Fetuin-A and Change in Body Composition in Older Persons
Context: Fetuin-A inhibits the insulin receptor in vitro. Higher serum fetuin-A concentrations are associated with type 2 diabetes longitudinally and greater adiposity in cross-sectional analyses. Whether higher fetuin-A concentrations are associated with accumulation of adiposity over time is unknown.
Objective: To determine the association of fetuin-A levels with changes in body composition over 5 yr.
Study Design: Observational cohort study nested in the Health Aging and Body Composition Study.
Predictor: Serum fetuin-A levels.
Outcomes: Visceral adipose tissue (VAT), abdominal sc adipose tissue, and thigh muscle area by computed tomography, and waist circumference and body mass index were measured at baseline and again after 5 yr. Percent change and extreme change (>1.5 SDs) in each measure were calculated.
Results: Over 5 yr, subjects lost body mass in each measure, including 6% decline in VAT. Yet each SD (0.42 g/liter) higher fetuin-A concentration was associated with a 5.5% increase in VAT over 5 yr (95% confidence interval 1.9-9.2%; P = 0.003) in models adjusted for age, sex, race, clinical site, diabetes, physical activity, triglycerides, kidney function, and the baseline VAT score. Similarly, higher fetuin-A concentrations were associated with extreme VAT gain (relative risk 1.70, 95% confidence interval 1.12-2.60, P = 0.01). Fetuin-A concentrations were not statistically significant associated with change in any other measures of body composition (P > 0.20).
Conclusions: Higher fetuin-A concentrations are associated with the accumulation of VAT in well-functioning, community-living older persons. The mechanisms linking fetuin-A, VAT, and insulin resistance remain to be determined.