Within-individual stability of obesity-related biomarkers among women.

OBJECTIVE

Novel biomarkers including proinflammatory cytokines and adipokines are being explored as potential mediators of cancer and other obesity-related conditions. Prospective studies linking biomarker levels with disease outcomes often measure biomarkers at a single time point and assume that the within-individual variation in levels is small compared with the interindividual variation. However, this assumption is seldom tested.

METHODS

This study examined the within-individual stability over time of plasma adiponectin, resistin, leptin, plasma activator inhibitor type 1, hepatocyte growth factor, tumor necrosis factor alpha, interleukin 6, and insulin among healthy young women.

RESULTS

The study included 17 women (9 Black non-Hispanic, 2 Black Hispanic, 2 White Hispanic, and 4 other race/ethnicity) with mean age of 32.3 years, mean body mass index of 31.2 kg/m2, and 76% prevalence of smoking. Analysis of intraclass correlation (ICC) suggested high to moderate correlation over repeated samples taken over 3 years in levels of resistin (ICC = 0.95), hepatocyte growth factor (0.91), plasma activator inhibitor type 1 (0.84), adiponectin (0.73), insulin (0.62), and leptin (0.58). ICCs were weaker for levels of proinflammatory cytokines, tumor necrosis factor alpha (0.39), and interleukin 6 (0.47).

CONCLUSION

In this population of minority young females with a high prevalence of overweight and smoking, several obesity-related endocrine markers were stable over a period of 3 years. This supports the feasibility of longitudinal studies relating these biomarkers to the future occurrence of cancer and other health consequences of obesity.