Biomedical subjects
Publications and source records attributed to J D Killen.
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.
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.
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.
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.
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.
We surveyed 646 tenth grade females in Northern California to assess the prevalence of binge eating and purging behaviors. Of these, 10.3 per cent met study criteria for bulimia and an additional 10.4 per cent reported purging behaviors for weight control. Bulimics and purgers were heavier, had greater triceps and subscapular skinfold thicknesses, and reported higher rates of drunkenness, marijuana use, cigarette use, and greater levels of depressive symptomatology.
Bulimia (binge-purge syndrome) is a recently described but apparently common eating disorder. Purging behaviors associated with bulimia can cause serious medical complications. Prevalence data on purging behaviors are lacking for younger adolescents. A survey was conducted with 1,728 tenth-grade students to assess their attitudes about eating, dieting, weight control, and frequency of purging. Height, weight, and skin-fold thicknesses were also measured. Thirteen percent reported purging behavior. Female purgers outnumbered male purgers 2 to 1. Male purgers were significantly heavier than male nonpurgers and had significantly greater skin-fold thicknesses and weight/height2 ratios. Both male and female purgers felt guiltier after eating large amounts of food, counted calories more often, dieted more frequently, and exercised less than nonpurgers. Our findings suggest that an alarming number of young adolescents may employ unhealthy weight regulation strategies. Physicians who see adolescents should look for the presence of the attitudes and behaviors that characterize bulimia; this will enhance the likelihood of detection of the disorder and prevention of its complications.
This study examined the psychosocial and behavioral correlates of seat-belt use among 1,728 10th-graders in four Northern California high schools. Parent and friend seat-belt use patterns were most highly correlated with student seat-belt use (r = 0.66 and r = 0.61, respectively) and together accounted for 46% of the variation in use. These relationships held across differences in sex, ethnicity, and socioeconomic status. Failure to wear seat belts was associated with a higher use of alcohol, cigarettes, marijuana, and cocaine; more tolerance toward speeding and drinking while driving; less exercise; and more preference for fat in the diet. Our findings attest to the power of parent and peer influences in shaping seat-belt use by adolescents and suggest that not wearing seat belts can be conceptualized as one facet of a pattern of general risk-taking behavior. These findings suggest several possible educational interventions to increase seat-belt use by adolescents.
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Seventh graders (N = 353) in one junior high school received an experimental smoking prevention program aimed at teaching students to resist the social pressures to smoke cigarettes. Seventh graders (N = 217) in another school served as controls. Teams of high-school students trained in basic behavior change skills led seven classroom sessions of instruction in counter-arguing during the school year. Significant differences were found between groups in reported smoking at a 9-month posttest. Results were maintained at 21- and 33-month follow-ups.
Twelve good sleepers and 12 insomniacs were recorded over three nights in their homes. Subjective assessment of sleep indicated minimal disruption due to sleep recording procedures. A cut point of 88 per cent sleep efficiency resulted in correct classification of nine poor sleepers and 10 good sleepers. Multiple discriminant function analyses, using variables related to rapid eye movement sleep, resulted in the same number of correct classifications. The two indices combined resulted in 100 per cent exclusion of false positives for good sleepers and insomniacs. Insomniacs also showed more night-to night variability in sleep and greater difficulty in returning to sleep once aroused. These results show that good sleepers and insomniacs can be distinquished with a high degree of resolution using variables derived from the home all-night sleep recording.
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Home sleep recordings were conducted over four consecutive nights with 12 good sleepers and 12 sleep-maintenance insomniacs. Good sleepers showed decreased sleep efficiency and increased min awake after sleep onset on night 1. Insomniacs showed extended latency to onset of the first REM period and decreased REM in the first third of the initial recording night. Good sleepers and insomniacs reported no significant differences in adequacy of sleep between the first and subsequent sleep nights.
We report results of a prospective examination of the influence of outcome expectancy variables and inherited temperaments on the onset of drinking over a 12-month period in a sample of 1,164 high school students. While univariate prospective analysis indicated that drinkers and nondrinkers were different both on measures of outcome expectancy and temperament, multivariate analysis supported, most strongly, a social learning account of the processes influencing the onset and maintenance of drinking behavior in this sample. The multivariate analysis revealed that only expectancies for enhanced social behavior were consistently associated with the onset of drinking from baseline to 12-month follow-up (p < .001). Among all nondrinkers at baseline, those entertaining higher expectancies about the positive effects of alcohol on social interaction were more likely to begin drinking between baseline and follow-up. At present, few, if any, alcohol abuse prevention studies with adolescents have explicitly attempted to alter alcohol expectancies or to establish a link between expectancy and behavior change. Our results suggest that it may be useful to do so.
Recent reviews of studies concerning panic attacks in adolescents have emphasized research limitations, noting problems of validity, reliability, and lack of normative data. To address some of these limitations we evaluated two methods of panic ascertainment (questionnaire versus interview), reliability of interview-determined panic, and clinical correlates of panic symptoms in a large sample (N = 1013) of early adolescent girls. The 5.4% of the sample who, when interviewed, reported ever experiencing a panic attack scored significantly higher on measures of depression, anxiety sensitivity, and alcohol use, but were not more avoidant than others. Using the interview as the standard, the questionnaire had a specificity of 81% and a sensitivity of 72%. Adolescents do experience panic attacks-whether identified by questionnaire or interview-although for many the attacks may not be salient. Longitudinal studies are required to determine those qualities of nonclinical panic (severity, context, interpretation/attribution), which render some episodes as clinically meaningful.
The goal of this study was to evaluate a correspondence weight control program, and to assess the impact of three program elements (weekly homework, interim weigh-ins, and participation deposits) individually and in combination. All treated participants received 15 weekly standard lessons by mail. Three program features were varied factorially: a) homework assignments, b) interim weigh-ins and c) a deposit refunded contingent on returning homework and/or attending interim weigh-ins. Participants were assigned randomly to active treatment conditions or a delayed treatment control group. Among treated males (N = 14), initial average weight loss and BMI reduction were 9.6 kg and 3.1 respectively; average net weight loss and BMI reduction at one year follow-up were 5.8 kg and 1.9 respectively. Among treated females (N = 128), initial average weight loss and BMI reduction were 3.1 kg and 1.2 respectively; average net weight loss and BMI reduction at one year were 2.3 kg and .88 respectively. Women in all treated groups, except lessons only, showed a greater BMI reduction than untreated controls at the end of treatment. Women in conditions including both homework and interim weigh-ins had greater initial BMI reductions (M = 1.6) than those who received lessons only (M = .76). At one year, net BMI reductions were comparable across all treated groups. Of the 42 women initially registered in conditions that included both homework and weigh-ins, 12 who denied joining other programs lost at least 4.5 kg (M = 7.1) during treatment, and 7 had a net loss of at least 4.5 kg (M = 8.0) at one year without apparent involvement in any other program.