Obesity-related increases in multiple inflammatory markers may contribute to the
persistent subclinical inflammation common with advancing age. However, it is unclear if
a specific combination of markers reflects the underlying inflammatory state. We used
factor analysis to identify inflammatory factor(s) and examine their associations with
adiposity in older adults at risk for disability.
Adiponectin, CRP, IL-1ra, IL-1sRII, IL-2sRα, IL-6, IL-6sR, IL-8, IL-15, sTNFRI,
sTNFRII, and TNF-α were measured in 179 participants from the Lifestyle
Interventions and Independence for Elders Pilot (Mean ± SD age
77 ± 4 years, 76% white, 70% women). Body mass index, waist circumference, and
total fat mass were assessed by anthropometry and dual-energy x-ray absorptiometry.
IL-2sRα, sTNFRI, and sTNFRII loaded highest on the first factor (factor 1). CRP,
IL-1ra, and IL-6 loaded highest on the second factor (factor 2). Factor 2, but not
factor 1, was positively associated with 1-SD increments in waist
circumference (β = 0.160 ± 0.057, p = .005),
body mass index (β = 0.132 ± 0.053, p = .01),
and total fat mass (β = 0.126 ± 0.053, p =
.02) after adjusting for age, gender, race/ethnicity, site, smoking, anti-inflammatory
medications, comorbidity index, health-related quality of life, and physical function.
These associations remained significant after further adjustment for grip strength, but
only waist circumference remained associated with inflammation after adjusting for total
lean mass. There were no significant interactions between adiposity and muscle mass or
strength for either factor.
Greater total and abdominal adiposity are associated with higher levels of an
inflammatory factor related to CRP, IL-1ra, and IL-6 in older adults, which may provide
a clinically useful measure of inflammation in this population.