Table 2.

Hazard ratio (HR) and 95% confidence interval of incident coronary heart disease or ischemic stroke by fasting insulin quintile, the Atherosclerosis Risk In Communities (ARIC) Study, 1987 to 2005

Variable	Fasting Insulin (μU/ml)					Per Quintile	p Value*
	<6	6 to <8	8 to <11	11 to <15	≥15
Coronary heart disease
Events (n)	164	147	208	173	268		—
Person-years	42,075	35,496	43,157	33,718	38,623		—
Hazard ratio, model 1† (95% CI)	1.00 (Referent)	1.02 (0.82–1.28)	1.13 (0.92–1.39)	1.17 (0.94–1.44)	1.59 (1.31–1.94)	1.12 (1.07–1.17)	<0.0001
Hazard ratio, model 2‡ (95% CI)	1.00 (Referent)	1.04 (0.83–1.30)	1.09 (0.88–1.34)	1.05 (0.83–1.34)	1.28 (1.02–1.62)	1.05 (1.00–1.11)	0.058
Hazard ratio, model 3§ (95% CI)	1.00 (Referent)	0.90 (0.72–1.13)	0.92 (0.75–1.14)	0.85 (0.67–1.07)	1.01 (0.80–1.29)	1.00 (0.95–1.06)	0.99
Ischemic stroke
Events (n)	75	61	97	87	125		—
Person-years	42,590	36,192	43,839	34,340	39,537		—
Hazard ratio, model 1† (95% CI)	1.00 (Referent)	0.90 (0.64–1.26)	1.13 (0.84–1.53)	1.21 (0.89–1.65)	1.45 (1.09–1.94)	1.11 (1.04–1.19)	0.0018
Hazard ratio, model 4¶ (95% CI)	1.00 (Referent)	0.89 (0.63–1.25)	1.11 (0.82–1.51)	1.10 (0.80–1.53)	1.28 (0.92–1.78)	1.07 (0.99–1.16)	0.079

^*Test for linear trend across 5 categories of fasting insulin.

^†From proportional hazards regression model adjusted for age, gender, race, and ARIC study center.

^‡Adjustments as for model 1, plus systolic blood pressure, current smoking, use of antihypertensive medication, and BMI.

^§Adjustments as for model 2, plus HDL and non-HDL cholesterol.

^¶Adjustments as for model 1, plus systolic blood pressure, current smoking, use of antihypertensive medication, BMI, and prevalent left ventricular hypertrophy (Cornell definition).