Joel D. Killen

Naturalistic weight-reduction efforts prospectively predict growth in relative weight and onset of obesity among female adolescents.

This study examined the prospective relations of naturalistic weight-reduction efforts to growth in relative weight and onset of obesity with data from a community study of female adolescents (N = 692). Initial self-labeled dieting, appetite suppressant/laxative use, incidental exercise, vomiting for weight-control purposes, and binge eating predicted elevated growth in relative weight over the 4-year period. Dietary restraint, self-labeled dieting, exercise for weight-control purposes, and appetite suppressant/laxative use predicted an increased risk for obesity onset. Data imply that the weight-reduction efforts reported by adolescents are more likely to result in weight gain than in weight loss and suggest the need to educate youth on more effective weight-control strategies.

Pursuit of thinness and onset of eating disorder symptoms in a community sample of adolescent girls: A three-year prospective analysis.

Community-based prospective studies are needed to shed light on mechanisms that may influence development of eating disorders and identify variables that could serve as potential targets for prevention efforts. In this paper we examine level of weight preoccupation and other variables prospectively associated with age of onset of eating disorder symptoms over a 3-year interval in a community sample (N = 939) of young adolescent girls. 3.6% (32/887) experienced onset of symptoms over the interval. Only one factor, a measure of Weight Concerns, was significantly associated with onset (p < .001). Girls scoring in the highest quartile on the measure of Weight Concerns had the shortest survival time (12% incidence by age 14.5) and those scoring in the lowest quartile had the highest survival time (2% incidence by age 14.5; p < .001). This finding is consistent with both theoretical and clinical perspectives and represents one of the first prospective demonstrations of a linkage between weight and body shape concerns and later onset of eating disorder symptoms. An understanding of the independent variables that predispose girls to development of symptoms is a useful step towards the establishment of a rational basis for the choice of a prevention intervention target.

Body-image and eating disturbances predict onset of depression among female adolescents: a longitudinal study.

This study examined data from a 4-year school-based longitudinal study (n = 1,124), to test whether the increase in major depression that occurs among girls during adolescence may be partially explained by the body-image and eating disturbances that emerge after puberty. Elevated body dissatisfaction, dietary restraint, and bulimic symptoms at study entry predicted onset of subsequent depression among initially nondepressed youth in bivariate analyses controlling for initial depressive symptoms. Although the unique effect for body dissatisfaction was not significant in the multivariate model, this set of risk factors was able to fairly accurately foretell which girls would go on to develop major depression. Results were consistent with the assertion that the body-image- and eating-related risk factors that emerge after puberty might contribute to the elevated rates of depression for adolescent girls.

Smoking Cessation after Acute Myocardial Infarction: Effects of a Nurse-Managed Intervention

STUDY OBJECTIVE To determine the effect of a nurse-managed intervention for smoking cessation in patients who have had a myocardial infarction. DESIGN Randomized, with a 6-month treatment period and a 6-month follow-up. SETTING Kaiser Foundation hospitals in Redwood City, Santa Clara, Hayward, and San Jose, California. PATIENTS Sequential sample of 173 patients, 70 years of age or younger, who were smoking before hospitalization for acute myocardial infarction. Eighty-six patients were randomly assigned to the intervention and 87 to usual care; 130 patients (75%) completed the study and were available for follow-up. INTERVENTION Nurse-managed and focused on preventing relapse to smoking, the intervention was initiated in the hospital and maintained thereafter primarily through telephone contact. Patients were given an 18-page manual that emphasized how to identify and cope with high-risk situations for smoking relapse. MEASUREMENTS AND MAIN RESULTS One year after myocardial infarction, the smoking cessation rate, verified biochemically, was 71% in the intervention group compared with 45% in the usual care group, a 26% difference (95% CI, 9.5% to 42.6%). Assuming that all surviving patients lost to follow-up were smoking, the 12-month smoking cessation rate was 61% in the intervention group compared with 32% in the usual care group, a 29% difference (95% CI, 14.5% to 43.5%). Patients who either resumed smoking within 3 weeks after infarction or expressed little intention of stopping in the hospital were unlikely to have stopped by 12 months. CONCLUSIONS A nurse-managed smoking cessation intervention largely conducted by telephone, initiated in the hospital, and focused on relapse prevention can significantly reduce smoking rates at 12 months in patients who have had a myocardial infarction.

Predictors of Panic Attacks in Adolescents

OBJECTIVE To identify risk factors for onset of panic attacks in adolescents, a prospective cohort design was used to evaluate the following risk factors: negative affectivity, female sex, anxiety sensitivity, and childhood separation anxiety disorder. These risk factors were also evaluated for predicting onset of major depression to test their specificity. METHOD The sample consisted of 2,365 high school students assessed over a 4-year period. Assessments included self-report questionnaires and structured clinical interviews. Cox proportional hazards models were used to evaluate risk. RESULTS Consistent with previous studies, prior major depression predicted onset of panic attacks and a history of panic attacks predicted onset of major depression. After adjusting for the effects of prior major depression, negative affectivity and anxiety sensitivity, but not female sex or childhood separation anxiety disorder, predicted onset of 4-symptom panic attacks. However, female sex and negative affectivity but not anxiety sensitivity or childhood separation anxiety disorder predicted onset of major depression after adjustment for the effects of prior panic attacks. CONCLUSION Negative affectivity appears to be a nonspecific risk factor for panic attacks and major depression, whereas anxiety sensitivity appears to be a specific factor that increases the risk for 4-symptom panic attacks in adolescents.

Linking Self-Reported Childhood Behavioral Inhibition to Adolescent Social Phobia

OBJECTIVE Behavioral inhibition in children has been hypothesized to be a risk factor for the later development of social phobia. However, this hypothesis has yet to be demonstrated in a prospective study. The purpose of the study presented here is to test whether behavioral inhibition in childhood constitutes a risk factor for social phobia during adolescence. METHOD The sample consisted of 2,242 high school students assessed over a 4-year period. Assessments included self-report questionnaires, structured clinical interviews, and measurements of heart rate. Cox proportional hazards models were used to evaluate risk. RESULTS Social avoidance, a component of behavioral inhibition, predicted onset of social phobia during high school. However, social avoidance was not related to depression in adolescence. Another component of behavioral inhibition, fearfulness, increased the risk for both social phobia and depression. Among subjects who were both socially avoidant and fearful, 22.3% developed social phobia--a risk more than four times greater than that for subjects with neither feature of behavioral inhibition. CONCLUSION This prospective study demonstrates that behavioral inhibition in childhood increases the risk of social phobia in adolescence.

Factors associated with weight concerns in adolescent girls.

OBJECTIVE This study examined the association of weight concerns with potential risk factors for the development of eating disorders. METHOD A self-report survey was given to 103 elementary (Grades 4 and 5) and 420 middle (Grades 6-8) school students in Arizona and California. Of these, 78 elementary and 333 middle school students provided complete data and were used in the analyses. RESULTS In a multivariate stepwise regression analysis, the importance that peers put on weight and eating was most strongly related to weight concerns in the elementary school girls, accounting for 34% of the variance after adjusting for site differences. Trying to look like girls/women on TV and in magazines as well as body mass index (BMI) entered the final model that accounted for 57% of the variance in weight concerns. In middle school, the importance that peers place on weight and eating was also the strongest predictor accounting for 33% of the variance followed by confidence, BMI, trying to look like girls/women on TV and in magazines, and being teased about weight. Together these variables accounted for 55% of the variance. DISCUSSION Prevention programs aimed at reducing weight concerns need to address these factors.

Psychosocial predictors of physical activity in adolescents

Regular physical activity consistently demonstrates an inverse relationship with coronary heart disease and has positive effects on quality of life and other psychological variables. Despite the benefits of exercise, many youth and adults maintain a sedentary lifestyle. Interventions are needed, particularly with youth, to increase levels of physical activity. A better understanding of the psychosocial predictors of physical activity will aid in structuring these interventions. Longitudinal data from a cohort of 743 10th-grade students from the control condition of the Stanford Adolescent Heart Health Program were analyzed. Regression analysis indicated that psychosocial variables were significantly related to physical activity after controlling for baseline levels of physical activity and BMI. Associations with physical activity were found for intention to exercise, self-efficacy, stress, and direct social influence. The designers of future interventions should consider including program components that target these variables.

Age of Onset for Binge Eating and Purging During Late Adolescence A 4-Year Survival Analysis

This prospective study examined age of onset for binge eating and purging among girls during late adolescence and tested whether dieting and negative affectivity predicted these outcomes. Of initially asymptomatic adolescents, 5% reported onset of objective binge eating, 4% reported onset of subjective binge eating, and 4% reported onset of purging. Peak risk for onset of binge eating occurred at age 16, whereas peak risk for onset of purging occurred at age 18. Adolescents more often reported onset of a single symptom rather than multiple symptoms, and symptoms were episodic. Dieting and negative affectivity predicted onset of binge eating and purging. Findings suggest that late adolescence is a high-risk period for onset of bulimic behaviors and identify modifiable risk factors for these outcomes.

Modifying smoking behavior of teenagers: a school-based intervention.

Tenth grade health classes in three high schools received a special program focusing on the immediate physiological effects of cigarette smoking and the social cues influencing adoption of the smoking habit, and classes in two control schools received standard information on the long-term effects of smoking. Only subjects in the special program reported a decrease in smoking from pre to post-test; they also scored higher than controls on a knowledge test. Carbon monoxide levels were significantly lower for subjects in the special group at post-test.