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Biomedical subjects

J D Killen

Publications and source records attributed to J D Killen.

At least 19 recordsLinked to original sources
PubMed1992

Is puberty a risk factor for eating disorders?

OBJECTIVE: To examine the association between stage of sexual maturation and eating disorder symptoms in a community-based sample of adolescent girls. PARTICIPANTS: All sixth- and seventh-grade girls (N = 971) enrolled in four northern California middle schools. MAIN VARIABLES EXAMINED: Pubertal development measured using self-reported Tanner stage and body mass index (kg/m2). The section of the Structured Clinical Interview for DSM-III-R Disorders (SCID) discussing bulimia nervosa was used to evaluate symptoms of bulimia nervosa. RESULTS: Girls manifesting eating disorder symptoms, while not significantly older than their peers without such symptoms, were more developmentally advanced as determined with Tanner self-staging. The odds ratio for the association between sexual maturity and symptoms was 1.8 (95% confidence interval, 1.2 to 2.8); ie, at each age, an increase in sexual maturity of a single point was associated with a 1.8-fold increase in the odds of presenting symptoms. The odds ratio for the association between body mass index (adjusted for sexual maturity) and symptoms was 1.02 (95% confidence interval, 1.0 to 1.05). There was no independent effect of age or of the interaction between age and the sexual maturity index. CONCLUSIONS: These results suggest that (1) puberty may be a risk factor for the development of eating disorders, and (2) prevention efforts might best be directed at prepubertal and peripubertal adolescents.

Adolescent↗
PubMed1992

Who will relapse? Symptoms of nicotine dependence predict long-term relapse after smoking cessation.

Results of a prospective examination (N = 618) of factors associated with smoking relapse are reported. At 1-year follow-up, a modified version of the Fagerstrom Tolerance Questionnaire (Dependence Index; DI) and a measure of craving entered the logistic model (odds ratio of 2.7 [p less than .001]). At Year 2, only the DI entered the model (odds ratio of 2.2 [p less than .001]). The ability of signal detection analysis (SDA) to produce clinically useful decision rules was also examined. At Year 1, SDA produced 1 subgroup with a 25% nonrelapse rate and another with a 9% nonrelapse rate (odds ratio of 3.4 [p less than .001]). At Year 2, SDA produced 1 subgroup with a nonrelapse rate of 19% and another with a nonrelapse rate of 7% (odds ratio of 3.0 [p less than .001]). The use of signal detection methods may help clinicians to identify those at greater or lesser risk of relapse.

Adult↗
PubMed1992

Pubertal stage and panic attack history in sixth- and seventh-grade girls.

OBJECTIVE: Although the incidence of first panic attacks appears to peak during adolescence, little is known about which features of adolescence contribute to the risk of a first panic episode. The purpose of this study was to compare the relative importance of age and pubertal stage in explaining the occurrence of panic attacks in adolescents. METHOD: From a school-based sample of sixth- and seventh-grade girls, 754 subjects completed both a structured clinical interview determining history of one or more panic episodes and a self-assessment of Tanner stages of pubertal development. A multiple logistic regression analysis was performed with panic attack history as the dependent variable and pubertal stage, age, and their interaction as the independent variables. RESULTS: A history of one or more four-symptom panic attacks was found in 5.3% of the girls (N = 40). After age was controlled for, pubertal stage was significantly related to panic attack history. At each age, higher rates of panic attacks were found in the more physically mature girls. CONCLUSIONS: Pubertal stage, after adjustment for the effects of age, appears to predict panic attack occurrence in young adolescent girls. Understanding the link between puberty and panic may offer clues regarding the onset and etiology of panic attacks.

Adolescent↗
PubMed1992

Insulin-like growth factor binding protein-3 in normal pubertal girls.

IGFBP-3 concentrations rise in the second decade of life. To test the hypothesis that the stage of pubertal development, independent of chronological age, was associated with these increases we measured serum IGFBP-3 concentrations by radioimmunoassay in 324 sixth and seventh grade girls (12.3 +/- 0.7 years) at the beginning of a multisite school-based health curriculum. The mean (+/- SD) serum IGFBP-3 among the 242 girls with complete data was 4.0 +/- 0.7 mg/l. Pubertal stage was significantly associated with IGFBP-3 (p less than 0.0001, ANOVA). Mean concentrations rose from 3.5 +/- 0.7 mg/l among those with the earliest pubertal stages to 4.2 +/- 0.7 mg/l among the mature girls. IGF-I and IGFBP-3 concentrations were significantly correlated (Spearman's r = 0.43, p less than 0.0001). After controlling for the association between pubertal development and IGFBP-3 concentrations, only the waist/hip ratio, among the various measures of body composition, was significantly associated with IGFBP-3 concentration (Spearman's r = -0.23, p = 0.0002). Likewise, none of the measures of nutrition: intake of total calories, protein, fat and carbohydrate; serum iron; red cell mean corpuscular volume; or cholesterol; were significantly associated with IGFBP-3 concentrations. There was, however, a small, but significant association between IGFBP-3 concentrations and both serum transferrin and blood hemoglobin concentrations. Pubertal stage has a significant impact on IGFBP-3 concentrations and those attempting to utilize IGFBP-3 concentrations during adolescence should be cognizant of the subject's pubertal stage.

Adolescent↗
PubMed1991

Prospective study of factors influencing the development of craving associated with smoking cessation.

There have been few prospective studies of craving following smoking cessation. This paper presents findings from a prospective examination of factors associated with craving over an 8-week treatment period. Two findings merit attention: (1) dependence, as measured by the Dependence Index (DI), was associated with craving at 48 h, 4 and 8 weeks post-cessation. The magnitude of the association between the DI and short-term craving was, at the least, comparable to that previously reported among several biochemical measures of smoke intake; (2) a measure of craving obtained 48 h after smoking cessation was associated with treatment outcome. Forty-three per cent of participants with low initial craving scores were abstinent at a 2-month follow-up compared to only 26% of those with high craving scores. The DI was also associated with participants' status at follow-up. This result is interesting because evidence that craving or other abstinence effects are prospectively associated with outcome has been lacking.

Adult↗
PubMed1991

Impact of pubertal development on body fat distribution among white, Hispanic, and Asian female adolescents.

Variation in the waist/hip ratio (WHR) may be related to changes in hormonal secretion associated with pubertal maturation. We therefore studied the effects of race, pubertal development, and body fatness on WHR during adolescence in a multiethnic population. A total of 688 white, Asian, and Hispanic female adolescents (mean (+/- SD) 12.4 +/- 0.7 years), participating in the evaluation of a multisite school-based health education program, were included in these analyses. Self-assessed stage of puberty and measurements of height, weight, waist circumference, and hip circumference were obtained from each participant. The WHR and age-adjusted body mass index were calculated. Analysis of covariance demonstrated that puberty significantly affects hip circumference and WHR but not waist circumference among female adolescents. Age and fatness, as reflected by age-adjusted body mass index, contributed significantly to both circumferences and to the WHR. There was a significant effect of ethnicity on hip circumference but not on waist circumference or the WHR. These results confirm that pubertal stage exerts a significant effect on the hip circumference and WHR in female adolescents, even after the effects of fatness and age are controlled. Studies of body fat distribution during late childhood and adolescence should include assessments of pubertal maturation.

Adipose Tissue↗
PubMed1991

Insulin-like growth factor-I as a reflection of body composition, nutrition, and puberty in sixth and seventh grade girls.

Large variations in nutritional intake have profound effects on the GH-insulin-like growth factor-I (IGF-I) axis in children and adults, but the effect of normal variations in nutrition on IGF-I concentrations is largely unstudied, particularly during puberty. We measured serum IGF-I concentrations in 325 sixth and seventh grade girls (12.4 +/- 0.7 yr) at the beginning of a multisite school-based health curriculum. The mean serum IGF-I level among the 243 girls with complete data was 573 +/- 244 micrograms/L. Pubertal stage was significantly associated with IGF-I (P less than 0.0001, by analysis of variance). Mean concentrations rose from 427 +/- 198 micrograms/L among those at the earliest pubertal stages to 639 +/- 219 micrograms/L among the mature girls. After adjusting for the association with the stage of pubertal development, serum IGF-I was not significantly associated with measures of body composition (body mass index, triceps skin fold thickness, waist/hip ratio, height, and weight). Additionally, IGF-I concentrations were not associated with nutritional intake (total calories, total protein, total fat, and total carbohydrate) or such measures of nutrition as serum iron, hemoglobin, red cell mean corpuscular volume, white cell count, and cholesterol. IGF-I concentrations, however, were significantly correlated with transferrin concentrations, another possible index of nutritional status (r = 0.29; P less than 0.0001). IGF-I is not a clinically useful index of nutritional status among normal pubertal girls.

Adolescent↗
PubMed1990

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.

Adult↗
PubMed1990

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.

Adolescent↗
PubMed1990

Social influences approach to smoking prevention: the effects of videotape delivery with and without same-age peer leader participation.

This study tested the hypothesis that cigarette smoking adoption among adolescents could be suppressed by providing school-based videotape instruction for resisting social influences to smoke. The utilization of same-age peer leaders was also varied to test whether their participation in the classroom would enhance program effects. Seventh grade students (N = 540) from one junior high school in Southern California were randomly assigned by classrooms (N = 15) to: (a) videotape instruction, (b) videotape instruction plus peer leader involvement, or (c) survey-only. Seventh grade students (N = 234) in a second junior high school served as a measurement-only control. Assessments were conducted at the beginning and end of the academic year. Results revealed a marked suppression in the onset of both experimental and regular smoking among those students exposed to the pressure resistance training with peer leader involvement. Pressure resistance training without peer leader involvement produced a more variable and less powerful effect on students' smoking behavior. Data collected on students' use of alcohol and marijuana revealed a generalized suppression effect, albeit weaker than for tobacco, among those students exposed to the social resistance training with peer leader involvement. Results provide further encouraging support for the use of peer-led pressure resistance training in preventing adolescent drug use.

Adolescent↗
PubMed1990

Weight change among participants in a large sample minimal contact smoking relapse prevention trial.

Weight at baseline and posttreatment was measured for 1096 participants in a smoking relapse prevention trial: 42.1% maintained their weight, 42.5% gained more than 1 kg and 15.4% lost more than 1 kg during the eight-week treatment program. Abstainers (n = 383) gained more than four times the weight gained by relapsers (n = 713) (Abstainers: 1.6 kg, Relapsers: 0.4 kg, p less than .0001). In order to examine the anorexic properties of nicotine gum. Abstainers were classified into nicotine gum user and non-user categories. Users gained significantly less weight than non-users although the difference was small (Users: 1.1 kg, Non-users: 1.8 kg, p less than .004). A dose-response relationship was observed between number of cigarettes smoked per day at baseline and weight gain. Higher cigarette consumption was associated with increased weight gain in both gum user (p less than .004), and non-user groups (p less than .02). There was no significant difference in weight gain between Abstainers who later relapsed at 6 months and those who maintained abstinence (p less than .29). Although the impact of nicotine gum on weight gain was small, this apparent property of the substance may be useful in encouraging cessation among smokers who perceive weight gain as a potential stumbling block to success.

Adult↗
PubMed1990

Evaluation of a treatment approach combining nicotine gum with self-guided behavioral treatments for smoking relapse prevention.

1,218 smokers able to quit smoking for 48 hr were randomly assigned to one of 12 cells in a 4 x 3 fully crossed factorial experiment. A pharmacologic factor contained four levels: nicotine polacrilex (gum) delivered ad lib or on a fixed regimen, placebo gum, and no gum. A self-guided behavioral treatment factor contained three levels: self-selected relapse prevention modules, randomly administered modules, and no modules. Those receiving nicotine gum were more likely to be abstinent at the 2- and 6-month follow-ups. The fixed regimen accounted for most of the effect for gum. There was no effect for the relapse prevention module factor. Men and women showed a differential treatment response. Men who received nicotine gum were more likely to be abstinent at each follow-up (2, 6, and 12 months). No treatment was significantly better among women. We conclude that research on different gum chewing regimens is warranted and that further examination of possible gender differences in response to replacement therapy is needed.

Adolescent↗
PubMed1989

Panic attacks in young adolescents.

The lifetime prevalence of interview-determined four-symptom panic attacks in 95 ninth graders was 11.6%. Those with panic attacks were significantly more depressed, were significantly more likely to have separated or divorced parents, and tended to be more likely to have tried cigarette smoking.

Adolescent↗
PubMed1989

The Stanford Adolescent Heart Health Program.

This study was designed to create, implement, and test a school-based multiple risk factor reduction program for high school students. All tenth graders in four senior high schools (N = 1447) from two school districts participated in the study. Within each district, one school was assigned at random to receive a special 20-session CVD risk reduction intervention and one school served as a control. The schools were matched for size and distribution of racial groups before randomization. At a two-month follow-up, knowledge gains were significantly greater for students in the treatment group on each of the risk factor domains tested: nutrition/diet (p less than 0.0001), physical activity (p less than 0.0001), and cigarette smoking (p less than 0.0001). Compared to controls, a higher proportion of those in the treatment group who were not exercising regularly at baseline, reported regular exercise at follow-up (p less than 0.0003). Almost twice as many baseline experimental smokers in the treatment group reported quitting at follow-up while only 5.6% of baseline experimental smokers in the treatment group graduated to regular smoking compared to 10.3% in the control group (p = 0.009). Students in the treatment group were more likely to report that they would choose heart healthy snack items (p less than 0.0001). Beneficial treatment effects were observed for resting heart rate (p less than 0.0001), BMI (p = 0.05), triceps skinfold thickness (p = 0.003), and subscapular skinfold thickness (p = 0.01). The results suggest that it is feasible to provide CVD risk reduction training to a large segment of the population through school-based primary prevention approaches.

Adolescent↗
PubMed1988

Minimal contact treatment for smoking cessation. A placebo controlled trial of nicotine polacrilex and self-directed relapse prevention: initial results of the Stanford Stop Smoking Project.

To determine the effectiveness of nicotine polacrilex combined with self-administered relapse prevention materials in maintaining smoking cessation, we conducted a randomized, double-blind, placebo controlled trial. Volunteers aged 18 to 65 years responding to media announcements were required to quit smoking for 48 hours without assistance. Of 1844 potential participants, 136 were medically excluded, 535 declined to make a quit attempt, and 573 were unable to quit, leaving 600 participants (35%) who were randomized. Eight self-help relapse prevention modules were mailed weekly. Gum was used either ad lib for smoking urges or on a fixed, hourly schedule (12 pieces per day). Only 15% of the subjects in each gum group stopped using the gum altogether because of side effects, but only 20% of the ad lib groups and 40% of the fixed-dosage group used at least eight pieces of gum per day during the first week. The abstinence rates (for at least seven days) at the six-month follow-up were 31% in both active gum groups and 22% in the placebo and no gum groups. Relapse rates in the two active gum groups were about half those in the placebo and no gum groups. Nicotine polacrilex may be a useful adjunct to minimal contact smoking cessation formats, which have broad appeal. Also, minimal contact relapse prevention programs may assist physicians in helping patients to maintain smoking cessation using nicotine polacrilex.

Adolescent↗
PubMed1988

Are heavy smokers different from light smokers? A comparison after 48 hours without cigarettes.

Correlates of heavy smoking (greater than or equal to 25 cigarettes per day) were examined in a group of 380 smokers participating in a minimal-contact smoking relapse prevention trial. The results indicate that heavy smokers are more dependent on cigarettes. Compared with smokers consuming 15 or fewer cigarettes per day, heavy smokers reported greater difficulty quitting, were more troubled by withdrawal symptoms, experienced stronger urges and cravings, and had higher scores on a modified version of the Fagerstrom tolerance questionnaire. Heavy smokers weighed more and were more obese as measured by body mass index. Eighty percent of heavy smokers were classified correctly using discriminant function analysis with two dependence-related measures entering as the most important discriminator variables. Logistic regression analyses yielded similar results. The findings underscore the importance of addressing potential physical dependence factors when developing smoking-cessation treatments for heavy smokers.

Adult↗
PubMed1987

Perspectives on adolescent substance use. A defined population study.

We asked 1447 tenth graders to complete a survey on physical activity, nutrition, stress, and substance use and to undergo basic physical assessments. In a multiple regression analysis, increased level of substance use by both boys and girls was most strongly predicted by friends' marijuana use. For boys, this was followed by perceived safety of cigarette smoking; poor school performance; parents' education; and use of diet pills, laxatives, or diuretics for weight control, accounting for 44% of the overall variation in substance use. For girls, friends' marijuana use was followed by poor school performance; self-induced vomiting for weight control; perceived safety of cigarette smoking; use of diet pills, laxatives, or diuretics for weight control; parents' education; perceived adult attitudes about cigarettes; and nonuse of seat belts, accounting for 53% of the overall variance. Separate multiple regression analyses for each substance produced similar results. The homogeneity of the study population precluded ethnic comparisons. These findings suggest that for many purposes substance use may be considered a single behavior regardless of the specific substance(s) used and that substance use may exist as part of a syndrome of adolescent problem behaviors. In addition, the potent influence of perceived social environment suggests that a social influence resistance model may represent the most successful preventive strategy.

Adolescent↗