Table 3. Trends in Hazards Ratios of Incident Atrial Fibrillation for Risk Factors Across Time Periods.
| No. individuals | Decade of Atrial Fibrillation Onset Age- and Sex-Adjusted Hazards Ratios (95% Confidence Interval) |
P for Trend | ||||
|---|---|---|---|---|---|---|
| 1958-1967 4292 |
1968-1977 5119 |
1978-1987 5151 |
1988-1997 5235 |
1998-2007 4295 |
||
| Male vs. Female | 1•60(1•00-2•57) | 1•84(1•36-2•47) | 1•67(1•32-2•11) | 2•10(1•71-2•57) | 1•49(1•23-1•80) | 0•76 |
| Age, years | ||||||
| 50-59 (referent) | 1•00 | 1•00 | 1•00 | 1•00 | 1•00 | |
| 60-69 | 3•48(1•96-6•19) | 9•38(5•49-16•0) | 3•89(2•57-5•89) | 2•42(1•67-3•50) | 4•98(3•49-7•10) | 0•56 |
| 70-79 | 3•00(1•42-6•36) | 12•3(7•20-21•0) | 4•53(3•00-6•85) | 6•05(4•34-8•43) | 7•35(5•28-10•2) | 0•27 |
| 80-89 | -- | -- | 7•39(4•80-11•4) | 7•83(5•49-11•2) | 9•33(6•68-13•0) | 0•59 |
| Current smoking | 0•96(0•57-1•62) | 0•74(0•50-1•10) | 1•00(0•74-1•34) | 1•01(0•77-1•34) | 0•99(0•74-1•32) | 0•18 |
| Alcohol consumption, % | ||||||
| None (referent) | 1•00 | 1•00 | 1•00 | 1•00 | 1•00 | |
| Mild | 0•82(0•47-1•44) | 1•04(0•73-1•48) | 0•85(0•66-1•11) | 1•21(0•98-1•50) | 1•07(0•88-1•31) | 0•07 |
| Moderate or heavy | 0•82(0•33-2•04) | 2•20(1•31-3•72) | 0•86(0•55-1•35) | 1•31(0•85-2•03) | 1•10(0•71-1•69) | 0•91 |
| Body mass index, kg/m2 | ||||||
| Normal, <25 (referent) | 1•00 | 1•00 | 1•00 | 1•00 | 1•00 | |
| Overweight, 25 to <30 | 1•43(0•81-2•56) | 1•17(0•82-1•67) | 1•02(0•77-1•34) | 1•27(1•00-1•62) | 1•13(0•87-1•46) | 0•92 |
| Obese, ≥30 | 2•63(1•39-4•99) | 2•04(1•32-3•15) | 1•47(1•07-2•03) | 1•33(1•01-1•76) | 1•37(1•05-1•78) | 0•19 |
| Systolic blood pressure, mm Hg | ||||||
| Optimal, <120 (referent) | 1•00 | 1•00 | 1•00 | 1•00 | 1•00 | |
| Normal, 120-129 | 1•76(0•59-5•25) | 0•53(0•26-1•07) | 0•75(0•46-1•21) | 1•11(0•76-1•61) | 0•94(0•69-1•29) | 0•71 |
| High-normal 130-139 | 1•29(0•42-3•95) | 0•79(0•43-1•45) | 0•97(0•63-1•49) | 1•27(0•89-1•81) | 1•19(0•89-1•60) | 0•53 |
| Stage I Hypertension, 140-159 | 1•95(0•73-5•21) | 1•39(0•83-2•34) | 1•16(0•79-1•72) | 1•47(1•06-2•03) | 0•89(0•67-1•19) | 0•01* |
| Stage II-IV Hypertension ≥160 | 2•63(1•00-6•93) | 1•36(0•79-2•32) | 1•21(0•79-1•85) | 1•28(0•89-1•83) | 1•15(0•84-1•58) | 0•02* |
| Hypertension treatment | 1•71(0•96-3•06) | 1•63(1•18-2•27) | 1•35(1•06-1•71) | 1•68(1•37-2•06) | 1•32(1•08-1•60) | 0•31 |
| Diabetes | 1•06(0•38-2•90) | 1•42(0•93-2•17) | 1•59(1•15-2•20) | 1•49(1•15-1•95) | 1•25(0•98-1•60) | 0•58 |
| Electrocardiographic LVH | 3•12(1•54-6•33) | 2•41(1•52-3•81) | 1•95(1•22-3•13) | 2•49(1•63-3•82) | 2•15(1•21-3•83) | 0•40 |
| Significant heart murmur | 6•19(3•43-11•2) | 2•84(1•92-4•20) | 3•31(2•41-4•54) | 1•92(1•39-2•67) | 1•58(1•09-2•29) | 0•0003* |
| Heart failure | 2•62(0•95-7•25) | 3•15(1•84-5•41) | 2•33(1•42-3•82) | 2•36(1•54-3•62) | 1•43(0•85-2•40) | 0•01* |
| Myocardial infarction | 2•45(1•04-5•79) | 1•70(1•01-2•86) | 1•66(1•11-2•49) | 1•58(1•16-2•16) | 1•46(1•07-1•98) | 0•19 |
Decreasing hazards ratios over decades.
Characteristics were assessed at index examinations. For atrial fibrillation cases, the index examination was the last examination attended prior to atrial fibrillation diagnosis but no more than 10 years earlier; For individuals without atrial fibrillation, it was the last examination prior to censoring date also within 10 years, where censoring date was either end of a decade, or last contact date or death date whichever came first.
Hazard ratios are expressed for the condition present in dichotomous variables.
Categories for alcohol consumption were mild alcohol consumption: 1-7 drinks per week in women, 1-14 drinks per week in men, moderate or heavy alcohol consumption: >7 drinks per week in women, >14 drinks per week in men.
P for trend was obtained by testing whether the regression coefficient of interaction term of risk factor and period in Cox model equals 0. For trend time periods were coded 1(1958-1967), 2(1968-1977), 3(1978-1987), 4(1989-1997) and 5(1998-2007). For details on the statistics please see the Supplementary Material.