Whether kidney dysfunction is associated with coronary artery calcium (CAC) in 
young and middle-aged adults who have a cystatin C-derived estimated glomerular 
filtration rate (eGFRcys) greater than 60 mL/min/1.73 m(2) is unknown. In the 
Coronary Artery Risk Development in Young Adults (CARDIA) cohort (recruited in 
1985 and 1986 in Birmingham, Alabama; Chicago, Illinois; Minneapolis, Minnesota; 
and Oakland, California), we examined 1) the association of eGFRcys at years 10 
and 15 and detectable CAC over the subsequent 5 years and 2) the association of 
change in eGFRcys and subsequent CAC, comparing those with stable eGFRcys to 
those whose eGFRcys increased (>3% annually over 5 years), declined moderately 
(3%-5%), or declined rapidly (>5%). Generalized estimating equation Poisson 
models were used, with adjustment for age, sex, race, educational level, income, 
family history of coronary artery disease, diabetes, body mass index, 
low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and 
tobacco use. Among 3,070 participants (mean age 35.6 (standard deviation, 4.1) 
years and mean eGFRcys 106.7 (standard deviation, 18.5) mL/min/1.73 m(2)), 529 
had detectable CAC. Baseline eGFRcys was not associated with CAC. Moderate 
eGFRcys decline was associated with a 33% greater relative risk of subsequent 
CAC (95% confidence interval: 5, 68; P = 0.02), whereas rapid decline was 
associated with a 51% higher relative risk (95% confidence interval: 10, 208; P 
= 0.01) in adjusted models. In conclusion, among young and middle-aged adults 
with eGFRcys greater than 60 mL/min/1.73 m(2), annual decline in eGFRcys is an 
independent risk factor for subsequent CAC.