Exercise training and plasma C-reactive protein and interleukin-6 in elderly people.

OBJECTIVES: To determine the effects of a long-term exercise intervention on two prominent biomarkers of inflammation (C-reactive protein (CRP) and interleukin-6 (IL-6)) in elderly men and women.

DESIGN: Single-blind, randomized, controlled trial: The Lifestyle Interventions and Independence for Elders (LIFE) Trial.

SETTING: The Cooper Institute, Dallas, Texas; Stanford University, Stanford, California; University of Pittsburgh, Pittsburgh, Pennsylvania; and Wake Forest University, Winston-Salem, North Carolina.

PARTICIPANTS: Four hundred twenty-four elderly (aged 70-89), nondisabled, community-dwelling men and women at risk for physical disability.

INTERVENTION: A 12-month moderate-intensity physical activity (PA) intervention and a successful aging (SA) health education intervention.

MEASUREMENTS: CRP and IL-6.

RESULTS: After adjustment for baseline IL-6, sex, clinic site, diabetes mellitus, treatment group, visit, and group-by-visit interaction, the PA intervention resulted in a lower (P=.02) IL-6 concentration than the SA intervention. Adjusted mean IL-6 at month 12 was 8.5% (0.21 pg/mL) higher in the SA than the PA group. There were no significant differences in CRP between the groups at 12 months (P=.09). Marginally significant interaction effects of the PA intervention according to baseline functional status (P=.05) and IL-6 (above vs below the median; P=.06) were observed. There was a greater effect of the PA intervention on participants with lower functional status and those with a higher baseline IL-6.

CONCLUSION: Greater PA results in lower systemic concentrations of IL-6 in elderly individuals, and this benefit is most pronounced in individuals at the greatest risk for disability and subsequent loss of independence.