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With Comments from Russell H. Greenfield, MD, Dr. Greenfield is Clinical Assistant Professor, School of Medicine, University of North Carolina, Chapel Hill, NC; and Visiting Assistant Professor, University of Arizona, College of Medicine, Tucson, AZ.
Tai Gee! Immune Augmentation and Tai Chi
Source: Irwin MR, et al. Augmenting immune responses to varicella zoster virus in older adults: A randomized, controlled trial of Tai Chi. J Am Geriatr Soc 2007;55:511-517.
Goal: To compare the effects of tai chi (TC) to that of health education (HE), an active control intervention, on resting and vaccine-stimulated levels of cell-mediated immunity (CMI) to varicella zoster virus (VZV), and on health functioning in older adults.
Study design: Prospective, randomized, controlled trial performed in two urban California communities.
Subjects: Healthy adults aged 59-86 years (n = 112, mean age 70 years).
Methods: Participants were recruited through community advertisements and randomized to receive either TC (n = 59) or HE (n = 53) in groups of 7-10. Both TC and HE sessions were provided each week for a total of 120 minutes. A specific set of exercises was used in TC, and individual skill attainment monitored by TC instructors. HE involved 16 didactic sessions addressing various health-related themes and offered by a physician or psychologist, with group discussion following. After 16 weeks of the specified intervention all subjects received a single dose of VARIVAX (live attenuated varicella vaccine). The primary endpoint of interest was a quantitative measure of VZV-CMI as assessed on five occasions (baseline, weeks 8, 12, and 16 before vaccination, and at week 25, or nine weeks post-vaccination) using peripheral blood mononuclear cells. Secondary outcomes included scores on measures of quality of life (SF-36) and the Beck Depression Inventory (BDI), both of which were administered at the same five time frames. Other potentially important factors were also evaluated, including daily TC practice time and average weekly metabolic equivalents.
Results: Subjects in the TC group showed higher levels of VZV-CMI than the HE group at every measurement period after intervention initiation, with a rate of increase in VZV-CMI almost twice that of the HE group. Notably, the increase in VZV-CMI with TC alone was comparable to that obtained with HE plus vaccination. In addition, the effects of TC and varicella vaccine combined were additive (TC + vaccine produced levels of VZV-CMI significantly higher than that produced by the vaccine alone). Specific scores on the SF-36 were also better in the TC group (physical functioning, bodily pain, vitality, and mental health). Symptoms of depression were improved by both interventions, and subjects in both groups reported with equal confidence that the interventions they had experienced would help improve the health of older adults.
Conclusion: In healthy older adults, TC enhances resting levels of VZV-specific CMI and the VZV-CMI associated with varicella vaccination.
Study strengths: Use of intention-to-treat analysis; high rate of attendance at sessions and completion rate for interventions.
Study weaknesses: Use of varicella vaccine rather than ZOSTAVAX; questionable generalizability (only healthy people were studied); lack of longterm follow-up to test durability of effects.
Of note: TC incorporates meditation, relaxation, and aerobic activity, each of which has separately been reported to enhance CMI responses; people with a prior history of shingles were excluded from the study; subjects in the current trial had experienced varicella earlier in life and were thus already immune; subjects were compensated for participation in and completion of the study; two of the authors hail from the Cousins Center for Psychoneuroimmunology at the University of California-Los Angeles; one small, controlled pilot study employing a standardized form of TC showed increased levels of VZV-CMI; prior research showed that administration of a high-potency VZV vaccine (ZOSTAVAX) reduces the incidence of herpes zoster by 51% and the incidence of post-herpetic neuralgia (PHN) by > 60% in people aged 60 years and older, but the numbers belie that risk of herpes zoster was not completely eliminated; the ZOSTAVAX vaccine used in the Shingles Prevention Study was not used in this trial (VARIVAX, the vaccine used in this study, contains < 7% of the amount of VZV found in ZOSTAVAX); subjects in the HE group had higher baseline scores on SF-36 role physical and bodily pain assessments, but this had no impact on VZV assessments; overall metabolic equivalents for the TC group were unchanged in the face of increasing levels of TC practice, implying that participants substituted TC for other fitness activities; neither the number of weekly minutes of practice nor the number of TC sessions attended per week was related to magnitude of increase in VZV-CMI; subjects in the TC group achieved a level of post-vaccination VZV-CMI similar to that reported in studies of healthy young adults; over the course of the trial, people in the TC group showed an increase in the number of minutes of at-home TC practice per week, and maintained a high level of practice after the intervention period; the technician performing the VZV-CMI assays was blinded to subjects' group allocation.
We knew that: Older adults often respond poorly to immunization; shingles (herpes zoster) results from reactivation of latent VZV, manifests in the form of a painful vesicular rash, and occurs most often in people over age 60 years; levels of pain and disability experienced by people with shingles and PHN create a diminished quality of life comparable to that experienced by people with heart failure, diabetes, or major depression; immunosuppressed patients should not receive live-attenuated vaccines; the level of VZV-specific CMI appears to be very important with respect to risk of developing herpes zoster; levels of antibody to VZV remain relatively constant in old age and thus do not correlate with risk for development of herpes zoster, but VZV-specific memory T-cells decline progressively with advancing age; TC is known to decrease sympathetic nervous system activity.
Comments: Not very long ago the very idea that a behavioral intervention like TC could have a beneficial impact on immune system functioning would be deemed preposterous. Consider the remarkable implications of these data—in healthy people who "normally" develop a less responsive immune system with advancing age, a technique readily accessible to the elderly (TC) can better immune system function, as well as help improve a number of measures of quality of life. In addition, one should not lose sight of the fact that immune system improvements were also identified in those subjects who simply participated in HE. In this instance, it appears that the specific activity plays a role in the degree of immune augmentation elicited, but being part of a group, being social, again appears to have its role in good health, too. As the authors of the trial point out, if these findings were to be extrapolated to other clinical circumstances the ramifications are significant: Could TC have a positive impact on response to other immunizations, such as against the flu or pneumococcal pneumonia? We're left to wait for additional data in this regard, but there is now ample reason for optimism.
What to do with this article: Make a hard copy to hand out to your peers.