Table 4.

Rate ratios (RR) and 95% confidence intervals (CI) of coronary heart disease to quintiles of protein C, ARIC, 1987–2005

	Protein C Percentiles
	<20^th	20^th–39^th	40^th–59^th	60^th–79^th	≥80^th	P for trend
Range, μg/mL	<2.6	2.7–2.9	3.0–3.2	3.3–3.6	≥3.7
No. at risk	2,705	2,650	2,899	2,871	2,754
No. of cases	233	236	271	238	279
Person-years of follow-up	41,323	41,196	45,201	44,857	43,072
Incidence rate/1000 person-years	5.6	5.7	6.0	5.3	6.5
Age-, race-, and sex-adjusted RR (95% CI)	0.74 (0.62–0.88)	0.78 (0.65–0.93)	0.85 (0.72–1.00)	0.76 (0.64–0.90)	1.0	0.002
Multivariate-adjusted^* RR (95% CI)	0.75 (0.63–0.90)	0.83 (0.69–0.99)	0.92 (0.77–1.09)	0.83 (0.70–0.99)	1.0	0.004
Multivariate-adjusted^† RR (95% CI)	0.92 (0.76–1.11)	0.95 (0.80–1.14)	1.01 (0.85–1.20)	0.89 (0.74–1.06)	1.0	0.57

Adjusted for age, race-field center, sex, systolic blood pressure, use of antihypertensive medication, smoking status, diabetes mellitus, and education.

^†

Further adjustment for LDL cholesterol, HDL cholesterol, fibrinogen, and von Willebrand factor.