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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 >=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 >=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. [ABSTRACT FROM AUTHOR]

OBJECTIVES: To identify factors associated with cigarette smoking in the 6th-grade through 10th-grade youth population of Sarasota County, Florida. METHODS: A closed-ended, quantitative survey was completed by 2004 youth and used to extract population-specific data on the correlates of cigarette use. RESULTS: A range of factors influence cigarette use including self-efficacy to refuse offers of cigarettes, perceived emotional benefits, and perceived maternal disapproval of smoking. CONCLUSIONS: Results underscore the need for multiple-component interventions. This study is unique in that it represents population-specific research in which community partners are using the findings to develop community-specific prevention marketing interventions. [ABSTRACT FROM AUTHOR]

Although youth involvement in health promotion efforts is not a new concept, projects that actively involve youths in planning research, collecting data, and making research design decisions are rare. This article describes the evaluation process and outcomes for a youth-directed data collection initiative. Eleven youth researchers conducted 112 personal in-depth interviews and 22 focus groups involving 206 youths in 5th through 12th grade. Youth researchers felt confident they could conduct focus groups and in-depth interviews and staff ratings of youths' effectiveness in moderating focus groups indicated they were successful in carrying out the qualitative research. [ABSTRACT FROM AUTHOR]

OBJECTIVE: To examine associations between insufficient sleep (<8h on average school nights) and health-risk behaviors. METHODS: 2007 national Youth Risk Behavior Survey data of U.S. high school students (n=12,154) were analyzed. Associations were examined on weighted data using multivariate logistic regression. RESULTS: Insufficient sleep on an average school night was reported by 68.9% of students. Insufficient sleep was associated with higher odds of current use of cigarettes (age-adjusted odds ratio [AOR], 1.67; 95% confidence interval [CI], 1.45-1.93), marijuana (AOR, 1.52; 95% CI, 1.31-1.76), and alcohol (AOR, 1.64; 95% CI, 1.46-1.84); current sexual activity (AOR, 1.41; 95% CI, 1.25-1.59); seriously considered attempting suicide (AOR, 1.86; 95% CI, 1.60-2.16); feeling sad or hopeless (AOR, 1.62; 95% CI, 1.43-1.84); physical fighting (AOR, 1.40; 95% CI, 1.24-1.60), not being physically active at least 60min>=5days in the past 7days (AOR, 1.16; 95% CI, 1.04-1.29), using the computer >=3h/day (AOR, 1.58; 95% CI, 1.38-1.80), and drinking soda/pop >1time/day (AOR, 1.14; 95% CI, 1.03-1.28). CONCLUSION: Two-thirds of adolescent students reported insufficient sleep, which was associated with many health-risk behaviors. Greater awareness of the impact of sleep insufficiency is vital. [ABSTRACT FROM AUTHOR]

We describe the prevalence of insufficient, borderline, and optimal sleep hours among U.S. high school students on an average school night. Most students (68.9%) reported insufficient sleep, whereas few (7.6%) reported optimal sleep. The prevalence of insufficient sleep was highest among female and black students, and students in grades 11 and 12. [ABSTRACT FROM AUTHOR]

A critical prelude to any community odor assessment should be the prioritization of specific chemical odorants that are most responsible for targeted downwind odors. Unfortunately, and historically, this is a step that has often been bypassed or overlooked. However, correct understanding of the specific impactful volatile organic compounds (VOCs) can inform the follow-on sampling, analytical, and remediation strategies that are most appropriate and efficient, based upon the chemistry behind the issue. With this understanding, the techniques and sampling strategies presented herein should be viewed as a qualitative prelude rather than an addendum to a follow-up routine, automated downwind odor monitoring. Downwind odor characteristics can vary depending upon the size of the upwind source, interim topography, and wind conditions. At one extreme, the downwind odor plume from a relatively large source located on a flat open plain and under stable, near-straight line wind conditions can be rather broad, sustained, and predictable. In contrast, the plume from a small point source (e.g., a roof vent stack) located on irregular topography and under rapidly shifting wind conditions can be intermittent and fleeting ("spikes" or "bursts"). These transient odor events can be surprisingly intense and offensive, despite their fleeting occurrence and perception. This work reports on improving and optimizing an environmental sampling strategy for odorant prioritization from such transient downwind odor conditions. This optimization addresses the challenges of (1) sampling of transient odor "spikes" and (2) prioritizing odors/odorants from multiple, closely colocated point sources under transient event conditions. Prioritizing is defined as identifying the key impactful odorants downwind. Grab air sampling protocol refinement has emerged from actual community environmental odor assessment projects. The challenge of assessing transient odor events has been mitigated by utilizing (a) rapid, odor-cued whole-air grab sampling (i.e., activated by and synchronous with the perceived sensory spikes) into metalized fluorinated ethylene polymer (m-FEP) gas sampling bags; (b) immediate transfer from bags onto solid-phase microextraction (SPME) fibers or sorbent tubes; and (c) maintaining refrigerated storage and shipment conditions between field collection and in-laboratory analysis. Results demonstrated approximately 11-fold increases in target odorant yields for 900 mL air sample capture on sorbent tube transfers from 2 to 3 s "burst" odor event bag captures compared to equivalent direct collections (with sorbent tubes) at the same downwind receptor location but during perceived (stable) odor "lull" periods. An application targeting general odor sampling and point-source differentiation utilizing tracer gases is also presented., Competing Interests: The authors declare the following competing financial interest(s): Three commercial entities are represented among the collaborative team (Don Wright & Associates, LLC, The Epsilon Company, LLC, and Volatile Analysis Corporation). The funders (USDA-SBIR Phase II, Iowa Agriculture and Home Economics Experiment Station) had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript, or in the decision to publish the results., (© 2024 The Authors. Published by American Chemical Society.)

Purpose: To determine the prevalence and correlates of missing meals among adolescents., Design: The 2010 National Youth Physical Activity and Nutrition Study, a cross-sectional study., Setting: School based., Participants: A nationally representative sample of 11 429 high school students., Measures: Breakfast, lunch, and dinner consumption; demographics; measured and perceived weight status; physical activity and sedentary behaviors; and fruit, vegetable, milk, sugar-sweetened beverage, and fast-food intake., Analysis: Prevalence estimates for missing breakfast, lunch, or dinner on ≥1 day during the past 7 days were calculated. Associations between demographics and missing meals were tested. Associations of lifestyle and dietary behaviors with missing meals were examined using logistic regression controlling for sex, race/ethnicity, and grade., Results: In 2010, 63.1% of students missed breakfast, 38.2% missed lunch, and 23.3% missed dinner; the prevalence was highest among female and non-Hispanic black students. Being overweight/obese, perceiving oneself to be overweight, and video game/computer use were associated with increased risk of missing meals. Physical activity behaviors were associated with reduced risk of missing meals. Students who missed breakfast were less likely to eat fruits and vegetables and more likely to consume sugar-sweetened beverages and fast food., Conclusion: Breakfast was the most frequently missed meal, and missing breakfast was associated with the greatest number of less healthy dietary practices. Intervention and education efforts might prioritize breakfast consumption.

Background: Epi-Aids, or epidemiologic assistance investigations, are an important mechanism through which Centers for Disease Control and Prevention supports public health organizations. We described the characteristics of Epi-Aids conducted during 2005-2014 and summarized the publication outcome of Epi-Aid related scientific information products., Methods: We performed a descriptive analysis of all Epi-Aids conducted during January 1, 2005-December 31, 2014; investigations were categorized by health topic and geographic distribution. We highlighted investigations of substantial public health importance, e.g., multistate investigations and investigations of epidemics and pandemics. We identified the Epi-Aid publication outcome by searching PubMed for Epi-Aid related publications, which included Morbidity and Mortality Weekly Reports (MMWRs) and peer-reviewed publications with an Epidemic Intelligence Service Officer (EISO) as a coauthor. We calculated publication timeliness and categorized publications by journal impact factor., Results: During the study period, 698 EISOs and their collaborators participated in 807 Epi-Aids throughout the United States and globally. Approximately 81 Epi-Aids were conducted annually (range, 62-104); 632 (78.3%) were infectious disease-related; 161 (20.0%) were international, supporting 68 countries. As of June 2015, EISOs, in collaboration with partners, published 131 MMWRs and 280 scientific manuscripts on the basis of the 807 Epi-Aids conducted during the study period; 394 (48.8%) Epi-Aids resulted in publications in 80 peer-reviewed journals., Conclusions: EISOs play a critical role in conducting Epi-Aids, which require qualified field epidemiologists who can rapidly respond to requests for assistance during public health emergencies. Publications based on Epi-Aids share new knowledge with the scientific community, furthering progress of public health science and practice.

Objective: To describe the percentage of US public health schools and programs offering graduate-level courses with disability content as a potential baseline measurement for Healthy People 2020 objective DH-3 and compare the percentage of public health schools that offered disability coursework in 1999 with those in 2011., Design: In 2011, using SurveyMonkey.com, cross-sectional information was collected from the deans, associate deans, directors, or chairpersons of master of public health-granting public health schools and programs that were accredited and listed with the Council on Education for Public Health. Two rounds of follow-up were conducted at 4-month intervals by e-mails and phone calls to program contacts who had not responded. The responses from schools and programs were calculated and compared., Results: There were 78 responses (34 schools and 44 programs) for a response rate of 63%. Fifty percent of public health schools and programs offered some disability content within their graduate-level courses. A greater percentage of schools than programs (71% vs 34%; P = .003) offered some graduate-level disability coursework within their curricula. The percentage of schools that offered disability coursework was similar in 1999 and 2011., Conclusion: This assessment provides a potential baseline measurement for Healthy People 2020 objective DH-3. Future assessments should focus on clarifying disability content within courses and identifying capacity to offering disability training within public health schools and programs.

Purpose: To examine behavioral and environmental factors that may be related to dietary behaviors among U.S. high school students., Design: Data were obtained from the 2010 National Youth Physical Activity and Nutrition Study, a cross-sectional study., Setting: The study was school-based., Subjects: Study subjects were a nationally representative sample of students in grades 9 to 12 (n = 11,458)., Measures: Variables of interest included meal practices, in-home snack availability, and intakes of healthful foods/beverages (fruits, vegetables, water, and milk) and less healthful foods/beverages (fried potatoes, pizza, and sugar-sweetened beverages)., Analysis: Sex-stratified logistic regression models were used to examine associations of meal practices and snack availability with dietary intake. Odds ratios (ORs) were adjusted for race/ethnicity and grade., Results: Eating breakfast daily, frequent family dinners, and bringing lunch from home were associated with higher odds of consuming at least three healthful foods or beverages. High fast-food intake was associated with lower odds of healthful dietary intake and higher odds of sugar-sweetened beverage intake (female OR = 3.73, male OR = 4.60). Students who mostly/always had fruits and vegetables available at home had increased odds of fruits (female OR = 3.04, male OR = 2.24), vegetables (female OR = 2.12, male OR = 1.65), water (female OR = 1.82, male OR = 1.85), and milk intake (female OR = 1.45, male OR = 1.64)., Conclusion: Encouraging daily breakfast consumption, frequent family dinners, and fruit and vegetable availability at home may lead to higher intakes of healthful foods among high school students.

To examine trends in weight management goals and behaviors among U.S. high school students during 1999-2009. Data from six biennial cycles (1999-2009) of the national Youth Risk Behavior Survey were analyzed. Cross-sectional, nationally representative samples of 9th-12th grade students (approximately 14,000 students/cycle) completed self-administered questionnaires. Logistic regression models adjusted for grade, race/ethnicity, and obesity were used to test for trends in weight management goals and behaviors among subgroups of students. Combined prevalences and trends differed by sex and by race/ethnicity and weight status within sex. During 1999-2009, the prevalence of female students trying to gain weight decreased (7.6-5.7 %). Among female students trying to lose or stay the same weight, prevalences decreased for eating less (69.6-63.2 %); fasting (23.3-17.6 %); using diet pills/powders/liquids (13.7-7.8 %); and vomiting/laxatives (9.5-6.6 %) for weight control. During 1999-2009, the prevalence of male students trying to lose weight increased (26.1-30.5 %). Among male students trying to lose or stay the same weight, the prevalence of exercising to control weight did not change during 1999-2003 and then increased (74.0-79.1 %) while the prevalence of taking diet pills/powders/liquids for weight control decreased (6.9-5.1 %) during 1999-2009. Weight management goals and behaviors changed during 1999-2009 and differed by subgroup. To combat the use of unhealthy weight control behaviors, efforts may be needed to teach adolescents about recommended weight management strategies and avoiding the risks associated with unhealthy methods.

Background: This study investigated associations of violence-related behaviors with physical activity (PA)-related behaviors among U.S. high school students., Methods: Data from the 2009 national Youth Risk Behavior Survey, a cross-sectional survey of a nationally representative sample of 9th-12th grade students, were analyzed. Sex-stratified, adjusted odds ratios (aORs) and 95% confidence intervals (CIs) were estimated for associations between violence-related behaviors and being physically active for ≥60 minutes daily, sports participation, TV watching for ≥3 hours/day, and video game/computer use for ≥3 hours/day., Results: Among male students, at-school bullying victimization was negatively associated with daily PA (aOR: 0.72; 95% CI: 0.58-0.87) and sports participation; skipping school because of safety concerns was positively associated with video game/computer use (1.42; 1.01-2.00); and physical fighting was positively associated with daily PA. Among female students, at-school bullying victimization and skipping school because of safety concerns were both positively associated with video game/computer use (1.46; 1.19-1.79 and 1.60; 1.09-2.34, respectively), and physical fighting at school was negatively associated with sports participation and positively associated with TV watching., Conclusions: Bullying victimization emerged as a potentially important risk factor for insufficient PA. Schools should consider the role of violence in initiatives designed to promote PA.

Objectives: To compare 7 beverage intake survey questions against criterion data from 24-hour dietary recall interviews (24HrDRIs) among adolescents., Methods: Data were available from 610 US high school students completing a survey and ≥3 24HrDRIs. Analyses compared mean intake (times/day) calculated from the survey to intake (servings/day) from the 24HrDRIs. Proportions of students reporting intake of ≥1 times/day were compared to the 24HrDRI results., Results: Survey data significantly correlated with 24HrDRI data (all corrected r: 0.26-0.49). Survey results differed from 24HrDRI results on reported intake of 5 beverages., Conclusion: Intake from these beverage questions should be reported in times/day, which is related to, but not a proxy for, servings/day. These questions are useful for population-level surveillance of beverage intake and monitoring trends over time.

Objective: To describe electronic media exposure and its associations with beverage intake among United States high school students., Methods: School-based survey data from a nationally representative sample of 9th- through 12th-grade students from the National Youth Physical Activity and Nutrition Study were analyzed using chi-square and multivariate logistic analyses., Results: On an average school day, 23.5% of students used a computer or played video/computer games ≥ 3 h/d, 28.3% watched television (TV) ≥ 3 h/d, 79.9% had ≥ 3 TVs in the home, 70.2% had a TV in their bedroom, and 41.0% most of the time or always had a TV on while eating dinner at home. Students with high media exposure were more likely to drink sugar-sweetened beverages ≥ 3 times per day and less likely to drink water ≥ 3 times per day and drink ≥ 2 glasses of milk per day., Conclusions and Implications: Efforts to reduce sugar-sweetened beverage intake among adolescents may include limiting exposure to electronic media., (Published by Elsevier Inc.)

Purpose: National data related to physical activity (PA) and nutrition among adolescents are needed to help develop effective obesity prevention programs. The 2010 National Youth Physical Activity and Nutrition Study (NYPANS) was conducted to provide nationally representative data on behaviors and behavioral correlates related to healthy eating and PA., Methods: NYPANS used a three-stage cluster sample design to obtain data representative of public- and private-school students in grades 9 through 12 in the United States (n = 11,429). Students completed an anonymous, self-administered questionnaire in their classrooms during a regular class period. Trained data collectors directly measured the students' height and weight at school using a standard protocol., Results: Analyses revealed that 19.0% of students were obese and 17.8% were overweight. Students participated in a range of physical activities during the 12 months before the survey; prevalence ranged from 5.0% for ice hockey to 83.9% for walking. In addition, 52.5% of students enjoyed the physical education classes they took at school. During the 7 days before the survey, 74.8% of students ate at least one meal or snack from a fast food restaurant, with black students more likely than white and Hispanic students to have done so. Forty-one percent of students always or most of the time have a TV on while eating dinner at home., Conclusions: These and other NYPANS results can be used to develop obesity prevention programs that address specific behaviors and behavioral correlates, and target subgroups in which behaviors and behavioral correlates related to obesity are most prevalent., (Published by Elsevier Inc.)

Background: Fruit and vegetable (F/V) intake surveillance can provide information critical to the design and evaluation of interventions and the assessment of progress toward national intake objectives. The CDC's Youth Risk Behavior Surveillance System (YRBSS) assesses F/V intake among high school students using six questions about the frequency of intake in times per day. It is not known whether F/V intake frequency in times per day can be used as a proxy for intake in servings per day., Objective: To compare F/V intake estimates based on responses to three sets of survey questions, including the standard set of six YRBSS questions, with criterion F/V intake in servings per day based on data from 24-hour dietary recall interviews., Participants/setting: Study participants were 610 high school students who completed an in-class questionnaire and three telephone-administered 24-hour dietary recall interviews. The questionnaire asked students how many times they consumed 100% fruit juice and ate fruit, carrots, potatoes, green salad, and other vegetables during the "past 7 days" (set 1), the number of times they did so "yesterday" (set 2), and the number of cup-equivalents of fruits and vegetables they consumed per day (set 3)., Main Outcome Measure: Mean estimated F/V intake either as "times/day" or "servings/day" and the percentage of students whose estimated F/V intake was ≥1, ≥2, and ≥3 times/day or servings/day., Statistical Analyses Performed: t tests and corrected Pearson correlations were used to compare F/V intake estimates based on survey question responses with estimates based on responses to the 24-hour dietary recall interviews., Results: Mean F/V intake estimates (in times/day or servings/day) based on responses to all sets of survey questions were significantly more than servings/day estimates based on responses to the 24-hour dietary recall interviews, and the percentages of students meeting each intake cutpoint were also more. Of the three sets of survey questions, the standard YRBSS questions produced estimates and percentages that were most consistently closest to 24-hour dietary recall interview estimates., Conclusions: For brief self-administered questionnaires of high school students, the current YRBSS questions are recommended for monitoring F/V intake even though mean intake estimates in times/day will likely be higher than, and are not a proxy for, mean intake estimates in servings/day., (Copyright © 2013 Academy of Nutrition and Dietetics. Published by Elsevier Inc. All rights reserved.)

Objective: To assess the prevalence of texting/e-mailing while driving (TWD) and association of TWD with other risky motor vehicle (MV) behaviors among US high school students., Methods: Data were used from the Centers for Disease Control and Prevention's 2011 national Youth Risk Behavior Survey, which assessed TWD during the 30 days before the survey among 8505 students aged ≥16 years from a nationally representative sample of US high school students. TWD frequency was coded into dichotomous and polychotomous variables. Logistic regression assessed the relationship between TWD and other risky driving behaviors, controlling for age, race/ethnicity, and sex., Results: The prevalence of TWD on ≥1 days during the 30 days before the survey was 44.5% (95% confidence interval: 40.8%-48.2%). Students who engaged in TWD were more likely than their non-TWD counterparts to not always wear their seatbelt (prevalence ratio; 95% confidence interval: 1.16; 1.07-1.26), ride with a driver who had been drinking alcohol (1.74; 1.57-1.93), and drink alcohol and drive (5.33; 4.32-6.59). These other risky MV behaviors were most likely to occur among students who frequently engaged in TWD., Conclusions: Nearly half of US high school students aged ≥16 years report TWD during the past 30 days; these students are more likely to engage in additional risky MV behaviors. This suggests there is a subgroup of students who may place themselves, their passengers, and others on the road at elevated risk for a crash-related injury or fatality by engaging in multiple risky MV behaviors.

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.

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.

Increasing attention is being focused on sleep duration as a potential modifiable risk factor associated with obesity in children and adolescents. We analyzed data from the national Youth Risk Behavior Survey to describe the association of obesity (self-report BMI ≥95th percentile) with self-reported sleep duration on an average school night, among a representative sample of US high school students. Using logistic regression to control for demographic and behavioral confounders, among female students, compared to 7 hours of sleep, both shortened (≤4 hours of sleep; adjusted odds ratio (95% confidence interval), AOR = 1.50 (1.05-2.15)) and prolonged (≥9 hours of sleep; AOR = 1.54 (1.13-2.10)) sleep durations were associated with increased likelihood of obesity. Among male students, there was no significant association between obesity and sleep duration. Better understanding of factors underlying the association between sleep duration and obesity is needed before recommending alteration of sleep time as a means of addressing the obesity epidemic among adolescents.

Background: School-based risk behavior surveys traditionally have been administered via paper-and-pencil. This study assessed the feasibility of conducting in-class online surveys in US high schools., Methods: A paper-and-pencil questionnaire assessing computer availability and perceptions of online surveys was mailed to a nationally representative sample of public and private high school principals in fall 2008. Completed surveys were returned by principals from 580 of 704 selected schools. Prevalence and 95% confidence intervals were computed., Results: Most high schools have at least 1 computer lab, most computers in computer labs are connected to the Internet, and just under half of schools with a stationary computer lab had a sufficient number of computers to accommodate an in-class online survey administration. The 2 most common problems associated with online surveys were logistics of providing enough computers for an entire class and rotating classes into computer labs. Nearly two thirds of principals preferred online to paper-and-pencil surveys when administered to 4 randomly selected classes that met at different times during the school day, but less than half reported this preference when administered to 4 randomly selected classes that met at the same time during the school day., Conclusion: Many schools do not have sufficient computer capacity to participate in a voluntary in-class online survey. An online survey could impose significant perceived and actual burden on schools and therefore could result in unacceptably low school participation rates. Online administration for in-class surveys of students in US high schools are not recommended., (© Published 2011. This article is a US Government work and is in the public domain in the USA.)

Background: People who engage in unprotected sexual intercourse or use injection drugs are at increased risk for HIV infection and sexually transmitted diseases (STDs). Monitoring changes in behaviors over time can provide information about the effectiveness of new policies and programs., Purpose: To measure trends in HIV- and STD-related risk behaviors among high school students in the U.S. during 1991-2009., Methods: Nationally representative data from the 1991-2009 biennial national Youth Risk Behavior Surveys were analyzed to describe trends in HIV- and STD-related risk behaviors. For each cross-sectional national survey, students completed anonymous, self-administered questionnaires assessing risk behavior participation. This study was approved by the CDC IRB, and parental permission was obtained. To assess the significance of time trends for each behavior, logistic regression analyses were conducted that controlled for gender, grade, and race/ethnicity and simultaneously assessed linear and quadratic effects. Data were analyzed in 2010., Results: During 1991-2009, decreases were observed in the percentage of U.S. high school students who ever had sexual intercourse, had multiple sex partners, and who were currently sexually active. The prevalence of condom use increased during 1991-2003 and then leveled off during 2003-2009. However, these changes in risk behaviors were not observed in some gender and racial/ethnic subgroups., Conclusions: Additional efforts to reduce HIV- and STD-related risk behaviors, particularly among black and Hispanic students, must be implemented to decrease rates of HIV infection and STDs., (Published by Elsevier Inc.)

Objectives: We provided national prevalence estimates for selected health-risk behaviors for Asian American and Pacific Islander high school students separately, and compared those prevalence estimates with those of white, black, and Hispanic students., Methods: We analyzed data from the Youth Risk Behavior Surveillance System. To generate a sufficient sample of Asian American and Pacific Islander students, we combined data from four nationally representative surveys of U.S. high school students conducted in 2001, 2003, 2005, and 2007 (total n = 56,773)., Results: Asian American students were significantly less likely than Pacific Islander, white, black, or Hispanic students to have drunk alcohol or used marijuana. Asian American students also were the least likely to have carried a weapon, to have been in a physical fight, to have ever had sexual intercourse, or to be currently sexually active. Once sexually active, Asian American students were as likely as most other racial/ethnic groups to have used alcohol or drugs at last sexual intercourse or to have used a condom at last sexual intercourse. Pacific Islander students were significantly more likely than Asian American, white, black, or Hispanic students to have seriously considered or attempted suicide., Conclusions: The prevalence estimates of health-risk behaviors exhibited by Asian American students and Pacific Islander students are very different and should be reported separately whenever feasible. To address the different health-risk behaviors exhibited by Asian American and Pacific Islander students, prevention programs should use culturally sensitive strategies and materials.

The objective of this study was to identify factors that may account for the disproportionately high prevalence of suicidal behaviors among Hispanic/Latina youth by examining whether associations of health risk behaviors with suicidal ideation and suicide attempts vary by race/ethnicity among female students. Data from the school-based 2007 national Youth Risk Behavior Survey were analyzed. Analyses were conducted among female students in grades 9 through 12 and included 21 risk behaviors related to unintentional injuries and violence; tobacco use; alcohol and other drug use; sexual behaviors that contribute to unintended pregnancy and sexually transmitted infections, including human immunodeficiency virus; physical activity; obesity and weight control; and perceived health status. With the exception of physical activity behaviors and obesity, all risk behaviors examined were associated with suicidal ideation and suicide attempts. Associations of risk behaviors with suicidal ideation varied by race/ethnicity for 5 of 21 behaviors, and for 0 of 21 behaviors for suicide attempts. Stratified analyses provided little insight into factors that may account for the higher prevalence of suicidal behaviors among Hispanic/Latina female students. These results suggest that the increased risk of suicidal behaviors among Hispanic/Latina female students cannot be accounted for by differential associations with these selected risk behaviors. Other factors, such as family characteristics, acculturation, and the socio-cultural environment, should be examined in future research.

The authors examined whether paper-and-pencil and Web surveys administered in the school setting yield equivalent risk behavior prevalence estimates. Data were from a methods study conducted by the Centers for Disease Control and Prevention (CDC) in spring 2008. Intact classes of 9th- or 10th-grade students were assigned randomly to complete a survey via paper-and-pencil or Web. Data from 5,227 students were analyzed using logistic regression to identify associations of mode with reporting of 74 risk behaviors. Mode was associated with reporting of only 7 of the 74 risk behaviors. Results indicate prevalence estimates from paper-and-pencil and Web school-based surveys are generally equivalent.

Background: Approximately one-quarter of high school students currently use cigarettes. Previous research has suggested some youth use smoking as a method for losing weight. The purpose of this study was to describe the association of current cigarette use with specific healthy and unhealthy weight control practices among 9th-12th grade students in the United States., Methods: Youth Risk Behavior Survey data (2005) were analyzed. Behaviors included current cigarette use, trying to lose weight, and current use of 2 healthy and 3 unhealthy behaviors to lose weight or to keep from gaining weight. Separate logistic regression models calculated adjusted odds ratios (AORs) for associations of current cigarette use with trying to lose weight (Model 1) and the 5 weight control behaviors, controlling for trying to lose weight (Model 2)., Results: In Model 1, compared with students who were not trying to lose weight, students who were trying to lose weight had higher odds of current cigarette use (AOR = 1.30, 95% CI: 1.15-1.49). In Model 2, the association of current cigarette use with the 2 healthy weight control behaviors was not statistically significant. Each of the 3 unhealthy weight control practices was significantly associated with current cigarette use, with AORs for each behavior approximately 2 times as high among those who engaged in the behavior, compared with those who did not., Conclusion: Some students may smoke cigarettes as a method of weight control. Inclusion of smoking prevention messages into existing weight management interventions may be beneficial.

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.

Background: Nearly 10% of students enrolled in US public schools are absent daily. Although previous research has shown associations of school absenteeism with participation in risk behaviors, it is unclear if these associations vary by whether the absence was excused. The purpose of this study was to examine the associations of health risk behaviors with being absent from school with and without permission among high school students., Methods: During spring 2004, questionnaires similar to the Youth Risk Behavior Survey questionnaire were completed by 4517 ninth- and eleventh-grade students. Responses to items assessing frequency of school absences during the past 30 days for any reason and without permission were combined to create a variable coded as absent on: 0 days; > or =1 day, all with permission (WP); and > or =1 day, at least 1 day without permission (WOP). Logistic regression analyses controlling for gender, grade, and race/ethnicity examined the association of risk behaviors with absenteeism., Results: Controlling for demographic variables, compared to students who were absent 0 days, students who were absent WP had significantly higher odds of engaging in 25 of 55 risk behaviors examined and students who were absent WOP had significantly higher odds of engaging in 43 of the 55 behaviors. Students who were absent WOP also had approximately twice the odds of engaging in risk behaviors compared to students who were absent WP., Conclusions: School absenteeism, with and without permission, is associated with risk behaviors. Schools should recognize absenteeism for any reason as a warning sign for a variety of risk behaviors.

Purpose: To evaluate the associations of physical activity and sports team participation with suicidal behavior among U.S. high school students., Methods: Data were from the 2003 Youth Risk Behavior Survey (N = 10,530 respondents). Exposure variables included physical activity (inactive, insufficient, moderately intensive, regular vigorously intensive, and frequent vigorously intensive) and sports team participation. Outcome variables were suicide ideation (seriously considering and/or planning suicide) and suicide attempts. Hierarchical logistic regressions were run, controlling for age, race, smoking, alcohol use, drug use, geographic region, unhealthy weight-control practices, and body mass index/weight perceptions., Results: Compared with inactive students or sports team nonparticipants, the odds of suicide ideation were lower among boys reporting frequent vigorous-intensity physical activity (adjusted odds ratio (AOR) = 0.48; 95% confidence interval (CI) = 0.29, 0.79) and sports team participation, respectively (AOR = 0.65; 95% CI = 0.48, 0.86). The odds of suicide attempts were also lower among frequently vigorously active boys (AOR = 0.44; 95% CI = 0.21, 0.96) and sports team participants (AOR = 0.61; 95% CI = 0.40, 0.93). The odds of suicide attempts were lower for regular vigorously active girls compared with inactive girls (AOR = 0.67; 95% CI = 0.45, 0.99) and sports team participants compared with nonparticipants (AOR = 0.73; 95% CI = 0.57, 0.94). Associations with one exposure variable generally weakened when adjustment was made for the other exposure variable, or for feeling sad and hopeless., Conclusions: The association of physical activity and sports team participation with suicide ideation and suicide attempts varied by sex. Further research is needed to clarify these different associations.

Purpose: In 2005, the format for assessing race/ethnicity on the national Youth Risk Behavior Survey (YRBS) was changed from one to two questions. The 2005 Chicago YRBS included the single-question and two-question formats, providing an opportunity to identify how the change affects reporting of race/ethnicity., Methods: Students in grades 9-12 (n = 808) were asked at the beginning of a 91-item questionnaire, "How do you describe yourself?" with "Hispanic or Latino" as one of several response options. At the end of the questionnaire, students were asked, "Are you Hispanic or Latino?" and then "What is your race?", Results: Using standard algorithms to categorize students, 10.6% were classified as White, 46.2% as Black, 33.2% as Hispanic/Latino, 9.2% as other, and .9% as missing based on the single-question format. The two-question format yielded a similar distribution: 10.3% White, 41.1% Black, 34.8% Hispanic/Latino, 8.2% other, and 5.7% missing. The difference between these distributions was explained by the disproportionate number of Black students who left multiple questions blank at the end of the questionnaire. Regardless of whether the single-question or two-question format was used, 92.0% of students were classified the same (kappa = .85) when comparing distributions of the four-category race/ethnicity variable., Conclusions: These results suggest self-reported race/ethnicity among high school students is similar regardless of which question format is used, and the changed format will not affect the ability of YRBS data users to conduct trend analysis by race/ethnicity.

Background: US schools employ an estimated 6.7 million workers and are thus an ideal setting for employee wellness programs. This article describes the characteristics of school employee wellness programs in the United States, including state-, district-, and school-level policies and programs., Methods: The Centers for Disease Control and Prevention conducts the School Health Policies and Programs Study every 6 years. In 2006, computer-assisted telephone interviews or self-administered mail questionnaires were completed by state education agency personnel in 49 states plus the District of Columbia and among a nationally representative sample of school districts (n=445). Computer-assisted personal interviews were conducted with personnel in a nationally representative sample of elementary, middle, and high schools (n=873)., Results: During the 2 years preceding the study, 67.3% of states provided assistance to districts or schools on how to develop or implement faculty and staff health promotion activities or services. Although nearly all schools offered at least 1 health promotion service or activity, few schools offered coordinated activities and services within a comprehensive employee wellness program. During the 12 months preceding the study, none of the health screenings were offered by more than one third of schools; only a few of the health promotion activities and services were offered by more than one third of schools; about one third of schools offered physical activity programs, employee assistance programs, and subsidies or discounts for off-site health promotion activities; and only 1 in 10 schools provided health-risk appraisals for faculty and staff., Conclusions: More schools should implement comprehensive employee wellness programs to improve faculty and staff health behaviors and health status.

This study examined the association of victimization in a physically violent dating relationship with risk behaviors, age of risk behavior initiation, and co-occurrence of risk behaviors among students in grades 9 through 12 in the United States. Data were from the 2003 national Youth Risk Behavior Survey (YRBS). Nearly 9% of students reported experiencing dating violence victimization. Dating violence victimization was associated with alcohol use, marijuana use, and having ever had sexual intercourse among female students and having ever had sexual intercourse among male students. Dating violence victimization also was associated with early initiation of alcohol use among female students. The odds of dating violence victimization increased as the number of risk behaviors increased and as the number of lifetime sexual partners increased. These risk behavior patterns should serve as warning signs of elevated risk for dating violence victimization and may be helpful in identifying adolescents who could benefit from targeted, preventive interventions.

Odor profiling efforts were directed at applying to high-density livestock operations some of the lessons learned in resolving past, highly diverse, odor-focused investigations in the consumer product industry. Solid-phase microextraction (SPME) was used for field air sampling of odorous air near and downwind of a beef cattle feedyard and a swine finisher barn in Texas. Multidimensional gas chromatography-olfactometry (MDGC-O) was utilized in an attempt to define and prioritize the basic building blocks of odor character associated with these livestock operations. Although scores of potential odorant volatiles have been previously identified in high-density livestock operations, the odor profile results developed herein suggest that only a very few of these may constitute the preponderance of the odor complaints associated with these environments. This appeared to be especially true for the case of increasing distance from both cattle feedyard and swine barn facilities, with p-cresol consistently taking on the dominant odor impact role with ever increasing distance. In contrast, at- or near-site odor profiles were shown to be much more complex, with many of the well-known lower tier odorant compounds rising in relative significance. For the cattle feedyard at- or near-site odor profiles, trimethylamine was shown to represent a significantly greater individual odor impact relative to the more often cited livestock odorants such as hydrogen sulfide, the organic sulfides, and volatile fatty acids. This study demonstrates that SPME combined with a MDGC-O-mass spectrometry system can be used for the sampling, identification, and prioritization of odors associated with livestock.

Background: Previous research with adolescents has shown associations of body weight and perceptions of body size with suicide ideation and suicide attempts, but it is unclear whether these associations are direct or whether a mediating effect exists., Objectives: To determine if body mass index and perceived weight are associated significantly with suicide ideation and suicide attempts, controlling for weight control practices, and if perceived weight mediates the associations of body mass index with suicide ideation and suicide attempts., Design, Setting, and Participants: Data were analyzed from the 2001 Youth Risk Behavior Survey, a school-based survey administered to a nationally representative sample of students in grades 9 through 12 (N = 13 601)., Main Outcome Measure: Self-reported past-year suicide ideation and suicide attempts, compared by perceived weight and body mass index category, calculated from self-reported height and weight., Results: Body mass index category was associated significantly with suicide ideation (among all students) and suicide attempts (among white and Hispanic students) without perceived weight in the model but not with perceived weight added to the model. In contrast with those who perceive themselves as about the right weight, students who perceived themselves as very underweight (odds ratio [OR], 2.29 [95% confidence interval (CI), 1.46-3.59]), slightly underweight (OR, 1.36 [95% CI, 1.03-1.79]), slightly overweight (OR, 1.33 [95% CI, 1.12-1.58]), and very overweight (OR, 2.50 [95% CI, 1.73-3.60]) had greater adjusted odds of suicide ideation. Among white students, perceiving oneself as very underweight (OR, 3.04 [95% CI, 1.40-6.58]) or very overweight (OR, 2.74 [95% CI, 1.21-6.23]) was associated with greater odds of suicide attempts. Perceiving oneself as very underweight was associated with greater odds for suicide attempts among black (OR, 2.86 [95% CI, 1.10-7.45]) and Hispanic (OR, 3.40 [95% CI, 1.54-7.51]) students., Conclusions: How adolescents perceive their body weight may be more important than their actual weight in terms of increased likelihood of suicidal behavior. Regardless of body mass index, extreme perceptions of weight appear to be significant risk factors for suicidal behavior; important racial/ethnic differences exist.

This study investigates whether the type of parental permission affects prevalence estimates for risk behaviors from the national 2001 Youth Risk Behavior Survey. Participants were 13,195 students from 143 schools, of which 65% used passive permission and 35% active permission. Student participation rates were 86.7% in passive permission schools and 77.3% in active permission schools. For 24 of 26 behaviors tested, no significant differences were seen in the prevalence of risk behavior by type of parental permission. As long as high response rates are obtained, type of parental permission does not affect prevalence estimates for risk behaviors that are based on self-report.

Objective: To assess the association between weight perception and BMI among a large, diverse sample of adolescents. This study used both measured and self-reported height and weight to calculate BMI., Research Methods and Procedures: A convenience sample of students (n = 2032) in grades 9 through 12 completed a questionnaire assessing demographic characteristics, self-reported height and weight, and body weight perception. These students were then weighed and had their height measured using a standard protocol., Results: Using BMI calculated from measured height and weight, 1.5% of students were classified as underweight or at risk for underweight, 51.2% of students were normal weight, and 47.4% were overweight or at risk for overweight. Among this same sample of students, however, 34.8% perceived themselves as underweight, 42.9% perceived themselves as about the right weight, and 22.3% perceived themselves as overweight. Even when using BMI calculated from self-reported height and weight, >20% of students who were overweight or at risk for overweight perceived themselves as underweight., Discussion: Because perception of overweight is a key determinant of adolescent nutritional habits and weight management, many students who are overweight or at risk for overweight but who do not perceive themselves as such are unlikely to engage in weight control practices. Increasing awareness of medical definitions of overweight might improve accuracy of weight perceptions and lead to healthier eating and increased physical activity.

Alcohol consumption by youth can produce negative health outcomes. This study identified correlates of lifetime alcohol use, recent alcohol use, and binge drinking among youth in sixth through 10th grade (n = 2,004) in Sarasota County, Fla. Results from a closed-ended, quantitative survey acknowledged a range of personal, social, and environmental influences. Breadth of these influences supports a need for multifaceted, community-based interventions for effective prevention of youth alcohol use. This study was unique because it represents population-specific research in which community partners are using the findings to develop community-specific social marketing interventions to prevent underage drinking and promote alternative behaviors.

Despite a gradual overall decrease in alcohol consumption in the United States, alcohol remains the most widely used and abused drug in society. This study assessed lifetime and recent alcohol use in a cohort of fifth graders, and examined attitudes and beliefs held by these youth concerning alcohol. An instrument addressing alcohol use, other substance use, and other health-related problem behaviors was completed by 813 fifth graders in a west central Florida school district. Among respondents, 48.9% had "ever tried" alcohol, and 17.9% had consumed alcohol in the past 30 days (active drinkers). Significant differences in alcohol-related attitudes and beliefs were found according to current drinking status, gender, and race/ethnicity. Possible reasons for these differential findings are presented, and implications for prevention and intervention are discussed.

Insulin concentrations were measured in the aqueous humors of insulin-treated and untreated diabetic rabbits. The aqueous humor insulin concentration of diabetic rabbits after feeding was less than that of normal control animals. When diabetic rabbits were treated with insulin, the aqueous humor insulin concentration rose to concentrations much greater than in normal ones. The aqueous: plasma concentration ratios of both insulin and total protein for diabetic animals were greater than those for normal ones and suggest that the permeability of the blood-aqueous barrier was greater in the diabetic rabbits. Since insulin is known to be capable of influencing the metabolism of the lens, it is conceivable that abnormal insulin concentrations in aqueous humor may influence the development of cataract in diabetes.

Since increased lens sorbitol and osmotic swelling are central causative features of cataract in diabetic rats, the effects of insulin treatment on lens sorbitol, water, sodium, and potassium were studied. The sorbitol concentration in early stage diabetic lenses was greater than in normal ones by 83 mmol/kg water, and the lens water was greater by 1.3%. Sodium was greater by 9 mmol/kg water; potassium was less by the same amount so that the sum of sodium and potassium was not different. In insulin-treated diabetic lenses, the sorbitol was less than in untreated diabetic lenses by 39 mmol/kg water, and the lens water was not different. Insulin restored the potassium, but not the sodium, to normal concentration so that the sum of sodium and potassium was greater by 16 mmol/kg water. The differences in lens water were less than would be expected on the basis of osmosis due to differences in sorbitol and suggested that the lenses were able to maintain their water content within a narrow range by losing or gaining solutes to offset the differences in sorbitol.

A method for the determination of arsenic in whole human blood is presented. To decrease the matrix effects from this complex sample, the blood was prediluted with a matrix modifier solution. The modifier solution contained a surfactant, Triton X-100, which homogenized the sample and allowed accurate pipetting by an autosampler. The modifier also contained nickel nitrate which stabilized the arsenic and allowed ash temperatures of 1400 degrees C without loss of the arsenic. The method exhibited a sensitivity of 5 micrograms/L (concentration/1% absorption) which was sufficient for the forensic evaluation of elevated arsenic levels in the blood.

Although the lens has been shown to have the capacity to respond to insulin in vitro, little is known concerning the biochemical relationships of insulin to the lens in vivo. Therefore we have measured insulin in the aqueous humor of rabbits by a sensitive radioimmunoassay after paracentesis and feeding. The insulin concentration in aqueous humor was 3% of that in plasma. One hour after paracentesis the aqueous humor insulin concentration was increased sixfold, apparently due to breakdown of the blood-aqueous barrier, but 1 week after paracentesis it had returned to its original level, apparently because of restoration of the blood-aqueous barrier within that time. After feeding, the aqueous humor insulin concentration was increased by 30% compared to a 175% increase in plasma. Factors influencing the aqueous humor insulin concentration and the possibility of insulin influence on lens metabolism are discussed.