Related Health and Development Issues

Nutritional Needs and Dietary Behavior

Adolescents actually have greater nutritional needs than younger children due to rapid growth, sexual maturation, changes in body composition, skeletal mineralization, and physical activity. These changes result in an increase in total energy needs due to the maintenance of a larger body size. For example, during their peak growth years (11–14 years of age) girls require approximately 2200 kcal/day to sustain growth, whereas boys during ages 15 to 18 require 2500–3000 kcal/day (Mascarenhas, Zemel, Tershakovec, & Stallings, 2001).

In addition to the need for increased calories, adolescents also require more protein, calcium, iron, and zinc in their diet. Although these additional vitamins and nutrients are required for optimal physical growth and development, rarely does the average adolescent consume a diet that consists of these recommended levels. One national study (see ) found that adolescents, particularly girls, demonstrated an insufficient intake of calcium, iron, and vitamins A and C (NHANES III, 1988–1994). When 12,500 children aged 11 to 18 years were surveyed, researchers found that vegetable intake was lower in all age groups than the recommended five servings per day (remember, new guidelines recommend nine servings per day). In fact, french-fried potatoes made up 25% of all vegetables consumed! Intake of simple sugars (like those found in soda and noncitrus juices) exceeded the intake of complex carbohydrates, and more than one-third of the dietary fat was saturated (Gavadini, Sieja-Riz, & Popkin, 2000). Diets poor in essential vitamins and minerals can result in slowed or retarded maturation (zinc deficiency), nonopti mal bone mass accrual or bone mineral density (poor calcium intake), or anemia (iron deficiency).

Adolescents differ from children and adults in that they are more likely to skip meals, eat more meals outside their homes, eat unhealthy snacks that include soda and candy, diet, or consume fast foods. Excessive consumption of simple sugars and saturated fats can contribute to weight gain or obesity in some adolescents (Neumark-Sztainer, Story, Hannan, & Croll, 2002).

Recent findings show that more teens are overweight than ever before (CDC, 2003a). In 1991 the prevalence of overweight adolescents was 11%; by 1999 this had increased to 14%. Recent surveys indicate that the greatest increases in the prevalence of obesity are in minority groups (especially African Americans) and in the proportion of adolescents in the highest percentile of obesity (BMIs > 95th percentile) (Neumark-Sztainer et al., 2002). Health risks associated with obesity in adolescence include increased risk for obesity in adulthood, coronary heart disease in adulthood, and type 2 diabetes. The long-term health care consequences and costs of obesity in adolescents are enormous. Prevention programs encourage not only healthier eating styles but also an increase in regular exercise (U.S. Department of Health and Human Services, 2005).

Disordered Eating Behavior

Adolescence is a developmental period in which individuals experience increased awareness of body image, or how they think and feel about their bodies. A preoccupation with body image and size may be further exacerbated by school transitions and the simultaneous occurrence of puberty, dating, and associated social and academic pressures (Levine, Smolak, Moodey, Shuman, & Hessen, 1994). Research illustrates that body and weight dissatisfaction occurs as early as third grade; is greater in European American than in African American children, females than males, and those with a heterosexual orientation; and increases over time, peaking around eighth or ninth grade (Thompson, Rafiroiu, & Sargent, 2003). These patterns of body dissatisfaction also tend to occur in other affluent countries, such as Hong Kong, Australia, and Sweden (Lam et al., 2002; Lunner et al., 2000).

Body dissatisfaction and weight concerns can lead to unhealthy dieting behaviors, which in turn may promote the development of disordered eating in adolescents (Killen et al., 1996). Studies of middle-school students have reported that between 30 and 55% have dieted at some time (Shisslack et al., 1998) and that, among females, about one-third of normal dieters progress to other problem dieting behaviors (Shisslack, Crago, & Estes, 1995). Problem dieting behavior includes fasting or skipping meals, the use of diet pills, vomiting or using laxatives, smoking cigarettes, or binge eating (Neumark-Sztainer, Story, Falkner, Beuhring, & Resnick, 1999; Croll, Neumark-Sztainer, Story, & Ireland, 2002). These unhealthy dieting behaviors are far more prevalent among adolescents than among children in middle childhood and often go unaddressed because of the varied unmonitored settings within which teenagers consume food. In addition, most unhealthy dieting patterns fall below the criteria for diagnosable eating disorders and may not be viewed as problematic.

Health consequences result from both disturbed eating patterns and eating disorders. Health problems associated with disturbed eating patterns are delayed sexual maturation, menstrual irregularity, constipation, weakness, irritability, sleep problems, and poor concentration (Story & Alton, 1996). Health consequences for eating disorders, however, are much more severe.

Sleep

While the majority of this chapter deals with adolescent behavior during the waking hours, adolescent sleep patterns and their relationship to adolescent health are equally important. Research shows that sleep and waking behaviors change significantly during the adolescent years (for a review, see Carskadon, 2002). More specifically, adolescents go to sleep later than preadolescents and, if allowed, sleep later in the morning. This delayed onset of sleep has both a physiological and a sociocultural explanation.

First, researchers have identified that the circadian cycle, which is responsible for sleep/wake cycles in humans and other animals, shifts during adolescence. The shift involves releasing melatonin, a sleep-inducing hormone, approximately one hour later (10:30 p.m.) than in middle childhood (9:30 p.m.). This is why adolescents report “not feeling sleepy” until much later at night. In addition, studies show that adolescents also stay up later voluntarily as a result of late-night jobs, extracurricular activities, academic pressures (e.g., homework), and social activities (Wolfson et al., 1995). So later sleep onsets for adolescents are a function of both biological and psychosocial change.

During the school year, a later sleep onset paired with an earlier wake time results in insufficient amounts of sleep for many adolescents. Adolescents need 9.5 hours of sleep per night to report feeling “rested.” But most are getting on average 7.5–8 hours of sleep per night, and those adolescents who work more than 20 hours a week are getting even less (Vinha, Cavalcante, & Andrade, 2002). One consequence of this sleep deprivation is that adolescents play catch-up on the weekends, sleeping approximately 2 hours longer a night than preadolescents. Other consequences that are a source of concern for parents, teachers, practitioners, and health care workers are

• Increased daytime sleepiness
• Increased daytime naps (even during school!)
• Poorer concentration and ability to focus attention
• Poorer school performance
• Increased moodiness and mood disorders
• Higher accident rates
• Higher rates of substance abuse
• Higher use of products with caffeine and tobacco (adapted from Dahl & Lewin, 2002; Wolfson & Carskadon, 1998).

These sleep/wake trends and similar outcomes have also been found in adolescent populations in other countries (Andrade & Menna-Barreto, 2002; Gau & Soong, 1995; Giannotti & Cortesi, 2002; Park, Matsumoto, Seo, Kang, & Nagashima, 2002; Strauch & Meier, 1988).

The research on sleep patterns and subsequent effects in adolescence has prompted a reevaluation of high school starting times in cities across the United States. When researchers examined the transition that adolescents made from a ninth-grade start time of 8:25 a.m. to a tenth-grade start time of 7:20 a.m., they found that compared to the previous year students in the tenth grade showed less sleep, earlier rising times, and greater morning sleepiness (Carskadon et al., 1998). Conversely, school districts that have moved to a later high school starting time have shown improved school performance, graduation rates, attendance, and continuous enrollment (Wahlstrom, 2002).

Substance Use and Abuse

Researchers who have examined the health status of adolescents conclude that the main threats to adolescents’ health are the health-risk behaviors in which they engage and choices they make. Deciding to experiment with drugs or to engage in their continuous use compromises the health of adolescents. Although the reasons why adolescents use substances are numerous and diverse, there exists a prevalent perception that adolescent recreational drug use is normative (MacDonald & Marsh, 2000). In some countries (e.g., the United States, England, and Finland) there is a greater societal tolerance of drug use among youth and a proliferation of references to drugs and drug use within the youth culture. In addition, drug use in adolescence is often dictated by social contexts such as dance clubs and “raves.” Drug use in the club cultural context is a means of maintaining social categories and distinctions and promoting peer inclusion (Salasuo & Seppala, 2004). Therefore, the societal and social contexts that support recreational drug use must be considered when identifying the variables that predispose teens to use or abuse illegal substances.

Alcohol

There has been an overall decline in alcohol use among adolescents over the past decade.  However, 83% of high school seniors reported having drunk alcohol at least once, 55.9% had at least one drink in the past 30 days, and—of more concern—37.2% reported having five or more drinks in a row within a couple of hours. In other words, over one-third admit to binge drinking. In 2003, females had more experiences with alcohol than males, at all grade levels, but males reported more binge drinking at all grade levels. In 2003, Hispanic high-schoolers showed higher lifetime drinking experience (79.5%) compared to Caucasians (75.4%), African Americans (71.4%), and other groups (68.4%) (CDC, 2003b).

Alcohol use has also been implicated in adolescent sexual activity and injurious behavior to self and others (Sindelar, Barnett, & Spirito, 2004). For example, approximately one quarter of high school students (grades 9–12) said they used drugs or drank alcohol before their last sexual intercourse. And 41% of all deaths from motor vehicle crashes involved alcohol (U.S. Department of Transportation, 2004).

The health consequences of long-term alcohol misuse are liver disease, cancer, cardiovascular disease, and neurological damage as well as psychiatric problems such as depression, anxiety, and antisocial personality disorder (Naimi, Brewer, Mokdad, Serdula, Marks, & Binge, 2003). discusses the effects of alcohol consumption on the developing brain.

Factors associated with alcohol use are low grades in school, low educational aspirations, and engagement in antisocial behavior/delinquency (Lerner, 2002; Perkins & Borden, 2003). Frequent use of alcohol is also associated with accidental deaths (e.g., drowning; Mitic & Greschner, 2002). In addition, poor parental monitoring and discipline and having one or more alcoholic parents or an alcohol-addicted sibling predict alcohol use in adolescents (Masten & Coatsworth, 1998). Finally, one of the most powerful predictors of adolescent alcohol use is the alcohol use of a teen’s best friend (Borden, Donnermeyer, & Scheer, 2001). This last finding might suggest that peer use “influences” an adolescent’s drinking behavior. But when researchers followed 755 6-year-old boys for 7 years to determine whether individual characteristics (e.g., fighting, hyperactivity, likability) or peer influences were linked to subsequent substance abuse, they found that individual characteristics are more predictive of later substance abuse than having deviant peers (Dobkin et al., 1995). In other words, a given adolescent with certain behavioral characteristics is attracted to peers who like the same involvement in high-risk behavior rather than being “turned bad” by deviant friends.

Cigarette smoking

The initiation of smoking appears to occur between grades 7 and 9, and nearly all first use occurs by age 18 (U.S. Department of Health and Human Services [USDHHS], 1994). A consistent finding among national surveys is that the younger the age at which teens begin to smoke regularly, the more regular and heavier the use and the more likely they are to be nicotine dependent in adulthood (Chassin, Presson, Pitts, & Sherman, 2000).

Data from the Center for Disease Control’s online Youth Risk Behavior Survey (2003c)  show that smoking increased at all grade levels from 1997 to 1999 and then decreased for all grade levels between 1999 and 2003. Declines in smoking rates in adolescence have been attributed to the increased cost of cigarettes, the prohibition of adolescent-targeted advertising, more prevalent antismoking messages, and increased negative public images of tobacco companies (Johnston, Terry-McElrath, O’Malley, & Wakefield, 2005; Myers & MacPherson, 2004). Despite recent trends that show a decline in use, 23% of high school seniors still report daily smoking, with 8.9% of seniors smoking more than 10 cigarettes per day (CDC, 2000c).

The health risks of smoking include increased respiratory infections, lessened lung capacity, and permanent lung damage (USDHHS, 1994). Perhaps the greater health risks occur over a longer period of time. Nearly one-third of young people who take up smoking in adolescence will eventually die of a smoking-related illness (Gilpin, Choi, Berry, & Pierce, 1999).

Research shows that the time interval between first use (experimentation) and regular use is quite variable, with an average length of several years (USDHHS, 1994). This finding suggests that there is a small window following first use in which smoking can be either encouraged or discouraged. Factors associated with the increased likelihood of regular cigarette use are accessibility, affordability, peer and parental smoking, academic difficulty, school misbehavior (e.g., skipped classes, truancy, suspensions), and peer encouragement of such misbehaviors (Alexander et al., 2001; Bryant et al., 2000; Bryant, Schulenberg, O’Malley, Bachman, & Johnston, 2003; Robinson, Klesges, Zbikowski, & Glaser, 1997). Early experience with nonusing peers, parents who convey nonuse messages and monitor time spent with deviant peers, successful school achievement, high levels of motivation, and commitment to school are protective factors against increased cigarette use over time (Bryant et al., 2003).

Adolescents resemble adults in that they report frequent attempts to quit smoking and experience nicotine withdrawal when nicotine abstinent (Colby, Tiffany, Shiffman, & Niaura, 2000). In a review of 17 cessation programs for adolescents, 10 were found to be effective—but with only a 12% success rate. This finding means that it is as difficult for adolescents who are regular smokers to quit smoking as it is for adults (Sussman et al., 1999). The key lies in prevention, although the most successful prevention programs begin early (grade 6) and are interactive. They teach young teens refusal skills (i.e., how to say “no”), use peer leaders, and emphasize that fewer adolescents actually smoke than teens frequently believe (Tobler et al., 2000). It also appears that recent antitobacco media campaigns may be effective when paired with the prevention components mentioned above (Pechman, 1997).