Table 3.

Association between socioeconomic status and level of C-reactive protein (CRP) (<1, 1 to 3, >3 mg/L)

	Proportion With CRP >3 mg/L	Unadjusted OR (95% CI)	p Value	Adjusted OR (95% CI)*	p Value	Adjusted OR (95% CI)†	p Value
Education
≤11 yrs	51% (65/127)	2.4 (1.6–3.5)	<0.0001	2.2 (1.4–3.5)	0.001	2.2 (1.3–3.6)	0.002
High school degree	43% (222/516)	1.7 (1.3–2.2)	<0.0001	1.4 (1.0–1.9)	0.03	1.5 (1.1–2)	0.02
College degree or higher	30% (103/340)	1	—	1	—
Annual income
<$20,000	42% (199/474)	2.1 (1.5–2.8)	<0.0001	1.4 (.96–2.1)	0.08	1.2 (0.8–1.9)	0.34
$20,000–29,999	46% (61/133)	2.4 (1.6–3.7)	<0.0001	2.2 (1.4–3.6)	0.001	2.1 (1.2–3.5)	0.006
$30,000–50,000	41% (78/189)	2.0 (1.3–2.9)	0.0005	1.8 (1.2–2.8)	0.007	1.7 (1.1–2.7)	0.02
≥$50,000	28% (52/183)	1	—	1	—	1	—

^*All variables were entered into a backward elimination ordinal logistic regression model with a p value <0.05 for retention. Other variables associated with high CRP level (at p <0.05) in the education model were white ethnicity, smoker, history of congestive heart failure, not currently depressed, little or no physical activity, not using a β blocker, using hormone therapy, increased systolic blood pressure, high cholesterol level, low high-density lipoprotein level, low creatinine clearance and high body mass index. Other variables associated with high CRP level (at p <0.05) in the income model were white ethnicity, smokers, history of congestive heart failure, not currently depressed, little or not physically activity, not using a β blocker, using hormone therapy, increased systolic blood pressure, low cholesterol level, high low-density lipoprotein level, high triglyceride level, low creatinine clearance, and high body mass index.

^†Further adjusted for other socioeconomic variable (education or income).

CI = confidence interval; OR = odds ratio.