Trends in Adolescent and Young Adult Health in the United States

Demographic profile 

The adolescent and young adult population is diverse and growing. Between 1990 and 2006, the population ages 10 to 24 increased from 40.1 to 63.3 million [7], [8]. In 2006, 55.2% were White, non-Hispanic (NH); 16.5% Hispanic; 13.6% Black; 3.9% Asian/Pacific Islander; 0.9% American Indian/Alaskan Native; and 9.9% other [8]. One in 10 15- to 24-year-olds were immigrants or foreign-born in 2006; they were primarily of Hispanic (63.5%) or Asian/Pacific Islander origin (21.1%) [9].

In 2006, 64.9% of adolescents ages 12 to 17 lived in two-parent households (range: 80.2% for Asians to 49.9% for Blacks) [10]. No comparable data for young adults were located. The marriage rate among females ages 20 to 24 is almost twice that of same-age males (26.7% vs. 16.0%); among females, rates are highest among Hispanics and lowest among Blacks [11].

In 2006, 17.0% of children ages 0 to 17 living in families lived in poverty; for ages 18 to 24, this figure was 17.8%. These figures represent small changes since 1994. For both age groups, rates remain highest among Black-NHs and Hispanics [12], [13].

School enrollment has increased among adolescents and young adults. High school dropout rates (ages 16–24) decreased from 12.1% in 1990 to 9.4% in 2005 [14]. Among 18- to 24-year-olds, enrollment in a degree-granting institution increased from 25.7% in 1980 to 37.3% in 2006 [15].

Mortality 

The mortality rate (per 100,000) for ages 10 to 24 decreased from 76.1 in 1990 to 60.3 in 2005, with the largest decreases between 1990 and 1999. Mortality rates have decreased the most for males and Black-NHs. In 2005, over 7 in 10 deaths for ages 10 to 24 were because of motor vehicle accidents (MVAs), homicide, and suicide. Males have higher mortality rates than females (Figure 1). Disparities by race/ethnicity are sizeable: rates are highest among NH American Indians/Alaskan Natives and Blacks, and lowest among Asian/Pacific Islander-NHs. These disparities are driven primarily by high MVA mortality and suicide rates among American Indian/Alaskan Native-NH males and high homicide rates among Black-NH males [17].

MVA and related behavior 

The mortality rate (per 100,000) for MVAs, the single leading cause of death for 10- to 24-year-olds, decreased from 25.3 in 1990 to 18.8 in 1999. Since then, the rate has fluctuated and stood at 18.6 in 2005. MVA rates peak in young adulthood and then decrease until about age 70. Rates are higher among males, especially American Indian/Alaskan Native-NH and White-NH males [17].

Alcohol remains a significant factor in MVA mortality. In 2007, alcohol involvement in fatal crashes was reported for 23% of drivers ages 16 to 20 and 41% of drivers ages 21 to 24. These figures represent slight increases from 1999 (21%, ages 16–20; 36%, ages 21–24) [18], [19]. Rates of alcohol-related MVA fatalities peak in young adulthood [18]. Fewer high school students report risky behaviors related to alcohol and driving: about 30% of high school students reported riding with a driver who had been drinking alcohol in 2007, down from 39.9% in 1991; over the same period, the percent of students reporting drinking and driving fell from 16.7% to 10.5%. Hispanic students report higher rates of riding with a driver who has been drinking, whereas male and White-NH students are most likely to report driving when they had been drinking [20].

Seat belt use has improved among high school students: in 2007, 88.9% reported wearing a seat belt “always, most of the time, or sometimes” when riding as a passenger in a vehicle, an increase from 74.1% in 1991 [20].

Nonfatal injuries far outweigh fatal injuries for adolescents and young adults involved in MVAs. Among ages 16 to 24 in 2005, there were 161 nonfatal injuries for every MVA-related death [17].

Violence 

Trends in violence are encouraging, although there remains room for improvement. The homicide rate for ages 10 to 24 (per 100,000) decreased from 14.1 in 1990 to 8.9 in 1999, and has changed little since then (9.0 in 2005). Homicide, the second leading cause of death for ages 10 to 24, peaks in young adulthood and then decreases throughout the life span. In this age group, 81.6% of homicides are firearm-related [17]. Most perpetrators and victims of homicide (and other violent crimes) are adolescent and young adult males [17], [21], [22]. Homicide disproportionately involves Black-NH males, for whom homicide is the leading cause of death [17].

Rates of homicide offense follow similar patterns. Between 1993 and 2005, the homicide offending rate (per 100,000) decreased considerably for adolescents ages 14 to 17 (31.3 vs. 9.3) and young adults ages 18 to 24 (42.8 vs. 26.5). Homicide offending rates are highest in young adulthood, particularly for Black-NH males (203.3, 2005) [21].

Nonfatal crime rates decreased dramatically between 1996 and 2005 across ages 12 to 24. Overall victimization rates peak in late adolescence (ages 16–19) and are higher for males, especially Black males. Rates for Black males peak in late adolescence, while rates for White males peak in young adulthood [22].

High school students also report a decrease in violent behavior. Between 1991 and 2007 the percentage reporting getting into a physical fight fell from 42.5% to 35.5%. Weapon carrying decreased from 26.1% to 18.0% [20].

Suicide and mental health 

The rate (per 100,000) for suicide, the third leading cause of death for ages 10 to 24, decreased from 9.5 in 1990 to 7.0 in 1999. It has fluctuated since then, and was 7.1 in 2005. Rates are higher for males and American Indian/Alaskan Native-NH youths and lower for Asian/Pacific Islander-NH youths [17]. In 2007, 6.9% of high school students reported a suicide attempt, a figure only slightly lower than in 1991 (7.3%), with higher rates for females [20].

National mental health data are fairly limited, with trend data nearly nonexistent. Nonetheless, adolescence and young adulthood are critical periods to identify and treat mental health problems, as symptoms of nearly half of lifetime diagnosable problems appear by age 14 and symptoms of nearly three quarters of lifetime diagnosable problems begin by age 24 [23]. A recent review of national data suggests that one in five adolescents experience significant emotional distress and 1 in 10 faces more serious impairment [24]. Depression is the most widely reported disorder. Females are more likely than males to report feelings of sadness or hopelessness for 2 weeks or more in the past year; rates are highest for Hispanic females (42.3%) and lowest for White-NH males (17.8%) [20]. Table 3 presents additional measures related to suicide attempts and depression.

Mental health data beyond depression are even more limited. Data from 2005 for ages 12 to 17 show that males are more likely than females to have learning disabilities (11% vs. 7.4%) and attention deficit–hyperactivity disorder (12.6% vs. 5.1%) [24]. Although no national data on eating disorders could be located, measures of unhealthy weight loss behavior from 2007 show that about 10% of high school students reported use of diet pills, powders, and liquids, vomiting, or use of laxatives. Rates of all these behaviors have decreased since 1999. Female students, especially White-NHs and Hispanics, are more likely to report these behaviors [20].

Substance use 

Current use of alcohol, tobacco, and marijuana and other illicit drugs is well below the peaks of the late 1970s and early 1980s. Rates for most substances fell to near or all-time lows in the early 1990s, then rose again in the mid-1990s. Since the late 1990s, trends have diverged by substance [25]. Adolescent experimentation with substances can begin early. Figure 2 shows mixed patterns of substance use among ninth graders between 1991 and 2007. This period saw a large decrease in frequent cigarette smoking, modest decreases in alcohol use, and increases in cigarette and marijuana experimentation [20]. Most indicators of substance use peak in young adulthood and decrease over the life span. Differences by gender in adolescence are mostly fairly small, whereas males generally report higher rates in young adulthood. (Trend data in the text come from the Monitoring the Future Survey. The current use data in Table 3 come from the National Survey on Drug Use and Health.)

Past-month alcohol use among 12th graders has decreased since 1997 (52.7%) and was 43.1% in 2008, a considerable decrease from 57.1% in 1990 [25], [26]. Indicators of alcohol use increase three- to sixfold between adolescence and young adulthood, with young adult males reporting higher rates than females. Use is higher among American Indian/Alaskan Native-NH and White-NH adolescents and young adults and lowest among their Black and Asian peers [27].

By most measures, cigarette use has decreased since rising in the early 1990s. Past-month cigarette smoking among 12th graders went from 29.4% in 1990, to 36.5% in 1997, to 20.4% in 2008. Past-month daily smoking shows a similar pattern: 19.1% in 1990, 24.6% in 1997, to 11.4% in 2008 [25], [26]. Rates of past-month smoking nearly quadruple between adolescence and young adulthood [28].

By contrast, past-month illicit drug use among 12th graders has changed less since 1990. Any past-month use increased from 17.2% in 1990 to 25.6% in 1997. Rates from 2007 and 2008 are similar: 21.9% and 22.3%, respectively [25], [26]. Rates double between adolescence and young adulthood. American Indian/Alaskan Native-NHs and White-NHs report the highest rates of past-month illicit drug use among adolescents and young adults [27]. Trends in use of marijuana, the most widely used illicit drug, parallel trends in illicit drug use. The overall prevalence in use of illicit drugs besides marijuana has changed little since 1990, but the “drug of choice” has changed [25]. More recently, use of nonprescribed prescription drugs has increased among 12th graders [29].

Substance dependence or abuse is also prevalent among adolescents and young adults. Between 2000 and 2007, rates of dependence or abuse were identical for 12- to 17-year-olds (7.7%) and increased for 18- to 25-year-olds (15.4% vs. 20.7%) [28], [30]. Male and female adolescents report similar levels of substance dependence or abuse, whereas young adult males report higher rates than same-age females. Among racial/ethnic groups, American Indian/Alaskan Native-NH adolescents and young adults report the highest rates of substance dependence or abuse [27].

Reproductive health 

Trends in reproductive health indicators have been encouraging since the early 1990s. However, some of these trends, including rates of being sexually experienced, first sex before age 13, and condom use appear to have plateaued since 2004 to 2005. National data on sexual activity between same-gender partners are limited. In 2002, 10.6% of young females reported a same-gender sexual partner, compared to 4.5% of males. Among young adults ages 20 to 24, this gender difference widens (14.2% vs. 5.5%) [31]. The remaining data address sexual behavior with an opposite gender partner.

The percentage of high school students who have had sexual intercourse decreased from 54.1% in 1991 to 46.8% in 2005 then increased slightly to 47.8% in 2007 [20]. In 2002, about four-fifths of young adults aged 18 to 24 reported being sexually experienced [32].

The percentage of sexually active students reporting condom use at most recent intercourse increased steadily from 46.2% in 1991 to 62.8% in 2005 and then decreased to 61.5% in 2007 [20]. In 2002, only 28.2% of males 20 to 24 years old reported using a condom at every intercourse [33]. Among females at risk of unintended pregnancy, 82% of adolescents (ages 15–19) and 87% of young adults (ages 20–24) report current contraceptive use; birth control pills are the most widely used method [34].

Rates of most risky sexual behaviors among high school students have decreased overall: the proportion reporting first sex before age 13 decreased slightly from 10.2% in 2001 to 7.1% in 2007. Similarly, the proportion having four or more lifetime sexual partners decreased from 18.7% in 1991 to 14.2% in 2001, and has changed little since then (14.9% in 2007). By contrast, there has been virtually no net change in the proportion of students who report drinking alcohol or using drugs prior to sex (21.6% in 1991; 25.6% in 2003; 22.5% in 2007) [20]. Males are more likely to report these behaviors than females. Among 20- to 24-year-olds, males were more likely than females to report seven or more partners in their lifetime (30.0% vs. 21.3%) [31].

Pregnancy, abortion, and birth rates (all per 1000) have decreased substantially for 15- to 19-year-old females. The pregnancy rate fell from 116.8 in 1990 to 72.2 in 2004; the abortion rate decreased from 40.3 to 19.8 over the same period. For women ages 20 to 24, declines were smaller during this period: pregnancy rates decreased from 198.5 to 163.7; abortion rates declined from 56.7 to 39.9 [35]. Birth rates for adolescents ages 15 to 19 decreased from 59.9 in 1990 to 40.5 in 2005, then increased slightly to 42.5 in 2007. Similarly, the birth rate for ages 20 to 24 fell from 116.5 in 1990 to 102.2 in 2005, then increased to 106.4 in 2007 [36], [37].

The rates of gonorrhea decreased from 1996 to 2003, but increased from 2004 to 2007. Chlamydia rates increased from 1996 to 2007 [38], [39]; this may reflect wider screening and use of more sensitive tests [40]. Rates of STIs peak in late adolescence and early young adulthood, with 15- to 24-year-olds accounting for nearly half of all new STIs [40]. Female youths continue to be disproportionately affected by STIs, especially Black females [38].

In 2006, 14.2% of all new HIV diagnoses were among 15-24 year-olds. Estimated numbers of new HIV/AIDS cases in this age group increased from 2002 to 2006 and are highest for Black-NHs [41], [42]. Deaths of persons with AIDS remained stable or increased slightly for 15- to 24-year-olds during this period [42].

Exercise, diet, and overweight 

Exercise levels have remained stable since 1993. The percentage of high school students reporting exercising three or more times per week 20+ minutes was 65.8% in 1993 and 64.0% in 2007. Males were more likely to report this than females [20], [43]. Among young adults ages 18 to 24 in 2005, 60.9% reported 30+ minutes of moderate physical activity 5 or more days a week, or vigorous physical activity for 20+ minutes 3 or more days per week [44]. Sedentary activity, measured by watching television for 3 or more hours per day, decreased from 42.8% in 1999 to 35.4% in 2007 among high school students [20].

National data on diet and nutrition are limited. For high school students, consumption of fruits and vegetables at least five times a day in the past week is low, with little change from 1999 (23.9%) to 2007 (21.4%) [20].

The prevalence of overweight among 12- to 19-year-olds almost doubled between 1988-1994 and 2003-2006 (10.5% vs. 17.6%) [45]. Among 18- to 24-year-olds in 2005, more than one in four were overweight (body mass index [BMI] 25.0–29.9) and 16.2% were obese (BMI 30.0–99.8) (see Table 3 for BMI definition) [44].