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In 2001, individuals ages 13-19 accounted for roughly 10 percent of the U.S. population. Generally, adolescents are a healthy population. Adolescence is a period during which many lifelong health habits are formed, such as diet, exercise, and the use of health care services. National data related to physical activity and overweight are explored in this section.
Adolescence is also a time of physical and emotional growth and exploration. As a result, many adolescents engage in risk-taking behaviors that may result in acute illnesses and infections, poor long-term health outcomes, and even disability and death. For example, adolescents may experiment with cigarettes and drugs, engage in sex, or be involved in motor vehicle crashes. This section features many health status indicators related to cigarette smoking, use of illicit drugs, adolescent mortality, injury, sexual intercourse, sexually transmitted diseases, and pregnancy. Many of these data are presented by age, gender, race and ethnicity.
In 2001, birth rates among adolescents ages 15-19 dropped to 45.8 per 1,000 teenagers. This represents a historic low and a decrease of 26 percent since 1991. In 2001, there was also a decline in the birth rates among adolescents ages 10-14, which fell to 0.8 per 1,000 teenagers. Birth rates were highest among the oldest adolescents, those ages 18-19, at 75.5 births per 1,000 teenagers.
Birth rates among adolescents varied considerably by race and ethnicity. In 2001, birth rates for adolescents 15-19 were 20.4 for Asian/Pacific Islanders, 41.4 for Whites, 66.0 for American Indians, 73.2 for Blacks, and highest at 92.5 for Hispanics. Although all racial and ethnic groups saw a decline in adolescent births in the past decade, the steepest declines have occurred among Black adolescents. Between 1991 and 2001, the birth rate among Black adolescents ages 15-19 decreased by 36 percent. In the same time period, the birth rate among Hispanic adolescents fell the least, by just 13 percent, leaving Hispanic teens with the highest birth rate among the five racial and ethnic groups.
In 2001, 45.6 percent of high school students had ever had sexual intercourse, representing a nearly 9 percent decrease since 1999. Though Black students (60.8 percent) had a higher prevalence of ever having had sexual intercourse than Hispanic (48.4 percent) and White students (43.2 percent), the percentage of Black students ever having had sexual intercourse dropped by 14 percent from 1999, with smaller declines seen for Hispanic and White students.
Approximately 48 percent of 12th grade students reported having sexual intercourse during the three months preceding the survey. The prevalence rate of current sexual activity increased significantly from grades 9 through 12 among both females (19.9 percent to 51.0 percent) and males (25.9 percent to 44.6 percent). More than half of high school students report abstaining from sexual activity.
In 2001, more than half of sexually active students reported condom use during their last sexual intercourse. Males were significantly more likely than females to have reported that a condom was used. Black students were significantly more likely than White and Hispanic students to report using a condom during last sexual intercourse.
Sexually Transmitted Diseases
Adolescents (ages 15-19) and young adults (ages 20-24) are at much higher risk of contracting sexually transmitted diseases (STDs) than are older adults. Within these age groups, reported rates of chlamydia, gonorrhea, and syphilis are significantly higher among Black non-Hispanic youth than White non-Hispanics. Rates of STDS among Hispanic adolescents and young adults are about twice those of non-Hispanic Whites.
Chlamydia continues to be the most common STD in adolescents and young adults with a rate of 1,436 cases per 100,000 adolescents and 1,524 per 100,000 young adults. Gonorrhea followed in prevalence with an overall rate of approximately 500 cases per 100,000 adolescents and 613 cases per 100,000 young adults. Across both age groups, gonorrhea decreased slightly among Blacks but increased slightly among Whites. Syphilis is less common among young people, with only 1.9 cases per 100,000 adolescents and 4.4 cases per 100,000 young adults in 2001, a slight decline in both age groups from 2000.
Although these conditions are treatable with antibiotics, STDs can have serious health consequences. Active infections can increase the likelihood of contracting HIV and untreated STDs can lead to pelvic inflammatory disease and infertility in women.
Adolescent HIV Infection
Of the 7,446 cases of HIV infection ever reported among adolescents (ages 13-19), males made up close to 44 percent and represented the same proportion of the new HIV infection cases reported in 2002 among adolescents. Over half of these new cases were transmitted by men having sex with men. In 33 percent of new adolescent male cases, the risk category was not reported. From 1981 through 2002, Black males were more likely to report HIV infection and comprised almost 60 percent of the infected male adolescent population.
Fifty-six percent of adolescent HIV infection cases ever reported were among females. The percentage of new HIV infection cases in adolescent females has been decreasing in recent years. Of the new cases in 2002, about 40 percent acquired HIV infection through heterosexual contact and 5.2 percent were injecting drug users. The risk category was not reported for 54 percent of new adolescent female cases in 2002. Similar to the trend among adolescent males, Black females are significantly more likely to contract HIV and comprised 60 percent of female adolescents living with HIV infection.
An adult or adolescent with HIV is defined as having AIDS if he or she has a CD4 count of less than 200 cells/uL or a CD4 percentage of less than 14 or if he or she is diagnosed with pulmonary tuberculosis, recurrent pneumonia, or invasive cervical cancer.
Males comprised about 57 percent of the 4,819 AIDS cases ever reported among adolescents ages 13-19 years old, and represented 50 percent of the new AIDS cases reported among adolescents in 2002. Of the 204 new cases reported in 2002 among adolescent males, the largest exposure category (47 percent) was identified as men who have sex with men. In 38.7 percent of new cases, a risk category was not reported or identified.
Approximately 43 percent of adolescent AIDS cases ever reported were among females. Females comprised of 50 percent of new AIDS cases reported in 2002 among adolescents, which is a 4 percent decrease from 54 percent in 2000. Among adolescent females, there were 704 new AIDS cases. In 34.8 percent of these new cases, heterosexual contact was reported as the risk category, but in most cases (59.3 percent), a risk category was not reported or identified.
Young Adult AIDS
As of December 31, 2001, 28,665 cases of AIDS had been reported in young adults ages 20-24 years. This total includes 1,461 newly reported cases in 2001, which is an increase of 8.5 percent from the number reported in 2000. Between 2000 and 2001, a higher percentage increase was seen among females (9.4 percent) than among males (8.0 percent) in this age group.
Males represented 59.2 percent of the AIDS cases reported in 2001 among adults 20-24 years old. In over half of these new cases, the exposure category was identified as men having sex with men. Among new female cases reported in 2001, heterosexual sex (48.5 percent) was reported as the primary exposure category. In about one third of new cases (32.5 percent) for all young adults 20-24, the exposure category was not identified or reported.
Violence among adolescents is a critical public health issue in the United States: homicide was the second leading cause of death among persons ages 15-24 in 2000.
Results from the 2001 Youth Risk Behavior Survey reveal that 17.4 percent of students had carried a weapon, such as gun, knife, or club, on one or more days in the last 30 days; nearly 6 percent had carried a gun. Boys (29.3 percent) were significantly more likely to carry a weapon than girls (6.2 percent). The percent of high school students who carry weapons had decreased significantly since 1991 but has remained level since 1997.
Some high school students also reported taking weapons to school. In 2001, 6.4 percent of students had carried a weapon on school property in the last 30 days— a 46 percent decrease since 1993. However, despite this decline, nearly 9 percent of students reported being threatened or injured with a weapon on school property in 2001. In addition, 6.6 percent of students had missed one or more days of school because they felt unsafe at school or on their way to school. Younger students and Black and Hispanic students expressed the most concern for their safety.
Physical Activity and Overweight
Results from the 2001 National Youth Risk Behavior Survey show that over two-thirds of high school students regularly participated in vigorous physical activity and one quarter participated in moderate physical activity. Furthermore, 53 percent participated in regular strengthening exercises, while 55 percent played on one or more sports teams. Nationwide, 52 percent of high school students were enrolled in a physical education class, though students in the 9th grade were significantly more likely to be enrolled than students in higher grades. The percentage of students enrolled in daily physical education has declined over the past decade, from 42 percent in 1991 to 32 percent in 2001.
While 29 percent of high school students thought they were overweight, 46 percent were trying to lose weight. Female students were more than twice as likely as male students to be attempting weight loss (62 percent versus 29 percent). Although males were more likely to be overweight, female students were significantly more likely than male students to perceive themselves as overweight. In an effort to lose weight or keep from gaining weight, nearly 60 percent had exercised and 44 percent of students had consumed fewer calories, eaten less, or eaten foods low in fat. However, a substantial minority had also attempted weight control in potentially unhealthy ways—14 percent had fasted for 24 hours or more, 9 percent had taken diet aids without a doctor’s advice, and 5 percent had vomited or taken laxatives.
The Healthier U.S. Initative provides credible, accurate information about physical fitness, nutrition, and prevention to help Americans of all ages to make healthy choices.
Cigarette smoking declined significantly among 8th, 10th, and 12th graders in 2002 from the previous year, as reported by the University of Michigan’s Monitoring the Future Study. In the 30 days preceding the survey, 10.7 percent, 17.7 percent, and 26.7 percent of 8th, 10th, and 12th graders, respectively, reported smoking. These figures represent a 49 percent, 42 percent, and 27 percent decline in smoking for 8th, 10th, and 12th graders, respectively, since these levels peaked in 1996 and 1997. The younger age groups have shown the largest improvement over this time period. Researchers speculate that these declines resulted from an increase in the perceived risk and disapproval of smoking, increases in cigarette price, and declining accessibility to cigarettes.
The prevalence of smoking among teens increased substantially between 1991 and 1996. These increases occurred in virtually every socio-demographic group; among both sexes, among those college-bound or not, among the four regions of the country, among those living in rural or urban areas, and among Whites, Blacks, and Hispanics. The recent decline since 1996 has also occurred across all demographic groups. Although absolute rates of smoking have declined among adolescents, certain subgroups are less likely to smoke than others. Students who are not college-bound are considerably more likely to smoke than are college-bound high school students. The use of cigarettes among Black adolescents is dramatically lower than for White adolescents. These improvements are likely to have significant long-term health consequences for this generation of adolescents.
Prevalence and Incidence
Results of the Substance Abuse and Mental Health Services Administration's (SAMHSA) 2001 National Household Survey on Drug Abuse (NHSDA) show that the percentage of adolescents ages 12-17 who reported using alcohol in the month prior to the survey increased to 17.3 percent. In this age group, boys and girls reported similar rates of alcohol use in 2001, although rates of binge drinking and heavy alcohol use were higher among boys.
In 2001, among youths ages 12-17, illicit drug use increased slightly to 10.8 percent from 9.7 percent in 2000. Usage patterns within this group varied considerably based on age. In the month prior to the survey, illicit drug use was lowest among adolescents ages 12-13 at 3.8 percent and highest among adolescents ages 16-17 at 17.8 percent. Although there was no significant difference among girls, there was a significant increase in illicit drug use among boys from rates reported in 2000. The NHSDA survey also found correlations between illicit drug use and smoking among adolescents. In 2001, the rate of current illicit drug use was approximately 9 times higher among youths who smoked cigarettes (48.0 percent) than it was among those who did not smoke (5.3 percent).
Between 2000 and 2001, the use of marijuana, the most commonly used illicit drug, increased. Among youths ages 12-17, 8.9 percent of boys and 7.1 percent of girls reported using marijuana in the month prior to the survey. Rates of substance use initiation, or incidence, are another indication of usage patterns. The number of yearly marijuana initiates among youth 12-17 years of age steadily increased from 0.8 million in 1990 to 1.6 million in 1996, and has remained stable.
Perception of Risk and Access to Drugs
The perceived risks of using marijuana or cocaine decreased slightly from 2000. In 2001, 35.7 percent of adolescents perceived smoking marijuana once a month as risky. The percentage of adolescents who perceived monthly cocaine use to be risky decreased from 55.4 percent in 2000 to 54.1 percent in 2001.
Marijuana was perceived as the illicit drug easiest to acquire, with 55.4 percent of adolescents reporting that it would be easy to obtain. The perceived availability of drugs among youths ages 12-17 was lowest for heroin; only 16.7 percent indicated heroin would be easy to obtain.
In 2001, there were 13,435 deaths of adolescents ages 15-19 years. After a moderate increase in mortality rates for this age group in the early 1980's, there has been a gradual decrease since that time. Unintentional injury has remained the leading cause of death and accounted for approximately 48 percent of all deaths among adolescents ages 15-19 years in 2001. Homicide and suicide were the next leading causes of death, accounting for 14 and 12 percent, respectively, of all deaths among 15-19-year-olds.
Deaths Due to Injury
Within the classification of deaths due to injury or external causes, motor vehicle crashes were the leading cause of injury mortality among 15-to-19-year-olds in 2001, and accounted for 77 percent of injuries among adolescents overall. Firearms were the next leading cause of injury death, and represented 38 percent of injury deaths in this age group. Adolescent death rates due to motor vehicle injuries and firearms were similar in the early 1990's until 1994, after which they began to diverge. Adolescent firearm deaths decreased at a much faster rate and were recorded at a rate of 12.1 per 100,000 population in 2001 compared to the rate of motor vehicle injury deaths of 24.4 per 100,000.
Adolescent Deaths Due to Injury
The National Center for Health Statistics (NCHS) reports that the two leading causes of deaths due to external causes among adolescents are motor vehicle crashes and firearms. In 2001, motor vehicle crashes caused the deaths of 4,938 adolescents 15-19 year olds. The vast majority of those killed were in motor vehicle accidents, either as a passenger or driver. Deaths of pedestrians, motorcyclists, and others accounted for the remainder of motor vehicle mortality among adolescents.
Results of the 2001 Youth Risk Behavior Survey revealed that 14.1 percent of students had rarely or never worn seat belts when riding in a car driven by someone else. Additionally, 30.7 percent of students had ridden on one or more occasions with a driver who had been drinking alcohol in the 30 days preceding the survey. Young drivers are more likely to be involved in alcohol-related crashes than any other comparable age group.
In 2001, 2,458 adolescents ages 15 to 19 were killed by firearms. Of these, homicide accounted for 60 percent of firearm deaths, suicide accounted for 34 percent, and 4 percent were considered to be unintentional.
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