Elevated levels of serum cystatin C are associated with prediabetes in non-obese adults in the U.S., a study found.
Compared with individuals in the lowest quartile of serum cystatin C, those in the highest quartile had a twofold increased likelihood of prediabetes, after adjusting for body mass index (BMI), blood pressure, C-reactve protein and cholesterol levels, and other potential confounders, researchers reported online ahead of print in the European Journal of Epidemiology.
The researchers, led by Charumathi Sabanayagam, MD, of the Singapore Eye Research Institute in Singapore, studied 2,033 non-obese participants in the National Health and Nutrition Examination Survey (NHANES) 1999-2002. The participants were at least 20 years old, were free of diabetes and chronic kidney disease, and had a body mass index below 30 kg/m2.
The investigators defined prediabetes as a two-hour glucose concentration of 140-199 mg/dL, a fasting glucose concentration of 110-125 mg/dL, or a hemoglobin A1C value of 5.7%-6.4%. Prediabetes is an early stage in the hyperglycemic continuum associated with increased future risk of developing diabetes and cardiovascular disease, the authors explained.
The association of elevated serum cystatin C levels with prediabetes was strongest among women and non-Hispanic whites. Compared with women in the lowest quartile of serum cystatin C, those in the highest quartile had a significant fourfold increased risk of prediabetes. Among men, those in the highest quartile had a non-significant 48% increased likelihood of prediabetes compared with those in the lowest quartile.
Among non-Hispanic whites, those in the highest quartile had a significant 2.7 times greater likelihood of prediabetes compared with those in the lowest quartile. Among participants of other races or ethnicities, those in the highest quartile had a non-significant 16% increased likelihood of prediabetes compared with subjects in the lowest quartile.
NHANES includes a nationally representative sample of the civilian, non-institutionalized U.S. population.