Effects of Mindfulness-Based Interventions on Salivary Cortisol in Healthy Adults: A Meta-Analytical Review.
Objective:The aim of the present study was to elucidate the effects of Mindfulness-based interventions (MBIs) on salivary cortisol levels in healthy adult populations.Method:We conducted a systematic review and meta-analysis of randomized controlled trials (RCTs), published between January 1980 and June 2015 in PubMed, EMBASE, PsycINFO and the Cochrane library. The PRISMA and Cochrane guidelines were followed. The pooled effect sizes were calculated with the random-effects model, using Hedges'g-values, and heterogeneity was measured using theI2statistic. The contribution of different characteristics of participants and programmes were assessed by meta-regression models, using beta coefficients.Results:Five RCTs with 190 participants in total were included in this systematic review. The overall effect size (ES) for improving the state of health related to cortisol levels was moderately low (g= 0.41;p= 0.025), although moderate heterogeneity was found (I2= 55;p= 0.063). There were no significant differences between active (g= 0.33;p= 0.202) and passive (g= 0.48;p= 0.279) controls, but significant differences were found when comparing standard (g= 0.81;p= 0.002) and raw (g= 0.03;p= 0.896) measures. The percentage of women in each study was not related to ES. Nevertheless, age (beta = -0.03;p= 0.039), the number of sessions (beta = 0.33;p= 0.007) and the total hours of the MBI (beta = 0.06;p= 0.005) were significantly related to ES, explaining heterogeneity (R2= 1.00).Conclusions:Despite the scarce number of studies, our results suggest that MBIs might have some beneficial effect on cortisol secretion in healthy adult subjects. However, there is a need for further RCTs implemented in accordance with standard programmes and measurements of salivary cortisol under rigorous strategies in healthy adult populations.
Primary Care, Aragon Health Sciences InstituteZaragoza, Spain; Department of Psychiatry, Showa University School of MedicineTokyo, Japan.
Kenji
K
Sanada
Faculty of Health Sciences and Sports, University of ZaragozaZaragoza, Spain; The Primary Care Prevention and Health Promotion Research NetworkBarcelona, Spain.
Jesus
J
Montero-Marin
The Primary Care Prevention and Health Promotion Research NetworkBarcelona, Spain; Department of Psychiatry, Miguel Servet University Hospital, University of ZaragozaZaragoza, Spain.
Marta
M
Alda Díez
Primary Care, Aragon Health Sciences Institute Zaragoza, Spain.
Montserrat
M
Salas-Valero
Primary Care, Aragon Health Sciences InstituteZaragoza, Spain; The Primary Care Prevention and Health Promotion Research NetworkBarcelona, Spain.
María C
MC
Pérez-Yus
Primary Care, Aragon Health Sciences InstituteZaragoza, Spain; The Primary Care Prevention and Health Promotion Research NetworkBarcelona, Spain.
Héctor
H
Morillo
Department of Preventive Medicine, "Mente Aberta" Brazilian Centre for Mindfulness and Health Promotion, Federal University of São PauloSão Paulo, Brazil; Hospital Israelita Albert EinsteinSão Paulo, Brazil.
Marcelo M P
MM
Demarzo
The Primary Care Prevention and Health Promotion Research NetworkBarcelona, Spain; Research Institute of Health Sciences, University of the Balearic IslandsPalma, Spain.
Mauro
M
García-Toro
The Primary Care Prevention and Health Promotion Research NetworkBarcelona, Spain; Department of Psychiatry, Miguel Servet University Hospital, University of ZaragozaZaragoza, Spain.
Javier
J
García-Campayo
MBI; RCT; healthy adult subjects; meta-analysis; salivary cortisol