Table 1.

Comparison of NHANES 1988–1994 and 1999–2002 participants

Participants with Cystatin C LevelsAll Participants
1988–1994 (n = 6877)1999–2002 (n = 4563)P1988–1994 (n = 17,030)1999–2002 (n = 9471)P
Age, yrs44.6 (0.8)46.0 (0.4)0.1244.7 (0.5)46.1 (0.3)0.03
Age category, yrs (%)<0.001
    20–3946.2 (2.1)39.9 (1.3)46.2 (1.0)39.9 (1.0)
    40–5931.2 (1.2)37.7 (1.4)31.2 (0.6)37.7 (0.8)
    60–6911.4 (0.9)10.5 (0.6)11.3 (0.5)10.5 (0.5)
    ≥ 7011.3 (1.0)12.0 (0.5)11.3 (0.6)12.0 (0.5)
Women (%)52.4 (1.5)52.2 (1.1)0.9452.4 (0.4)52.2 (0.4)0.82
Race/ethnicity (%)<0.001<0.001
    White76.6 (2.0)71.7 (2.1)76.3 (1.3)71.5 (1.8)
    African American10.9 (1.0)10.9 (1.3)10.9 (0.7)10.9 (1.2)
    Hispanic5.1 (0.6)13.0 (2.2)5.1 (0.4)13.9 (2.0)
    Other7.4 (1.2)4.4 (0.6)7.7 (0.8)3.7 (0.5)
Diabetes (%)5.0 (0.5)6.7 (0.4)<0.015.5 (0.3)6.7 (0.3)<0.01
Hypertension (%)23.8 (0.9)26.3 (1.2)0.1023.9 (0.6)25.7 (0.8)0.11
Smoker (%)28.7 (1.3)20.5 (1.2)<0.00128.4 (0.8)20.5 (0.8)<0.001
Body mass index, kg/m226.6 (0.2)28.1 (0.2)<0.00126.5 (0.1)28.0 (0.1)<0.001
Body mass index category, kg/m2 (%)<0.001
    < 2543.6 (1.5)36.1 (1.5)45.1 (0.9)35.2 (0.8)
    25–2933.9 (1.2)33.9 (1.3)32.7 (0.6)34.7 (0.8)
    ≥ 3022.5 (1.2)30.0 (1.4)22.2 (0.7)30.2 (0.9)
  • The analysis was adjusted for the sampling weights used in the study design. The chi-square test (for categorical variables) and analysis of variance (for continuous variable) were used to compare the characteristics of 1988–1994 and 1999–2002 participants. Standard errors are shown in parentheses.