Cystatin C and Preeclampsia: A Case Control Study

Figures & data

Figure 1. The log odds of preeclampsia risk by maternal plasma cystatin C after adjusting for all the other confounders, including gestational age at delivery (using a generalizing additive model). Straight line represents the estimates, and dotted lines the 95% percentiles. Dots represent the density of the measures by level of cystatin C.

Table 1 Characteristics of preeclampsia cases and controls according to selected characteristics, Seattle and Tacoma, Washington, 1998–2002

Characteristics	Preeclampsia cases (n = 100)	Controls (n = 100)
Maternal age (years)	%	%
<20	3.0	2.0
20–34	68.0	64.0
≥35	24.0	30.0
Missing	5.0	2.0
Maternal race/ethnicity
White/non-Hispanic	66.0	79.0
African American	13.0	5.0
Other	16.0	14.0
Missing	5.0	2.0
Unmarried	27.0	16.0
Education, <12 years	27.0	9.0
Nulliparous	68.0	64.0
Family history of chronic hypertension	50.0	47.0
Physical inactivity during pregnancy	47.0	32.0
Smoked during pregnancy
No	62.0	71.0
Yes, smoked throughout pregnancy	22.0	5.0
Yes, quit during pregnancy	11.0	22.0
Missing	5.0	2.0
Pre-pregnancy body mass index (kg/m^2)
<19.9	6.0	21.0
20–24.9	41.0	51.0
25–29.9	19.0	19.0
≥30	28.0	6.0
Missing	6.0	3.0
Gestational age at delivery	35.2 ± 0.4	39.5 ± 0.1
Maternal plasma cystatin C (mg/L)	1.38 ± 0.04	1.22 ± 0.03^†
In median (inter-quartile range)	1.30 (1.14, 1.56)	1.21 (1.02, 1.37)^‡

Results are percentages except otherwise stated.

*Mean ± standard error.

^†p value from Student t-test < 0.01.

^‡p value from rank sum test < 0.01.

Table 2 Odds ratios and 95% confidence intervals of preeclampsia according to the quartile of cystatin C concentrations in control subjects, Seattle and Tacoma, Washington, 1998–2002

Cystatin C (ng/mL)	Preeclampsia cases (n = 100)	Controls (n = 100)	Unadjusted OR (95% CI)	Adjusted OR (95% CI)	Adjusted OR^† (95% CI)
Quartile 1 (<1.02 mg/L)	14	25	1.0	1.0	1.0
Quartile 2 (1.02–1.21 mg/L)	25	25	1.8 (0.8–4.2)	5.1 (1.3–20.7)	7.9 (1.5–42.1)
Quartile 3 (1.22–1.37 mg/L)	18	25	1.3 (0.5–3.1)	3.9 (0.97–15.8)	3.6 (0.7–20.1)
Quartile 4 (≥1.37 mg/L)	43	25	3.1 (1.4–7.0)	10.3 (2.7–39.4)	12.4 (2.4–64.0)
p value for trend			0.013	0.008	0.008

*Model adjusted for gestational age at delivery.

^†Model adjusted for maternal age (continuous), pre-pregnancy body mass index (continuous), physical inactivity, and maternal smoking status (yes vs. no in current situation) as well as gestational age at delivery. First quartile is the referent.

Abbreviations: OR  =  odds ratio, CI  =  confidence intervals. Cystatin C quartiles were based on control distribution.

Figure 2. The scatterplot and regression line of maternal plasma cystatin C with gestational age at delivery.