Is self-rated health associated with blood immune markers in healthy individuals?

BACKGROUND Although self-rated health (SRH) has been established as a robust predictor of morbidity and mortality, the immunological mechanisms underpinning this relationship are poorly understood. PURPOSE This study examined the association of SRH with humoral and cellular immune markers in healthy individuals who reported no physical illnesses. METHOD A total of 116 healthy Japanese white-collar employees (79 women and 37 men) at a pharmaceutical company, aged 23-62 (mean 32) years, underwent a blood draw for the measurement of circulating immune (T, B, and natural killer) cells, inflammatory cytokines (interleukin-6 and tumor necrosis factor-alpha), and plasma immunoglobulin G (IgG) and completed a health survey including SRH. The question regarding SRH ranged from "very good" (coded 1) to "very poor" (coded 5). Hierarchical multiple regression analysis was carried out to calculate the relationship between SRH and immune markers. RESULTS In this sample, poor SRH was positively correlated with B (CD19(+)) cell numbers (beta = 0.260, p < 0.05) and IgG levels (beta = 0.335, p < 0.01) even after adjusting for depressive symptoms, age, education, marital status, smoking, alcohol consumption, physical activity, body mass index, sex, and sex x SRH interaction. The interaction between SRH and sex on the immune markers was not significant. CONCLUSION Although the connection between SRH and immune markers was not strong in this context, the results suggest that poor SRH may be associated with reduced humoral immune system capacity to respond to new/latent challenges. The results provide some support for the immunological basis of SRH in healthier individuals.