Table 3.
Incidence and risk of atrial fibrillation according to the hemoglobin concentrations in each sex.
| Hb Groups | AF cases | Person-years | AF incidence* | Model 1 HR (95% CI) | Model 2 HR (95% CI) | Model 3 HR (95% CI) | Model 4 HR (95% CI) | Model 5 HR (95% CI) |
|---|---|---|---|---|---|---|---|---|
| Male | ||||||||
| <12 | 4,558 | 473,386 | 9.63 | 2.75 (2.67–2.84)† | 1.31 (1.27–1.35)† | 1.39 (1.34–1.43)† | 1.34 (1.30–1.38)† | 1.24 (1.20–1.28)† |
| 12–12.9 | 8,235 | 1,208,864 | 6.81 | 1.94 (1.89–1.98)† | 1.10 (1.07–1.13)† | 1.14 (1.11–1.17)† | 1.12 (1.09–1.14)† | 1.08 (1.05–1.11)† |
| 13–13.9 | 19,853 | 4,224,888 | 4.70 | 1.33 (1.31–1.36)† | 1.02 (1.00–1.04)‡ | 1.04 (1.02–1.06)† | 1.03 (1.01–1.05)† | 1.02 (1.00–1.04)§ |
| 14–14.9 | 30,593 | 8,678,822 | 3.53 | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) |
| 15–15.9 | 26,872 | 8,740,244 | 3.07 | 0.87 (0.86–0.89)† | 1.05 (1.04–1.07)† | 1.03 (1.02–1.05)† | 1.04 (1.02–1.05)† | 1.04 (1.03–1.06)† |
| ≥16 | 16,211 | 4,892,803 | 3.31 | 0.94 (0.92–0.96)† | 1.27 (1.24–1.29)† | 1.21 (1.19–1.24)† | 1.21 (1.19–1.24)† | 1.22 (1.20–1.25)† |
| Female | ||||||||
| <11 | 4,654 | 1,464,439 | 3.18 | 1.15 (1.11–1.19)† | 1.18 (1.14–1.21)† | 1.22 (1.18–1.26)† | 1.19 (1.16–1.23)† | 1.12 (1.09–1.16)† |
| 11–11.9 | 11,057 | 3,353,110 | 3.30 | 1.19 (1.16–1.22)† | 1.06 (1.03–1.08)† | 1.08 (1.05–1.10)† | 1.06 (1.04–1.09)† | 1.04 (1.02–1.07)† |
| 12–12.9 | 26,177 | 9,442,045 | 2.77 | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) | 1.00 (reference) |
| 13–13.9 | 25,652 | 9,867,829 | 2.60 | 0.94 (0.92–0.96)† | 1.01 (0.99–1.03)§ | 0.99 (0.97–1.01)§ | 0.99 (0.97–1.01)§ | 1.00 (0.99–1.02)§ |
| 14–14.9 | 10,842 | 3,799,451 | 2.85 | 1.03 (1.01–1.05)† | 1.10 (1.08–1.13)† | 1.06 (1.03–1.08)† | 1.05 (1.03–1.07)† | 1.06 (1.04–1.09)† |
| ≥15 | 2,498 | 639,550 | 3.91 | 1.41 (1.36–1.47)† | 1.41 (1.35–1.46)† | 1.31 (1.26–1.37)† | 1.28 (1.23–1.34)† | 1.29 (1.24–1.35)† |
AF indicates atrial fibrillation; CI, confidence interval; Hb, hemoglobin; HR, hazard ratio.
*Incidence rates were calculated per 1,000 person-years. †P < 0.001, ‡P < 0.05, §P ≥ 0.05
Model 1: Cox proportional hazards model without adjustment. Model 2: Model 1 with adjustment for age. Model 3: Model 2 with additional adjustment for body mass index, smoking, alcohol consumption, exercise frequency, and low income. Model 4: Model 3 with additional adjustment for hypertension, diabetes, and dyslipidemia. Model 5: Model 4 with additional adjustment for ischemic heart disease, congestive heart failure, stroke, chronic obstructive pulmonary disease, estimated creatinine clearance, obstructive sleep apnea, and thyroid disease.