Exercise and psychosocial factors modulate immunity to influenza vaccine in elderly individuals.
BACKGROUND
Decreases in immune responsiveness with age contribute to the increased incidence and severity of infectious disease among elderly adults. The immune response to immunization also decreases with advancing age. Lifestyle factors (exercise, diet) have been established to play an important role in immunosenescence, and the practice of "healthy" behavior may minimize the age-associated decline of immune function. The objective of this study was to determine whether exercise, diet, and psychosocial factors were associated with altered immune response to influenza vaccine.


METHODS
Adults aged 62 years and older were categorized into one of three groups: active (> or =20 min vigorous exercise three or more times per week), moderately active (regular exercise but with less intensity, frequency, and/or duration), or sedentary (no exercise). Two weeks postimmunization, serum was frozen for antibody analysis, and peripheral blood mononuclear cells (PBMC) were cultured in vitro with influenza vaccine to elicit antigen-specific responses (proliferation and cytokine [IL-2, IFN-gamma, IL-10] production). Cytokines and antibody were measured by enzyme-linked immunosorbent assay.


RESULTS
The results demonstrated that anti-influenza IgG and IgM were greater in active as compared with moderately active or sedentary participants. PBMC proliferation was lowest in sedentary subjects. Perceived stress was a significant predictor of IL-2. Greater optimism and social activity were associated with greater IL-10. Daily multivitamin intake was significantly correlated with IL-2.


CONCLUSIONS
These results suggest that lifestyle factors including exercise may influence immune response to influenza immunization. The practice of regular, vigorous exercise was associated with enhanced immune response following influenza vaccination in older adults.
Department of Health and Human Performance, Iowa State University, Ames 50011, USA. mkohut@iastate.edu
Marian L
ML
Kohut
Megan M
MM
Cooper
Michael S
MS
Nickolaus
Dan R
DR
Russell
Joan E
JE
Cunnick
D000368:Aged / Q000502:physiology* / Q000523:psychology; D000914:Antibodies, Viral / Q000097:blood; D017252:CD3 Complex / Q000032:analysis; D015704:CD4 Antigens / Q000032:analysis; D016827:CD8 Antigens / Q000032:analysis; D004032:Diet; D015444:Exercise / Q000502:physiology*; D006801:Humans; D007075:Immunoglobulin M / Q000097:blood; D007252:Influenza Vaccines / Q000276:immunology*; D007251:Influenza, Human / Q000517:prevention & control; D007371:Interferon-gamma / Q000097:blood; D016753:Interleukin-10 / Q000097:blood; D007376:Interleukin-2 / Q000097:blood; D007958:Leukocyte Count; D007963:Leukocytes, Mononuclear; D008019:Life Style; D008875:Middle Aged; D009747:Nutritional Physiological Phenomena / Q000502:physiology; D013315:Stress, Psychological; D011795:Surveys and Questionnaires; D014611:Vaccination
D000914:Antibodies, Viral; D017252:CD3 Complex; D015704:CD4 Antigens; D016827:CD8 Antigens; D007075:Immunoglobulin M; D007252:Influenza Vaccines; D007376:Interleukin-2; D016753:Interleukin-10; D007371:Interferon-gamma