Background: African ancestry populations are at the epicenter of the obesity and diabetes epidemic. Secreted frizzled-related protein 5 (SFRP5) is a novel adipokine and Wnt pathway modulator which is thought to be inversely related with adiposity and diabetes risk, however data in humans is conflicting. Therefore, we examined the association of SFRP5 with parameters of obesity and insulin resistance among an African ancestry population.
Methods: We measured fasting serum SFRP5 in a pilot study of 139 elderly Afro-Caribbean men (mean age 71.7years, mean BMI 27.6 kg/m2). These men represented a random subset of a population-based study comprising ∼3000 African ancestry men with anthropometrics, DXA measured adiposity, and fasting morning blood collections for biomarker analysis. SFRP5 was measured in duplicate in previously unthawed serum with ELISA.
Results: Using Pearson correlations, we found SFRP5 level to be positively associated with age (R = 0.18, p = 0.03) and negatively associated with BMI (R = - 0.14, p = 0.09), waist circumference (R = - 0.18, p = 0.02) and DXA trunk fat (R = - 0.24, p = 0.003), independent of age. Among nondiabetics (N=87), SFRP5 was inversely associated with fasting insulin levels (R = - 0.21, p= 0.04) and to some extent with HOMA-IR (R = -0.20, p = 0.06), independent of age and BMI. However, after adjustment for age and waist circumference, the associations between SFRP5 and fasting serum insulin and HOMA-IR were no longer significant.
Conclusion: Our findings suggest that among African ancestry men, SFRP5 might have a beneficial role against general and central obesity. Our findings also suggest that the link between SFRP5 and diabetes risk in African Ancestry men may be explained by its correlation with central adiposity. Additional larger studies among African ancestry populations are needed to explore this novel biomarker along with its temporal relationship with clinically relevant metabolic outcomes.
H. Ali: None. J.M. Zmuda: None. R. Cvejkus: None. E.E. Kershaw: Consultant; Self; Regeneron Pharmaceuticals, Inc.. A.L. Kuipers: None. C.H. Bunker: None. I. Miljkovic: None.