Correlates of adherence and contamination in a randomized controlled trial of exercise in cancer survivors: an application of the theory of planned behavior and the five factor model of personality

In this study, we examined correlates of adherence and contamination in a randomized controlled trial (RCT) of exercise in cancer survivors using the theory of planned behavior and the Five Factor Model of personality (FFM). We randomly assigned cancer survivors in group psychotherapy classes to either a waiting-list control group (n = 45) or a home-based, moderate intensity exercise program (n = 51). At baseline, participants completed measures of the theory of planned behavior, the FFM, past exercise, physical fitness, medical variables, and demographics. We then monitored exercise over a 10-week period by weekly self-reports. Hierarchical multiple regression analyses indicated that the independent predictors of overall RCT exercise across both conditions were past exercise (beta = .36, p < .001), assignment to experimental condition (beta = .34, p < .001), sex (beta = .30, p < .001), and intention (beta = .14, p < .10). For exercise adherence in the exercise condition, the independent predictors were sex (beta = .38, p < .01), extraversion (beta = .30, p < .05), normative beliefs (beta = -.27, p < .05), and perceived behavioral control (beta = .23, p < .10). Finally, the independent predictors of exercise contamination in the control condition were past exercise (beta = .70, p < .001), sex (beta = .20, p < .05), and intention (beta = .17, p < .10). We conclude that the correlates of exercise adherence and contamination differ in kind as well as in degree. Explanations for these findings and practical implications for conducting exercise RCTs in this population are offered.

Investigating multiple components of attitude, subjective norm, and perceived control: an examination of the theory of planned behaviour in the exercise domain

The presence of two subcomponents within each theory of planned behaviour (TPB) concept of attitude (affective and instrumental), subjective norm (injunctive and descriptive), and PBC (self-efficacy and controllability) has been widely supported. However, research has not examined whether the commonality of variance between these components (i.e. a general factor) or the specificity of variance within the subcomponents influences intention and behaviour. Therefore, the purpose of this study was to examine the optimal conceptualization of either two subcomponents or a general common factor for each TPB concept within an omnibus model. Further, to test whether conceptualizations may differ by population even within the same behavioural domain, we examined these research questions with 300 undergraduates (M age = 20) and 272 cancer survivors (M age = 61) for exercise behaviour. Results identified that a general subjective norm factor was an optimal predictive conceptualization over two separate injunctive and descriptive norm components. In contrast, a specific self-efficacy component, and not controllability or a general factor of PBC, predicted intention optimally for both samples. Finally, optimal models of attitude differed between the populations, with a general factor best predicting intention for undergraduates but only affective attitude influencing intention for cancer survivors. The findings of these studies underscore the possibility for optimal tailored interventions based on population and behaviour. Finally, a discussion of the theoretical ambiguity of the PBC concept led to suggestions for future research and possible re-conceptualization.

Relationships between personality, an extended theory of planned behaviour model and exercise behaviour

OBJECTIVES

The purpose of this study was to investigate the theory of planned behaviour's (TPB) mediating hypothesis between the five-factor model of personality and exercise behaviour using an extended TPB model including concepts of affective and instrumental attitude, injunctive and descriptive norm, controllability, and selfefficacy. It was hypothesized that extraversion's activity facet would have a significant direct effect on exercise behaviour while controlling for the TPB, based on the presupposition that activity may represent a disposition that predicts exercise beyond planned behaviour.

DESIGN

To test the replicability of these findings, we examined this research question with undergraduate students prospectively and cancer survivors, using a cross-sectional design.

RESULTS

Using structural equation modelling, the results indicated that activity had a significant effect (p <.05) on exercise behaviour (study 1 =.20; study 2 =.31) while controlling for the TPB.

CONCLUSIONS

This study suggests the importance of extraversion's activity facet on exercise behaviour, even when controlling for a TPB model with additional socialcognitive concepts and disparate population samples.

Temporal relationships of self-efficacy and social support as predictors of adherence in a 6-month strength-training program for older women

The present study investigated how self-efficacy and social support predicted adherence to a strength training program for elderly women over two time periods in the initial 6 mo. of the program. Participants were 30 elderly women volunteers aged 75 to 80 who completed measures of barrier self-efficacy and general social support at baseline and 3 mo. later. Social support from the program was also measured at 3 mo. Adherence to the program was measured by attendance. Hierarchical regression equations were utilized to identify the contributions of self-efficacy and social support for adherence at 0 to 3 mo. and 4 to 6 mo. For prediction of the first 3 mo. of adherence, both self-efficacy and social support contributed significant unique variance towards the total explained variance of 36%. For the 4- to 6-mo. period, self-efficacy explained significant (12%) variance in adherence even when controlling for the previous 3-mo. adherence. Inclusion of general social support and social support from the program, however, did not account for significant variance. Researchers must continue to examine self-efficacy and social support in exercise adherence within various time periods among older adults to develop effective intervention strategies.

Personality and exercise participation across the breast cancer experience

The purpose of this study was to investigate the relationship between personality and exercise participation across the breast cancer experience. Based on the Five-Factor Model and previous exercise research, it was hypothesized that high scores of extraversion (E) and conscientiousness (C), and low scores of neuroticism (N) would discriminate exercise stage during and following cancer treatment as well as changes in exercise stage across the cancer experience (i.e. from prediagnosis through treatment to posttreatment). Participants were 175 non-metastatic breast cancer survivors who completed a mailed questionnaire that assessed demographic and medical information, personality (the NEO-Five Factor Inventory), and exercise stage recalled for three time periods (prediagnosis, during treatment, and posttreatment). Multivariate analysis of variance showed differences in personality based on exercise stage both during cancer treatment and posttreatment and also for exercise pattern across the cancer experience. Univariate F-tests and post hoc analyses identified N, E, and C as the key personality dimensions. N was associated with earlier exercise stages and a maladaptive exercise pattern whereas E and C were associated with more advanced exercise stages and adaptive exercise patterns. It was concluded that personality may be an important determinant of exercise following breast cancer diagnosis.

Factors associated with exercise adherence among older adults. An individual perspective

This paper reviews the literature concerning factors at the individual level associated with regular exercise among older adults. Twenty-seven cross-sectional and 14 prospective/longitudinal studies met the inclusion criteria of a mean participant age of 65 years or older. The findings are summarised by demographics, exercise experience, exercise knowledge, physiological factors, psychological factors, activity preferences and perceived social influences. In general, education and exercise history correlate positively with regular exercise, while perceived physical frailty and poor health may provide the greatest barrier to exercise adoption and adherence in the elderly. Social-cognitive theories identify several constructs that correlate with the regular exercise behaviour of older adults, such as exercise attitude, perceived behavioural control/self-efficacy, perceived social support and perceived benefits/barriers to continued activity. As well, stage modelling may provide additional information about the readiness for regular exercise behaviour among older adults. However, relatively few studies among older adults exist compared with middle-aged and younger adults. Further, the majority of current research consists of cross-sectional designs or short prospective exercise trials among motivated volunteers that may lack external validity. Future research utilising longitudinal and prospective designs with representative samples of older adults will provide a better understanding of significant causal associations between individual factors and regular exercise behaviour.

Hemorrhagic adrenal adenoma simulating myelolipoma: CT evaluation

We present a hemorrhagic adrenal adenoma surrounding and encompassing adjacent retroperitoneal fat to simulate the appearance of a myelolipoma by CT. A well-defined fibrous capsule, punctate calcification, and several macroscopic foci of fat within the mass led to an erroneous preoperative diagnosis. Lesions displaying large amounts of soft tissue attenuation material in addition to fat preclude a confident diagnosis of myelolipoma and should undergo directed percutaneous needle biopsy or surgery.

Walker-Warburg syndrome

The Walker-Warburg syndrome (WWS) is a rare autosomal recessive disorder characterized by lissencephaly, cerebellar and retinal malformations, and congenital muscular dystrophy. We report a new case of WWS identified with the aid of cranial MR and briefly review the radiologic findings of this lethal syndrome.

Talc granulomatosis presenting as spontaneous pneumothorax

Spontaneous pneumothorax has been described in association with conglomerate masses and bullous disease in end-stage talc granulomatosis. Our case demonstrates that pneumothorax can occur earlier in the course of the disease before these end-stage radiographic changes are present.

Opioid receptors and endogenous opioids in diverse human and animal cancers

Receptor binding studies demonstrated specific high-affinity, saturable binding of a number of opioid ligands to a wide variety of neural and nonneural human and animal tumors. Radioimmunoassays revealed the presence of beta-endorphin and methionine-enkephalin in these tumors. Both methionine- and leucine-enkephalin were detected in tumor tissue by immunocytochemistry, with immunoreactivity related to the cortical cytoplasm of tumor cells, but not to cell nuclei. Endogenous opioids and receptors were found in benign and malignant tumors representative of ectodermal, mesodermal, and endodermal origin. Receptors and endogenous opioid peptides were present in tumors from many different species, including those transplanted into nude mice. These results suggest that opioid receptors and endogenous opioids are fundamental features of human and animal cancers.

Localization of enkephalin immunoreactivity in diverse tissues and cells of the developing and adult rat

The distribution of enkephalin, an endogenous opioid, in tissues and cells of the developing and adult rat was determined by immunocytochemistry with antibodies to met- and leu-enkephalin. Met- and leu-enkephalin were found in all developing cells investigated, with staining generally located throughout the cytoplasm; cell nuclei were not immunoreactive. In comparison to developing cells, immunoreactive analogues to met-enkephalin were usually difficult to detect in the adult. Some notable exceptions were reaction products in leukocytes in blood, lung, and cortex of thymus, fibroblasts in the skin, and seminiferous tubules. These results, in concert with earlier reports that opioid receptors are found largely in developing, but not adult, tissues, indicate that endogenous opioids are specifically involved in biological development, particularly cell proliferation and differentiation. Immunoreactivity in adult non-neural cells may be related to their development in some cases, but also could indicate other functions.

Distribution of enkephalin immunoreactivity in germinative cells of developing rat cerebellum

The cellular distribution of enkephalin, an endogenous opioid, in the developing rat cerebellum was determined by immunocytochemistry. Methionine and leucine enkephalin were concentrated in the external germinal layer, a matrix of proliferative cells; staining was confined to the cortical cytoplasm. Enkephalin was not detected by immunocytochemistry in differentiated neural cells. These results indicate that endogenous opioids are involved specifically in early phases of nervous system development, particularly cell proliferation and differentiation.