Introduction
Methods
The Tromsø Study
Measurements and questionnaires
Identification of myocardial infarction cases and follow-up
Analytical sample
Statistical analysis
Results
Characteristics of cases of incident MI
Men (n = 11,762) | Women (n = 13,206) | |||
---|---|---|---|---|
No MI (N = 10,993) | MI (N = 769) | No MI (N = 12,753) | MI (N = 453) | |
Age | 44.7 (13.5) | 60.7 (12.8) | 45.8 (14.8) | 68.0 (11.7) |
BMI (kg/m2) | 25.5 (3.3) | 26.6 (3.6) | 24.7 (4.2) | 26.8 (4.8) |
Serum lipids (mmol/l) | ||||
Total cholesterol | 5.96 (1.20) | 6.82 (1.17) | 5.97 (1.36) | 7.28 (1.35) |
HDL | 1.35 (0.35) | 1.31 (0.35) | 1.65 (0.40) | 1.58 (0.44) |
Blood pressure (mm Hg) | ||||
Systolic | 136.3 (16.4) | 149.4 (21.6) | 130.8 (21.5) | 161.6 (26.5) |
Diastolic | 79.4 (11.5) | 86.9 (13.2) | 75.8 (12.3) | 88.5 (15.5) |
Physical activity (%) | ||||
Inactive | 16.7 | 24.2 | 19.2 | 39.3 |
Moderate | 44.1 | 51.0 | 55.8 | 51.2 |
Active | 39.2 | 24.8 | 25.0 | 9.5 |
Smoking habits (%) | ||||
Never-smoker | 32.3 | 15.0 | 39.8 | 46.6 |
Stopped ≥20 years ago | 9.0 | 19.6 | 5.1 | 5.7 |
Stopped 10–19 years ago | 7.9 | 10.9 | 7.1 | 3.5 |
Stopped <10 years ago | 13.4 | 12.1 | 12.1 | 5.5 |
Current <10 cigarettes/day | 7.6 | 8.8 | 11.7 | 15.5 |
Current 10–19 cigarettes/day | 19.5 | 21.2 | 20.0 | 18.3 |
Current ≥20 cigarettes/day | 10.3 | 12.4 | 4.3 | 4.9 |
Living with a smokera (%) | ||||
Never | 33.3 | 24.7 | 30.8 | 17.0 |
<10 years | 21.4 | 7.3 | 20.6 | 3.3 |
10–19 years | 18.3 | 13.3 | 19.1 | 10.4 |
20–29 years | 13.9 | 18.6 | 14.1 | 17.2 |
≥30 years | 13.0 | 36.2 | 15.4 | 52.1 |
Time spent in smoke-filled rooms (%) | ||||
0 h/day | 41.7 | 48.9 | 55.9 | 59.4 |
1–6 h/day | 39.8 | 27.2 | 29.5 | 23.2 |
>6 h/day | 18.4 | 23.9 | 14.6 | 17.4 |
Active and passive smoking
Men (n = 11,762) | Women (n = 13,206) | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Na
| nb
| HRc (95 % CI) | HRd (95 % CI) | HRe (95 % CI) | N | n | HRc (95 % CI) | HRd (95 % CI) | HRe (95 % CI) | |
Own smoking habits | ||||||||||
Never-smoker | 3,668 | 115 | 1 (–) | 1 (–) | 1 (–) | 5,285 | 211 | 1 (–) | 1 (–) | 1 (–) |
Stopped ≥20 years ago | 1,141 | 151 | 1.3 (1.0–1.6) | 1.2 (1.0–1.6) | 1.2 (0.9–1.5) | 672 | 26 | 0.8 (0.5–1.1) | 0.8 (0.5–1.2) | 0.8 (0.5–1.2) |
Stopped 10–19 years ago | 947 | 84 | 1.5 (1.1–2.0) | 1.3 (1.0–1.8) | 1.3 (0.9–1.7) | 919 | 16 | 0.8 (0.5–1.3) | 0.9 (0.5–1.4) | 0.8 (0.5–1.4) |
Stopped <10 years ago | 1,569 | 93 | 1.4 (1.1–1.9) | 1.3 (1.0–1.7) | 1.2 (0.9–1.6) | 1,572 | 25 | 1.2 (0.8–1.9) | 1.3 (0.9–2.0) | 1.2 (0.8–1.8) |
Current <10 cigarettes/day | 898 | 68 | 1.5 (1.1–2.1) | 1.6 (1.2–2.2) | 1.5 (1.1–2.0) | 1,560 | 70 | 2.3 (1.8–3.1) | 2.6 (1.9–3.4) | 2.2 (1.6–3.0) |
Current 10–19 cigarettes/day | 2,312 | 163 | 1.9 (1.5–2.4) | 1.8 (1.4–2.3) | 1.7 (1.3–2.2) | 2,633 | 83 | 2.5 (1.9–3.2) | 2.7 (2.0–3.5) | 2.2 (1.6–3.1) |
Current ≥20 cigarettes/day | 1,227 | 95 | 2.5 (1.9–3.3) | 2.2 (1.7–2.9) | 1.9 (1.4–2.6) | 565 | 22 | 3.5 (2.2–5.6) | 3.6 (2.3–5.7) | 3.1 (1.8–5.1) |
p value linear trend | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | <0.001 | ||||
Living with a smokerf
| ||||||||||
Never | 3,853 | 190 | 1 (–) | 1 (–) | 1 (–) | 4,011 | 77 | 1 (–) | 1 (–) | 1 (–) |
<10 years | 2,412 | 56 | 0.8 (0.6–1.1) | 0.9 (0.7–1.2) | 0.8 (0.6–1.1) | 2,643 | 15 | 0.6 (0.4–1.1) | 0.7 (0.4–1.2) | 0.7 (0.4–1.2) |
10–19 years | 2,119 | 102 | 1.2 (1.0–1.6) | 1.2 (0.9–1.5) | 1.1 (0.8–1.4) | 2,477 | 47 | 1.2 (0.8–1.7) | 1.3 (0.9–1.8) | 1.2 (0.8–1.7) |
20–29 years | 1,674 | 143 | 1.5 (1.2–1.9) | 1.4 (1.1–1.7) | 1.2 (1.0–1.5) | 1,872 | 78 | 1.5 (1.1–2.1) | 1.5 (1.1–2.1) | 1.3 (1.0–1.9) |
≥30 years | 1,704 | 278 | 1.5 (1.2–1.8) | 1.3 (1.1–1.6) | 1.1 (0.9–1.4) | 2,203 | 236 | 1.8 (1.4–2.3) | 1.8 (1.4–2.3) | 1.4 (1.1–1.9) |
p value linear trend | <0.001 | < 0.001 | 0.145 | <0.001 | <0.001 | 0.004 | ||||
Time spent in smoke-filled rooms | ||||||||||
0 h/day | 4,965 | 376 | 1 (–) | 1 (–) | 1 (–) | 7,392 | 269 | 1 (–) | 1 (–) | 1 (–) |
1–6 h/day | 4,589 | 209 | 1.1 (0.9–1.3) | 1.1 (1.0–1.4) | 1.0 (0.8–1.2) | 3,873 | 105 | 1.8 (1.5–2.3) | 1.9 (1.5–2.3) | 1.2 (0.9–1.6) |
>6 h/day | 2,208 | 184 | 1.7 (1.4–2.0) | 1.6 (1.3–1.9) | 1.2 (0.9–1.4) | 1,941 | 79 | 2.1 (1.6–2.7) | 2.0 (1.6–2.7) | 1.1 (0.8–1.5) |
p value linear trend | <0.001 | <0.001 | 0.198 | <0.001 | <0.001 | 0.182 |
Passive smoking and incident MI in never and ever smokers
Men (n = 3,668) | Women (n = 5,285) | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Na
| Nb
| HRc (95 % CI) | HRd (95 % CI) | HRe (95 % CI) | Na
| Nb
| HRc (95 % CI) | HRd (95 % CI) | HRe (95 % CI) | |
Living with smokerf
| ||||||||||
Never | 2,226 | 68 | 1 (–) | 1 (–) | 1 (–) | 2,529 | 49 | 1 (–) | 1 (–) | 1 (–) |
< 10 years | 759 | 10 | 0.7 (0.4–1.4) | 0.7 (0.4–1.4) | 0.7 (0.4–1.5) | 803 | 8 | 0.9 (0.4–1.8) | 0.9 (0.4–2.0) | 1.0 (0.5–2.1) |
10–19 years | 364 | 13 | 1.2 (0.6–2.1) | 1.2 (0.6–2.1) | 1.2 (0.6–2.1) | 583 | 22 | 1.4 (0.8–2.3) | 1.4 (0.8–2.2) | 1.4 (0.8–2.3) |
20–29 years | 194 | 8 | 0.8 (0.4–1.7) | 0.7 (0.3–1.5) | 0.7 (0.3–1.6) | 528 | 31 | 1.4 (0.9–2.2) | 1.3 (0.8–2.1) | 1.3 (0.9–2.1) |
≥30 years | 125 | 16 | 1.2 (0.7–2.1) | 1.1 (0.6–2.0) | 1.1 (0.6–2.1) | 842 | 101 | 1.4 (1.0–2.0) | 1.5 (1.0–2.1) | 1.6 (1.1–2.2) |
p value linear trend | 0.731 | 0.959 | 0.885 | 0.028 | 0.021 | 0.009 | ||||
Time spent in smoke-filled rooms | ||||||||||
0 h/day | 2,272 | 86 | 1 (–) | 1 (–) | 1 (–) | 4,220 | 189 | 1 (–) | 1 (–) | 1 (–) |
1–6 h/day | 1,231 | 26 | 1.1 (0.7–1.7) | 1.0 (0.6–1.6) | 1.0 (0.6–1.6) | 866 | 15 | 0.8 (0.5–1.3) | 0.7 (0.5–1.3) | 0.7 (0.4–1.2) |
>6 h/day | 165 | 3 | 0.7 (0.2–2.3) | 0.8 (0.3–2.6) | 0.8 (0.3–2.7) | 199 | 7 | 0.9 (0.4–1.8) | 0.8 (0.4–1.7) | 0.7 (0.3–1.5) |
p value linear trend | 0.865 | 0.785 | 0.761 | 0.393 | 0.348 | 0.138 |
Men (n = 8,094) | Women (n = 7,921) | |||||||||
---|---|---|---|---|---|---|---|---|---|---|
Na
| Nb
| HRc (95 % CI) | HRd (95 % CI) | HRe (95 % CI) | Na
| Nb
| HRc (95 % CI) | HRd (95 % CI) | HRe (95 % CI) | |
Living with smokerf
| ||||||||||
Never | 1,627 | 122 | 1 (–) | 1 (–) | 1 (–) | 1,482 | 28 | 1 (–) | 1 (–) | 1 (–) |
<10 years | 1,653 | 46 | 0.8 (0.5–1.1) | 0.8 (0.6–1.2) | 0.9 (0.6–1.2) | 1,840 | 7 | 0.4 (0.2–0.9) | 0.4 (0.2–1.0) | 0.5 (0.2–1.1) |
10–19 years | 1,755 | 89 | 1.1 (0.8–1.4) | 1.0 (0.8–1.4) | 1.1 (0.8–1.4) | 1,894 | 25 | 0.9 (0.5–1.6) | 1.0 (0.6–1.7) | 1.0 (0.6–1.7) |
20–29 years | 1,480 | 135 | 1.4 (1.1–1.8) | 1.3 (1.0–1.6) | 1.3 (1.0–1.6) | 1,344 | 47 | 1.4 (0.9–2.2) | 1.4 (0.9–2.2) | 1.3 (0.8–2.1) |
≥30 years | 1,579 | 262 | 1.4 (1.1–1.7) | 1.2 (1.0–1.5) | 1.1 (0.9–1.4) | 1,361 | 135 | 1.8 (1.2–2.7) | 1.7 (1.1–2.6) | 1.3 (0.9–2.0) |
p value linear trend | <0.001 | 0.01 | 0.108 | <0.001 | <0.001 | 0.044 | ||||
Time spent in smoke-filled rooms | ||||||||||
0 h/day | 2,693 | 290 | 1 (–) | 1 (–) | 1 (–) | 3,172 | 80 | 1 (–) | 1 (–) | 1 (–) |
1–6 h/day | 3,358 | 183 | 1.0 (0.8–1.2) | 1.1 (0.9–1.4) | 1.0 (0.8–1.2) | 3,007 | 90 | 2.6 (1.9–3.5) | 2.5 (1.8–3.4) | 1.7 (1.2–2.4) |
>6 h/day | 2,043 | 181 | 1.5 (1.2–1.8) | 1.5 (1.2–1.8) | 1.2 (0.9–1.5) | 1,742 | 72 | 2.6 (1.9–3.6) | 2.4 (1.7–3.4) | 1.4 (1.0–2.1) |
p value linear trend | <0.001 | <0.001 | 0.132 | <0.001 | <0.001 | 0.084 |