Table 4.

Incidence rate, relative hazard (95% confidence intervals) and population attributable fractions for atrial fibrillation for risk factors in the Atherosclerosis Risk in Communities (ARIC) study, 1987 – 2007

	No. at Risk	No. Incident AF	IR*	RH (95% CI) †	PAF %	95% CI
History of Cardiac Disease (%)
Optimal	13398	1259	5.00	0.54 (0.46-0.62)	0.00	-
Elevated	1200	261	12.17	1 [Ref]	5.35	3.32 to 7.45
Blood pressure (%)
Optimal	5626	381	3.93	0.55 (0.48-0.63)	0.00	-
Borderline	3317	304	4.72	0.65 (0.56-0.74)	2.89	−0.11 to 5.64
Elevated	5655	835	7.65	1 [Ref]	21.6	16.8 to 26.7
BMI (%)
Optimal	4889	389	4.27	0.65 (0.56-0.74)	0.00	-
Borderline	5767	591	5.28	0.70 (0.62-0.79)	5.16	0.93 to 9.26
Elevated	3942	531	7.36	1 [Ref]	12.7	9.30 to 16.3
Diabetes (%)
Optimal	7558	645	4.68	0.67 (0.58-0.78)	0.00	-
Borderline	5491	617	5.83	0.71 (0.61-0.82)	0.78	−3.52 to 4.84
Elevated	1533	253	8.77	1 [Ref]	3.08	0.91 to 5.30
Smoking (%)
Optimal	6077	510	4.23	0.55 (0.48-0.62)	0.00	-
Borderline	4769	550	5.76	0.60 (0.52-0.68)	2.06	−2.05 to 6.05
Elevated	3752	460	7.45	1 [Ref]	9.78	6.74 to 12.9

IR = Incidence Rate of AF per 1000 person-years adjusted for age (mean age = 54.2 years);

^†Adjusted for age, gender, race, study site, education, income and height and each of the other risk factors.