Impact of age and sex on mycobacterial immunity in an area of high tuberculosis incidence.

SETTING: The extent of immune reactivity measured by the tuberculin skin test (TST) and interferon-gamma (IFN-gamma) T-cell assays is usually not analysed. OBJECTIVE: To determine the impact of age and sex on assay positivity and on the extent of reactivity of both TST and T-cell assays in young persons in an area of South Africa with high TB transmission. RESULTS: Age had a strong impact on assay positivity for all seven immune phenotypes tested (P < 0.0007). Among positive responders, the extent of purified protein derivative (PPD) triggered IFN-gamma release (P < 0.003) was sensitive to age. ESAT-6 triggered IFN-gamma release (day 7, P = 0.03) and the frequency of PPD-specific IFN-gamma(+)CD4(+) (P = 0.03) and IFN-gamma(+)CD8(+) cells (P = 0.04) were weakly dependent on age. By contrast, the extent of TST induration was insensitive to age (P > 0.05), and sex had no significant impact on any phenotype measured (P > 0.05). The high proportion of positive responders in the 1-10 year age-group observed with long-term whole blood assays, but not with 3-day assays and TST, suggests that long-term whole blood assays may be confounded by bacille Calmette-Guérin vaccination in this age group. CONCLUSION: There is a significant impact of age, but not sex, on different assays of immune reactivity in this high TB transmission setting.

Reduced in vitro functional activity of human NRAMP1 (SLC11A1) allele that predisposes to increased risk of pediatric tuberculosis disease.

Polymorphic variants within the human natural resistance-associated macrophage protein-1 (NRAMP1, also known as SLC11A1) gene have been shown to impact on susceptibility to tuberculosis in different human populations. In the mouse, Nramp1 is expressed at the macrophage phagosomal membrane and its activity can be assayed by the relative acquisition of mannose 6-phosphate receptor (M6PR) in Salmonella-containing vacuoles. Based on this M6PR recruitment assay, we have now developed an assay in primary human macrophages to test the function of human NRAMP1 gene variants. First, we established that M6PR acquisition was significantly higher (P = 0.002) in human U-937 monocytic cell lines transfected with NRAMP1 as compared to untransfected U-937 cells. Second, the M6PR assay was shown to be highly reproducible for NRAMP1 activity in monocyte-derived macrophages (MDM) from healthy volunteers. Finally, the assay was investigated in MDM from pediatric tuberculosis patients and significantly lower NRAMP1 activity was detected in MDM from individuals homozygous for the NRAMP1-274 high-risk allele (CC genotype) in comparison to heterozygous individuals (CT genotype; P=0.013). The present study describes both an assay for human NRAMP1 functional activity and concomitant evidence for reduced NRAMP1 function in the common genetic variant shown to be associated with tuberculosis susceptibility in pediatric patients.

Effects of a parent-child communications intervention on young adolescents' risk for early onset of sexual intercourse.

CONTEXT: The quality of parent-child communications about sex and sexuality appears to be a strong determinant of adolescents' sexual behavior. Evaluations of interventions aimed at improving such communications can help identify strategies for preventing early onset of sexual behavior. METHODS: A school-based abstinence-only curriculum was implemented among 351 middle school students, who were randomly assigned to receive either the classroom instruction alone or the classroom instruction enhanced by five homework assignments designed to be completed by the students and their parents. An experimental design involving pretest and posttest surveys was used to assess the relative efficacy of the curriculum delivered with and without the parent-child homework assignments. RESULTS: In analyses of covariance controlling for baseline scores, immediately after the intervention, adolescents who received the enhanced curriculum reported greater self-efficacy for refusing high-risk behaviors than did those who received the classroom instruction only (mean scores, 16.8 vs. 15.8). They also reported less intention to have sex before finishing high school (0.4 vs. 0.5), and more frequent parent-child communications about prevention (1.6 vs. 1.0) and sexual consequences (1.6 vs. 1.1). In all significant comparisons, the direction of the findings favored adolescents who received the enhanced curriculum. Dose-response relationships supported the findings. CONCLUSIONS: Parent-child homework assignments designed to reinforce and support school-based prevention curricula can have an immediate impact on several key determinants of sexual behavior among middle school adolescents.

Strategies to maximize retention of a sample of young adolescents in a longitudinal evaluation of Healthy & Alive!

The authors implemented strategies to maximize cohort retention to avert loss of statistical power and minimize bias in a longitudinal evaluation of a middle school HIV/STD prevention intervention. A retention rate of 80% of the baseline sample (n = 2,975) at six months and 73% at 18 months was achieved despite high reported rates of student mobility and a major system reorganization in one urban district. The strategies increased retention but did not eliminate differences in demographic characteristics and behaviors between the groups of retained and lost students. Results confirm the need to implement retention strategies early and to maintain them throughout data collection. Information from a tracking data base can be used to prioritize students for follow-up to reduce bias from sample loss.

Longitudinal shifts in employees' stages and processes of exercise behavior change.

PURPOSE: This study examines the usefulness of using the stages and processes of change model to explore exercise adoption and maintenance over time. DESIGN: Data for this study were collected as part of the baseline and follow-up survey of participants in a worksite health promotion project. SUBJECTS: Three hundred fourteen employees completed exercise questionnaires. The average age was 41 years, mean body mass index was 26, average years of education were 13, and 66% were women. SETTING: The study was conducted in two worksites, a retail outlet and a manufacturing company. MEASURES: Previously validated questionnaires to determine stages and processes of exercise adoption were administered at baseline and 6-month follow-up, along with questions about demographic variables. RESULTS: Four patterns of stage change emerged: subjects who became more active (adopters, 26%), those who became less active (relapsers, 15%), and those who did not change over time (stable sedentary, 32%; stable active, 27%). Adopters displayed increases in use of the processes of change, whereas relapsers displayed decreases in process use. Stable profiles were associated with no change in process use. CONCLUSIONS: These findings have important implications for research on exercise adoption and maintenance. Interventions tailored specifically to subjects' stage of readiness to be active and using specific processes to help in the change process are warranted at this time.

Oral habits and TMJ dysfunction in facial pain and non-pain subjects.

Multifactorial theories for facial pain aetiology have been proposed in the past, although little research has been produced to support a multifactorial aetiology. The present study assessed self-rated oral habits over a 7 day period for facial pain and non-pain subjects with and without a clinical symptom of TMJ dysfunction. The results indicate a significant effect for TMJ dysfunction and teeth clenching and an interaction between TMJ dysfunction and facial pain for biting of the lips and mouth. A significant chi-square test showed that most non-pain controls with TMJ dysfunction reported that they never clenched. The results are discussed in terms of support for a multifactorial aetiology in some facial pain patients and the need for future research to delineate subgroups of facial pain and non-pain subjects.

Exercise enhances the maintenance of smoking cessation in women.

We examined the effects of physical exercise on smoking relapse. Twenty previously sedentary female smokers were randomly assigned to smoking cessation plus exercise or smoking cessation with frequency contact control. The smoking cessation program included 12 professionally led sessions over 12 weeks. Exercise treatment included three supervised exercise sessions per week for 15 weeks. Contact control included three women's health/wellness lectures per week for 15 weeks. Smoking abstinence was validated by carbon monoxide and saliva cotinine. Mean exercise attendance for exercise subjects was 88% with an increase in estimated VO2 of 25%. The percentage of subjects who quit for 24 hours was 80% for the exercise and 90% for the contact group. One subject in the contact group remained abstinent at the end of the 12-week treatment and at 1-, 3-, and 12-month follow-ups, whereas three subjects in the exercise group were abstinent at these time points. These results suggest that exercise training improves short-term quit rates and may prove a useful strategy for long-term maintenance of smoking cessation.

The transtheoretical model: applications to exercise behavior.

The transtheoretical model has been used to understand the stages individuals progress through, and the cognitive and behavioral processes they use while changing health behaviors. The model postulates that individuals engaging in a new behavior move through the stages of Precontemplation, Contemplation, Preparation, Action, and Maintenance. Movement through these stages does not always occur in a linear manner, but may also be cyclical as many individuals must make several attempts at behavior change before their goals are realized. The amount of progress people make as a result of intervention tends to be a function of the stage they are in at the start of treatment. Instruments have been developed to measure the stages and processes of exercise adoption and maintenance and the related constructs of exercise specific self-efficacy and decision making. Psychometric data on these instruments are reviewed. Additionally, data collected on these measures from worksites in the U.S. and Australia are presented along with data from interventions aimed at increasing the adoption of physical activity among community volunteers and worksite employees. Applications of the transtheoretical model for the initiation, adoption, and maintenance of exercise behavior from clinical, community, and public health perspectives are discussed.

Application of theoretical models to exercise behavior among employed women.

PURPOSE: This study examines the utility of three theoretical models--the stages of change model, self-efficacy theory, and the decisional balance model--in understanding exercise behavior among employed women. DESIGN: Data for this cross-sectional study were collected as part of a routine follow-up of a worksite-based smoking and health risk appraisal study. SETTING: The study was conducted in three Rhode Island worksites, including one manufacturing company, one medical center, and one retail outlet. SUBJECTS: Of a sample of 431 women who completed exercise questionnaires, 293 reported participation in a physical activity over the previous week. The average age of the sample was 41.1 years, and mean years of education was 12.8. MEASURES: Previously validated measures to determine stage of exercise behavior, exercise self-efficacy, exercise decisional balance, and physical activity participation were administered. Additional demographic information was also obtained. RESULTS: Frequency counts revealed that 39% of the population was sedentary, 34% were participating in irregular activity, and 27% were active. MANOVAs followed by one way ANOVAs revealed that women in Precontemplation scored the lowest and those in Maintenance scored the highest on the self-efficacy, pro, and decisional-balance indices, with the trend reversed on the con scale. A chi-square test revealed that women with one or more young children in the home were more likely to be in a lower stage of exercise adoption. CONCLUSIONS: Most of the women in this cross-sectional study did not engage in regular activity. Presence of young children in the home was significantly related to decreased activity.(ABSTRACT TRUNCATED AT 250 WORDS)

Assessment of coping with high-risk situations for exercise relapse among healthy women.

Twenty-nine healthy women's coping responses to situations interfering with planned exercise and subsequent patterns of relapse were evaluated. Participants adopted exercise without formal intervention; their activity was monitored prospectively for 14 weeks. Cardiovascular fitness was assessed at baseline, 3 months, and 9 months. At 1-week exercise activity lapse was experienced by 66% of participants, and 41% experienced a 3-week relapse episode. Relapsers initially reported significantly fewer behavioral and cognitive coping strategies in response to high-risk situations compared with nonrelapsers, controlling for baseline level of self-motivation. Coping responses also predicted short-term fitness. These data demonstrate the importance of coping or problem-solving ability in exercise and suggest that relapse may result from ineffective coping with exercise barriers.

The stages of exercise behavior.

The stages of change model has shown promise in advancing knowledge about smoking behavior change and other negative addictive behaviors. The model was applied to the study of exercise, a healthy rather than unhealthy behavior. A stages of exercise behavior questionnaire was administered to a sample of 235 employees. Next, the ability of a second questionnaire measuring physical activity behavior to differentiate employees according to stage of exercise was tested. Results revealed that 51% of employees were participating in no physical activity (Precontemplation, Contemplatation) and 49% were participating in occasional or regular physical activity (Preparation, Action, Maintenance). Scores on physical activity behavior items significantly differentiated employees among the stages. This model developed on smoking and other behaviors can be generalized to exercise behavior. Understanding the stages of exercise behavior could yield important information for enhancing rates of participation in physical activity.

Specific and nonspecific effects of EMG biofeedback.

This study investigated the effects of performance feedback and EMG biofeedback on perceptions of the "self" (i.e., self-esteem, self-control, self-efficacy, and locus of control) as well as on a self-control behavior (study skills) the subjects performed outside the laboratory. Forty-seven college students were randomly assigned to one of four groups in a 2(high and low success feedback) x 2(true and false EMG biofeedback) factorial experiment with repeated measures. All of the participants received four sessions of EMG biofeedback, and later they were asked to self-monitor their study habits for 2 weeks. Results showed that the self-esteem measure and perceptions of study skills improvement were differentially affected by success feedback but unrelated to the true or false EMG manipulation. Shifts toward an internal locus of control and perceptions of improved self-control were also noted, but they were independent of the subjects' group membership. Implication of the results are briefly discussed.