care CD4+ T-cell enumeration with results immediately returned. HIV-positive blood samples underwent laboratory-based confirmatory testing, HIV incidence testing, RNA polymerase chain reaction (viral load), DNA polymerase chain reaction (early infant diagnosis), and serum antiretroviral drug detection. Data were weighted for survey design, and chi square automatic interaction detection-based methods were used to adjust for nonresponse.

RESULTS

Each survey recruited a nationally representative, household-based sample of children and adults over a 6-10-month period in 2015 and 2016. Most (84%-90%) of the 12,000-14,000 eligible households in each country participated in the survey, with 77%-81% of eligible adults completing an interview and providing blood for HIV testing. Among eligible children, 59%-73% completed HIV testing. Across the 3 surveys, 97.8% of interview data were complete and had no errors.

CONCLUSION

Conducting a national population-based HIV impact assessment with immediate return of HIV and other point-of-care test results was feasible, and data quality was high.

Unawareness of HIV Infection Among Men Aged 15-59 Years in 13 Sub-Saharan African Countries: Findings From the Population-Based HIV Impact Assessments, 2015-2019

BACKGROUND

Identifying men living with HIV in sub-Saharan Africa (SSA) is critical to end the epidemic. We describe the underlying factors of unawareness among men aged 15-59 years who ever tested for HIV in 13 SSA countries.

METHODS

Using pooled data from the nationally representative Population-based HIV Impact Assessments, we fit a log-binomial regression model to identify characteristics related to HIV positivity among HIV-positive unaware and HIV-negative men ever tested for HIV.

RESULTS

A total of 114,776 men were interviewed and tested for HIV; 4.4% were HIV-positive. Of those, 33.7% were unaware of their HIV-positive status, (range: 20.2%-58.7%, in Rwanda and Cote d'Ivoire). Most unaware men reported they had ever received an HIV test (63.0%). Age, region, marital status, and education were significantly associated with HIV positivity. Men who had HIV-positive sexual partners (adjusted prevalence ratio [aPR]: 5.73; confidence interval [95% CI]: 4.13 to 7.95) or sexual partners with unknown HIV status (aPR: 2.32; 95% CI: 1.89 to 2.84) were more likely to be HIV-positive unaware, as were men who tested more than 12 months compared with HIV-negative men who tested within 12 months before the interview (aPR: 1.58; 95% CI: 1.31 to 1.91). Tuberculosis diagnosis and not being circumcised were also associated with HIV positivity.

CONCLUSION

Targeting subgroups of men at risk for infection who once tested negative could improve yield of testing programs. Interventions include improving partner testing, frequency of testing, outreach and educational strategies, and availability of HIV testing where men are accessing routine health services.

Data Architecture to Support Real-Time Data Analytics for the Population-Based HIV Impact Assessments

BACKGROUND AND SETTING

Electronic data capture facilitates timely use of data. Population-based HIV impact assessments (PHIAs) were led by host governments, with funding from the President's Emergency Plan for AIDS Relief, technical assistance from the Centers for Disease Control, and implementation support from ICAP at Columbia University. We described data architectures, code-based processes, and resulting data volume and quality for 14 national PHIA surveys with concurrent timelines and varied country-level data governance (2015-2020).

METHODS

PHIA project data were collected through tablets, point-of-care and laboratory testing instruments, and inventory management systems, using open-source software, vendor solutions, and custom-built software. Data were securely uploaded to the PHIA data warehouse daily or weekly and then used to populate survey-monitoring dashboards and return timely laboratory-based test results on an ongoing basis. Automated data processing allowed timely reporting of survey results.

RESULTS

Fourteen data architectures were successfully established, and data from more than 450,000 participants in 30,000 files across 13 countries with completed PHIAs, and blood draws producing approximately 6000 aliquots each week per country, were securely collected, transmitted, and processed by 17 full-time equivalent staff. More than 25,600 viral load results were returned to clinics of participants' choice. Data cleaning was not needed for 98.5% of household and 99.2% of individual questionnaires.

CONCLUSION

The PHIA data architecture permitted secure, simultaneous collection and transmission of high-quality interview and biomarker data across multiple countries, quick turnaround time of laboratory-based biomarker results, and rapid dissemination of survey outcomes to guide President's Emergency Plan for AIDS Relief epidemic control.

HIV-Related Risk Behaviors Among Male High School Students Who Had Sexual Contact with Males - 17 Large Urban School Districts, United States, 2009-2013

Young persons aged 13-24 years accounted for an estimated 22% of all new diagnoses of human immunodeficiency virus (HIV) infection in the United States in 2014. Most new HIV diagnoses among youths occur among males who have sex with males (MSM). Among all MSM, young black MSM accounted for the largest number of new HIV diagnoses in 2014 (1). To determine whether the prevalence of HIV-related risk behaviors among black male high school students who had sexual contact with males differed from the prevalence among white and Hispanic male students who had sexual contact with males, potentially contributing to the racial/ethnic disparities in new HIV diagnoses, CDC analyzed data from Youth Risk Behavior Surveys conducted by 17 large urban school districts during 2009-2013. Although other studies have examined HIV-related risk behaviors among MSM (2,3), less is known about MSM aged <18 years. Black male students who had sexual contact with males had a lower or similar prevalence of most HIV-related risk behaviors than did white and Hispanic male students who had sexual contact with males. These findings highlight the need to increase access to effective HIV prevention strategies for all young MSM.

Youth risk behavior surveillance--United States, 2013

PROBLEM

Priority health-risk behaviors contribute to the leading causes of morbidity and mortality among youth and adults. Population-based data on these behaviors at the national, state, and local levels can help monitor the effectiveness of public health interventions designed to protect and promote the health of youth nationwide.

REPORTING PERIOD COVERED

September 2012-December 2013.

DESCRIPTION OF THE SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults: 1) behaviors that contribute to unintentional injuries and violence; 2) tobacco use; 3) alcohol and other drug use; 4) sexual behaviors that contribute to unintended pregnancy and sexually transmitted infections (STIs), including human immunodeficiency virus (HIV) infection; 5) unhealthy dietary behaviors; and 6) physical inactivity. In addition, YRBSS monitors the prevalence of obesity and asthma. YRBSS includes a national school-based Youth Risk Behavior Survey (YRBS) conducted by CDC and state and large urban school district school-based YRBSs conducted by state and local education and health agencies. This report summarizes results for 104 health-risk behaviors plus obesity, overweight, and asthma from the 2013 national survey, 42 state surveys, and 21 large urban school district surveys conducted among students in grades 9-12.

RESULTS

Results from the 2013 national YRBS indicated that many high school students are engaged in priority health-risk behaviors associated with the leading causes of death among persons aged 10-24 years in the United States. During the 30 days before the survey, 41.4% of high school students nationwide among the 64.7% who drove a car or other vehicle during the 30 days before the survey had texted or e-mailed while driving, 34.9% had drunk alcohol, and 23.4% had used marijuana. During the 12 months before the survey, 14.8% had been electronically bullied, 19.6% had been bullied on school property, and 8.0% had attempted suicide. Many high school students nationwide are engaged in sexual risk behaviors that contribute to unintended pregnancies and STIs, including HIV infection. Nearly half (46.8%) of students had ever had sexual intercourse, 34.0% had had sexual intercourse during the 3 months before the survey (i.e., currently sexually active), and 15.0% had had sexual intercourse with four or more persons during their life. Among currently sexually active students, 59.1% had used a condom during their last sexual intercourse. Results from the 2013 national YRBS also indicate many high school students are engaged in behaviors associated with chronic diseases, such as cardiovascular disease, cancer, and diabetes. During the 30 days before the survey, 15.7% of high school students had smoked cigarettes and 8.8% had used smokeless tobacco. During the 7 days before the survey, 5.0% of high school students had not eaten fruit or drunk 100% fruit juices and 6.6% had not eaten vegetables. More than one-third (41.3%) had played video or computer games or used a computer for something that was not school work for 3 or more hours per day on an average school day.

INTERPRETATION

Many high school students engage in behaviors that place them at risk for the leading causes of morbidity and mortality. The prevalence of most health-risk behaviors varies by sex, race/ethnicity, and grade and across states and large urban school districts. Long term temporal changes also have occurred. Since the earliest year of data collection, the prevalence of most health-risk behaviors has decreased (e.g., physical fighting, current cigarette use, and current sexual activity), but the prevalence of other health-risk behaviors has not changed (e.g., suicide attempts treated by a doctor or nurse, having ever used marijuana, and having drunk alcohol or used drugs before last sexual intercourse) or has increased (e.g., having not gone to school because of safety concern and obesity and overweight).

PUBLIC HEALTH ACTION

YRBSS data are used widely to compare the prevalence of health-risk behaviors among subpopulations of students; assess trends in health-risk behaviors over time; monitor progress toward achieving 20 national health objectives for Healthy People 2020 and one of the 26 leading health indicators; provide comparable state and large urban school district data; and help develop and evaluate school and community policies, programs, and practices designed to decrease health-risk behaviors and improve health outcomes among youth.

Methodology of the Youth Risk Behavior Surveillance System--2013

Priority health-risk behaviors (i.e., interrelated and preventable behaviors that contribute to the leading causes of morbidity and mortality among youths and adults) often are established during childhood and adolescence and extend into adulthood. The Youth Risk Behavior Surveillance System (YRBSS), established in 1991, monitors six categories of priority health-risk behaviors among youths and young adults: 1) behaviors that contribute to unintentional injuries and violence; 2) sexual behaviors that contribute to human immunodeficiency virus (HIV) infection, other sexually transmitted diseases, and unintended pregnancy; 3) tobacco use; 4) alcohol and other drug use; 5) unhealthy dietary behaviors; and 6) physical inactivity. In addition, YRBSS monitors the prevalence of obesity and asthma among this population. YRBSS data are obtained from multiple sources including a national school-based survey conducted by CDC as well as schoolbased state, territorial, tribal, and large urban school district surveys conducted by education and health agencies. These surveys have been conducted biennially since 1991 and include representative samples of students in grades 9-12. In 2004, a description of the YRBSS methodology was published (CDC. Methodology of the Youth Risk Behavior Surveillance System. MMWR 2004;53 [No RR-12]). Since 2004, improvements have been made to YRBSS, including increases in coverage and expanded technical assistance.This report describes these changes and updates earlier descriptions of the system, including questionnaire content; operational procedures; sampling, weighting, and response rates; data-collection protocols; data-processing procedures; reports and publications; and data quality. This report also includes results of methods studies that systematically examined how different survey procedures affect prevalence estimates. YRBSS continues to evolve to meet the needs of CDC and other data users through the ongoing revision of the questionnaire, the addition of new populations, and the development of innovative methods for data collection.

ILI-related school dismissal monitoring system: an overview and assessment

OBJECTIVE

This report provides an overview and assessment of the School Dismissal Monitoring System (SDMS) that was developed by the Centers for Disease Control and Prevention (CDC) and the US Department of Education (ED) to monitor influenza-like illness (ILI)-related school dismissals during the 2009-2010 school year in the United States.

METHODS

SDMS was developed with considerable consultation with CDC's and ED's partners. Further, each state appointed a single school dismissal monitoring contact, even if that state also had its own school-dismissal monitoring system in place. The SDMS received data from three sources: (1) direct reports submitted through CDC's Web site, (2) state monitoring systems, and (3) media scans and online searches. All cases identified through any of the three data sources were verified.

RESULTS

Between August 3, 2009, and December 18, 2009, a total of 812 dismissal events (ie, a single school dismissal or dismissal of all schools in a district) were reported in the United States. These dismissal events had an impact on 1947 schools, approximately 623 616 students, and 40 521 teachers.

CONCLUSIONS

The SDMS yielded real-time, national summary data that were used widely throughout the US government for situational awareness to assess the impact of CDC guidance and community mitigation efforts and to inform the development of guidance, resources, and tools for schools.

Youth risk behavior surveillance - United States, 2011

PROBLEM

Priority health-risk behaviors, which are behaviors that contribute to the leading causes of morbidity and mortality among youth and adults, often are established during childhood and adolescence, extend into adulthood, and are interrelated and preventable.

REPORTING PERIOD COVERED

September 2010-December 2011.

DESCRIPTION OF THE SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults: 1) behaviors that contribute to unintentional injuries and violence; 2) tobacco use; 3) alcohol and other drug use; 4) sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases (STDs), including human immunodeficiency virus (HIV) infection; 5) unhealthy dietary behaviors; and 6) physical inactivity. In addition, YRBSS monitors the prevalence of obesity and asthma. YRBSS includes a national school-based Youth Risk Behavior Survey (YRBS) conducted by CDC and state and large urban school district school-based YRBSs conducted by state and local education and health agencies. This report summarizes results from the 2011 national survey, 43 state surveys, and 21 large urban school district surveys conducted among students in grades 9-12.

RESULTS

Results from the 2011 national YRBS indicated that many high school students are engaged in priority health-risk behaviors associated with the leading causes of death among persons aged 10-24 years in the United States. During the 30 days before the survey, 32.8% of high school students nationwide had texted or e-mailed while driving, 38.7% had drunk alcohol, and 23.1% had used marijuana. During the 12 months before the survey, 32.8% of students had been in a physical fight, 20.1% had ever been bullied on school property, and 7.8% had attempted suicide. Many high school students nationwide are engaged in sexual risk behaviors associated with unintended pregnancies and STDs, including HIV infection. Nearly half (47.4%) of students had ever had sexual intercourse, 33.7% had had sexual intercourse during the 3 months before the survey (i.e., currently sexually active), and 15.3% had had sexual intercourse with four or more people during their life. Among currently sexually active students, 60.2% had used a condom during their last sexual intercourse. Results from the 2011 national YRBS also indicate many high school students are engaged in behaviors associated with the leading causes of death among adults aged ≥ 25 years in the United States. During the 30 days before the survey, 18.1% of high school students had smoked cigarettes and 7.7% had used smokeless tobacco. During the 7 days before the survey, 4.8% of high school students had not eaten fruit or drunk 100% fruit juices and 5.7% had not eaten vegetables. Nearly one-third (31.1%) had played video or computer games for 3 or more hours on an average school day.

INTERPRETATION

Since 1991, the prevalence of many priority health-risk behaviors among high school students nationwide has decreased. However, many high school students continue to engage in behaviors that place them at risk for the leading causes of morbidity and mortality. Variations were observed in many health-risk behaviors by sex, race/ethnicity, and grade. The prevalence of some health-risk behaviors varied substantially among states and large urban school districts.

PUBLIC HEALTH ACTION

YRBS data are used to measure progress toward achieving 20 national health objectives for Healthy People 2020 and one of the 26 leading health indicators; to assess trends in priority health-risk behaviors among high school students; and to evaluate the impact of broad school and community interventions at the national, state, and local levels. More effective school health programs and other policy and programmatic interventions are needed to reduce risk and improve health outcomes among youth.

Sexual identity, sex of sexual contacts, and health-risk behaviors among students in grades 9-12--youth risk behavior surveillance, selected sites, United States, 2001-2009

PROBLEM

Sexual minority youths are youths who identify themselves as gay or lesbian, bisexual, or unsure of their sexual identity or youths who have only had sexual contact with persons of the same sex or with both sexes. Population-based data on the health-risk behaviors practiced by sexual minority youths are needed at the state and local levels to most effectively monitor and ensure the effectiveness of public health interventions designed to address the needs of this population.

REPORTING PERIOD COVERED

January 2001-June 2009.

DESCRIPTION OF SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors priority health-risk behaviors (behaviors that contribute to unintentional injuries, behaviors that contribute to violence, behaviors related to attempted suicide, tobacco use, alcohol use, other drug use, sexual behaviors, dietary behaviors, physical activity and sedentary behaviors, and weight management) and the prevalence of obesity and asthma among youths and young adults. YRBSS includes state and local school-based Youth Risk Behavior Surveys (YRBSs) conducted by state and local education and health agencies. This report summarizes results from YRBSs conducted during 2001-2009 in seven states and six large urban school districts that included questions on sexual identity (i.e., heterosexual, gay or lesbian, bisexual, or unsure), sex of sexual contacts (i.e., same sex only, opposite sex only, or both sexes), or both of these variables. The surveys were conducted among large population-based samples of public school students in grades 9-12.

RESULTS

Across the nine sites that assessed sexual identity, the prevalence among gay or lesbian students was higher than the prevalence among heterosexual students for a median of 63.8% of all the risk behaviors measured, and the prevalence among bisexual students was higher than the prevalence among heterosexual students for a median of 76.0% of all the risk behaviors measured. In addition, the prevalence among gay or lesbian students was more likely to be higher than (rather than equal to or lower than) the prevalence among heterosexual students for behaviors in seven of the 10 risk behavior categories (behaviors that contribute to violence, behaviors related to attempted suicide, tobacco use, alcohol use, other drug use, sexual behaviors, and weight management). Similarly, the prevalence among bisexual students was more likely to be higher than (rather than equal to or lower than) the prevalence among heterosexual students for behaviors in eight of the 10 risk behavior categories (behaviors that contribute to unintentional injuries, behaviors that contribute to violence, behaviors related to attempted suicide, tobacco use, alcohol use, other drug use, sexual behaviors, and weight management). Across the 12 sites that assessed sex of sexual contacts, the prevalence among students who had sexual contact with both sexes was higher than the prevalence among students who only had sexual contact with the opposite sex for a median of 71.1% of all the risk behaviors measured, and the prevalence among students who only had sexual contact with the same sex was higher than the prevalence among students who only had sexual contact with the opposite sex for a median of 29.7% of all the risk behaviors measured. Furthermore, the prevalence among students who had sexual contact with both sexes was more likely to be higher than (rather than equal to or lower than) the prevalence among students who only had sexual contact with the opposite sex for behaviors in six of the 10 risk behavior categories (behaviors that contribute to violence, behaviors related to attempted suicide, tobacco use, alcohol use, other drug use, and weight management). The prevalence among students who only had sexual contact with the same sex was more likely to be higher than (rather than equal to or lower than) the prevalence among students who only had sexual contact with the opposite sex for behaviors in two risk behavior categories (behaviors related to attempted suicide and weight management).

INTERPRETATIONS

Sexual minority students, particularly gay, lesbian, and bisexual students and students who had sexual contact with both sexes, are more likely to engage in health-risk behaviors than other students.

PUBLIC HEALTH ACTION

Effective state and local public health and school health policies and practices should be developed to help reduce the prevalence of health-risk behaviors and improve health outcomes among sexual minority youths. In addition, more state and local surveys designed to monitor health-risk behaviors and selected health outcomes among population-based samples of students in grades 9-12 should include questions on sexual identity and sex of sexual contacts.

Youth risk behavior surveillance - United States, 2009

PROBLEM

Priority health-risk behaviors, which are behaviors that contribute to the leading causes of morbidity and mortality among youth and adults, often are established during childhood and adolescence, extend into adulthood, and are interrelated and preventable.

REPORTING PERIOD COVERED

September 2008- December 2009.

DESCRIPTION OF THE SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults: 1) behaviors that contribute to unintentional injuries and violence; 2) tobacco use; 3) alcohol and other drug use; 4) sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases (STDs), including human immunodeficiency virus (HIV) infection; 5) unhealthy dietary behaviors; and 6) physical inactivity. In addition, YRBSS monitors the prevalence of obesity and asthma. YRBSS includes a national school-based Youth Risk Behavior Survey (YRBS) conducted by CDC and state and local school-based YRBSs conducted by state and local education and health agencies. This report summarizes results from the 2009 national survey, 42 state surveys, and 20 local surveys conducted among students in grades 9-12.

RESULTS

Results from the 2009 national YRBS indicated that many high school students are engaged in behaviors that increase their likelihood for the leading causes of death among persons aged 10-24 years in the United States. Among high school students nationwide, 9.7% rarely or never wore a seat belt when riding in a car driven by someone else. During the 30 days before the survey, 28.3% of high school students rode in a car or other vehicle driven by someone who had been drinking alcohol, 17.5% had carried a weapon, 41.8% had drunk alcohol, and 20.8% had used marijuana. During the 12 months before the survey, 31.5% of high school students had been in a physical fight and 6.3% had attempted suicide. Substantial morbidity and social problems among youth also result from unintended pregnancies and STDs, including HIV infection. Among high school students nationwide, 34.2% were currently sexually active, 38.9% of currently sexually active students had not used a condom during their last sexual intercourse, and 2.1% of students had ever injected an illegal drug. Results from the 2009 YRBS also indicated that many high school students are engaged in behaviors associated with the leading causes of death among adults aged >or=25 years in the United States. During 2009, 19.5% of high school students smoked cigarettes during the 30 days before the survey. During the 7 days before the survey, 77.7% of high school students had not eaten fruits and vegetables five or more times per day, 29.2% had drunk soda or pop at least one time per day, and 81.6% were not physically active for at least 60 minutes per day on all 7 days. One-third of high school students attended physical education classes daily, and 12.0% were obese.

INTERPRETATION

Since 1991, the prevalence of many health-risk behaviors among high school students nationwide has decreased. However, many high school students continue to engage in behaviors that place them at risk for the leading causes of morbidity and mortality. The prevalence of most risk behaviors does not vary substantially among cities and states.

PUBLIC HEALTH ACTION

YRBS data are used to measure progress toward achieving 15 national health objectives for Healthy People 2010 and three of the 10 leading health indicators, to assess trends in priority health-risk behaviors among high school students, and to evaluate the impact of broad school and community interventions at the national, state, and local levels. More effective school health programs and other policy and programmatic interventions are needed to reduce risk and improve health outcomes among youth.

Youth risk behavior surveillance--Pacific Island United States Territories, 2007

PROBLEM

Priority health-risk behaviors, which are behaviors that contribute to the leading causes of morbidity and mortality among youth and adults in Pacific Island territories, often are established during adolescence and extend into adulthood.

REPORTING PERIOD COVERED

January--June 2007.

DESCRIPTION OF THE SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults, including behaviors that contribute to unintentional injuries and violence; tobacco use; alcohol and other drug use; sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases, including human immunodeficiency virus infection; unhealthy dietary behaviors; and physical inactivity. In addition, the YRBSS monitors the prevalence of obesity and asthma. YRBSS includes a national school-based survey conducted by CDC and state, territorial, tribal, and local school-based surveys conducted by state, territorial, tribal, and local education and health agencies. This report summarizes results from surveys of students in grades 9--12 conducted in five territories (American Samoa, Commonwealth of the Northern Mariana Islands, Guam, Republic of the Marshall Islands, and Republic of Palau) during January--June 2007.

RESULTS

Across the five Pacific Island territories, the leading causes of mortality among all ages include unintentional injuries, including motor-vehicle crashes; cancer; cardiovascular diseases; stroke; and diabetes. Results from the Youth Risk Behavior Survey (YRBS) indicated that high school students in the Pacific Island territories engaged in behaviors that increased their risk for mortality or morbidity from these causes. Across the five territories during 2007, the percentage of high school students who had rarely or never worn a seat belt when riding in a car driven by someone else ranged from 11.8% to 83.2% (median: 30.9%). During the 30 days before the survey, the percentage who had ridden in a car or other vehicle driven by someone who had been drinking alcohol ranged from 34.8% to 49.8% (median: 42.8%), the percentage who had driven a car or other vehicle when they had been drinking alcohol ranged from 7.8% to 16.1% (median: 11.9%), and the percentage who had carried a weapon ranged from 16.9% to 32.0% (median: 19.6%). The percentage of students who had smoked cigarettes during the 30 days before the survey ranged from 23.1% to 37.6% (median: 31.1%), the percentage who had not eaten fruits and vegetables five or more times per day during the 7 days before the survey ranged from 72.8% to 83.6% (median: 79.5%), and the percentage who had not met recommended levels of physical activity ranged from 64.0% to 77.2% (median: 68.9%).

INTERPRETATION

The prevalence of many health-risk behaviors varies across the five Pacific Island territories, and many high school students engage in behaviors that place them at risk for the leading causes of mortality and morbidity.

PUBLIC HEALTH ACTION

YRBSS data will be used in the territories for decision making and program planning, resulting in more effective school health and youth health programs. More evidence-based interventions and programs are needed to reduce risk behaviors and improve health outcomes among youth.

Youth risk behavior surveillance--United States, 2007

PROBLEM

Priority health-risk behaviors, which are behaviors that contribute to the leading causes of morbidity and mortality among youth and adults, often are established during childhood and adolescence, extend into adulthood, are interrelated, and are preventable.

REPORTING PERIOD COVERED

January--December 2007.

DESCRIPTION OF THE SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults, including behaviors that contribute to unintentional injuries and violence; tobacco use; alcohol and other drug use; sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases (STDs), including human immunodeficiency virus (HIV) infection; unhealthy dietary behaviors; and physical inactivity. In addition, YRBSS monitors the prevalence of obesity and asthma. YRBSS includes a national school-based survey conducted by CDC and state and local school-based surveys conducted by state and local education and health agencies. This report summarizes results from the national survey, 39 state surveys, and 22 local surveys conducted among students in grades 9--12 during 2007.

RESULTS

In the United States, 72% of all deaths among persons aged 10--24 years result from four causes: motor-vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the 2007 national Youth Risk Behavior Survey (YRBS) indicated that many high school students engaged in behaviors that increased their likelihood of death from these four causes. Among high school students nationwide during 2007, 11.1% had never or rarely worn a seat belt when riding in a car driven by someone else. During the 30 days before the survey, 29.1% of high school students had ridden in a car or other vehicle driven by someone who had been drinking alcohol, 18.0% had carried a weapon, and 5.5% had not gone to school because they felt they would be unsafe at school or on their way to or from school. During the 12 months before the survey, 6.9% of high school students had attempted suicide. In addition, 75.0% of high school students had ever drunk alcohol, and 4.4% had ever used methamphetamines. Substantial morbidity and social problems among youth also result from unintended pregnancies and STDs, including HIV infection. Results from the 2007 survey indicated that 47.8% of students had ever had sexual intercourse, 35.0% of high school students were currently sexually active, and 38.5% of currently sexually active high school students had not used a condom during last sexual intercourse. Among U.S. adults aged >or=25 years, 59% of all deaths result from two causes: cardiovascular disease and cancer. Results from the 2007 national YRBS indicated that risk behaviors associated with these two causes of death were present during adolescence. Among high school students nationwide during 2007, 20.0% had smoked cigarettes during the 30 days before the survey, 35.4% had watched television 3 or more hours per day on an average school day, and 13.0% were obese. During the 7 days before the survey, 78.6% of high school students had not eaten fruits and vegetables five or more times per day, 33.8% had drunk soda or pop at least one time per day, and 65.3% had not met recommended levels of physical activity.

INTERPRETATION

Since 1991, the prevalence of many health-risk behaviors among high school students nationwide has decreased. However, many high school students continue to engage in behaviors that place them at risk for the leading causes of mortality and morbidity. The prevalence of most risk behaviors does not vary substantially among cities and states.

PUBLIC HEALTH ACTION

YRBS data are used to measure progress toward achieving 15 national health objectives for Healthy People 2010 and three of the 10 leading health indicators, to assess trends in priority health-risk behaviors among high school students, and to evaluate the impact of broad school and community interventions at the national, state, and local levels. More effective school health programs and other policy and programmatic interventions are needed to reduce risk and improve health outcomes among youth.

Youth risk behavior surveillance--selected steps communities, 2005

PROBLEM

Unhealthy dietary behaviors, physical inactivity, and tobacco use contribute to chronic disease and other health conditions, including obesity, diabetes, and asthma. These behaviors often are established during childhood and adolescence, extend into adulthood, are interrelated, and are preventable.

REPORTING PERIOD COVERED

January-May 2005.

DESCRIPTION OF SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors priority health-risk behaviors, general health status, and the prevalence of overweight and asthma among youth and young adults. YRBSS includes a national school-based survey conducted by CDC and state and local school-based surveys conducted by state and local education and health agencies. As a component of YRBSS, in 2005, communities participating in the Steps to a HealthierUS Cooperative Agreement Program (Steps Program) also conducted school-based surveys of students in grades 9-12 in their program intervention areas. These communities used a modified core questionnaire that asks about dietary behaviors, physical activity, and tobacco use and monitors the prevalence of overweight, diabetes, and asthma. This report summarizes results from surveys of students in 15 Steps communities that conducted surveys in 2005.

RESULTS

Results from the 15 Steps communities indicated that a substantial proportion of adolescents engaged in health risk behaviors associated with obesity, diabetes, and asthma. During 2005, across surveys, the percentage of high school students who had not eaten fruits and vegetables > or =5 times/day during the 7 days preceding the survey ranged from 80.1% to 85.2% (median: 83.1%), the percentage who were overweight ranged from 6.6% to 19.6% (median: 11.5%), the percentage who did not attend physical education classes daily ranged from 53.7% to 95.1% (median: 74.2%), and the percentage who had smoked cigarettes during the 30 days preceding the survey ranged from 9.2% to 26.5% (median: 17.1%).

INTERPRETATION

Although the prevalence of many health-risk behaviors and health conditions varies across Steps communities, a substantial proportion of high school students engage in behaviors that place them at risk for chronic disease.

PUBLIC HEALTH ACTION

Steps Program staff at the national, tribal, state, and local levels will use YRBSS data for decision making, program planning, and enhancing technical assistance. These data will be used to focus existing programs on activities with the greatest promise of results, identify opportunities for strategic collaboration, and identify and disseminate lessons learned.

Youth risk behavior surveillance--United States, 2005

In the United States, 71% of all deaths among persons aged 10-24 years result from 4 causes: motorvehicle crashes, other unintentional injuries, homicide, and suicide. Results from the 2005 national Youth Risk Behavior Survey (YRBS) indicated that during the 30 days preceding the survey, many high school students engaged in behaviors that increased their likelihood of death from these 4 causes: 9.9% had driven a car or other vehicle when they had been drinking alcohol, 18.5% had carried a weapon, 43.3% had drunk alcohol, and 20.2% had used marijuana. In addition, during the 12 months preceding the survey, 35.9% of high school students had been in a physical fight and 8.4% had attempted suicide. Substantial morbidity and social problems among youth also result from unintended pregnancies and sexually transmitted diseases, including human immunodeficiency virus infection. During 2005, a total of 46.8% of high school students had ever had sexual intercourse, 37.2% of sexually active high school students had not used a condom at last sexual intercourse, and 2.1% had ever injected an illegal drug. Among adults aged > or =25 years, 61% of all deaths result from 2 causes: cardiovascular disease and cancer. Results from the 2005 national YRBS indicated that risk behaviors associated with these 2 causes of death were initiated during adolescence. During 2005, a total of 23.0% of high school students had smoked cigarettes during the 30 days preceding the survey, 79.9% had not eaten > or =5 times/day of fruits and vegetables during the 7 days preceding the survey, 67.0% did not attend physical education classes daily, and 13.1% were overweight.

Youth risk behavior surveillance--United States, 2005

PROBLEM

Priority health-risk behaviors, which contribute to the leading causes of morbidity and mortality among youth and adults, often are established during childhood and adolescence, extend into adulthood, are interrelated, and are preventable.

REPORTING PERIOD COVERED

October 2004-January 2006.

DESCRIPTION OF THE SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults, including behaviors that contribute to unintentional injuries and violence; tobacco use; alcohol and other drug use; sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases (STDs), including human immunodeficiency virus (HIV) infections; unhealthy dietary behaviors; and physical inactivity. In addition, the YRBSS monitors general health status and the prevalence of overweight and asthma. YRBSS includes a national school-based survey conducted by CDC and state and local school-based surveys conducted by state and local education and health agencies. This report summarizes results from the national survey, 40 state surveys, and 21 local surveys conducted among students in grades 9-12 during October 2004-January 2006.

RESULTS

In the United States, 71% of all deaths among persons aged 10-24 years result from four causes: motor-vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the 2005 national Youth Risk Behavior Survey (YRBS) indicated that, during the 30 days preceding the survey, many high school students engaged in behaviors that increased their likelihood of death from these four causes: 9.9% had driven a car or other vehicle when they had been drinking alcohol; 18.5% had carried a weapon; 43.3% had drunk alcohol; and 20.2% had used marijuana. In addition, during the 12 months preceding the survey, 35.9% of high school students had been in a physical fight and 8.4% had attempted suicide. Substantial morbidity and social problems among youth also result from unintended pregnancies and STDs, including HIV infection. During 2005, a total of 46.8% of high school students had ever had sexual intercourse; 37.2% of sexually active high school students had not used a condom at last sexual intercourse; and 2.1% had ever injected an illegal drug. Among adults aged >/=25 years, 61% of all deaths result from two causes: cardiovascular disease and cancer. Results from the 2005 national YRBS indicated that risk behaviors associated with these two causes of death were initiated during adolescence. During 2005, a total of 23.0% of high school students had smoked cigarettes during the 30 days preceding the survey; 79.9% had not eaten >/=5 times/day of fruits and vegetables during the 7 days preceding the survey; 67.0% did not attend physical education classes daily; and 13.1% were overweight.

INTERPRETATION

Since 1991, the prevalence of many health-risk behaviors among high school students nationwide has decreased. However, many high school students continue to engage in behaviors that place them at risk for the leading causes of mortality and morbidity. The prevalence of many health-risk behaviors varies across cities and states.

PUBLIC HEALTH ACTION

YRBS data are used to measure progress toward achieving 15 national health objectives for Healthy People 2010 and three of the 10 leading health indicators, to assess trends in priority health-risk behaviors among high school students, and to evaluate the impact of broad school and community interventions at the national, state, and local levels. More effective school health programs and other policy and programmatic interventions are needed to reduce risk and improve health outcomes among youth.

Youth risk behavior surveillance--United States, 2003

PROBLEM/CONDITION

Priority health-risk behaviors, which contribute to the leading causes of morbidity and mortality among youth and adults, often are established during youth, extend into adulthood, are interrelated, and are preventable.

REPORTING PERIOD

This report covers data collected during February-December 2003.

DESCRIPTION OF SYSTEM

The Youth Risk Behavior Surveillance System (YRBSS) monitors six categories of priority health-risk behaviors among youth and young adults--behaviors that contribute to unintentional injuries and violence; tobacco use; alcohol and other drug use; sexual behaviors that contribute to unintended pregnancy and sexually transmitted diseases (STDs), including human immunodeficiency virus (HIV) infection; unhealthy dietary behaviors; and physical inactivity--plus overweight. YRBSS includes a national school-based survey conducted by CDC as well as state and local school-based surveys conducted by education and health agencies. This report summarizes results from the national survey, 32 state surveys, and 18 local surveys conducted among students in grades 9-12 during February-December 2003.

RESULTS AND INTERPRETATION

In the United States, 70.8% of all deaths among persons aged 10-24 years result from only four causes: motor-vehicle crashes, other unintentional injuries, homicide, and suicide. Results from the 2003 national Youth Risk Behavior Survey demonstrated that, during the 30 days preceding the survey, numerous high school students engage in behaviors that increase their likelihood of death from these four causes: 30.2% had ridden with a driver who had been drinking alcohol; 17.1% had carried a weapon; 44.9% had drunk alcohol; and 22.4% had used marijuana. In addition, during the 12 months preceding the survey, 33.0% of high school students had been in a physical fight, and 8.5% had attempted suicide. Substantial morbidity and social problems among young persons also result from unintended pregnancies and STDs, including HIV infection. In 2003, 46.7% of high school students had ever had sexual intercourse; 37% of sexually active students had not used a condom at last sexual intercourse; and 3.2% had ever injected an illegal drug. Among adults aged > or =25 years, 62.9% of all deaths results from two causes: cardiovascular diseases and cancer. Results from the 2003 national Youth Risk Behavior Survey demonstrate that the majority of risk behaviors associated with these two causes of death are initiated during adolescence. In 2003, a total of 21.9% of high school students had smoked cigarettes during the 30 days preceding the survey; 78% had not eaten > or =5 servings/day of fruits and vegetables during the 7 days preceding the survey; 33.4% had participated in an insufficient amount of physical activity; and 13.5% were overweight.

ACTIONS TAKEN

YRBSS data are being used to measure progress toward achieving 15 national health objectives for 2010 and three of the 10 leading health indicators. In addition, education and health officials at national, state, and local levels are using these YRBSS data to improve policies and programs to reduce priority health-risk behaviors among youth.

The effect of using different reference dates for control exposure measurement on relative risk estimates in a case-control study

In case-control studies in which case and control enrollment periods are not identical, exposure status for time-dependent variables is often measured relative to a reference date. Using data from a case-control study of the relation between cervical cancer and oral contraceptive (OC) use in which control enrollment began 6 months after the end of case enrollment, we evaluated the effect on odds ratios from using five different reference dates to determine the controls' exposure status. The choice of reference date had little effect on the odds ratios in this study. Reference dates for time-dependent exposure variables should be considered carefully in studies when case and control enrollment periods are not identical.