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A Large Randomized Trial: Effects of Mindfulness-Based Stress Reduction (MBSR) for Breast Cancer (BC) Survivors on Salivary Cortisol and IL-6.
Lengacher, CA, Reich, RR, Paterson, CL, Shelton, M, Shivers, S, Ramesar, S, Pleasant, ML, Budhrani-Shani, P, Groer, M, Post-White, J, et al
Biological research for nursing. 2019;21(1):39-49
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Breast cancer survivors (BCS) often experience physiological and psychological stressors related to their diagnosis and treatment, and a disruption of cortisol function can affect cancer risk and progression. Increased levels of the stress hormone cortisol and interleukin-6 (IL-6), a pro-inflammatory immune mediator, have been associated with acute and chronic stress levels. Mindfulness-Based Stress Reduction (MBSR) is a clinical stress-reducing program, which has been found to decrease psychological and physical symptoms associated with stress. The purpose of this randomised study, involving 299 BCS, was to evaluate the efficacy of MBSR in reducing cortisol and IL-6 levels, compared to a usual-care control treatment. Statistically significant reductions in cortisol levels were seen after the delivery of the MBSR program at both time points (week 1 and 6), and at week 6 only for IL-6. There was no significant difference in change in cortisol or IL6 levels over time between the MBSR and the usual-care groups. An association was observed between levels of IL-6 and psychological and physical symptoms and quality of life, but not for cortisol. The authors conclude that MBSR can alleviate the stress response in the short term for breast cancer survivors.
Abstract
Breast cancer survivors (BCS) often experience psychological and physiological symptoms after cancer treatment. Mindfulness-based stress reduction (MBSR), a complementary and alternative therapy, has reduced subjective measures of stress, anxiety, and fatigue among BCS. Little is known, however, about how MBSR affects objective markers of stress, specifically the stress hormone cortisol and the pro-inflammatory cytokine interleukin-6 (IL-6). In the present study, BCS ( N = 322) were randomly assigned to a 6-week MBSR program for BC or usual-care control. Measurements of cortisol, IL-6, symptoms, and quality of life were obtained at orientation and 6 weeks. Cortisol and IL-6 were also measured prior to and after the MBSR(BC) class Weeks 1 and 6. The mean age of participants was 56.6 years and 69.4% were White non-Hispanic. Most had Stage I (33.8%) or II (35.7%) BC, and 35.7% had received chemotherapy and radiation. Cortisol levels were reduced immediately following MBSR(BC) class compared to before the class Weeks 1 and 6 (Wilcoxon-signed rank test; p < .01, d = .52-.56). IL-6 was significantly reduced from pre- to postclass at Week 6 (Wilcoxon-signed rank test; p < .01, d = .21). No differences were observed between the MBSR(BC) and control groups from baseline to Week 6 using linear mixed models. Significant relationships with small effect sizes were observed between IL-6 and both symptoms and quality of life in both groups. Results support the use of MBSR(BC) to reduce salivary cortisol and IL-6 levels in the short term in BCS.
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No effect of caloric restriction on salivary cortisol levels in overweight men and women.
Tam, CS, Frost, EA, Xie, W, Rood, J, Ravussin, E, Redman, LM
Metabolism: clinical and experimental. 2014;63(2):194-8
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Alterations in normal cortisol patterns have been observed in people who are obese. The effect of weight loss on cortisol levels, a measure of hypothalamic pituitary adrenal (HPA) activity, in overweight individuals is not known. The aim of this study was to test the hypothesis that 6 months of moderate caloric restriction would alter morning and diurnal salivary cortisol levels. Thirty-five overweight adults (average BMI 27.8 kg/m2) took part in this randomised control trial. Participants were assigned to either calorie restriction (CR: 25% reduction in energy intake), calorie restriction+exercise (CR+EX: 12.5% reduction in energy intake+12.5% increase in exercise energy expenditure) or control (healthy weight-maintenance diet) for 6 months. Salivary cortisol was measured at 8:00, 8:30, 11:00, 11:30, 12:30, 13:00, 16:00 and 16:30. Morning cortisol was defined as the mean cortisol concentration at 08:00 and 08:30. Diurnal cortisol was calculated as the mean of the 8 cortisol measures across the day. Across all groups, higher morning and diurnal cortisol levels were associated with impaired insulin sensitivity. There was no significant effect of group, time or sex on morning or diurnal cortisol levels. The authors concluded that a 10% weight loss with a 25% CR diet alone or with exercise did not impact morning or diurnal salivary cortisol levels in overweight individuals. Their findings suggest that prolonged restriction of energy intake is not perceived by the body as a stressor, and therefore CR may present a viable intervention.
Abstract
OBJECTIVE The effect of weight loss by diet or diet and exercise on salivary cortisol levels, a measure of hypothalamic pituitary adrenal activity, in overweight individuals is not known. The objective was to test the hypothesis that 24 weeks of moderate caloric restriction (CR) (25%) by diet or diet and aerobic exercise would alter morning and diurnal salivary cortisol levels. DESIGN AND SETTING Randomized control trial in an institutional research center. PARTICIPANTS Thirty-five overweight (BMI: 27.8±0.7 kg/m(2)) but otherwise healthy participants (16 M/19 F). INTERVENTION Participants were randomized to either calorie restriction (CR: 25% reduction in energy intake, n=12), calorie restriction+exercise (CR+EX: 12.5% reduction in energy intake+12.5% increase in exercise energy expenditure, n=12) or control (healthy weight-maintenance diet, n=11) for 6 months. MAIN OUTCOME MEASURE Salivary cortisol measured at 8:00, 8:30, 11:00, 11:30, 12:30, 13:00, 16:00 and 16:30. Morning cortisol was defined as the mean cortisol concentration at 08:00 and 08:30. Diurnal cortisol was calculated as the mean of the 8 cortisol measures across the day. RESULTS In the whole cohort, higher morning and diurnal cortisol levels were associated with impaired insulin sensitivity (morning: P=0.004, r(2)=0.24; diurnal: P=0.02, r(2)=0.15). Using mixed model analysis, there was no significant effect of group, time or sex on morning or diurnal cortisol levels. CONCLUSION A 10% weight loss with a 25% CR diet alone or with exercise did not impact morning or diurnal salivary cortisol levels.